ALBERT

Description: We show evidence for mirror mode structures at comet Giacobini-Zinner. These are plasma structures with alternating high ß and low ß regions driven unstable when ß /ß 〉 1+ 1/. These structures are detected in a region just adjacent to the magnetic tail and have scale sizes of ≈ 12 H2O group ion cyclotron radii. Calculations are presented to show that mirror mode instability can occur due to the perpendicular pressure associated with H2O+ cometary pickup ions in the region of mirror mode observation. Adjacent regions (in the magnetic tail and further in the sheath) are found to be stable to the mirror mode. Plasma waves are detected in relation with the mirror mode structures. Low frequency 56 to 100 Hz waves are present in the high beta portions, and high frequency, 311 Hz to 10 kHz, waves are present in low beta regions. These may be electromagnetic lion roar waves and electrostatic festoon-shaped waves, respectively, in analogy to plasma waves detected in the Earth's magnetosheath.

Description: The discrete periodic inverse scattering transform (DPIST) has been shown to provide the salient features of nonlinear Fourier analysis for surface shallow water waves whose dynamics are governed by the Korteweg-de Vries (KdV) equation - (1) linear superposition of components with power spectra that are invariants of the motion of nonlinear dispersive waves and (2) nonlinear filtering. As it is well known that internal gravity waves also approximately satisfy the KdV equation in shallow stratified layers, this paper investigates the degree to which DPIST provides a useful nonlinear spectral analysis of internal waves by application to simulations and wave tank experiments of internal wave propagation from localized dense disturbances. It is found that DPIST analysis is sensitive to the quantity λ = (r/6s) * (ε/μ2), where the first factor depends parametrically on the Richardson number and the background shear and density profiles and the second factor is the Ursell number-the ratio of the dimensionless wave amplitude to the dimensionless squared wavenumber. Each separate wave component of the decomposition of the initial disturbance can have a different value, and thus there is usually just one component which is an invariant of the motion found by DPIST analysis. However, as the physical applications, e.g. accidental toxic gas releases, are usually concerned with the propagation of the longest wavenumber disturbance, this is still useful information. In cases where only long, monochromatic solitary waves are triggered or selected by the waveguide, the entire DPIST spectral analysis is useful.

Description: In this paper we establish links between turbulence dissipation and wave-particle interactions in the solar corona and wind. Based on quasilinear theory, a set of anisotropic, multi-component fluid equations is derived, which describe the wave-particle interactions of ions with Alfvén waves and ion-cyclotron waves or magnetosonic waves propagating along the mean magnetic field. The associated equations for the wave spectrum and the heating and acceleration of the ions are derived. In fast solar wind streams heavy ions have about equal thermal speeds as the protons and flow faster than them. In order to explain the observed relations, Tj / Tp ≈ mj /mp and Uj Up ≈ VA, a numerical fluid-type model is developed, which takes into account the relevant wave-particle interactions. It is shown that left- and right-handed polarized waves propagating away from the Sun parallel to the interplanetary magnetic field can resonantly heat and accelerate minor ions preferentially with respect to the protons in close agreement with the measured characteristics of ion velocity distributions. Finally, some results from a simple analytical model are discussed.

Description: The work considers three-dimensional crescent-shaped patterns often seen on water surface in natural basins and observed in wave tank experiments. The most common of these 'horse-shoe-like' patterns appear to be sporadic, i.e., emerging and disappearing spontaneously even under steady wind conditions. The paper suggests a qualitative model of these structures aimed at explaining their sporadic nature, physical mechanisms of their selection and their specific asymmetric form. First, the phenomenon of sporadic horse-shoe patterns is studied numerically using the novel algorithm of water waves simulation recently developed by the authors (Annenkov and Shrira, 1999). The simulations show that a steep gravity wave embedded into widespectrum primordial noise and subjected to small nonconservative effects typically follows the simple evolution scenario: most of the time the system can be considered as consisting of a basic wave and a single pair of oblique satellites, although the choice of this pair tends to be different at different instants. Despite the effective low-dimensionality of the multimodal system dynamics at relatively sho ' rt time spans, the role of small satellites is important: in particular, they enlarge the maxima of the developed satellites. The presence of Benjamin-Feir satellites appears to be of no qualitative importance at the timescales under consideration. The selection mechanism has been linked to the quartic resonant interactions among the oblique satellites lying in the domain of five-wave (McLean's class II) instability of the basic wave: the satellites tend to push each other out of the resonance zone due to the frequency shifts caused by the quartic interactions. Since the instability domain is narrow (of order of cube of the basic wave steepness), eventually in a generic situation only a single pair survives and attains considerable amplitude. The specific front asymmetry is found to result from the interplay of quartic and quintet interactions and non-conservative effects: the growing and grown satellites have a specific value of phase with respect to the basic wave that corresponds to downwind orientation of the convex sides of wave fronts. As soon as the phase relation is violated, the satellite's amplitude quickly decreases down to the noise level.

Description: A long AE index time series is used as a crucial magnetospheric quantity in order to study the underlying dynainics. For this purpose we utilize methods of nonlinear and chaotic analysis of time series. Two basic components of this analysis are the reconstruction of the experimental tiine series state space trajectory of the underlying process and the statistical testing of an null hypothesis. The null hypothesis against which the experimental time series are tested is that the observed AE index signal is generated by a linear stochastic signal possibly perturbed by a static nonlinear distortion. As dis ' ' ating statistics we use geometrical characteristics of the reconstructed state space (Part I, which is the work of this paper) and dynamical characteristics (Part II, which is the work a separate paper), and "nonlinear" surrogate data, generated by two different techniques which can mimic the original (AE index) signal. lie null hypothesis is tested for geometrical characteristics which are the dimension of the reconstructed trajectory and some new geometrical parameters introduced in this work for the efficient discrimination between the nonlinear stochastic surrogate data and the AE index. Finally, the estimated geometric characteristics of the magnetospheric AE index present new evidence about the nonlinear and low dimensional character of the underlying magnetospheric dynamics for the AE index.

Description: A simple phenomenological model for nonlinear interactions of gravity waves on the surface of deep water is developed. The Snl nonlinear interaction term in the kinetic equation for wave action is replaced by the nonlinear second-order diffusion-type operator. Analytical and numerical studies show that the new model gives a reasonably good description of a real situation, consuming three order of magnitude less computer time.

Description: The evolution of tracer "injected" into an equivalent barotropic eddy on the beta-plane is examined numerically. The eddy is governed by the standard quasigeostrophic equation, and the concentration of tracer is governed by the advection equation with diffusion. At the initial moment of time, the streamfunction and distribution of tracer are both radially or elliptically symmetric. After the first 10-30 days, a spirallike strip, where the gradient of concentration is large, develops in the tracer field, whereas the eddy remains smooth for a relatively long time. To put this conclusion in quantitative terms, a "tracer variability indicator" is introduced and shown to grow much faster than a similar characteristic of the potential vorticity field (notwithstanding the fact that the tracer concentration and PV satisfy the same governing equation). A simple explanation as to why the tracer is more affected by filamentation than PV is provided for eddies with small Burger number. It is demonstrated that the high-gradient strip develops, unless stopped by turbulent diffusion, into an inversion (non-monotonicity) of the tracer concentration field. Finally, the results of simulations are compared to the spiral patterns in the real-life eddies observed in the East Australian Current.

Description: We present the characteristics of the Electrostatic Solitary Waves (ESW) observed by the Geotail spacecraft in the plasma sheet boundary layer based on the statistical analyses. We also discuss the results referring to a model of ESW generation due to electron beams, which is proposed by computer simulations. In this generation model, the nonlinear evolution of Langmuir waves excited by electron bump-on-tail instabilities leads to formation of isolated electrostatic potential structures corresponding to "electron hole" in the phase space. The statistical analyses of the Geotail data, which we conducted under the assumption that polarity of ESW potentials is positive, show that most of ESW propagate in the same direction of electron beams, which are observed by the plasma instrument, simultaneously. Further, we also find that the ESW potential energy is much smaller than the background electron thermal energy and that the ESW potential widths are typically shorter than 60 times of local electron Debye length when we assume that the ESW potentials travel in the same velocity of electron beams. These results are very consistent with the ESW generation model that the nonlinear evolution of electron bump-on-tail instability leads to the formation of electron holes in the phase space.

Description: Magnetic field Decreases (MDs) are detected in the heliospheric polar regions. The MDs have minimum spatial scales sizes of 25 proton thermal gyroradii, and are typically bounded by tangential or rotational discontinuities. The distribution of the magnitudes of the decreases within AIDs is a continuum, with the smallest decreases being most frequent in occurrence. The largest decreases can be 80% of the ambient field. The thickness distribution is also a continuum, and is shown to be independent of the field magnitude decrease. Charged particle interactions with the MDs lead to particle guiding center displacements and hence particle cross-held diffusion. We develop a diffusion model to apply to energetic ion interactions with MDs using the MD properties described in this paper. One specific day of data is used to illustrate that the particle cross-field diffusion will be extremely rapid due to such interactions.

Description: Alfvénic solutions of nondissipative MHD are entirely determined by their magnetic configuration. With the supplementary assumption of incompressibility any solenoidal field can be used to construct an Alfvénic solution. It is demonstrated that for nondissipative and compressible MHD the energy equation constrains the magnetic field of Alfvénic solutions to have a constant strength along field lines. Some topological solitons known in nondissipative and incompressible MHD do not have this property. New localized axisymmetric Alfvénic solutions of nondissipative and compressible MHD are explicitly constructed.

Description: Interaction of nonlinear electrostatic pulses associated with electron phase density holes moving in a collisionless plasma is studied. An elementary event of the interaction is analyzed on the basis of the energy balance in the system consisting of two electrostatic solitary waves. It is established that an intrinsic property of the system is a specific irreversibility caused by a nonadiabatic modification of the internal structure of the holes and their effective heating in the process of the interaction. This dynamical irreversibility is closely connected with phase mixing of the trapped electrons comprising the holes and oscillating in the varying self-consistent potential wells. As a consequence of the irreversibility, the "collisions" of the solitary waves should be treated as "inelastic" ones. This explains the general tendency to the merging of the phase density holes frequently observed in numerical simulation and to corresponding coupling of the solitary waves.

Description: A nonlinear wave, in general, is equivalent to a nonlinear dynamical system, which exhibits the phenomena of chaos. By means of techniques of nonlinear dynamical systems, we have investigated the conditions under which nonlinear Alfvén waves and lower-hybrid waves can become chaotic. The role of heavy ions, in controlling the chaos in magnetoplasmas, is examined. Chaotic routes to Alfvénic turbulence, with k-1 spectra, are observed in case of externally driven nonlinear Alfvén waves. Anomalous heating and particle acceleration resulting from chaotic fields, generated by lower-hybrid waves, are briefly outlined.

Description: In this study we have used dynamical characteristies such as Lyapunov exponents, nonlinear dynamic models and mutual information for the nonlinear analysis of the magnetospheric AE index time series. Similarly with the geometrical characteristic studied in Pavlos et al. (1999b), we have found significant differences between the original time series and its surrogate data. These results also suggest the rejection of the null hypothesis that the AE index belongs to the family of stochastic linear signals undergoing a static nonlinear distortion. Finally, we believe that these results support the hypothesis of nonlinearity and chaos for the magnetospheric dynamics.

Description: Recent observations from satellites crossing regions of magnetic-field-aligned electron streams reveal solitary potential structures that move at speeds much greater than the ion acoustic/thermal velocity. The structures appear as positive potential pulses rapidly drifting along the magnetic field, and are electrostatic in their rest frame. We interpret them as BGK electron holes supported by a drifting population of trapped electrons. Using Laplace transforms, we analyse the behavior of one phase-space electron hole. The resulting potential shapes and electron distribution functions are self-consistent and compatible with the field and particle data associated with the observed pulses. In particular, the spatial width increases with increasing amplitude. The stability of the analytic solution is tested by means of a two-dimensional particle-in-cell simulation code with open boundaries. We consider a strongly magnetized parameter regime in which the bounce frequency of the trapped electrons is much less than their gyrofrequency. Our investigation includes the influence of the ions, which in the frame of the hole appear as an incident beam, and impinge on the BGK potential with considerable energy. The nonlinear structure is remarkably resilient

Description: We present detailed observations of electromagnetic waves and particle distributions from the Fast Auroral SnapshoT (FAST) satellite which reveal many important properties of large-amplitude, spatially-coherent plasma structures known as "fast solitary structures" or "electron phase space holes". Similar structures have been observed in several regions of the magnetosphere including the auroral zone, plasma sheet boundary layer, and bow shock. There has been rapid theoretical progress in understanding these structures. Solitary structures can develop from bidirectional electron beams. Once developed, the one-dimensional properties parallel to the magnetic field can be adequately described by analytical treatment as BGK structures. There remains, however, several unanswered questions. The origin of the bidirectional electron beams, the development of two-or three-dimensional structures, and the observed association with the ion cyclotron frequency are not well understood.

Description: Bipolar wave structures and nonthermal particle distributions measured by the FAST satellite in regions of downward current are interpreted in terms of the nonlinear evolution of a two-stream instability. The instability results in holes, both in the electron distribution in phase space and in the electron density in real space. The wave potential energy, which traps the electrons, has a single minimum, and the associated electric field is bipolar. The early bipolar structures are coherent over hundreds of Debye lengths in the direction perpendicular to the magnetic field. After thousands of plasma periods the perpendicular coherence is lost, the structures break up, and electrostatic whistlers begin to dominate. Simulations and preliminary analysis of this breakup and emission process are presented.

Description: The envelope formalism for the description of a small-amplitude parallel-propagating Alfvén wave train is tested against direct numerical simulations of the Hall-MHD equations in one space dimension where kinetic effects are neglected. It turns out that the magnetosonic-wave dynamics departs from the adiabatic approximation not only near the resonance between the speed of sound and the Alfvén wave group velocity, but also when the speed of sound lies between the group and phase velocities of the Alfvén wave. The modulational instability then does not anymore affect asymptotically large scales and strong nonlinear effects can develop even in the absence of the decay instability. When the Hall-MHD equations are considered in the long-wavelength limit, the weakly nonlinear dynamics is accurately reproduced by the derivative nonlinear Schrödinger equation on the expected time scale, provided no decay instabilities are present. The stronger nonlinear regime which develops at later time is captured by including the coupling to the nonlinear dynamics of the magnetosonic waves.

Description: The orbit of the Polar spacecraft has been ideally suited for studying the turbulent region of the cusp that is located near or just outside the magnetopause current sheet at 7-9 RE. The wave data obtained in this region show that electromagnetic turbulence is dominant in the frequency range 1-10 Hz. The waves responsible for this turbulence usually propagate perpendicular to the local magnetic field and have an index of refraction that generally falls between the estimated cold plasma theoretical values of the electromagnetic lower hybrid and whistler modes and may be composed of both modes in concert with kinetic Alfvén waves and/or fast magnetosonic waves. Fourier spectra of the higher frequency wave data also show the electromagnetic turbulence at frequencies up to and near the electron cyclotron frequency. This higher frequency electromagnetic turbulence is most likely associated with whistler mode waves. The lower hybrid drift and current gradient instabilities are suggested as possible mechanisms for producing the turbulence. The plasma and field environment of this turbulent region is examined and found to be extremely complex. Some of the wave activity is associated with processes occurring locally, such as changes in the DC magnetic field, while others are associated with solar wind and interplanetary magnetic field changes.

Description: In this study we present theoretical concepts and results concerning the hypothesis test of the magnetospheric chaos. For this reason we compare the observational behavior of the magnetospheric system with results obtained by analysing different types of stochastic and deterministic input-output systems. The results of this comparison indicate that the hypothesis of lowdimensional chaos for the magnetospheric dynamics remains a possible and fruitful concept which must be developed further.

Description: The present work examines the effects arising from the nonlinear Landau damping and the bounced motion of protons (trapped in the mirror geometry of the geomagnetic field) in the formation of nonlinear Alfvénic structures. These structures are observed at distances 1-5AU in the solar wind plasma (with ß ~ 1). The dynamics of formation of these structures can be understood using kinetic nonlinear Schrodinger (KNLS) model. The structures emerge due to balance of nonlinear steepening (of large amplitude Alfvén waves) by the linear Landau damping of ion-acoustic modes in a finite ß solar wind plasma. The ion-acoustic mode is driven nonlinearly by the large amplitude Alfvén waves. At the large amplitudes of Alfvén wave, the effects due to nonlinear Landau damping become important. These nonlinear effects are incorporated into the KNLS model by modifying the heat flux dissipation coefficient parallel to the ambient magnetic field. The effects arising from the bounced motion (of mirroring protons) are studied using a one-dimensional Vlasov equation. The bounced motion of the protons can lead to growth of the ion-acoustic mode, propagating in the mirror geometry of the geomagnetic field. The significance of these studies in the formation of dissipative quasistationary structures observed in solar wind plasma is discussed.

Description: A procedure to generate rainfall input for the EUROpean Soil Model is presented. To develop such a procedure, first of all the influence of rainfall event amount, rainfall event duration, and time to peak intensity of event rainfall on soil losses, calculated with EUROSEM, has been tested for several rainfall stations. Results revealed that every tested rainfall parameter had highly significant influence on computed soil loss. Therefore, distributions for each station of the dataset and for each of these rainfall parameters were calculated. To simulate rainfall event amounts, a mixed exponential distribution was applied. After transformation of rainfall event durations, their distribution could be simulated using a normal distribution. The location of the peak intensity was estimated using a kernel estimator, because no specific distribution characteristics could be identified. According to the respective distribution functions, parameter values for each of the tested rainfall event characteristic were then generated. These values were used to select rainfall events with identical parameter values out of the rainfall station-specific dataset. Computed soil losses for events selected this way were compared with soil losses calculated with available station specific rainfall event data. Comparisons for the respective means and medians generally revealed good agreement. A comparison of 75 % quartiles resulted in less good agreement, especially for test conditions with high soil losses. In general, the applied procedure was capable of simulation station-specific soil losses and of reflecting different environment conditions for the respective stations. Therefore, it seems possible to produce site specific appropriate rainfall input for EUROSEM, only with the knowledge of distributions for the investigated basic rainfall parameters. These are normally easier to obtain than long term rainfall information with high temporal resolution which would otherwise be necessary. In order to improve the procedure and make it practically useful, it will be necessary to account for seasonal changes of distributions of basic rainfall event parameters.

Description: A growth factor is the ratio of the T-year extreme value to an index extreme value such as the mean of annual maxima. Whereas a record length of ten or more years may suffice to estimate the index variable, it is generally necessary to blend data from several sites if estimates of exceptional extreme values are to be obtained. Methods of rainfall growth estimation are reviewed, including traditional methods which extend frequency curves to long return period by a distributional assumption, and methods which study spatial dependence in extreme rainfalls. It is desirable that estimates at neighbouring sites, and across different durations and return periods, are internally consistent. The review concludes that rather special techniques may be required if this goal of estimation extreme rainfall depth consistently is to be met. The motivation of the Focused Rainfall Growth Extension (FORGEX) method is presented.

Description: The Focused Rainfall Growth Extension (FORGEX) method produces rainfall growth curves focused on a subject site. Focusing allows the incorporation of rainfall extremes observed regionally while respecting local variations in growth rates. The starting point for the analysis is an extensive set of annual maximum rainfalls, with values at each gauged site standardized by the median. Following the philosophy of the earlier FORGE method, a strongly empirical approach is adopted. The rainfall growth curve is represented by linear segments on a Gumbel scale, and is fitted by a least-squares criterion. The selection of data points is intricate and includes both the traditional pooling of regional extremes and the incorporation of network maximum events. The latter comprise the largest events from successive hierarchical networks of gauges, focused on the site for which estimates are requires. Their treatment takes account of interdependence using the Dales and Reed model of spatial dependence in rainfall extremes.

Description: In crystalline basement regions of Africa, shallow weathered aquifers provide vital water resources for rural communities. To quantify evidence of the behaviour of these shallow aquifers, groundwater levels were observed at a network of 65 boreholes within the Romwe Catchment in southern Zimbabwe. Soil moisture was monitored at selected sites. Groundwater hydrographs showed considerable spatial and temporal variation. Where the soil profile was freely draining, groundwater levels typically responded within a few days of major rainstorms and large annual fluctuations in the water table of up to 7 m were recorded. In areas where a thick clay layer exists, annual fluctuations were smaller and groundwater levels rose more gradually in response to rainfall. In cultivated areas, vertical drainage was an important recharge mechanism. Groundwater hydrographs typically have an exponential recession and, by the end of the dry season in the years studied, levels were close to the base of the weathered aquifer. Variations in hydrograph response between years illustrate the importance of rainfall amount, intensity and distribution on groundwater recharge.

Description: Expressions for the upwelling and downwelling fluxes of optical and thermal radiation between soil, vegetation and the sky are derived, under certain simple assumptions. These are that interception of radiation by the vegetation is a purely geometric effect, while scattering is isotropic, with a strength given by a single-scattering albedo in the optical part of the spectrum, and by Kirchhoff's Law in the thermal. The soil is assumed to be a lambertian reflector, also scattering according to an albedo and Kirchhoff's Law. The model, called RM, conserves energy exactly. As part of a SVAT, it is driven by measured insolation instead of radiation, with little increase in computational cost and number of parameters.

Description: The reduction of chromate ions by Fe(OH)2 and the iron (II)-iron (III) hydroxysulphate green rust, GR(SO42-), was studied to evaluate whether such synthetic layered hydroxides and the corresponding natural green rust mineral could be involved in the natural attenuation of contaminated environments. The resulting Cr (III) bearing phases, which would govern the subsequent behaviour of chromium, were clearly characterised. Both compounds proved to be very reactive and oxidised instantaneously while chromate ions were reduced to Cr (III) as evidenced by X-ray photoelectron spectroscopy. Mass balance (ICP-AES) demonstrated that the Fe/Cr ratio inside the solid end product was equal to the initial Fe/Cr ratio. The solid phases, analysed by X-ray diffraction, Raman and Mossbauer spectroscopies were identified as Cr-substituted poorly crystallised iron (III) oxyhydroxides in both cases, more precisely δ-FeOOH when starting with Fe(OH)2 and ferrihydrite when starting with GR(SO42-).

Description: A semi-distributed conceptual model, HBV-SED, for estimation of total suspended sediment concentration and yield at the outlet of a catchment was developed and tested through a case study. The base of the suspended sediment model is a dynamic hydrological model, which produces daily series of areal runoff and rainfall for each sub-basin as input to the sediment routine. A lumped measure of available sediment is accumulated continuously based on a linear relationship between log-transformed values of rainfall and erosion, while discharge of suspended sediment at the sub-basin outlet is dependent on runoff and amount of stored available sediment. Four model parameter are empirically determined through calibration against observed records of suspended sediment concentration. The model was applied to a 200 km2 catchment with high altitude differences in the tropical parts of Bolivia, where recorded suspended sediment concentrations were available during a two-year period. 10,000 parameter sets were generated through a Monte Carlo procedure to evaluate the parameter sensitivity and interdependence. The predictability of the model was assessed through dividing the data record into a calibration and an independent period for which the model was validated and compared to the sediment rating curve technique. The results showed that the slope coefficients of the log-transformed model equations for accumulation and release were much stronger than the intercept coefficients. Despite and existing interdependence between the model parameters, the HBV-SED model gave clearly better results than the sediment rating curve technique for the validation period, indication that the supply-based approached has a promising future as a tool for basic engineering applications.

Description: This research quantified the role of topography and hydrological processes within and, hence, the development of, blanket bogs. Topographic characteristics were derived from digital elevation models (DEMs) developed for the surface and underlying substrate at three blanket bog sites on the southeastern lobe of the Avalon Peninsula, Newfoundland. A multinomial logit (MNL) model of the probability of bog occurrence was constructed in terms of relevant topographic characteristics. The resulting model was then used to investigate the probabilistic boundary conditions of bog occurrence within the landscape. Under average curvatures for the sites studied, substrate slopes up to 0.065 favoured blanket bog development. However, steeper slopes could, theoretically, be occupied by blanked bog where water is concentrated by convergent curvatures or large contributing areas. Near community boundaries, bog and heath communities both occupied similar topographic conditions. Since these boundary locations are capable of supporting the hydrological conditions necessary for bog development, the heath is likely to be encroached upon by bog.

Description: Fluid transmissivity (layer thickness times permeability) and electric transverse resistance (layer thickness time resistivity) are important parameter in groundwater and hydrocarbon exploration. Determination of these parameters provides a good knowledge of the potential of porous media, because they relate fluid flow to electric-current conduction, in terms of layer thickness, permeability and resistivity. In this study, both parameters were determined for shallow aquifers (Schleswig-Holstein, northern Germany) and deep reservoirs (Jeanne d'Arc Basin, offshore of eastern Canada), utilizing surface and well-log electric measurements. Direct relationships between both parameters, with coefficients of correlation of 0.99 (for the aquifers) and 0.94 (for the reservoirs), were obtained. The relationships suggest that an increase in both parameters indicate presence of zones of high fluid potential within the aquifers and the reservoirs.

Description: The matching of estimated to observed hydrograph shape is central to much hydrological analysis. This research note quantifies built-in biases that tend to inflate goodness of fit indicies, biases that arise from the similarity of geometry between observed and estimated hydrographs.

Description: The effects of ditch water management regimes on water tables are examined for two test sites in England, Halvergate in the Broads and Southlake Moor in the Somerset Levels and Moors Environmentally Sensitive Areas. It is observed that in some fields the effects of water management are only poorly transferred from the ditch to the field centre, especially where the hydraulic conductivity of the subsoil is small. Where there are large variations in the ditch water levels, reflecting the influence of major ditches subject to pump drainage, field soil water regimes differ significantly. Nevertheless, the effects of even quite small changes in the ditch regime cam be noticeable. Simple modelling studies show that much greater effects can be achieved by increasing the frequency of ditches within wetlands.

Description: The UP (Upscaled Physically-based) hydrological modelling system to the Arkansas-Red River basin (USA) is designed for macro-scale simulations of land surface processes, and aims for a physical basis and, avoids the use of discharge records in the direct calibration of parameters. This is achieved in a two stage process: in the first stage parametrizations are derived from detailed modelling of selected representative small and then used in a second stage in which a simple distributed model is used to simulate the dynamic behaviour of the whole basin. The first stage of the process is described in a companion paper (Ewen et al., this issue), and the second stage of this process is described here. The model operated at an hourly time-step on 17-km grid squares for a two year simulation period, and represents all the important hydrological processes including regional aquifer recharge, groundwater discharge, infiltration- and saturation-excess runoff, evapotranspiration, snowmelt, overland and channel flow. Outputs from the model are discussed, and include river discharge at gauging stations and space-time fields of evaporation and soil moisture. Whilst the model efficiency assessed by comparison of simulated and observed discharge records is not as good as could be achieved with a model calibrated against discharge, there are considerable advantages in retaining a physical basis in applications to ungauged river basins and assessments of impacts of land use or climate change.

Description: Calibration of conceptual hydrological models is frequently limited by a lack of data about the area that is being studied. The result is that a broad range of parameter values can be identified that will give an equally good calibration to the available observations, usually of stream flow. The use of total stream flow can bias analyses towards interpretation of rapid runoff, whereas water quality issues are more frequently associated with low flow condition. This paper demonstrates how model distinctions between surface an sub-surface runoff can be used to define a likelihood measure based on the sub-surface (or baseflow) response. This helps to provide more information about the model behaviour, constrain the acceptable parameter sets and reduce uncertainty in streamflow prediction. A conceptual model, DIY, is applied to two contrasting catchments in Scotland, the Ythan and the Carron Valley. Parameter ranges and envelopes of prediction are identified using criteria based on total flow efficiency, baseflow efficiency and combined efficiencies. The individual parameter ranges derived using the combined efficiency measures still cover relatively wide bands, but are better constrained for the Carron than the Ythan. This reflects the fact that hydrological behaviour in the Carron is dominated by a much flashier surface response than in the Ythan. Hence, the total flow efficiency is more strongly controlled by surface runoff in the Carron and there is a greater contrast with the baseflow efficiency. Comparisons of the predictions using different efficiency measures for the Ythan also suggest that there is a danger of confusing parameter uncertainties with data and model error, if inadequate likelihood measures are defined.

Description: Springs are important groundwater discharge points on the high altitude (〉800m) plateaux of the Cairngorm mountains, Scotland and form important wetland habitats within what is often a dry, sub-arctic landscape. The hydrogeochemistry of a typical spring in the Allt a'Mharcaidh catchment was examined between 1995-98 in order to characterise its chemical composition, identify the dominant controls on its chemical evolution and estimate groundwater residence time using 18O isotopes. Spring water, sustained by groundwater flow in shallow drift deposits and fractured bedrock, was moderately acidic (mean pH 5.89), with a very low alkalinity (mean 18 μeq l-1) and the ionic composition was dominated by sea-salts derived from atmospheric sources. Geochemical modelling using NETPATH, predicted that the dissolution of plagioclase mainly controls the release of Si, non-marine Na, Ca, K and Al into spring water. Hydrological conditions influenced seasonal variations in spring chemistry, with snowmelt associated with more rapid groundwater flows and lower weathering rates than summer discharges. Downstream of the spring, the chemistry of surface water was fundamentally different as a result of drainage from larger catchment areas, with increased soil and drift cover, and higher evaporation rates. Thus, the hydrogeochemical influence of springs on surface waters appears to be localized. Mean δ18O values in spring water were lower and more damped than those in precipitation. Nevertheless, a sinusoidal seasonal pattern was observed and used to estimate mean residence times of groundwater of around 2 years. Thus, in the high altitude plateau of the Cairngorms, shallow, coarse drift deposits from significant aquifers. At lower altitudes, deeper drift deposits, combined with larger catchment areas, increase mean groundwater residence times to 〉5 years. At high altitudes, the shallow, permeable nature of the drifts dictates that groundwater is vulnerable to impacts of environmental changes that could be usefully monitored at spring sites.

Description: The UP modelling system has been applied to the 570,000 km2 Arkansas-Red River Basin (ARRB) as part of the UK NERC Terrestrial initiative in Global Environmental Research (TIGER). The model can be run as a stand-alone basin hydrology model or be linked to existing climate and weather forecasting models. It runs on a grid comprising 1923 UP elements, each 17km by 17km in area, and each containing five water storage compartments: one each for the snowpack, vegetation canopy, surface water, root zone and groundwater. All the main transfers and processes of the terrestrial phase of the hydrological cycle are represented, including river network routing of the runoff from the UP elements. The parameters of the ARRB model are physically-based, being derived either from fine-scale, sub-grid, data on the topography and physical properties of the soils, aquifers and vegetation of the basin, or from the results of fine-scale physically-based simulations. With the approach, the parameters account for the effects of sub-grid variations in moisture status and spatial distribution and are sensitive to changes in the fine-scale property data. This sensitivity is either absent or less directly represented in existing large-scale hydrology models, yet it plays a central role in studies of the impact of changes in climate and land-use. The ARRB model, as described here and in Kilsby et al. (1999), is a first attempt at large-scale physically-based hydrological modelling of the type outlined in the "blueprint" for the UP system (Ewen, 1997), and gives a clear, positive, indication of the nature and quality of what is currently practical with the approach.

Description: Time domain reflectometry [TDR] was used to investigate the spatial and temporal variation in surface soil water dynamics under a number of types of vegetation, including both trees and crops grown in isolation, and grown together as an agroforestry system. The installation and operation of this technique are presented, and discussed in terms of its suitability to monitor rapid fluctuations in soil-water content in a spatially heterogeneous system such as that described in this experiment. The relatively small sampling volume of each of the TDR waveguides permitted discrete measurements to be made of soil water content (θv). In the tree-only and tree+crop treatments, this revealed considerable variation in θv resulting from spatial redistribution of rainfall under the tree canopies, with a significant input to soil close to the base of the trees being made by stemflow, i.e. water intercepted by the tree canopy and channelled down the stem. Over the experimental period (one rainy season) the TDR data suggested that net recharge to the soil profile in the sole crop system was 53 mm, almost 75% more than occurred in either of the two treatments containing trees, reflecting greater rainfall interception by the tree canopies.

Description: This paper illustrates the performance of the FORGEX method of rainfall growth estimation. Results are presented for three regions of the United Kingdom: the East Midlands, north-west England and south-west England. Focused rainfall growth curves are compared between regions and between different sites within each region. Typical growth curve shapes are discussed with reference to the climate of each region. Daily growth curves are derived from a large number of records of annual maximum rainfalls. A smaller number of hourly annual maximum series is available for estimation sub-daily rainfall growth curves. Rainfall growth rates are compared with the results of a widely used method. The present method allows more local and regional variation in growth rates. The new growth rates are higher for durations of 1 and 2 days in parts of south-west England, but lower for moderate return periods at some focal points in the north-west. In the East Midlands, the new 1-hour growth rates are considerably higher for long return periods. Confidence limits for growth rates are derived by bootstrapping. This is accomplished by fitting a large number of growth curves to resampled sets of rainfall data.

Description: In this study, it is shown that the complexity of Soil Vegetation Atmosphere Transfer (SVAT) models leads to an equifinality of functional behaviour - many parameterizations from many areas of the parameter space lead to very similar responses. Individual parameters derived by calibration (i.e. model inversion) against limited measurements are, therefore, highly uncertain. Due to the non-linear internal behaviour of SVAT models, aggregation of uncertainly known parameter fields to parameterize landscape scale variability in surface fluxes will yield highly uncertain predictions. A disaggregation approach suggested by Beven (1995) requires that the land surface be represented by a linear sum of a number of representative parameterizations or functional types. This study explores the nature of the parameter space in terms of a simple definition of functional behaviour. Parameter interactions producing similar predicted behaviours are investigated through application of Principal Component Analyses. These reveal the lack of a dominant global interaction indicating the presence of highly complex parameter interactions throughout the feasible parameter space.

Description: A transient, mixed analytical-numerical model of hillslope hydrological behaviour is used to study the patterns of infiltration, evapotranspiration, recharge and lateral flow across hillslopes. Computational efficiency is achieved by treating infiltration and phreatic surface movement analytically. The influence of dynamic coupling of the saturated and unsaturated zones on the division of hillslopes into units of distinct hydrological behaviour is analyzed. The results indicate the importance of downhill groundwater flow on the lateral distribution of soil moisture and hydrological fluxes; unsaturated lateral flow is shown to be of relatively minor importance. For most conditions, the hillslope organizes itself into three distinct regions; an uphill recharge and a downhill discharge zone separated by a midline zone over which there is, on average, no recharge or discharge. A temporal perturbation analysis of the phreatic surface, made to quantify the deviations between the equivalent-steady water table derived by Salvucci and Entekhabi (1995) and the long-term mean water table, shows that the equivalent-steady water table effectively couples the unsaturated and saturated zone dynamics across storm and interstorm periods and divides the hillslope into distinct hydrological regions. The second order closure terms in the perturbation analysis, expressed as the gradient of water table variance, quantify the deviations and tend to make the hydrological zones relatively less distinct.

Description: Geological fault zones are usually assumed to influence hydrocarbon migration either as high permeability zones which allow enhanced along- or across-fault flow or as barriers to the flow. An additional important migration process inducing along- or across-fault migration can be associated with dynamic pressure gradients. Such pressure gradients can be created by earthquake activity and are suggested here to allow migration along or across inactive faults which "feel" the quake-related pressure changes; i.e. the migration barriers can be removed on inactive faults when activity takes place on an adjacent fault. In other words, a seal is viewed as a temporary retardation barrier which leaks when a fault related fluid pressure event enhances the buoyancy force and allows the entry pressure to be exceeded. This is in contrast to the usual model where a seal leaks because an increase in hydrocarbon column height raises the buoyancy force above the entry pressure of the fault rock. Under the new model hydrocarbons may migrate across the inactive fault zone for some time period during the earthquake cycle. Numerical models of this process are presented to demonstrate the impact of this mechanism and its role in filling traps bounded by sealed faults.

Description: A Bayesian approach is described for dealing with the problem of infilling and generating stochastic flow sequences using rainfall data to guide the flow generation process, and including bounded (censored) observed flow and rainfall data to provide additional information. Solutions are obtained using a Gibbs sampling procedure. Particular problems discussed include developing new procedures for fitting transformations when bounded values are available, coping with additional information in the form of values, or bounds, for totals of flows across several sites, and developing relationships between annual flow and rainfall data. Examples are shown of both infilled values of unknown past river flows, with assessment of uncertainty, and realisations of flows representative of what might occur in the future. Several procedures for validating the model output are described and the central estimates of flows, taken as a surrogate for historical observed flows, are compared with long term regional flow and rainfall data.

Description: The spatial distribution of stream water composition, as determined by the Geochemical Baseline Survey of the Environment (G-BASE) conducted by the British Geological Survey (BGS) can be successfully related under baseflow conditions to bedrock geochemistry. Further consideration of results in conjunction with site-specific monitoring data enables factors controlling both spatial and temporal variability in major element composition to be highlighted and allows the value of the survey to be enhanced. Hence, chemical data (i) from streams located on Lower Silurian (Llandovery) bedrock at 1 km2 resolution collected as part of the G-BASE survey of Wales and the West Midlands and (ii) from catchment monitoring studies located in upland mid-Wales (conducted by Institute of Terrestrial Ecology), have been considered together as an example. Classification of the spatial survey data set in terms of potentially controlling factors was carried out so as to illustrate the level of explanation they could give in terms of observed spatial chemical variability. It was therefore hypothesised that on a geological lithostratigraphic series of limited geochemical contrast, altitude and land-use factors provide better explanation of this variability than others such as lithology at sampling site and stream order. At an individual site, temporal variability was also found to be of considerable significance and, at a monthly time-step, is explicable in terms of factors such as antecedent conditions and seasonality. Data suggest that the degree of this variability may show some relationship with stream order and land-use. Monitoring data from the region also reveal that relationships between stream chemistry and land-use may prove to be strong not only at base flow but also in storm flow conditions. In a wider context, predictions of the sensitivity of stream water to acidification based on classifications of soil and geology are successful on a regional scale. However, the study undertaken here has shown that use of such classification schemes on a catchment scale results in considerable uncertainty associated with prediction. Uncertainties are due to the large degree of variability in stream chemistry encountered both spatially within geological units and temporally at individual sampling sites.

Description: In Zimbabwe during the 1980s and early 1990s, a sequence of severe droughts caused widespread food shortages and great hardship to rural communities. The droughts exacerbated the problems of environmental degradation in communal lands and highlighted the lack of understanding of the links between the climate, land use and hydrology of dryland regions. The Romwe Catchment Study addresses these issues, and has led to the establishment of the first fully-instrumented research catchment in a communally-managed dryland environment in southern Africa. The key objectives were (a) to improve the understanding of hydrological processes in communal land areas, mostly underlain by crystalline basement aquifers, and (b) to investigate the impacts of variations in climate and changes in land use and management on the hydrology and water resources. In this introductory paper, the physical characteristics of the catchment are described together with the instrumentation to monitor hydrological processes and quantify the catchment water balance.

Description: Two contrasting models are used to account for the effects of vegetation on microwave emission from the soil. These are: a simple model which requires two empirically derived parameters as input data (optical depth and single scattering albedo); and a complex discrete model which requires a detailed description of all of the components of the vegetation canopy. Both models account effectively for the vegetation, although the simple model takes a fraction of the computation time compared to the discrete model. However, the simple model was fitted to the data, whereas the discrete model used measured parameters as input. In addition to predicting the microwave brightness temperature, the discrete model also calculates the optical depth and single scattering albedo. These calculated values were in agreement with those fitted using the simple model. Therefore, it is suggested that the discrete model could be used to calculate the input parameters for the simple model.

Description: This paper describes the application and testing of a method for deriving spatial estimates of albedo from multi-angle remote sensing data. Linear kernel-driven models of surface bi-directional reflectance have been inverted against high spatial resolution multi-angular, multi- spectral airborne data of the principal cover types within the HAPEX-Sahel study site in Niger, West Africa. The airborne data are obtained from the NASA Airborne Solid-state Imaging Spectrometer (ASAS) instrument, flown in Niger in September and October 1992. The maps of model parameters produced are used to estimate integrated reflectance properties related to spectral albedo. Broadband albedo has been estimated from this by weighting the spectral albedo for each pixel within the map as a function of the appropriate spectral solar irradiance and proportion of direct and diffuse illumination. Partial validation of the results was performed by comparing ASAS reflectance and derived directional-hemispherical reflectance with simulations of a millet canopy made with a complex geometric canopy reflectance model, the Botanical Plant Modelling System (BPMS). Both were found to agree well in magnitude. Broadband albedo values derived from the ASAS data were compared with ground-based (point sample) albedo measurements and found to agree extremely well. These results indicate that the linear kernel-driven modelling approach, which is to be used operationally to produce global 16 day, 1 km albedo maps from forthcoming NASA Earth Observing System spaceborne data, is both sound and practical for the estimation of angle-integrated spectral reflectance quantities related to albedo. Results for broadband albedo are dependent on spectral sampling and on obtaining the correct spectral weigthings.

Description: The land-surface parameters required as input to a GCM grid box (typically a few degrees) are often set to be those of the dominant vegetation type within the grid box. This paper discusses the use and effect of aggregation rules for specifying effective values of these land cover parameters by taking into account the relative proportion of each land-cover type within each individual grid box. Global land-cover classification data at 1 km resolution were used to define Biosphere Atmosphere Transfer Scheme (BATS) specific aggregate (using aggregation rules) land-cover parameters. Comparison of the values of the aggregate parameters and those defined using the single dominant vegetation type (default parameters) shows significant differences in some regions, particularly in the semi-desert and in forested regions, e.g. the Sahara Desert and the tropical forest of South America. These two different sets of parameters were used as input data for two 10-year simulations of the NCAR CCM3 model coupled to the BATS land-surface scheme. Statistical analyses comparing the results of the two model runs showed that the resulting effects on the land-surface diagnostics are significant only in specific regions. For example, the sensible heat flux in the Sahara Desert calculated for the aggregate parameter run increased due to the marked increase in the minimum stomatal resistance and the decrease in fractional vegetation cover in the aggregate parameters over the default parameters. The modelled global precipitation and surface air temperature fields were compared to observations: there is a general improvement in the performance of the aggregate parameter run over the default parameter run in areas where the differences between the aggregate and default parameter run are significant. However, most of the difference between the modelled and observed fields is attributable to other model deficiencies. It can be concluded that the use of aggregation rules to derive land-surface parameters results in significant changes in modelled climate and in some improvements in the land-surface diagnostics in selected regions. There is also some evidence that there is a response in the global circulation pattern, which is a focus of further work.

Description: In many experimental conditions, the evaporative fraction, defined as the ratio between evaporation and available energy, has been found stable during daylight hours. This constancy is investigated over fully covering vegetation by means of a land surface scheme coupled with a mixed-layer model, which accounts for entrainment of overlying air. The evaporation rate follows the Penman-Monteith equation and the surface resistance is given by a Jarvis type parameterization involving solar radiation, saturation deficit and leaf water potential. The diurnal course of the evaporative fraction is examined, together with the influence of environmental factors (soil water availability, solar radiation input, wind velocity, saturation deficit above the well-mixed layer). In conditions of fair weather, the curves representing the diurnal course of the evaporative fraction have a typical concave-up shape. Around midday (solar time) these curves appear as relatively constant, but always lower that the daytime mean value. Evaporative fraction decreases when soil water decreases or when solar energy increases. An increment of saturation deficit above the mixed-layer provokes only a slight increase of evaporative fraction, and wind velocity has almost no effect. The possibility of estimation daytime evaporation from daytime available energy multiplied by the evaporative fraction at a single time of the day is also investigated. It appears that it is possible to obtain fairly good estimates of daytime evaporation by choosing adequately the time of the measurement of the evaporative fraction. The central hours of the day, and preferably about 3 hr before or after noon, are the most appropriate to provide good estimates. The estimation appears also to be much better when soil water availability (or evaporation) is high than when it is low.

Description: Two applications of a river routing model based on the observed river network and a linearised solution to the convective-diffusion equation are presented. One is an off-line application to part of the Amazon basin (catchment area 2.15 M km2) using river network data from the Digital Chart of the World and GCM-generated runoff at a grid resolution of 2.5 degrees latitude and 3.75 degrees longitude. The other application is to the Arkansas (409,000 km2) and Red River (125,500 km2) basins as an integrated component of a macro-scale hydrological model, driven by observed meteorology and operating on a 17 km grid. This second application makes use of the US EPA reach data to construct the river network. In both cases, a method of computing parameter values a priori has been applied and shows some success, although some interpretation is required to derive `correct' parameter values and further work is needed to develop guidelines for use of the method. The applications, however, do demonstrate the possibilities for applying the routing model at the continental scale, with globally-available data and a priori parameter estimation, and its value for validating GCM output against observed flows.

Description: In order to investigate the aggregation effects of surface heterogeneity in land surface processes we have adapted a theory of aggregation. Two strategies have been adopted: 1) Aggregation of radiative fluxes. The aggregated radiative fluxes are used to derive input parameters that are then used to calculate the aerodynamic fluxes at different aggregation levels. This is equivalent to observing the same area at different resolutions using a certain remote sensor, and then calculating the aerodynamic fluxes correspondingly. 2) Aggregation of aerodynamic fluxes calculated at the original observation scale to different aggregation levels. A case study has been conducted to identify the effects of aggregation on areal estimates of sensible and latent heat fluxes. The length scales of surface variables in heterogeneous landscapes are estimated by means of wavelet analysis.

Description: At a regional scale, high nitrate (NO3‾) concentrations in upland surface waters generally occur in tandem with high nitrogen (N) deposition levels. However, significant differences in the patterns of surface water NO3‾ concentration have been observed within areas of similar N deposition yet relatively few studies have been undertaken which examine within-region variation of NO3‾ concentrations. A study of 76 lakes in Snowdonia, north Wales, an area of high deposition and sensitive catchments, was undertaken to assess variation in surface water NO3‾ concentration across a 20 x 20 km grid square and to identify catchments vulnerable to NO3‾ leaching. Nitrate concentrations vary considerably, particularly during winter when values range from 0.7 to 70 μeq l-1. Although retention by vegetation and soil microbes in summer reduces the amount of NO3‾ reaching the lakes, 37 % of sites are characterised by NO3‾ concentrations greater then 4 μeq l-1. The elevated concentrations occurring in summer suggests that N breakthrough has occurred. By examining the ratio of NO3‾ to total strong acid anions, it is shown that NO3‾ contributes significantly to freshwater acidity, particularly during the winter. Redundancy analysis shows that NO3‾ leaching is greatest, both in winter and summer, in catchments with high proportions of bare rock where soil and vegetation cover is limited. Nitrogen cycling in these catchments, generally at higher altitudes, may no longer be governed by seasonal biological controls. They are likely to be saturated with respect to nitrogen (i.e. incapable of further N retention) as a result of the elevated deposition levels in the area. The contribution of NO3‾ to acidity is also greatest at these sites. In winter, significant positive relationships are also evident between NO3‾ concentration and soil pH and coniferous woodland. The study demonstrates the importance of catchment factors in modifying the relationship between N deposition and N leaching in upland catchments.

Description: A Bayesian approach is described for dealing with the problem of infilling and generating stochastic flow sequences using rainfall data to guide the flow generation process, and including bounded (censored) observed flow and rainfall data to provide additional information. Solutions are obtained using a Gibbs sampling procedure. Particular problems discussed include developing new procedures for fitting transformations when bounded values are available, coping with additional information in the form of values, or bounds, for totals of flows across several sites, and developing relationships between annual flow and rainfall data. Examples are shown of both infilled values of unknown past river flows, with assessment of uncertainty, and realisations of flows representative of what might occur in the future. Several procedures for validating the model output are described and the central estimates of flows, taken as a surrogate for historical observed flows, are compared with long term regional flow and rainfall data.

Description: Soil water movement was studied within fields on two different soil types, a red clay soil and a duplex soil of sand over clay, at the Romwe Catchment in southern Zimbabwe. Each study site comprised two fields and formed a surface water sub-catchment (1.0-2.4 ha) from which runoff was gauged. Soil moisture was measured in-situ at up to 20 locations within each sub-catchment over an entire cropping season and the following dry season. Maize was cultivated at both sites according to the farmers' normal cropping practice and crop yields were recorded. Surface redistribution of rainfall through localised runon and runoff was shown to be an important process in both sub-catchments with rainfall concentration factors between 0.2 and 2.7 for major rainfall events. This process was a key factor controlling deep drainage to groundwater. Results indicate that surface water redistribution is of particular importance for groundwater recharge in years with low or evenly distributed rainfall, when it would not otherwise have occurred. The soil water conditions created by surface redistribution of rainfall are also actively exploited by farmers who vary cropping practices within fields to maximise crop yields and reduce the risks of crop failure.

Description: A large undisturbed sample (3.5 m3) of 22-year-old, biodegraded solid waste set up to estimate the volume fraction participating in the transport of solutes through the waste material. Altogether, five tracer tests were performed under ponding and sprinkling conditions, and under steady-state and transient conditions. The experimental break through curves (BTCs), which indicated a non-equilibrium transport of the solute by early peaks and long right-hand tails, were used to parameterize log-normal solute travel time probability density functions. The expected solute travel times (i.e. the median solute travel times) were assessed and the corresponding fraction of the experimental volumes active in the transport of solutes was estimated. The solute transport volume fractions defined by the median solute travel times were estimated to vary between 5 and 10% of the total experimental volume. Further, the magnitudes of the solute transport volume fractions defined by the modal (peak) solute travel times were estimated to vary between 1 and 2% of the total experimental volume. In addition, possible boundary effects in terms of rapid flow along the wall of the experimental column were investigated.

Description: The paper examines the stability of the relation between microwave emission from the soil and the average near-surface water content in the case of relatively smooth, bare soils, and then considers the extent to which microwave radiometry can be used to estimate the effective surface resistance to vapour transfer, which is also related to the near-surface water status. The analysis is based on the use of a model (MICRO-SWEAT) which couples a microwave radiative transfer model with a SVAT scheme that describes the exchanges of water vapour, energy and sensible heat at the land surface. Verification of MICRO-SWEAT showed good agreement (about 3K RMSE) between predicted L band (1.4 GHz) brightness temperature over soils with contrasting texture during a multi-day drydown, and those measured using a truck-mounted radiometer. There was good agreement between the measured and predicted relations between the average water content of the upper 2 cm of the soil profile and the brightness temperature normalised with respect to the radiometric surface temperature. Some of the scatter in this relationship was attributable to diurnal variation in the magnitude of near-surface gradients in temperature and water content, and could be accounted for by using the physically-based simulation model. The influence of soil texture on this relationship was well-simulated using MICRO-SWEAT. The paper concludes by demonstrating how MICRO-SWEAT can be used to establish a relationship between the normalised brightness temperature and the surface resistance for use in the prediction of evaporation using the Penman-Montheith equation.

Description: This article proposes a methodology for synthesising the rating curve in one or more cross-sections of a watercourse provided with stage data, when a reliable rating curve and stage data are also available in the upstream cross-section; the synthesised rating curves are consistent with each other. The proposed methodology uses a variable parameter Muskingum-Cunge model whose parameters take express account of travel times and attenuation of the flood wave, and are expressed in such a way that allows for an integration in the time-space domain even when a topographic survey of the river is not available. Furthermore, the methodology proposed implicitly provides a ready-calibrated simulation model whose ease of application suggests that it could also be useful in real time stage forecasting. The paper includes a description of a numerical application to a reach of the Po River (Italy).

Description: It has previously been argued that current Soil Vegetation Atmosphere Transfer (SVAT) models are over-parameterised given the calibration data typically available. Using the Generalised Likelihood Uncertainty Estimation (GLUE) methodology, multiple feasible model parameter sets are here conditioned on latent heat fluxes and then additionally on the sensible and ground heat fluxes at a single site in Amazonia. The model conditioning schemes were then evaluated with a further data set collected at the same site according to their ability to reproduce the latent, sensible and ground heat fluxes. The results indicate that conditioning the model on only the latent heat flux component of the energy balance does not constrain satisfactorily the predictions of the other components of the energy balance. When conditioning on all heat flux objectives, significant additional constraint of the feasible parameter space is achieved with a consequent reduction in the predictive uncertainty. There are still, however, many parameter sets that adequately reproduce the calibration/validation data, leading to significant predictive uncertainty. Surface temperature measurements, whilst also subject to uncertainty, may be employed usefully in a multi-objective calibration of SWAT models.

Description: This paper investigates the ability of the VIC-2L model coupled to a routing model to reproduce streamflow in the catchment of the lower Elbe River, Germany. The VIC-2L model, a hydrologically-based land surface scheme (LSS) which has been tested extensively in the Project for Intercomparison of Land-surface Parameterization Schemes (PILPS), is put up on the rotated grid of 1/6 degree of the atmospheric regional scale model (REMO) used in the Baltic Sea Experiment (BALTEX). For a 10 year period, the VIC-2L model is forced in daily time steps with measured daily means of precipitation, air temperature, pressure, wind speed, air humidity and daily sunshine duration. VIC-2L model output of surface runoff and baseflow is used as input for the routing model, which transforms modelled runoff into streamflow, which is compared to measured streamflow at selected gauge stations. The water balance of the basin is investigated and the model results on daily, monthly and annual time scales are discussed. Discrepancies appear in time periods where snow and ice processes are important. Extreme flood events are analyzed in more dital. The influence of calibration with respect to runoff is examined.

Description: Snow, whilst not a dominant feature of Britain's maritime climate, can exert a significant influence on major floods through its contribution as snowmelt. Flood warning systems which fail to take account of melting snow can prove highly misleading. Selected results of a study on methods for improved snowmelt forecasting using trail catchments in upland Britain are presented here. Melt models considered range from a temperature excess formulation, with the option to include wind and rain heating effects, to a full energy budget melt formulation. Storage of melt in the pack is controlled by a store with two outlets, allowing slow release of water followed by rapid release once a critical liquid water content is reached. For shallow snow packs, a partial cover curve determines the proportion of the catchment over which snow extends. The melt, storage and release mechanisms together constitute the PACK snowmelt module which provides inputs to the catchment model. Either a lumped or distributed catchment model can be used, configured to receive snowmelt inputs from elevation zones within the catchment; a PACK snowmelt module operates independently within each zone and its inputs are controlled by appropriate elevation lapse rates. Measurements of snow depth and/or water equivalent, from snow cores or a snow pillow, are assimilated to correct for a lack of direct snowfall measurements needed to maintain a water balance during snowfall. The updating scheme involves operating a PACK module at the measurement site (the "point model") in parallel to PACK modules in the catchment model, with point model errors being transferred using a proportioning scheme to adjust the snowpack water contents of the catchment model. The results of the assessment of different model variants broadly favour the simpler model formulations. Hourly automatic monitoring of water equivalent using the snow pillow can help in updating the model but preferential melting from the pillow can be a problem. The energy budget melt formulation proves useful in understanding the energy components of melt typical of upland Britain. It reveals that, during the main melt phase, melt can occur in almost equal measure by sensible heat exchange and by latent heat of condensation, as warm air near saturation in cloud condenses on the snowpack; net radiation makes a negligible contribution. This provides a physical explanation for the success of the simple temperature excess approach to snowmelt estimation.

Description: This paper compares the performance of two artificial neural network (ANN) models – the multi layer perceptron (MLP) and the radial basis function network (RBF) – with a stepwise multiple linear regression model (SWMLR) and zero order forecasts (ZOF) of river flow. All models were trained using 15 minute rainfall-runoff data for the River Mole, a flood-prone tributary of the River Thames, UK. The models were then used to forecast river flows with a 6 hour lead time and 15 minute resolution, given only antecedent rainfall and discharge measurements. Two seasons (winter and spring) were selected for model testing using a cross-validation technique and a range of diagnostic statistics. Overall, the MLP was more skillful than the RBF, SWMLR and ZOF models. However, the RBF flow forecasts were only marginally better than those of the simpler SWMLR and ZOF models. The results compare favourably with a review of previous studies and further endorse claims that ANNs are well suited to rainfall-runoff modelling and (potentially) real-time flood forecasting.

Description: The single source SVAT scheme (MOSES) used in the UK Meteorological Office GCM is modified to include two sources. The performances of the original and the new scheme are compared with minimal calibration against data from sparse vegetation taken from the HAPEX-Sahel experiment. Both schemes perform well; in particular the dual source SVAT successfully simulates the different temperatures of the sparse vegetation and soil. It is demonstrated that the two sources need to be coupled, rather than acting independently, for an accurate result. Some components of the single and dual source schemes are driven offline by measured surface temperature. In this case a dual source SVAT scheme performs significantly better than a single source scheme.

Description: Measurements of carbon dioxide concentration, temperature and windspeed were made in the nocturnal boundary layer over a tropical forest near Manaus, Brazil using a tethered balloon system. The measurements were made up to a maximum height of 300 m on ten consecutive nights in November 1995. Simultaneous surface flux and in-canopy concentration measurements were made at the surface close to the site. The observation period included several different types of conditions. Generally strong windshear and relatively weak temperature gradients prevented the formation of a strong capping inversion to the nocturnal boundary layer. On some nights, however, the inversion was sufficiently strong that the CO2 concentration at 100 m above the surface exceeded 400 ppm. The concentration within the canopy was largely controlled by the presence of an inversion very close to the canopy surface. The temperature and wind profiles are contrasted with conditions in Randônia, Brazil, where the windshear was found to be weaker and higher carbon dioxide concentrations were observed in the early morning. The difference in carbon dioxide concentrations in the nocturnal boundary layer between dusk and dawn is used to estimate the regional nighttime flux of carbon dioxide. The value obtained generally exceeds the measured surface flux and sometimes exceeds the sum of the surface flux and the in-canopy storage made at the tower site. The reasons for the discrepancy are not clear; either one of the methods is in error or the regional carbon dioxide budget differs significantly from the local budget measured at the tower site.

Description: Ten methods for estimating the loads of constituents in a river were tested using data from the River Don in North-East Scotland. By treating loads derived from flow and concentration data collected every 2 days as a truth to be predicted, the ten methods were assessed for use when concentration data are collected fortnightly or monthly by sub-sampling from the original data. Estimates of coefficients of variation, bias and mean squared errors of the methods were compared; no method consistently outperformed all others and different methods were appropriate for different constituents. The widely used interpolation methods can be improved upon substantially by modelling the relationship of concentration with flow or seasonality but only if these relationships are strong enough.

Description: To evaluate the effects of variations in rainfall on groundwater, long-term rainfall records were used to simulate groundwater levels over the period 1953-96 at an experimental catchment in south-east Zimbabwe. Two different modelling methods were adopted. Firstly, a soil water balance model (ACRU) simulated drainage from daily rainfall and evaporative demand; groundwater levels were predicted as a function of drainage, specific yield and water table height. Secondly, the cumulative rainfall departure method was used to model groundwater levels from monthly rainfall. Both methods simulated observed groundwater levels over the period 1992-96 successfully, and long-term simulated trends in historical levels were comparable. Results suggest that large perturbations in groundwater levels area a normal feature of the response of a shallow aquifer to variations in rainfall. Long-term trends in groundwater levels are apparent and reflect the effect of cycles in rainfall. Average end of dry season water levels were simulated to be almost 3 m higher in the late 1970s compared to those of the early 1990s. The simulated effect of prolonged low rainfall on groundwater levels was particularly severe during the period 1981-92 with a series of low recharge years unprecedented in the earlier record. More recently, above average rainfall has resulted in generally higher groundwater levels. The modelling methods described may be applied in the development of guidelines for groundwater schemes to help ensure safe long-term yields and to predict future stress on groundwater resources in low rainfall periods; they are being developed to evaluate the effects of land use and management change on groundwater resources.

Description: Dambos, seasonally saturated wetlands, are widespread in headwater catchments in sub-Saharan Africa. It is widely believed that they play an important role in regional hydrology but, despite research conducted over the last 25 years, their hydrological functions remain poorly understood. To improve conceptualisation of hydrological flow paths and investigate the water balance of a small Zimbabwean catchment containing a single dambo, measurements of alkalinity and chloride in different water types within the catchment have been used as chemical markers. The temporal variation in alkalinity is consistent with the premise that all stream water, including the prolonged dry season recession, is derived predominantly from shallow sources. The proposition that dry season recession flows are maintained by water travelling at depth within the underlying saprolite is not substantiated. There is evidence that a low permeability clay lens, commonly present in many dambos, acts as a barrier for vertical water exchange. However, the highly heterogeneous chemical composition of different waters precludes quantitative hydrograph split-ting using end member mixing analysis. Calculation of the chloride mass-balance confirms that, after rainfall, evaporation is the largest component of the catchment water budget. The study provides improved understanding of the hydrological functioning of dambos. Such understanding is essential for the development and implementation of sustainable management strategies for this landform.

Description: The 3-dimensional forest model MAESTRO was used to simulate daily and annual photosynthesis and transpiration fluxes of forest stands and the sensitivity of these fluxes to potential changes in atmospheric CO2 concentration ([CO2]), temperature, water stress and phenology. The effects of possible feed-backs from increased leaf area and limitations to leaf nutrition were simulated by imposing changes in leaf area and nitrogen content. Two different tree species were considered: Picea sitchensis (Bong.) Carr., a conifer with long needle longevity and large leaf area, and Betula pendula Roth., a broad-leaved deciduous species with an open canopy and small leaf area. Canopy photosynthetic production in trees was predicted to increase with atmospheric [CO2] and length of the growing season and to decrease with increased water stress. Associated increases in leaf area increased production further only in the B. pendula canopy, where the original leaf area was relatively small. Assumed limitations in N uptake affected B. pendula more than P. sitchensis. The effect of increased temperature was shown to depend on leaf area and nitrogen content. The different sensitivities of the two species were related to their very different canopy structure. Increased [CO2] reduced transpiration, but larger leaf area, early leaf growth, and higher temperature all led to increased water use. These effects were limited by feedbacks from soil water stress. The simulations suggest that, with the projected climate change, there is some increase in stand annual `water use efficiency', but the actual water losses to the atmosphere may not always decrease.

Description: Appropriate representation of hydrological processes within atmospheric General Circulation Models (GCMs) is important with respect to internal model dynamics (e.g. surface feedback effects on atmospheric fluxes, continental runoff production) and to simulation of terrestrial impacts of climate change. However, at the scale of a GCM grid-square, several methodological problems arise. Spatial disaggregation of grid-square average climatological parameters is required in particular to produce appropriate point intensities from average precipitation. Conversely, aggregation of land surface heterogeneity is necessary for grid-scale or catchment scale application. The performance of grid-based hydrological models is evaluated for two large (104km2) UK catchments. Simple schemes, using sub-grid average of individual land use at 40 km scale and with no calibration, perform well at the annual time-scale and, with the addition of a (calibrated) routing component, at the daily and monthly time-scale. Decoupling of hillslope and channel routing does not necessarily improve performance or identifiability. Scale dependence is investigated through application of distribution functions for rainfall and soil moisture at 100 km scale. The results depend on climate, but show interdependence of the representation of sub-grid rainfall and soil moisture distribution. Rainfall distribution is analysed directly using radar rainfall data from the UK and the Arkansas Red River, USA. Among other properties, the scale dependence of spatial coverage upon radar pixel resolution and GCM grid-scale, as well as the serial correlation of coverages are investigated. This leads to a revised methodology for GCM application, as a simple extension of current procedures. A new location-based approach using an image processing technique is then presented, to allow for the preservation of the spatial memory of the process.

Description: The paper outlines a perspective on tropical forest hydrology within the context of an international hydrological programme. Experience in tropical forest hydrology research in North East Australia is a focal point for comparison with international activities elsewhere. The impacts of climate variability and change are considered briefly, as well as those of reforestation of degraded land on the land use hydrology, which requires a longer term vision and support of long term experimental catchments. Sadly, too few long term experimental catchments have been maintained in the humid tropics and there have been some significant closures even of these sites in recent years. Yet the case for long-term experiments is strengthened by the problematic issue of separating anthropogenic influences (such as land use change) on the hydrology of landscapes from the effects of climate variability at a time of escalation in population and related socio-economic pressures in the humid tropics. Particular emphasis is made of the need for greater consideration for the social and cultural dimensions of forest management within forest hydrology. Furthermore, scientists must be committed to incorporating ‘societal needs' in their planning of research projects, as well as in publicizing the applications of their results, within the framework of forest-land-water policy. Alarm is expressed at the extensive disregard for the application of existing forest hydrology ‘know how' in forest-land management manipulations associated with the humid tropics.

Description: A simple method is proposed to partition a mixture of two populations in suspended particle size data. The method, termed here "the differentiation method" is based on the function of the lognormal distribution. Suspended material in marine or estuarine situations often consists of difficult-to-interpret complex populations. The treatment of particle size data by the method described enables the confirmation of the lognormal law and also the demonstration of the occurrence of a combination of a number of populations which may not be distinguished by the classical Gaussian transformation or automatic methods. A simple combination of graphical and numerical techniques permits the decomposition and the easy determination of the various statistical parameters (median diameter, mean diameter, etc...). The method is applied to interpret observed size distributions of suspended particulate matter in the Seine estuary. The method enables the determination of the relative sizes of the constituent sub-populations that comprise the total suspended matter. In the example used to illustrate the method, particles are shown to be resuspended as a function of different hydrodynamic parameter.

Description: Two-layer parameterisation of the surface energy budget proves to be realistic for sparse but homogeneously distributed vegetation. For semi-arid land surfaces however, sparse vegetation is usually interspersed by large patches of unshaded bare soil which may interact directly with the atmosphere with little interference with the vegetation. Therefore such surfaces might not be realistically represented by a two-layer parameterisation. The objective of this study is to investigate the issue of representing water and energy transfer processes in arid and semi-arid regions. Two different surface schemes, namely the classic two layer (one-compartment) approach and a two adjacent compartment ("mosaic") approach are used. The performance of both schemes is documented using data sets collected over two sparsely vegetated surfaces in the San Pedro river basin: homogeneously distributed grassland and heterogeneously distributed shrubs. In the latter case the mosaic scheme seems to be more realistic given the quality of the temperature estimates. But no clear statement can be made on the efficiency of both schemes for the total fluxes. Over each site, we investigate the possibility of artificially modifying some of the surface parameters in order to get the surface fluxes simulated by the one-compartment scheme to reproduce the two-compartment ones. The "cost" associated with this process in terms of surface temperature estimates is eventually discussed.

Description: The new calcareous dinoflagellate taxa Bitorus truncus n.sp., Calcigonellum ansatum n.sp. and Fuettererella fungiforma n.sp. are formally described on the basis of Eocene and Oligocene samples from DSDP Site 357 (western South Atlantic Ocean).

Description: A study of the family Cytheruridae in Recent sediments from the coast of northern Rio de Janeiro State revealed the presence of four new species: (Hemicytherura auriculata, Oculocytheropteron delicatum, Oculocytheropteron circumcostatum and Semicytherura caudata,) and four previously described species (Semicytherura rugosoreticulata Whatley, Chadwick, Coxill & Toy, 1988, Oculocytheropteron macropunctatum Whatley, Chadwick, Coxill & Toy, 1988, Oculocytheropteron reticulopunctatum Whatley, Chadwick, Coxill & Toy, 1988 and Paracytheridea bulbosa Purper & Ornellas, 1989). A further two species Cytheropteron sp. and Kangarina sp. are left in open nomenclature due to paucity of the material. The ecology and distribution of the fauna suggest that the presence of many of these species, which also occur in colder waters off the coast of Uruguay and Argentina, is probably due to the upwelling of the South Atlantic Central Water in this area.

Description: For such a large and ecologically diverse group of organisms, foraminifera have produced remarkably few examples of parasites. They have, however, been recorded as ectoparasites on other foraminifera (Le Calvez, 1947; Haynes, 1981) and on bivalve molluscs (Todd, 1965; Alexander and Delaca, 1987). With respect to foraminiferal hosts, Le Calvez (1947) described Entosolenia ( = Fissurina) marginata as an ectoparasite that fed on granules from the pseudopodial reticulum of Discorbis villardeboanus. He observed specimens of F. marginata positioning themselves over the aperture of Discorbis, either moving there on their own or being carried along by the host’s pseudopodia, and remaining until leaving to undertake vegetative reproduction. After secretion of their tests, the new gamonts returned onto Discorbis. From his studies of mixed cultures, Le Calvez considered Fissurina marginata to be restricted to this single host and to die in its absence. It is thus apparently an obligate parasite with high host specificity.Haynes (1981), apparently from unpublished data, considered both Fissurina and Lagena to be ectoparasitic on other foraminifera, with their tests and apertural regions evolved for parasitic feeding. However, to the best of our knowledge, the observations outlined above have not been repeated and there are few recent reports of an ectoparasitic lifestyle for Fissurina (see Haward & Haynes, 1976).Specimens of Fissurina spp. are not uncommon in Fijian sediments. During the study of a sample of recent sediment collected from Bligh Water off Viti Levu, Fiji, a specimen of Fissurina, here referred to F. submarginata (Boomgart), was found . . .

Description: Traditionally, different diagnostic characters have been used in the identification of fossil and Recent coralline algal genera. The taxonomy of fossil coralline algae has focused on well calcified features such as basal filaments and conceptacle perforation. In contrast, the taxonomy of Recent material uses a combination of several features with a low fossilization potential, such as epithallial cells and structures of sexual reproductive organs. In the studied material of the Late Eocene Austrian Molasse Zone Lithoporella, Neogoniolithon, Spongites, Phymatolithon and Sporolithon are identified and described applying features of neontological taxonomic concepts. These features are: (1) the arrangement of basal filaments; (2) the occurrence of cell fusions; (3) the relative length of subepithellial initials; (4) the conceptacle perforation; (5) the orientation of filaments around the conceptacle pore; and (6) the type of conceptacle roof formation. Some of these features were thought to be unpresentable in fossil material until recently. The fossilization potential of diagnostic features and the identification of the documented genera and species are discussed in detail. Moreover, a checklist for the description of fossil taxa is provided.

Description: In the course of publication of a large manuscript on earliest Ordovician conodont species and their utility for biostratigraphy (Nicoll et al., 1999), an error occurred, resulting in the lack of designation of holotypes for the type species of the genus Iapetonudus and some new species of Iapetognathus. Herein, we remedy this error so that the originally published specimens are regarded as fully established holotypes rather than as syntypes in the future.As the original authors of these species, we establish the following holotypes: For the species Iapetognathus fluctivagus Nicoll, Miller, Nowlan, Repetski and Ethington, we designate the Pa element illustrated on Pl. 11, fig. 6, USNM 498962. For the species Iapetognathus jilinensis Nicoll, Miller, Nowlan, Repetski and Ethington, we designate the Pa element illustrated as Pl. 14, fig. 4, USNM 498973. For the species Iapetognathus landingi Nicoll, Miller, Nowlan, Repetski and Ethington, we designate the Pa element illustrated as Pl. 20, fig. 3, USNM 498996. For the species Iapetonudus ibexensis Nicoll, Miller, Nowlan, Repetski and Ethington, we designate the Pa element illustrated as Pl. 23, fig. 3, USNM 499009.

Description: Spherical objects recovered from the acetic acid preparation residues of vertebrate fossils from the Santana Formation (Lower Cretaceous) of northeast Brazil are postulated as the eggs of the ostracod Pattersoncypris micropapillosa Bate, 1972 (Ostracoda). These spheres are phosphatized and range from 85 to 110 μm in diameter, and are comparable in many respects to the eggs of several Recent ostracod species.

Description: New palynological data have been obtained from the Late Famennian Evieux and Comblain au Pont Formations of the Chanxhe section located in the Ourthe Valley in the eastern part of the Dinant Basin. In the light of this new data the stratigraphic ranges of several zonally important miospore taxa are now significantly different to those previously recorded. This has necessitated a re-evaluation and revision of the late Famennian miospore zonation scheme for this region. Apiculiretusispora verrucosa and Vallatisporites hystricosus are now found to occur below the inception of Retispora lepidophyta. Consequently, a new biozone, the Apiculiretusispora verrucosa–Vallatisporites hystricosus VH Biozone is described for the late Fa2c interval. The problematical relationship between the Retispora lepidophyta– Apiculiretusispora verrucosa LV Biozone and the Retispora lepidophyta–Knoxisporites literatus LL Biozone is resolved, and part of the LL Biozone is now considered equivalent to the LV Biozone, which it consequently replaces. The Retispora lepidophyta–Indotriradites explanatus LE Biozone is recorded from the upper part of the Comblain au Pont Formation. A continuous succession of miospore zones is now established for the late Famennian Fa2c/Fa2d interval which permits more accurate correlations with other regions in Europe and North America. Correlation with the standard conodont biostratigraphy shows that the base of LL Miospore Biozone is correlated with the middle or late expansa Conodont Biozone and the base of LE Miospore Biozone with the early to middle praesulcata Conodont Biozone.

Description: In the coastal area of northeastern Cyrenaica (Libya), the excellent exposures of Cenozoic limestone sequences of Al Jabal al Akhdar average around 1000 m in thickness and allow detailed stratigraphic investigations to be undertaken. This study of the biostratigraphy and depositional environments has been augmented by an analysis of the microfacies and of matrix-free foraminiferal assemblages. The biotic contents of the microfacies provide a good tool for correlation with the Letter classification developed from the Indo-Pacific region. The palaeoecological significance of the biota has been evaluated by comparison with the ecological requirements of their present day counterparts. Limitations for the palaeoecological interpretations are mainly due to the inadequate relationships with existing ecological data sets and to some local bias in fossil recovery because of some unfavourable lithologies. In the investigated Eocene to Miocene shallow marine carbonate succession nine different microfacies and sub-microfacies were distinguished through depositional texture and biotic components. Wilson’s standard carbonate facies belts, integrated with present day foraminiferal distribution models, have been used for reference in microfacies analysis and description. Most of the microfossils present are foraminifera and a total of 150 taxa, including larger, small and planktonic foraminifera, have been recognized and their stratigraphic and palaeaeocological distribution reported. Physiographically, the rock sequences investigated are referred to a shelf–carbonate platform complex, in which the depositional environments range from open shelf to restricted platform conditions. The nature and distribution of the foraminiferal assemblages and related biota, in association with sedimentological evidence, indicate a generalized shallowing upward trend in which several bathymetric oscillations, especially in the Oligocene, are reported. These reflect the interplay between local tectonics and large-scale eustatic changes.

Description: This multidisciplinary study integrates fades studies and foraminiferal analyses to assess the palaeoenvironmental evolution of an Oligocene to Miocene cool-water carbonate succession in the Otway Basin, southeastern Australia. The cool-water carbonate succession in the Otway Basin records signals relating to the evolution of the Southern Ocean throughout the Cenozoic. The strata are correlated with the relative coastal onlap curve of Haq et al. (1988) and several sequences can be identified in three formations. The Early Oligocene Narrawaturk Formation (TA 4.5) comprises near the base high-energy, inner shelf biofacies (lowstand systems tracts) and up-section to lower energy mid- to outer shelf marls (TST and maximum flooding surfaces) with storm events and/or minor shallowing intervals. Foraminiferal reworking and post-depositional dolomitization occurs at the top of this unit. The Late Oligocene Clifton Formation (TB 1.1 and TB 1.2.) was deposited in a relatively high-energy inner to mid-shelf environment. The base of this unit preserves evidence of a shift in biofacies that correlates to a major sea-level fall at the Mid/Late Oligocene boundary coincident with a major ice advance in Antarctica, and correlates with other Mid-Oligocene unconformities world-wide. The Late Oligocene Gellibrand Marl Formation (TB 1.2 and TB 1.3) began with low-energy outer shelf cherty marly biofacies (TST and MFS) followed by mid- to outer shelf calcisiltites (HST). High-energy mid- to outer shelf conditions were established after an hiatus in the Late Oligocene. A relative sea-level rise at the base of the Lower Miocene (TB 1.5 and TB2.1) led to the deposition of lower energy outer shelf cherty marls.Four biofacies with distinctive foraminiferal faunas are distinguished. (1) Grey mid- to outer shelf low-energy bryozoal marls with infaunal foraminifera and high plankton values. Two foraminiferal assemblages occur: lagenids and Uvigerina are common in the Narrawaturk marls, whereas bolivinids and Astrononion occur in the Gellibrand marls. The faunal variation in the marls may relate to changes in nutrient supply, anoxia, the presence or absence of organic material and/or changes in depth. (2) Chalky packstone facies with a high epifaunal content were deposited in oligotrophic inner to mid-shelf palaeoenvironments subject to intermittent reworking. (3) Bryozoan-poor inner to outer shelf foraminiferal packstones and grainstones facies enriched in epifaunal forms. (4) Well-sorted coarsegrained regular echinoid and bryozoan-rich packstones to grainstones. Infaunal taxa are absent in this facies, where most preserved foraminifera are robust spherical to discoidal forms. The facies were deposited in inner to mid-shelf palaeoenvironments where reworking by intense wave action (either above normal wavebase or by storms) winnowed out all smaller foraminifera.The stratigraphic and palaeoenvironmental utility of the Cenozoic foraminifera studied is improved greatly by facies analyses. Similar integrated studies will lead to better correlations and palaeoenvironmental interpretations of southeastern Australian sequences and equivalent successions in the southern hemisphere.

Description: The major agglutinated constituents in test material of marginal marine foraminifera are identified as α-quartz and clay particles using complementary spectroscopic techniques. Electron dispersive scattering analysis, micro-laser Raman and Fourier transform infrared (FTIR) spectroscopic techniques revealed detail about elemental and mineral polymorph constituents in test walls. Additionally, FTIR identifies the existence of organic cements and lining materials in wall structures. Micro-laser Raman specifically characterized the titanium oxide mineral, anatase, as a distinctive fraction of agglutinate in Ammobaculites balkwilli Haynes. The mineral represents ≈10% of the test material, but comprises a minor component of the sediment and is identified in sediments only after heavy mineral separation. The enhanced concentration of anatase in the test of A. balkwilli suggests that there is a preferential selection for anatase. This provides further evidence that certain foraminifera can select grains specifically, which implies that there exists a selective mechanism and interaction between the organic (secreted) phases in the test walls and inorganic (grain surface) materials.

Description: The Maastrichtian ostracods recovered from ODP Holes 1049B, 1050C and 1052E on the Blake Nose, Western North Atlantic, are investigated. The three sites are located on a depth transect encompassing middle to lower bathyal, Late Cretaceous palaeodepths. Fourteen samples ranging in age from early to late Maastrictian are investigated from Hole 1052E, which is the shallowest site. The early Maastrichtian G. falsostuarti–G. gansseri Zone of Hole 1052E yields rare ostracods. The species richness, abundance and faunal density are on average considerably higher in the late Maastrichtian R. fructicosa and A. mayaroensis Zones of Hole 1052E, possibly, at least partly, as a result of palaeoceanographical changes that were also responsible for the disappearance of the inoceramid bivalves at this location. A palaeobathymetrical comparsion among the late Maastrichtian ostracod assemblages recorded from Holes 1049B, 1050C and 1052E shows that the faunal density and mean number of taxa are inversely correlated with palaeodepth; however, the dominance of the platycopid genus Cytherella increases with palaeodepth. A dominance of platycopids may signify environmental stress related to low oxygen content. The dominance of the benthic foraminifer Nuttalides trumpeyi in the Late Cretaceous of Holes 1049B and 1050C provides additional evidence of oxygen deficiency. From a total of 28 genera recorded from Holes 1049B, 1050C and 1052E, 14 were previously recorded from Hole 689B, a high latitude hole in the Southern Ocean, and show that many ostracod genera display a wide latitudinal distribution in the Late Cretaceous deep sea, although more geographically restricted genera are also present, analogous with modern and Tertiary oceans.

Description: Maria Lejeune was by training a zoologist, working on living and fossil hexacorals. However, over a period of 16 years, she devoted her research attention to the microfossils contained in flakes of Upper Cretaceous flints, some from C. G. Ehrenberg’s classic collection, others from Belgium and the Baltic region. The results were published in 16 short papers, remarkable for the detail and precision of her descriptions and drawings. In addition, she made the first—and, so far, finest—large-scale models of fossil dinoflagellates. These were lodged in the Museum of the University of Liège, where she served as curator for 33 years (1942–1975). Eighteen years after her own micropalaeontological studies had ended, she aided W. A. S. Sarjeant in an extended restudy of her type material, reported in two joint papers.

Description: Die glazialen Sedimente der Küstenkliffe von Usedom, NE-Deutschland, sind unter besonderer Berücksichtigung der Rekonstruktion der Entwicklung des Paläomiljeus untersucht worden. Im unteren Teil des Anschnittes ist der stark gescherte Langerberg-Till aufgeschlossen. Dieser ist wahrscheinlich Teil eines marginalen Stauchmoränenkomplexes, der während eines Eisvorstoßes, vermutlich aus dem NW, abgelagert worden ist. Der Vorstoß hinterließ einen weitflächigen marginalen Eiszerfallskomplex, auf den der Ückeritz-Sand, zum Teil in wassergefüllten Becken aufgeschüttet wurde. Supraglazialer Schutt wurde sowohl in Form von Diamiktit-Lagen im Sand, als auch als sporadische Diamiktdecke auf dem Sand abgesetzt. Die untersuchte Sequenz entspricht der letzten weichselzeitlichen Deglaziation in diesem Gebiet. Die Einheiten können mit den jüngsten glazialen Ablagerungen im Westteil von Wolin, NW-Polen, korreliert werden.

Description: Die Idee, die in den Moränenbildungen der norddeutschen Vereisungen erkennbaren Leitgeschiebe auszuzählen und diese Zählungen statistisch zu verwerten, geht auf Forchhammer zurück. Aber zwischen dessen Äußerung im Jahre 1843 und den ersten Zählungen durch J. Korn (in Schroeder & Stoller, 1905, 1909) und V. Milters (1909) lag die berühmte Frühphase der norddeutschen Vereisungslehre und des Polyglazialismus', und von statistisch brauchbaren Zählungen kann man eigentlich erst von Hesemann (1930) ab rechen, gefolgt von den Arbeiten von van der Lijn (1932) und K. Richter (1933 u. f.). Seit Beginn der 50er Jahre ist dann im gesamten Ausstrichbereich der nordischen Glaziärablagerungen von den Niederlanden bis nach Polen die Geschiebestatistik als Hilfswissenschaft, immerhin aber als etablierte Methode eingesetzt worden, und sie hat - ganz gleich welche Methode verwendet wurde - dann zur Unterstützung lithostratigraphischer Korrelationen in brauchbarer Weise beitragen können, wenn — durch an biostratigraphischen Profilen geeichte Proben ein verläßliches Gerüst in die Zählungen eingebaut werden konnte, — die statistischen Vergleiche auf vernünftig große Regionen beschränkt und — durch andere lithologische, petrographische und fazielle Betrachtungen unterstützt wurden. Quartärstratigraphie ist niemals mit Hilfe nur eines methodischen Ansatzes erarbeitbar; sie bedarf der multiplen stratigraphischen Klassifikation. So verstehen auch die Geschiebestatistiker ihre Arbeit als einen von verschiedenen möglichen Annäherungsversuchen.

Description: Die vorliegende Arbeit befaßt sich mit dem Meiendorf-Interstadial nach der Definition von Menke (1968). Das Meiendorf-Interstadial ist eine vorböllingzeitliche Wärmeschwankung, die durch einen Anstieg von Zwergbirke (Betula nana), Sanddorn (Hippophaë) und Beifuß (Artemisia) charakterisiert ist. Es wurde erstmals 1968 von Menke für Schleswig-Holstein vorgestellt und konnte seitdem im Rheinland (Schirmer 1995, 1996; Litt & Stebich 1996), an der Lahn (Schirmer 1998) und an der Weser (Merkt & Müller im Druck) nachgewiesen werden. Sowohl aus den östlichen Niederlanden als auch aus dem mitteldeutschen Raum und dem Alpenvorland sind Pollenprofile bekannt, in denen sich Hinweise auf diese vorböllingzeitliche Wärmeschwankung finden. Daher kann man von einem mitteleuropäischen Geltungsbereich für das Meiendorf-Interstadial ausgehen. Das Meiendorf-Interstadial erscheint demnach geeignet, eine einheitliche Abgrenzung vom Hochglazial zum Spätglazial zu erbringen. Es gibt zahlreiche Hinweise auf weitere mögliche Wärmeschwankungen, die jünger als das letztglaziale Maximum (LGM) und älter als das Bölling-Interstadial sind. Aufgrund der Tatsache, daß es sieh hierbei um schwimmende Interstadiale handelt, denen der palynologische Anschluß an das bekannte Spätglazial fehlt und deren zeitliche Stellung oft nur durch 14C-Daten belegt wird, ist eine Korrelation mit dem Meiendorf-Interstadial bisher nicht möglich.

Description: Vorgestellt werden Neuuntersuchungen an einem 1899 beim Sandabbau entdeckten spätglazialen Fundplatz im Kr. Nordvorpommern. Die z. T. Bearbeitungsspuren aufweisenden Knochenartefakte stammen zum größten Teil vom Elch, je einmal sind Riesenhirsch und Pferd vertreten. Lithische Artefakte sind nicht überliefert. Der in das frühe Alleröd datierende Elchjägerplatz Endingen VI repräsentiert den ältesten absolut datierten Nachweis einer menschlichen Besiedlung in Nordostdeutschland. Die Fundschicht selbst ist offenbar vollständig zerstört worden. Unmittelbar benachbarte Profile weisen eine Abfolge basaler Geschiebemergel, fluvialer Sand des Pleniglazials, spätglaziale Silikatmudde und fluvialer Sand der Jüngeren Dryas auf. Ein Pollendiagramm aus der Silikatmudde zeigt eine Palynostratigraphie vom „Bölling" (neu: „Hippophaë-Phase") bis zum mittleren Alleröd. Die Sedimentbildung und die Vegetationsentwicklung am Fundplatz werden erläutert sowie spätglaziale Nachweise des Riesenhirsches im nördlichen Mitteleuropa diskutiert.

Description: Am Tönchesberg und in Koblenz-Metternich sind über dem Bt-Horizont des Eems (OIS 5e) bis an die Basis des Oberweichsel-Löß (OIS 2) zehn eigenständige Bodenbildungen nachgewiesen, die durch Sedimentationsphasen voneinander getrennt sind. Bis auf die beiden jüngsten, die als braune Tundrenböden anzusprechen sind, handelt es sich um gut ausgeprägte Ah-Horizonte, z. T. um Bv-, Bt-Ah- bzw. Bt-Horizonte.

Description: Im Hinterland der Pommerschen Endmoräne in Nordostdeutschland sind zwei Kiesgruben (Kavelpaß und Wusseken) untersucht worden. Beide weisen glazifluviale Sedimente im unteren, sowie Geschiebemergel im oberen Teil der Lagerfolge auf. Sedimentologische Studien und Studien zur Eisbewegungsrichtung sind durchgeführt worden. Es ist deutlich, daß das Eis zu Beginn des Vorstoßes von Ost nach West, bzw. von Südsüdost nach Nordnordwest geflossen ist, und somit die Eisfließrichtung als abweichend von der erwarteten regionalen nordost-südwestlichen Bewegungsrichtung betrachtet werden muß. Eine Erklärung dieses Phänomens unter Zuhilfenahme des Marginaldomkonzeptes wird in dieser Arbeit vorgeschlagen.

Description: Eine sehr ähnliche Geländeposition der Moränen um 1850 zu den heutigen Gletschern z. B. in den Alpen, in den südöstlichen kanadischen Rockies oder im Tienshan als Ergebnis einer geringen Abnahme der Jahresmitteltemperatur führt zu der Hypothese, daß wesentlich größere quartäre Klimaschwankungen im Bereich von 10(5) Jahren (Glazial-Interglazial-Zyklus) und sogar von 10(4) Jahren (etwa der Länge eines Interglazials) weitestgehend gleichzeitig, jedenfalls im gemäßigten Klimabereich der Nordhemisphäre stattgefunden haben. Dieses Konzept ist wichtig für kontinentale pedostratigraphische Korrelationen: wenn eine Löß-Paläoboden-Abfolge der Brunhes-Epoche mit der δ18O-Tiefseekurve des gleichen Zeitabschnitts in gute Übereinstimmung gebracht werden kann, so müßte man Löß-Paläoboden-Sequenzen des Mittel- und Jung-pleistozäns selbst in verschiedenen Kontinenten miteinander korrelieren, insbesondere pedostratigraphische Lücken feststellen können. Das würde dann die Rekonstruktion einer Klimageschichte der letzten 800.000 Jahre für den gemäßigten Klimabereich der Nordhemisphäre erlauben. Für eine Löß-Boden-Stratigraphie und insbesondere für paläoklimatische Rückschlüsse ist es einerseits notwendig, die Genese der Paläoböden über seine Merkmale zu erschließen. Die meisten Paläoböden sind aber gekappt und vom hangenden Löß sekundär aufgekalkt. Die Bodenmikromorphologie erlaubt jedoch zwischen primären und sekundären Carbonaten zu unterscheiden und z. B. den Prozeß der Tonverlagerung zweifelsfrei zu erkennen. Dies erlaubt die Trennung von typischem Löß, pedogen überprägtem Löß sowie die Ansprache von genetischen Bodenhorizonten wie CB-, BC-, Ah-, Bw-, B- und Bt-Horizonten. Die Löß-Paläoboden-Abfolge der Brunhes-Epoche in Karamaydan/Tadjikistan ist noch wesentlich detaillierter gegliedert als die entsprechende Abfolge in Luochuan/China oder von mitteleuropäischen Lößprofilen mit Ausnahme der Würm-Kalkzeit. So entsprechen z.B. Paläoböden in China oder Mitteleuropa komplizierten Pedokomplexen in Karamaydan. Daher wird die Sequenz von Lössen und stärker entwickelten Böden von Karamaydan als Referenzprofil für die Rekonstruktion der mittel- und jungpleistozänen Klimageschichte vorgeschlagen. Die Löß-Boden-Abfolge erlaubt eine sehr gute Korrelation mit der δ18O-Tiefseekurve von Bassinot et al. (1994), für die präzise astronomische Zeitangaben abgeleitet wurden. Dadurch wird sogar eine Zuordnung von Böden innerhalb eines Pedokomplexes des Referenzprofils von Karamaydan zu Substadien der δ18O-Kurve ermöglicht (Abb. 1). – Für den größeren Teil der Matuyama-Epoche zeigt der mittlere und basale Teil des Lößprofils von Chashmanigar (Tadjikistan) mehr gut ausgebildete Paläoböden als entsprechende Abschnitte der Löß-Boden-Abfolgen von Luochuan/ China (Abb. 2) und sehr viel mehr als in Mitteleuropa. Dabei enthält die altpleistozäne Löß-Boden-Sequenz von Chashmanigar mehrere stratigraphische Lücken, belegt durch Ck- bzw. Ckm-Horizonte, deren zugehörige Paläoböden abgetragen sind. Dennoch ermöglicht diese Sequenz mehr paläoklimatische Informationen bezüglich kalt-trockener Lößzeiten und feuchterer Warmzeiten als die bisher bekannten Tiefseekurven. Für weitere paläoklimatische Interpretationen sind (ton)mineralogische Untersuchungen an den drei Schluff-Fraktionen sowie der Grob- und Mitteltonfraktion (2-0,2 µm) und Feintonfraktion (

Description: In Ost-Polen erbohrte Seesedimente mit einer Mächtigkeit bis zu 55 m (Ossówka-See) dokumentieren das ganze Holstein-Interglazial und die Anfangsperiode der Saale-Eiszeit. An ausgewählten Bohrkernen der Seen von Ossówka und Wilczyn wurden palaeobiologische (Malakofauna, Palynologie und Pflanzen-Makroreste) und Isotopen-Untersuchungen durchgeführt. Die für den längsten (55 m) und vollständigsten Bohrkern nahe der Ortschaft Ossówka bestimmten C- und O-Isotopenwerte betragen: δ13C: Minimalwerte bis -6,4 ‰ für Ablagerungen am Beginn des Interglazials, Maximalwerte bis +10,0‰ für Ablagerungen aus der kalten Frühglazialperiode; δ18O: Maximalwerte bis -3,6 ‰ für Ablagerungen aus dem ersten Abschnitt des Interglazial-Optimums, Minimalwerte bis -10,1 ‰ für Ablagerungen aus der kältesten Periode unmittelbar vor der nächsten Vereisung. Generell gibt der Kurvenverlauf der O-Isotopenwerte gut die palynologisch dokumentierten Klimaveränderungen wieder. Im Profil sind jedoch zwei Perioden zu beobachten, in denen das Isotopenbild nicht mit der palynologischen Aussage übereinstimmt, einmal im klimatischen Interglazial-Optimum und zum anderen im jüngeren Teil des frühen Saale-Glazials. 1. Während des klimatischen Optimums des Holstein-interglazials (Pollen-Zone G und H) sprechen die Isotopenkurven der Seesedimente für relativ kühle Klimaverhältnisse. Dies kann durch eine Zunahme der Niederschlagsmenge, die zu einer Seespiegel-Erhöhung führte und/oder durch den Einfluß von isotopisch leichten Zuflüssen erklärt werden. 2. Im oberen Teil des Profils, der eine kühle, der Vereisung vorangehende Phase darstellt, erreichen die δ13C-und δ18O-Isotope unerwartet hohe Werte, was möglicherweise auf die Redeposition von "warmen" interglazialen Ablagerungen und/oder auf eine Zunahme der Evaporation unter trockenen Steppenklima-Bedingungen mit Seespiegel-Tiefständen zurückzuführen ist. Abkühlungsphasen fallen mit der Verschiebung der Sauerstoffisotopenverhältnisse in Richtung einer 18O- Verarmung zusammen.

Description: Im ostwestfälischen Bergland entstanden seit der Tertiärzeit durch Auslaugung von Salinargesteinen (Steinsalz und Anhydrit) im Untergrund zahlreiche Subrosionssenken an der Erdoberfläche. In diesen Senken sammelten sich während des Tertiärs und Quartärs verschiedenartige Lockergesteine - Sande, Silte, Tone -, die hier vor Erosion geschützt waren. Dank systematischer Erkundung während der Neukartierung Ostwestfalens durch das Geologische Landesamt Nordrhein-Westfalen wurden bisher rund 80 Subrosionssenken zumeist durch Bohrungen entdeckt. Zehn von ihnen werden in der vorliegenden Arbeit beschrieben, wobei acht nach palynologischer Datierung warmzeitliche Sedimente des Unterpleistozän, Cromer, Holstein und Eem beinhalten, weitere zwei solche der Kaltzeiten Saale und womöglich Elster. Die mächtigste und vollständigste Abfolge vom Waal bis zum Cromer wurde in der Subrosionssenke von Mosebeck östlich Detmold angetroffen.

Description: Die Untersuchungen zum holozänen Landschaftswandel im südlichen Oberrheintiefland und Schwarzwald konzentrieren sich auf die Zeitscheibe II (5500 bis 3000 v. Chr.) und III (1500 v. Chr. bis 500 n. Chr.) des DFG-Schwerpunktprogramms „Wandel der Geo-Biosphäre während der letzten 15 000 Jahre - Kontinentale Sedimente als Ausdruck sich ändernder Umweltbedingungen". Trotz einiger neolithischer Funde in den klimabegünstigten Lößgebieten wird der spürbare Eingriff des Menschen in die Naturlandschaft erst ab der Bronzezeit durch Kolluvien (Lößlehm) und Auensedimente nachgewiesen. Ein verstärkter Einfluß des Menschen auf die Abtragungsprozesse ist in der vorrömischen Eisenzeit, vor allem in der Latènezeit, zu beobachten. Die Ursachen dafür sind die Ausweitung der landwirtschaftlichen Nutzflächen durch die wachsende Bevölkerung bei gleichzeitiger Klimaverschlechterung. Eine einschneidende Auswirkung auf den Landschaftshaushalt hat bereits der Bergbau in der Latènezeit. Der anthropogene Einfluß auf die Geomorphodynamik verstärkt sich zur Römerzeit durch intensive landwirtschaftliche Nutzung, Siedlungen und den Bergbau. Mit dem Rückzug der Römer verringert sich die Siedlungsaktivität, und es tritt eine Stabilitätsphase mit Regeneration der Vegetation und Bodenbildung ein. Die alamannische Landnahme wirkte sich nur in den lößbedeckten und klimabegünstigten Siedlungsgebieten des Oberrheintieflandes und der Vorbergzone aus. Insgesamt führten die Aktivitäten der vorrömischen Eisenzeit und der Römerzeit zu den schwerwiegendsten anthropogenen Veränderungen im Untersuchungsgebiet während der drei Zeitscheiben.

Description: After focusing on the changes in Hungarian temperature and preeipitation during this Century, possible hydrological, agricultural and ecological consequences of a future climate change are described. These results have been obtained using a modified version of empirical downscaling techniques, developed to analyse the local effects of global climate change in a twofold concentration of atmospheric greenhouse gases scenario. In addition, regional changes in temperature and precipitation were examined with the help of the more specific stochastic downscaling method. The climate of Hungary has become warmer and drier over the last Century. It is to be expected that an increasing concentration of atmospheric greenhouse gases will enhance the tendency towards aridification.

Description: This contribution discusses possible future prospects of regional geography. This is done against the background of current socio-spatial developments and of various theoretical and conceptional debates as they are taking place mainly in English- and French-speaking countries. By taking central elements of modern conceptions of science as a basis possible regional geographie research issues will be identified which promise to be both aeademieally stimulating and socially relevant. A key concern is to show that regional geography can be regarded a viable research task living up to the Standards of modern conceptions of science, thereby casting off the dated yet still lingering image that regional geography is mere description or – worse still – environmental determinism.

Description: Le PNR 31, conclu en 1998, a eu comme objectif une meilleure connaissance des processus climatiques et météorologiques conduisant aux catastrophes naturelles en Suisse, avec en particulier une analyse détaillée des interactions entre le climat, les dangers naturels et la société. Notre pays se trouve spécialement concerné par cette thématique, en effet les régions de montagne avec leurs zones périglaciaires se révèlent être très sensibles aux modifications climatiques et environnementales, de plus elles sont aussi le siège d'intenses activités humaines. Outre les catastrophes naturelles, l'impact des modifications climatiques sur notre société et notre économie est essentielle et intéresse à priori une vaste palette d'utilisateurs. Cependant, le réchauffement global ne semble pas constituer une préoccupation majeure des populations, la priorité étant clairement donnée aux problèmes locaux, rendus cruciaux dans le contexte socio- économique actuel difficile. Cette priorité va à l'encontre de l'attitude dominante traditionnelle, qui correspondait plutôt à une acceptation ou une accommodation aux risques naturels par les populations résidentes de montagne. Les informations acquises par le PNR 31 devraient dès lors placer les populations et leurs autorités devant des responsabilités nouvelles : s'informer et intégrer les connaissances actuelles en matière de changements climatiques et de prévention des catastrophes naturelles, permettant ainsi d'être à même de prendre des décisions dans le sens d'une planification prévoyante" des risques.

Description: Globalization and competition between cities require a new kind of planning policy. An urban development policy, which promotes a city's attractiveness for visitors and local enterprises as well as for residents is necessary in order to profitably seil the product «city». Therefore, urban marketing is not only a public relations campaign to attract tourists and investors, but a market oriented urban development policy. This should take into account the interests and needs of all of the city's customers. All target groups should take an active part in a common vision of the future development of Basle. Regarding this, the image analysis identifies a need for action. In the perception of many people Basle lacks a clear profile. Important image factors show weaknesses, and group-specific needs are partly neglected. Especially the identification with the city and a target-oriented marketing of specific attractions should be specifically promoted.

Description: Die Region Basel ist von Globalisierungstendenzen betroffen, die zu Restrukturierungsprozessen der Wirtschaft im Stadt-Umland-Bereich führen. Merkmale dieser Entwicklung sind Arbeitsplatzverluste, steigende Arbeitslosigkeit und sektorale Restrukturierung mit neuen, flexibleren Formen der Produktion und Beschäftigung. Weltweit beobachtete räumliche Konzentrations- bzw. Dekonzentrationstendenzen bestimmter Branchen sind im Wirtschaftsraum Basel nur in geringerem Umfang auszumachen. Regionsspezifische Besonderheiten und die Stellung Basels im nationalen Städtesystem wirken hier modifizierend. Von den Auswirkungen der Restrukturierung sind Stadt und Umland in unterschiedlichem Ausmass betroffen. Auch im Umland selbst vollzieht sich keine homogene Entwicklung. Entsprechend gilt es, die jeweiligen lokalen Stärken auszubauen und Ausgleichsmechanismen zur Sicherung der Wettbewerbsfähigkeit der Region als Ganzes zu implementieren.

Description: In the Brundtland report, certain notions such as «sustainable development», «ecodevelopment», «integrated development» shine forth like beacons and have since been taken up by international organisations. Intended originally for politicians and administrators, these expressions have now become part of the vocabulary of experts and scientists. Starting form situations in which expertise in the integrated management of coastal zones has been provided in an international context, the process is described of expert evaluation, the semantics used, the know-how exploited to target practices towards «sustainable management» ofthe environment.