ALBERT

Description: A Web-based spatial decision supporting system for land management and soil conservation Solid Earth, 6, 903-928, 2015 Author(s): F. Terribile, A. Agrillo, A. Bonfante, G. Buscemi, M. Colandrea, A. D'Antonio, R. De Mascellis, C. De Michele, G. Langella, P. Manna, L. Marotta, F. A. Mileti, L. Minieri, N. Orefice, S. Valentini, S. Vingiani, and A. Basile Today it is evident that there are many contrasting demands on our landscape (e.g. food security, more sustainable agriculture, higher income in rural areas, etc.) as well as many land degradation problems. It has been proved that providing operational answers to these demands and problems is extremely difficult. Here we aim to demonstrate that a spatial decision support system based on geospatial cyberinfrastructure (GCI) can address all of the above, so producing a smart system for supporting decision making for agriculture, forestry, and urban planning with respect to the landscape. In this paper, we discuss methods and results of a special kind of GCI architecture, one that is highly focused on land management and soil conservation. The system allows us to obtain dynamic, multidisciplinary, multiscale, and multifunctional answers to agriculture, forestry, and urban planning issues through the Web. The system has been applied to and tested in an area of about 20 000 ha in the south of Italy, within the framework of a European LIFE+ project (SOILCONSWEB). The paper reports – as a case study – results from two different applications dealing with agriculture (olive growth tool) and environmental protection (soil capability to protect groundwater). Developed with the help of end users, the system is starting to be adopted by local communities. The system indirectly explores a change of paradigm for soil and landscape scientists. Indeed, the potential benefit is shown of overcoming current disciplinary fragmentation over landscape issues by offering – through a smart Web-based system – truly integrated geospatial knowledge that may be directly and freely used by any end user ( www.landconsultingweb.eu ). This may help bridge the last very important divide between scientists working on the landscape and end users.

Description: High resolution satellite turbidity and sea surface temperature observations of river plume interactions during a significant flood event Ocean Science Discussions, 12, 1669-1692, 2015 Author(s): V. E. Brando, F. Braga, L. Zaggia, C. Giardino, M. Bresciani, D. Bellafiore, C. Ferrarin, F. Maicu, A. Benetazzo, D. Bonaldo, F. M. Falcieri, A. Coluccelli, A. Russo, and S. Carniel Sea surface temperature (SST) and turbidity ( T ) derived from Landsat-8 (L8) imagery were used to characterize river plumes in the Northern Adriatic Sea (NAS) during a significant flood event in November 2014. Sea surface salinity (SSS) from an operational coupled ocean-wave model supported the interpretation of the plumes interaction with the receiving waters and among them. There was a good agreement of the SSS, T , and SST fields at the sub-mesoscale and mesoscale delineation of the major river plumes. L8 30 m resolution enabled also the description of smaller plume structures. Sharp fronts in T and SST delimited each single river plume. The isotherms and turbidity isolines coupling varied among the plumes due to differences in particle loads and surface temperatures in the discharged waters. The different plumes reflectance spectra were related to the lithological fingerprint of the sediments in the river catchments.

Description: Spatial scales of temperature and salinity variability estimated from Argo observations Ocean Science Discussions, 12, 1793-1814, 2015 Author(s): F. Ninove, P. Y. Le Traon, E. Remy, and S. Guinehut Argo observations from 2005 to 2013 are used to characterize spatial scales temperature and salinity variations from the surface down to 1500 m. Simulations are first performed to analyze the sensitivity of results to Argo sampling; they show that several years of Argo observations are required to estimate the spatial scales of ocean variability over 20° × 20° boxes. Spatial scales are then computed over several large scale areas. Zonal and meridional spatial scales ( Lx and Ly which are also zero crossing of covariance functions) vary as expected with latitudes. Scales are of about 100 km at high latitudes and more of 700 km in the Indian and Pacific equatorial/tropical regions. Zonal and meridional scales are similar: except in these tropical/equatorial regions where zonal scales are much larger (by a factor of 2 to 3) than meridional scales. Spatial scales are the largest close to the surface and have a general tendency for temperature to increase in deeper layers. There are significant differences between temperature and salinity scales, in particular, in the deep ocean. Results are consistent with previous studies based on sparse in-situ observations or satellite altimetry. They provide, however, for the first time a global description of temperature and salinity scales of variability and a characterization of their variations according to depths.

Description: A semi-analytical model for diffuse reflectance in marine and inland waters Ocean Science Discussions, 12, 1893-1912, 2015 Author(s): J. D. Pravin, P. Shanmugam, and Y.-H. Ahn A semi-analytical model for predicting diffuse reflectance of coastal and oceanic waters is developed based on the water-column optical properties and illumination conditions. Diffuse reflectance ( R ) is an apparent optical property that is related to the Gordon's parameter ( b b /(a+b b ) ) through a proportionality factor " f ". The conventional assumption of " f " as a constant (0.33) yields large errors in case of turbid and productive coastal waters and a predictive model based on this assumption is generally restricted to open-ocean waters (low chlorophyll case). In this paper, we have sorted the dependent factors that influence " f " values in the water column. Here, the parameter " f " is modeled as a function of wavelength, depth, inherent optical properties (IOPs) and illumination conditions. This work eliminates the spectral constants ( K Chl and K SS ) associated with our previous model and constrains the present model to be solely dependent on the IOPs and illumination conditions. Data used for parameterization and validation are obtained from in situ measurements in different waters within coastal environments. Validation shows good agreement between the model R and in situ R values with the overall mean relative error of less than a few percent. The model is valid for a wide range waters within coastal and open-ocean environments.

Description: Impact of variable sea-water conductivity on motional induction simulated with an OGCM Ocean Science Discussions, 12, 1869-1891, 2015 Author(s): C. Irrgang, J. Saynisch, and M. Thomas Carrying high concentrations of dissolved salt, ocean water is a good electrical conductor. As sea-water flows through the Earth's ambient geomagnetic field, electric fields are generated, which in turn induce secondary magnetic fields. In current models for oceanic induced magnetic fields, a realistic consideration of sea-water conductivity is often neglected and the effect on the variability of the oceanic induced magnetic field unknown. To model magnetic fields that are induced by non-tidal global ocean currents, an electromagnetic induction model is implemented into the Ocean Model for Circulation and Tides (OMCT). This provides the opportunity to not only model oceanic induced magnetic signals, but to assess the impact of oceanographic phenomena on the induction process. In this paper, the sensitivity of the induction process due to spatial and temporal variations in sea-water conductivity is investigated. It is shown that assuming an ocean-wide uniform conductivity is insufficient to accurately capture the temporal variability of the magnetic signal. Using instead a realistic global sea-water conductivity distribution increases the temporal variability of the magnetic field up to 45 %. Especially vertical gradients in sea-water conductivity prove to be a key factor for the variability of the oceanic induced magnetic field. However, temporal variations of sea-water conductivity only marginally affect the magnetic signal.

Description: A fuzzy intelligent system for land consolidation – a case study in Shunde, China Solid Earth, 6, 997-1006, 2015 Author(s): J. Wang, A. Ge, Y. Hu, C. Li, and L. Wang Traditionally, potential evaluation methods for farmland consolidation have depended mainly on the experts' experiences, statistical computations or subjective adjustments. Some biases usually exist in the results. Thus, computer-aided technology has become essential. In this study, an intelligent evaluation system based on a fuzzy decision tree was established, and this system can deal with numerical data, discrete data and symbolic data. When the original land data are input, the level of potential of the agricultural land for development will be output by this new model. The provision of objective proof for decision-making by authorities in rural management is helpful. Agricultural land data characteristically comprise large volumes, complex varieties and more indexes. In land consolidation, it is very important to construct an effective index system. A group of indexes need to be selected for land consolidation. In this article, a fuzzy measure was adopted to accomplish the selection of specific features. A fuzzy integral based on a fuzzy measure is a type of fusion tool. The optimal solution with the fewest non-zero elements was obtained for the fuzzy measure by solving a fuzzy integral. This algorithm provides a quick and optimal way to identify the land-index system when preparing to conduct land consolidation. This new research was applied to Shunde's "Three Old" consolidation project which provides the data. Our estimation system was compared with a conventional evaluation system that is still accepted by the public. Our results prove to be consistent, and the new model is more automatic and intelligent. The results of this estimation system are significant for informing decision-making in land consolidation.

Description: Design and validation of MEDRYS, a Mediterranean Sea reanalysis over 1992–2013 Ocean Science Discussions, 12, 1815-1867, 2015 Author(s): M. Hamon, J. Beuvier, S. Somot, J. M. Lellouche, E. Greiner, G. Jordà, M. N. Bouin, T. Arsouze, K. Béranger, F. Sevault, C. Dubois, M. Drevillon, and Y. Drillet The French research community on the Mediterranean Sea modelling and the French operational ocean forecasting center Mercator Océan have gathered their skill and expertise in physical oceanography, ocean modelling, atmospheric forcings and data assimilation, to carry out a MEDiterranean sea ReanalYsiS (MEDRYS) at high resolution for the period 1992–2013. The ocean model used is NEMOMED12, a Mediterranean configuration of NEMO with a 1/12° (∼ 7 km) horizontal resolution and 75 vertical z levels with partial steps. At the surface, it is forced by a new atmospheric forcing dataset (ALDERA), coming from a dynamical downscaling of the ERA-Interim atmospheric reanalysis by the regional climate model ALADIN-Climate with a 12 km horizontal and 3 h temporal resolutions. This configuration is used to carry a 34 year free simulation over the period 1979–2013 (NM12-FREE) which is the initial state of the reanalysis in October 1992. The first version of MEDRYS uses the existing Mercator Océan data assimilation system SAM that is based on a reduced-order Kalman filter with a 3-D multivariate modal decomposition of the forecast error. Altimeter data, satellite SST and temperature and salinity vertical profiles are jointly assimilated. This paper describes the configuration we used to perform the MEDRYS simulation. We then first validate the skills of the data assimilation system. It is shown that the data assimilation restores a good averaged temperature and salinity in intermediate layers compared to the free simulation. No particular biases are identified in the bottom layers. However, the reanalysis show slight positive biases of 0.02 psu and 0.15 °C above 150 m depth. In the validation stage, it is also shown that the assimilation allows to better reproduce water, heat and salt transports through the Strait of Gibraltar. Finally, the ability of the reanalysis to represent the sea surface high frequency variability is pointed out.

Description: Technical Note: Could benzalkonium chloride be a suitable alternative to mercuric chloride for preservation of seawater samples? Ocean Science Discussions, 12, 1953-1969, 2015 Author(s): J. Gloël, C. Robinson, G. H. Tilstone, G. Tarran, and J. Kaiser Instrumental equipment unsuitable or unavailable for fieldwork as well as lack of ship space can necessitate the preservation of seawater samples prior to analysis in a shore-based laboratory. Mercuric chloride (HgCl 2 ) is routinely used for such preservation, but its handling and subsequent disposal incur significant risks and expense. Benzalkonium chloride (BAC) has been used previously for freshwater samples. Here, we assess BAC as a less hazardous alternative microbial inhibitor for marine samples prior to the measurement of oxygen-to-argon (O 2 /Ar) ratios, as used for the determination of plankton net community production. BAC at a concentration of 50 mg dm −3 inhibited microbial activity for at least three days in seawater with chlorophyll a (Chl a ) concentrations up to 1 mg m −3 , possibly longer when Chl a concentrations were lower. BAC concentrations of 100 and 200 mg dm −3 were no more effective than 50 mg dm −3 . With fewer risks to human health and the environment, and no requirement for expensive waste disposal, BAC could be a viable alternative to HgCl 2 for short-term preservation of seawater samples, but is not a replacement for HgCl 2 in the case of oxygen triple isotope analysis, which requires storage over weeks to months. In any event, further tests on a case-by-case basis should be undertaken if use of BAC was considered, since its inhibitory activity may depend on concentration and composition of the microbial community.

Description: Turbulence observations in the Gulf of Trieste under moderate wind forcing and different water column stratification Ocean Science Discussions, 12, 1729-1764, 2015 Author(s): F. M. Falcieri, L. Kantha, A. Benetazzo, A. Bergamasco, D. Bonaldo, F. Barbariol, V. Malačič, M. S. Sclavo, and S. Carniel During the oceanographic campaign CARPET2014, between 30 January and 4 February 2014, a total of 478 microstructure profiles (grouped into 145 ensembles) and 38 CTD casts were made in the Gulf of Trieste (Northern Adriatic Sea) under moderate wind forcing (average wind speed 10 m s -1 ) and heat fluxes (net negative heat flux in the range of 150 to 400 W m -2 ). Among the collected profiles, there were three sets of yoyo casts, each lasting for about 12 h for a total of 50 casts. Overall, these represent the first turbulence observations collected in the Gulf of Trieste. Microstructure profiles collected with a free-falling profiler must be taken in enables of repeated casts, with the objective of obtaining more statistically significant values for turbulence parameters. This approach is certainly feasible in shallow waters, but has a down side when the vertical density structure includes strong interfaces that can move up or down between subsequent casts, under the influence of tides and internal waves. In order to minimize the smearing effect of such interfacial displacements on mean quantities, we developed an algorithm to realign, according to the temperature profile, successive microstructure profiles to produce sharper and more meaningful mean profiles of measured turbulence parameters. During CARPET2014, the water column in the Gulf evolved from a well-mixed condition to a stratified one, due to Adriatic waters intruding at the bottom along the Gulf's south-eastern coast. These waters stratified the water column and changed its stability characteristics, which in turn prevented wind driven turbulence from penetrating to the bottom of the water column. In this study, we show that during a warm and relatively dry winter, such as in 2014, the Gulf of Trieste was not completely mixed because of the influence of bottom waters intruding from the open sea, even under moderate wind forcing. Inside the Gulf, two types of water intrusions from the Adriatic Sea were observed during the yoyo casts: one coming from its northern coast (i.e. warmer, saltier and more turbid) and one coming from the open sea in front of the Po Delta (i.e. cooler, fresher and less turbid). Those two intrusions behaved similarly but had a different impact on turbulence kinetic energy dissipation rate profiles. The former, with high turbidity, acted as a barrier to wind-driven turbulence, while the latter, with low sediment concentrations and a smaller density gradient when compared to the rest of the water column, was not able to suppress downward penetration of turbulence from the surface to the same degree.

Description: Monitoring Atlantic overturning circulation variability with GRACE-type ocean bottom pressure observations – a sensitivity study Ocean Science Discussions, 12, 1765-1791, 2015 Author(s): K. Bentel, F. W. Landerer, and C. Boening The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism for large-scale northward heat transport and thus plays an important role for global climate. Relatively warm water is transported northward in the upper layers of the North Atlantic Ocean, and after cooling at subpolar latitudes, sinks down and is transported back south in the deeper limb of the AMOC. The utility of in-situ ocean bottom pressure (OBP) observations to infer AMOC changes at single latitudes has been characterized in recent literature using output from ocean models. We extend the analysis and examine the utility of space-based observations of time-variable gravity and the inversion for ocean bottom pressure to monitor AMOC changes and variability between 20 and 60° N. Consistent with previous results, we find a strong correlation between the AMOC signal and OBP variations, mainly along the western slope of the Atlantic basin. We then use synthetic OBP data – smoothed and filtered to resemble the resolution of the GRACE gravity mission – and reconstruct geostrophic AMOC transport. Due to the coarse resolution of GRACE-like OBP fields, we find that leakage of signal across the step slopes of the ocean basin is a significant challenge at certain latitudes. However, overall, the inter-annual AMOC anomaly time series can be recovered from 20 years of monthly GRACE-like OBP fields with errors less than 1 Sverdrup.

Description: An improved method for the determination of dissolved nitric oxide (NO) in seawater samples Ocean Science Discussions, 12, 959-981, 2015 Author(s): H. E. Lutterbeck and H. W. Bange Nitric oxide (NO) is a short-lived intermediate of the oceanic nitrogen cycle, however, due to its high reactivity, measurements of dissolved NO in seawater are rare. Here we present an improved method to determine NO concentrations in discrete seawater samples. The set-up of our system consisted of a chemiluminescence NO analyser connected to a stripping unit. The limit of detection for our method was 5 pmol NO in aqueous solution which translates into 0.25 nmol L −1 when using a 20 mL seawater sample volume. Our method was applied to measure high resolution depth profiles of dissolved NO during a cruise to the eastern tropical South Pacific Ocean. Our method is fast and comparably easy to handle thus it opens the door for deciphering the distribution of NO in the ocean and it facilitates laboratory studies on NO pathways.

Description: Regime changes in global sea surface salinity trend Ocean Science Discussions, 12, 983-1011, 2015 Author(s): A. L. Aretxabaleta, K. W. Smith, and J. Ballabrera-Poy Recent studies have shown significant sea surface salinity (SSS) changes at scales ranging from regional to global. In this study, we estimate global salinity means and trends using historical (1950–2014) SSS data from the UK Met. Office Hadley Centre objectively analyzed monthly fields and recent data from the SMOS satellite (2010–2014). We separate the different components (regimes) of the global surface salinity by fitting a Gaussian Mixture Model to the data and using Expectation–Maximization to distinguish the means and trends of the data. The procedure uses a non-subjective method (Bayesian Information Criterion) to extract the optimal number of means and trends. The results show the presence of three separate regimes: Regime A (1950–1990) is characterized by small trend magnitudes; Regime B (1990–2009) exhibited enhanced trends; and Regime C (2009–2014) with significantly larger trend magnitudes. The salinity differences between regime means were around 0.01. The trend acceleration could be related to an enhanced global hydrological cycle or to a change in the sampling methodology.

Description: Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the North Adriatic Sea Ocean Science Discussions, 12, 1625-1668, 2015 Author(s): W. J. McKiver, G. Sannino, F. Braga, and D. Bellafiore In this work we consider a numerical study of hydrodynamics in the coastal zone using two different models, SHYFEM and MITgcm, to assess their capability to capture the main processes. We focus on the North Adriatic Sea during a strong dense water event that occurred at the beginning of 2012. This serves as an interesting test case to examine both the models strengths and weaknesses, while giving an opportunity to understand how these events affect coastal processes, like upwelling and downwelling, and how they interact with estuarine dynamics. Using the models we examine the impact of setup, surface and lateral boundary treatment, resolution and mixing schemes, as well as assessing the importance of nonhydrostatic dynamics in coastal processes. Both models are able to capture the dense water event, though each displays biases in different regions. The models show large differences in the reproduction of surface patterns, identifying the choice of suitable bulk formulas as a central point for the correct simulation of the thermohaline structure of the coastal zone. Moreover, the different approaches in treating lateral freshwater sources affect the vertical coastal stratification. The results indicate the importance of having high horizontal resolution in the coastal zone, specifically in close proximity to river inputs, in order to reproduce the effect of the complex coastal morphology on the hydrodynamics. A lower resolution offshore is acceptable for the reproduction of the dense water event, even if specific vortical structures are missed. Finally, it is found that nonhydrostatic processes are of little importance for the reproduction of dense water formation in the shelf of the North Adriatic Sea.

Description: Responses of atmospheric circulation to sea surface temperature anomalies in the South China Sea Ocean Science Discussions, 12, 1693-1710, 2015 Author(s): M. Zhou and G. Wang The sea surface temperature (SST) anomalies in the South China Sea (SCS) and their influences on global atmospheric circulation were studied. The results of the simple atmospheric model suggested that the SCS SST anomalies can induce several barotropic wave trains from the SCS to other regions such as North America, high latitudes of the Southern Hemisphere and the Mediterranean. The baroclinic stream function anomalies from the simple model showed an anticyclonic vortex pair in East Asia and southern tropical Indian Ocean and a cyclonic vortex pair in the North Pacific and the Southwest Pacific. It is suggested that the spatial pattern of SST anomalies in the SCS can affect the magnitude of stream function anomalies, although it cannot affect the spatial pattern of atmospheric circulation.

Description: Technical Note: Medium-term morphodynamics in an unprotected sandy beach of the Adriatic Sea Ocean Science Discussions, 12, 1711-1728, 2015 Author(s): M. Postacchini, L. Soldini, C. Lorenzoni, and A. Mancinelli In the recent years attention has been paid to the beach protection by means of soft and hard defenses. Along the Italian coasts of the Adriatic Sea, sandy beaches are the most common landscapes and around 70 % of the Marche-Region coasts (central Adriatic), is protected by defense structures. The longest free-from-obstacle nearshore area in the Region includes the beach of Senigallia, characterized by a multiple barred beach, frequently monitored during the last decades. The bathymetries surveyed in 2006, 2010, 2011, 2012 and 2013 show a good adaptation of the beach to the Dean-type equilibrium profile, though a strong short-/medium-term variability of the wave climate has been observed during the monitored periods. This suggests a slight influence of wave forcing on the long-term profiles, which seems to only depend on the sediment size. Further, the medium-term dynamics of the submerged bars and their geometric features have been related to the wave climate collected by a wave buoy located 40 km off Senigallia during the analyzed temporal windows. An overall interpretation of the complete dynamics, i.e. hydrodynamics (buoy data), sediment characteristics (equilibrium-profile A parameter) and morphodynamics (bathymetric surveys), suggests that the wave climate is fundamental for the morphodynamic changes of the beach in the medium term: waves coming from NNE/ESE are characterized by a larger/smaller steepness and induce seaward/shoreward bar migration, as well as bar smoothing/steepening. Moving southward, the bar dimension increases, while the equilibrium profile suggests a decrease of the sediment size in the submerged beach, this probably due to the presence of both harbor jetty and river mouth North of the investigated area.

Description: The near-inertial variability of meridional overturning circulation in the South China Sea as shown by an eddy-resolving ocean reanalysis Ocean Science Discussions, 12, 2123-2146, 2015 Author(s): J. Xiao, D. Wang, Q. Xie, Y. Shu, C. Liu, and J. Chen The near-inertial variability of the meridional overturning circulation in the South China Sea (SCSMOC) has been analyzed based on a global 1/12° ocean reanalysis. The wavelet analysis and power spectrum of deep SCSMOC time series shows that there is a significant signal in the near-inertial band. The maximum amplitude of the near-inertial signal in the SCSMOC is nearly 4 Sv. The spatial structure of the signal features regularly alternating counterclockwise and clockwise overturning cells. It is also found that the near-inertial signal of SCSMOC mainly originates from the Luzon Strait and propagates equatorward with the speed of 1–3 m s −1 . Further analyses suggest that the near-inertial signal in the SCSMOC is triggered by high-frequency wind variability near the Luzon Strait where geostrophic shear always exists due to Kuroshio intrusion.

Description: Precision of farmer-based fertility ratings and soil organic carbon for crop production on a Ferralsol Solid Earth, 6, 1063-1073, 2015 Author(s): P. Musinguzi, P. Ebanyat, J. S. Tenywa, T. A. Basamba, M. M. Tenywa, and D. Mubiru Simple and affordable soil fertility ratings are essential, particularly for the resource-constrained farmers in sub-Saharan Africa (SSA), in planning and implementing prudent interventions. A study was conducted on Ferralsols in Uganda to evaluate farmer-based soil fertility assessment techniques, hereafter referred to as farmers' field experiences (FFE), for ease of use and precision, against more formal scientific quantitative ratings using soil organic carbon (SQR-SOC). A total of 30 fields were investigated and rated using both techniques, as low, medium and high in terms of soil fertility – with maize as the test crop. Both soil fertility rating techniques were fairly precise in delineating soil fertility classes, though the FFE was inefficient in distinguishing fields 〉 1.2 % SOC with medium and high fertility. Soil organic carbon, silt and clay were exceptionally influential, accounting for the highest percentage in grain yield of 50 % in the topsoil (0–15 cm) and 67 % for the mean concentrations from 0 to 15 and 15 to 30 cm. Each unit increase in SOC concentration resulted in 966 to 1223 kg ha −1 yield gain. The FFE technique was effective in identifying low-fertility fields, and this was coherent with the fields categorized as low (SOC 〈 1.2 %). Beyond this level, its precision can be remarkably increased when supplemented with the SQR-SOC technique.

Description: Phase change in subducted lithosphere, impulse, and quantizing Earth surface deformations Solid Earth, 6, 1075-1085, 2015 Author(s): C. O. Bowin, W. Yi, R. D. Rosson, and S. T. Bolmer The new paradigm of plate tectonics began in 1960 with Harry H. Hess's 1960 realization that new ocean floor was being created today and is not everywhere of Precambrian age as previously thought. In the following decades an unprecedented coming together of bathymetric, topographic, magnetic, gravity, seismicity, seismic profiling data occurred, all supporting and building upon the concept of plate tectonics. Most investigators accepted the premise that there was no net torque amongst the plates. Bowin (2010) demonstrated that plates accelerated and decelerated at rates 10 −8 times smaller than plate velocities, and that globally angular momentum is conserved by plate tectonic motions, but few appeared to note its existence. Here we first summarize how we separate where different mass sources may lie within the Earth and how we can estimate their mass. The Earth's greatest mass anomalies arise from topography of the boundary between the metallic nickel–iron core and the silicate mantle that dominate the Earth's spherical harmonic degree 2 and 3 potential field coefficients, and overwhelm all other internal mass anomalies. The mass anomalies due to phase changes in olivine and pyroxene in subducted lithosphere are hidden within the spherical harmonic degree 4–10 packet, and are an order of magnitude smaller than those from the core–mantle boundary. Then we explore the geometry of the Emperor and Hawaiian seamount chains and the 60° bend between them that aids in documenting the slow acceleration during both the Pacific Plate's northward motion that formed the Emperor seamount chain and its westward motion that formed the Hawaiian seamount chain, but it decelerated at the time of the bend (46 Myr). Although the 60° change in direction of the Pacific Plate at of the bend, there appears to have been nary a pause in a passive spreading history for the North Atlantic Plate, for example. This, too, supports phase change being the single driver for plate tectonics and conservation of angular momentum. Since mountain building we now know results from changes in momentum, we have calculated an experimental deformation index value (1–1000) based on a world topographic grid at 5 arcmin spacing and displayed those results for viewing.

Description: Recent transient tracer distributions in the Fram Strait: estimation of anthropogenic carbon content and transport Ocean Science Discussions, 12, 2189-2229, 2015 Author(s): T. Stöven, T. Tanhua, M. Hoppema, and W.-J. von Appen The storage of anthropogenic carbon in the ocean's interior is an important process which modulates the increasing carbon dioxide concentrations in the atmosphere. The polar regions are expected to be net sinks for anthropogenic carbon. Transport estimates of dissolved inorganic carbon and the anthropogenic offset can thus provide information about the magnitude of the corresponding storage processes. Here we present a transient tracer, dissolved inorganic carbon (DIC) and total alkalinity (TA) data set along 78°50′ N sampled in the Fram Strait in 2012. A theory on tracer relationships is introduced which allows for an application of the Inverse Gaussian – Transit Time Distribution (IG-TTD) at high latitudes and the estimation of anthropogenic carbon concentrations. Current velocity measurements along the same section were used to estimate the net flux of DIC and anthropogenic carbon through the Fram Strait. The new theory explains the differences between the theoretical (IG-TTD based) tracer age relationship and the specific tracer age relationship of the field data by saturation effects during water mass formation and/or the deliberate release experiment of SF 6 in the Greenland Sea in 1996 rather than by different mixing or ventilation processes. Based on this assumption, a maximum SF 6 excess of 0.5–0.8 fmol kg −1 was determined in the Fram Strait at intermediate depths (500–1600 m). The anthropogenic carbon concentrations are 50–55 μmol kg −1 in the Atlantic Water/Recirculating Atlantic Water, 40–45 μmol kg −1 in the Polar Surface Water/warm Polar Surface Water and between 10–35 μmol kg −1 in the deeper water layers, with lowest concentrations in the bottom layer. The net DIC and anthropogenic carbon fluxes through the Fram Strait indicate a balanced exchange between the Arctic Ocean and the North Atlantic, although with high uncertainties.

Description: The dynamic connection of the Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current Ocean Science Discussions, 12, 2231-2256, 2015 Author(s): E. Lambert, D. Le Bars, and W. P. M. de Ruijter East of Madagascar, wind and surface buoyancy fluxes reinforce each other, leading to frontogenesis, outcrop and an eastward along-front flow: the South Indian Ocean Countercurrent (SICC). In the east the Leeuwin Current (LC) is a unique eastern boundary current which flows poleward along Australia. It is often described as a regional coastal current forced by an off-shore meridional density gradient or a sea surface slope, yet little is known of the forcing and dynamics that control these open ocean meridional gadients. To complete this understanding, we make use of both an ocean general circulation model and a conceptual two-layer model. The SICC impinges on west Australia and adds to a sea level slope and a southward geostrophic coastal jet: the Leeuwin Current. The SICC and the LC are thus dynamically connected. An observed transport maximum of the LC around 22° S is directly related to this impingement of the SICC. The circulation of the Indonesian Throughflow (ITF) through the Indian Ocean appears to be partly trapped in the upper layer north of the outcrop line and is redirected along this outcrop line to join the eastward flow of the SICC. Shutdown of the ITF in both models strongly decreases the Leeuwin Current transport and breaks the connection between the LC and SICC. In this case, most of the SICC was found to reconnect to the internal gyre circulation in the Indian Ocean. The Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current are thus dynamically coupled.

Description: Impact of vertical and horizontal advection on nutrient distribution in the South East Pacific Ocean Science Discussions, 12, 2257-2281, 2015 Author(s): B. Barceló-Llull, E. Mason, and A. Pascual An innovative approach is used to analyse the impact of vertical velocities associated with quasi-geostrophic (QG) dynamics on the distribution of a passive nutrient tracer (nitrate) in the South East Pacific. Twelve years of vertical and horizontal currents are derived from an observation-based estimate of the ocean state. Horizontal velocities are obtained through application of thermal wind balance to weekly temperature and salinity fields. Vertical velocities are estimated by integration of the QG Omega equation. Seasonal variability of the synthetic vertical velocity and kinetic energy associated with the horizontal currents are coincident, with peaks in austral summer (November–December) in accord with published observations. Two ensembles of Lagrangian particle tracking experiments that differ according to vertical forcing ( w = w QG vs. w = 0) enable a quantitative analysis of the impact of the vertical velocity. From identical initial distributions of nitrate-tagged particles, the Lagrangian results show that the impact of vertical advection on nutrient distribution is 30 % of the contribution of horizontal advection. Despite being weaker by a factor of up to 10 −4 than the horizontal currents, vertical velocity is demonstrated to make an important contribution to nutrient distributions in the region of study.

Description: Imprint of external climate forcing on coastal upwelling in past and future climate Ocean Science Discussions, 12, 2899-2930, 2015 Author(s): N. Tim, E. Zorita, B. Hünicke, X. Yi, and K.-C. Emeis The Eastern Boundary Upwelling Systems are the major coastal upwelling regions. The trade winds are driving these upwelling regimes located in the subtropics at the eastern boundary of the Atlantic and Pacific Ocean. Here we analyse the impact of the external climate forcing, e.g. the greenhouse gas concentration, solar activity and volcano eruptions, on these upwelling systems in simulations of ensembles of two Earth System Models. The ensembles contain three simulations for each time period which cover the past millennium (900–1850), the 20th century (1850–2005) and the near future (2006–2100). Using a set of simulations, differing only in their initial conditions, enables us to detect whether the variability is driven internally or externally. Our analysis shows that the variability of the simulated upwelling is to the most driven internally and that there are no significant trends except for the scenario with the most dramatic increase of greenhouse gas concentrations.

Description: Upwelling characteristics in the Gulf of Finland (Baltic Sea) as revealed by Ferrybox measurements in 2007–2013 Ocean Science Discussions, 12, 2863-2898, 2015 Author(s): V. Kikas and U. Lips Ferrybox measurements are carried out between Tallinn and Helsinki in the Gulf of Finland (Baltic Sea) in a regular basis since 1997. The system measures autonomously water temperature, salinity, chlorophyll a fluorescence and turbidity and takes water samples for further analyses at a pre-defined time interval. We aimed to show how the Ferrybox technology could be used to study the coastal upwelling events in the Gulf of Finland. Based on the introduced upwelling index and related criterion, 33 coastal upwelling events were identified in May–September 2007–2013. The number of events as well as frequency of their occurrence and intensity, expressed as a sum of daily average temperature deviations in the 20 km wide coastal area, were almost equal near the northern and southern coast. It is shown that the wind impulse needed to generate upwelling events of similar intensity differ between the two coastal areas whereas this difference is related to the average wind forcing in the area. Two types of upwelling events were identified – one characterized by a strong temperature front and the other revealing gradual decrease of temperature from the open to coastal area with maximum temperature deviation close to the shore.

Description: Tidal elevation, current and energy flux in the area between the South China Sea and Java Sea Ocean Science Discussions, 12, 2831-2861, 2015 Author(s): Z. X. Wei, G. H. Fang, R. D. Susanto, T. R. Adi, B. Fan, A. Setiawan, S. J. Li, Y. G. Wang, and X. M. Gao The South China Sea (SCS) and the Java Sea (JS) are connected through the Karimata Strait, Gaspar Strait, and the southern Natuna Sea, where the tides are often used as open boundary condition for tidal simulation in the SCS or Indonesian seas. Tides, tidal currents and tidal energy fluxes of the principle constituents K 1 , O 1 , Q 1 , M 2 , S 2 and N 2 at five stations in this area have been analyzed using in-situ observational data. The results show that the diurnal tides are the dominant constituents in the entire study area. The constituent K 1 has the largest amplitude, exceeding 50 cm, whereas the amplitudes of M 2 are smaller than 5 cm at all stations. The amplitudes of S 2 may exceed M 2 in Karimata and Gaspar Straits. Tidal currents are mostly of rectilinear type in this area. The major semi axis lengths of the diurnal tidal current ellipses are about 10 cm s −1 , and those of the semi-diurnal tidal currents are smaller than 5 cm s −1 . The diurnal tidal energy flows from the SCS to the JS. The semi-diurnal tidal energy flows from the SCS to the JS through the Karimata Strait and the eastern part of the southern Natuna Sea but flows in the opposite direction in the Gaspar Strait and the western part of the southern Natuna Sea. Harmonic analysis of sea level and current observation also suggest that the study area is located in the loop band of the diurnal tidal waves, and in the nodal band of the semi-diurnal tidal waves. Comparisons show that the existing models are basically consistent with the observational results, but further improvements are necessary.

Description: Responses of vertical soil moisture to rainfall pulses and land uses in a typical loess hilly area, China Solid Earth, 6, 595-608, 2015 Author(s): Y. Yu, W. Wei, L. D. Chen, F. Y. Jia, L. Yang, H. D. Zhang, and T. J. Feng Soil moisture plays a key role in vegetation restoration and ecosystem stability in arid and semiarid regions. The response of soil moisture to rainfall pulses is an important hydrological process, which is strongly influenced by land use during the implementation of vegetation restoration. In this study, vertical soil moisture variations of woodland ( Pinus tabulaeformis ), native grassland ( Stipa bungeana ), shrubland ( Hippophea rhamnoides ), cropland ( Triticum aestivum ) and artificial grassland ( Onobrychis viciaefolia ) in five soil profiles were monitored in a typical loess hilly area during the 2010 growing season. The results demonstrated that rainfall pulses directly affected soil moisture variation. A multi-peak pattern of soil moisture appeared during the growing season, notably in the surface soil layer. Meanwhile, the response of each vegetation type to rainfall was inconsistent, and a time-lag effect before reaching the peak value was detected, following each heavy rainfall event. The response duration of soil moisture, however, varied markedly with the size of rainfall events. Furthermore, higher soil water content was detected in grassland and shrubland. Woodland was characterized by relatively lower soil moisture values throughout the investigation period. Our research suggests that vegetation restoration efforts should give priority to grassland and shrubland at the research site. We suggest that more studies should be focused on the characteristics of community structure and spatial vegetation distribution on soil moisture dynamics, particularly within the grass and shrub ecosystems.

Description: Remediation of degraded arable steppe soils in Moldova using vetch as green manure Solid Earth, 6, 609-620, 2015 Author(s): M. Wiesmeier, M. Lungu, R. Hübner, and V. Cerbari In the Republic of Moldova, non-sustainable arable farming led to severe degradation and erosion of fertile steppe soils (Chernozems). As a result, the Chernozems lost about 40% of their initial amounts of soil organic carbon (SOC). The aim of this study was to remediate degraded arable soils and promote carbon sequestration by implementation of cover cropping and green manuring in Moldova. Thereby, the suitability of the legume hairy vetch ( Vicia sativa ) as cover crop under the dry continental climate of Moldova was examined. At two experimental sites, the effect of cover cropping on chemical and physical soil properties as well as on yields of subsequent main crops was determined. The results showed a significant increase of SOC after incorporation of hairy vetch mainly due to increases of aggregate-occluded and mineral-associated OC. This was related to a high above- and belowground biomass production of hairy vetch associated with a high input of carbon and nitrogen into arable soils. A calculation of SOC stocks based on equivalent soil masses revealed a sequestration of around 3 t C ha −1 yr −1 as a result of hairy vetch cover cropping. The buildup of SOC was associated with an improvement of the soil structure as indicated by a distinct decrease of bulk density and a relative increase of macroaggregates at the expense of microaggregates and clods. As a result, yields of subsequent main crops increased by around 20%. Our results indicated that hairy vetch is a promising cover crop to remediate degraded steppe soils, control soil erosion and sequester substantial amounts of atmospheric C in arable soils of Moldova.

Description: The open boundary equation Ocean Science Discussions, 12, 925-958, 2015 Author(s): D. Diederen, H. H. G. Savenije, and M. Toffolon We present a new equation describing the hydrodynamics in infinitely long tidal channels (i.e., no reflection) under the influence of oceanic forcing. The proposed equation is a simple relationship between partial derivatives of water level and velocity. It is formally derived for a progressive wave in a frictionless, prismatic, tidal channel with a horizontal bed. Assessment of a large number of numerical simulations, where an open boundary condition is posed at a certain distance landward, suggests that it can also be considered accurate in the more natural case of converging estuaries with nonlinear friction and a bed slope. The equation follows from the open boundary condition and is therefore a part of the problem formulation for an infinite tidal channel. This finding provides a practical tool for evaluating tidal wave dynamics, by reconstructing the temporal variation of the velocity based on local observations of the water level, providing a fully local open boundary condition and allowing for local friction calibration.

Description: Shifting momentum balance and frictional adjustment observed over the inner-shelf during a storm Ocean Science Discussions, 12, 897-924, 2015 Author(s): M. Grifoll, A. Aretxabaleta, J. L. Pelegrí, and M. Espino We investigate the rapidly changing equilibrium between the momentum sources and sinks during the passage of a two-peak storm over the Catalan inner-shelf (NW Mediterranean Sea). Velocity measurements at 24 m water depth are taken as representative of the inner shelf, and the cross-shelf variability is explored with additional measurements at 50 m water depth. At 24 m, as the storm-related wind stress accelerated the flow, velocity increased throughout the water column, resulting in bottom stress starting to become important. The sea level also responded, with the pressure gradient force opposing the wind stress. In particular, during the second wind pulse, there were rapid oscillations in the acceleration and advective terms, apparently reflecting the incapacity of the bottom stress to dissipate the high kinetic energy of the system. The Coriolis and wave induced terms (via radiation stresses) were less important in the momentum balance. The frictional adjustment time scale was around 10 h, consistent with the e-folding time obtained from bottom drag parameterizations. Estimates of the frictional time and Ekman depth confirm the prevailing frictional response at 24 m. The momentum evolution in deeper parts of the shelf (50 m) showed an increase in the Coriolis force at the expense of the frictional term, typical in the transition from the inner to the mid-shelf.

Description: Estimation of upward radiances and reflectances at the surface of the sea from above-surface measurements Ocean Science Discussions, 12, 1051-1082, 2015 Author(s): Ø. Kleiv, A. Folkestad, J. Høkedal, K. Sørensen, and E. Aas During four field days in the years 2009–2011, 22 series of measurement were collected in the Inner Oslofjord. The data consist of recordings of spectral sub-surface and above-surface nadir radiances, as well as spectral downward irradiance in air. The studied wavelengths are 351, 400 nm and the 10 former MERIS channels in the range 413–754 nm. The water-leaving radiance and the reflected radiance at the sea surface can be determined from the measured nadir radiances in water and air. A simpler and much faster method, which determines the radiance reflectance at the surface as well as the water-leaving and reflected radiances solely from the measurements of upward nadir radiance and downward irradiance in air, is presented. A comparison between the quantities determined by the two methods shows that the average relative deviations between their results are less than or equal to 15% for the reflected radiance, at the studied wavelengths. The average relative deviations of the water-leaving radiance at 560 nm is 24%. We consider this to be acceptable uncertainties for a first check of satellite products in coastal waters.

Description: Microstructures and deformation mechanisms in Opalinus Clay: insights from scaly clay from the Main Fault in the Mont Terri Rock Laboratory (CH) Ben Laurich, Janos L. Urai, and Christophe Nussbaum Solid Earth Discuss., doi:10.5194/se-2016-94,2016 Manuscript under review for SE (discussion: open, 0 comments) Scaly clay is a well-known rock fabric that can develop in tectonic systems and that can alter the physical rock properties of a formation. However, internal microstructure and evolution of this fabric remains poorly understood. We examined the scaly microstructure of progressively faulted Opalinus Clay using optical as well as scanning electron microscopy. We present an evolutionary model for scaly clay that is of interest in the evaluation of Opalinus Clay to host radioactive waste.

Description: Fixation kinetics of chelated and non-chelated zinc in semi-arid alkaline soils: application to zinc management Theophilus K. Udeigwe, Madeleine Eichmann, and Matthew C. Menkiti Solid Earth, 7, 1023-1031, doi:10.5194/se-7-1023-2016, 2016 Micronutrient fixation leads to the reduction of plant-available portions. This study examined the fixation kinetics of chelated and non-chelated zinc (Zn) in semi-arid soils. About 30 % more Zn was fixed in the non-chelated system in the first 14 days. Slope of change of Zn to Cu (i.e., Cu–Zn) was higher than other micronutrients. Zn fixation kinetics were better described by a power-function model. Tools developed from this study will be used to advance micronutrient management.

Description: Structure of Suasselkä Postglacial Fault in northern Finland obtained by analysis of local events and ambient seismic noise Nikita Afonin, Elena Kozlovskaya, Ilmo Kukkonen, and DAFNE/FINLAND Working Group Solid Earth Discuss., doi:10.5194/se-2016-90,2016 Manuscript under review for SE (discussion: open, 0 comments) Understanding inner structure of seismogenic faults and their ability to reactivate is particularly important in investigating continental intraplate seismicity regime. In our study we address this problem using analysis of local seismic events and ambient seismic noise recorded by the temporary DAFNE array in northern Fennoscandian Shield. The main purpose of the DAFNE/FINLAND passive seismic array experiment was to characterize the present-day seismicity of the Suasselkä post-glacial fault (SPGF) that was proposed as one potential target for the DAFNE (Drilling Active Faults in Northern Europe) project. The DAFNE/FINLAND array comprised the area of about 20 to 100 km and consisted of 8 short-period and 4 broad-band 3-component autonomous seismic stations installed in the close vicinity of the fault area. The array recorded continuous seismic data during September, 2011–May, 2013. Recordings of the array have being analyzed in order to identify and locate natural earthquakes from the fault area and to discriminate them from the blasts in the Kittilä Gold Mine. As a result, we found several dozens of natural seismic events originating from the fault area, which proves that the fault is still seismically active. In order to study the inner structure of the SPGF we use cross-correlation of ambient seismic noise recorded by the array. Analysis of azimuthal distribution of noise sources demonstrated that during the time interval under consideration the distribution of noise sources is close to the uniform one. The continuous data were processed in several steps including single station data analysis, instrument response removal and time-domain stacking. The data were used to estimate empirical Green’s functions between pairs of stations in the frequency band of 0.1–1 Hz and to calculate correspondent surface wave dispersion curves. The S-wave velocity models were obtained as a result of dispersion curves inversion. The results suggest that the area of the SPGF corresponds to a narrow region of low S-wave velocities surrounded by rocks with high S-wave velocities. We interpret this low velocity region as a non-healed mechanically weak fault damage zone (FDZ) that remained after the last major earthquake that occurred after the last glaciation.

Description: First year of the new Arctic AWIPEV-COSYNA cabled Underwater Observatory in Kongsfjorden, Spitsbergen Philipp Fischer, Max Schwanitz, Reiner Loth, Uwe Posner, Markus Brand, and Friedhelm Schröder Ocean Sci. Discuss., doi:10.5194/os-2016-52,2016 Manuscript under review for OS (discussion: open, 0 comments) We observed oceanographic and community data from October 2013 to November 2014 in the shallow waters of Kongsfjorden on the west coast of Svalbard (Norway) using remote controlled hydrographic and optic sensors. Daily vertical profiles of temperature, salinity and turbidity were sampled together with stereo images of the macrobiotic community, including fish. A distinct seasonal cycle in total species abundances was found with surprisingly high animal counts during the polar winter.

Description: sUAS and their application in observing geomorphological processes Jozef Gallik and Lenka Bolešová Solid Earth, 7, 1033-1042, doi:10.5194/se-7-1033-2016, 2016 Technology is moving ahead very fast, and so researchers have new possibilities for their research. We tried to demonstrate benefits of using remote-sensing technology (Phantom 1 drone) such as its accuracy in the terrain, easy access to hardly accessible areas, and the possibility to collect data even during unfavourable weather conditions. The high mountainous environment provided us great conditions for testing the drone as a device for very easy and accurate mapping of natural phenomena.

Description: Alpine tectonic wedging and crustal delamination in the Cantabrian Mountains (NW Spain) Jorge Gallastegui, Javier A. Pulgar, and Josep Gallart Solid Earth, 7, 1043-1057, doi:10.5194/se-7-1043-2016, 2016 We present the interpretation of deep seismic reflection profile ESCIN-2 across the boundary between the Cantabrian Mountains and the Cenozoic Duero Basin (NW Spain). 2-D seismic modelling allowed us to construct a N-S geological cross section which is compatible with the rest of the geophysical data. This profile shows the importance of the N-S Alpine deformation. A wedge of Cantabrian margin crust indented southwards into the delaminated Iberian crust, forcing its northward subduction.

Description: Studying local earthquakes in the area Baltic-Bothnia Megashear using the data of the POLENET/LAPNET temporary array Olga Usoltseva and Elena Kozlovskaya Solid Earth, 7, 1095-1108, doi:10.5194/se-7-1095-2016, 2016 We address the problem of seismicity in the intraplate area of northern Fennoscandia using the information on local events recorded by the POLENET/LAPNET seismic array. We relocate the seismic events, calculate a 3-D tomographic P wave velocity model of the uppermost crust and investigate a focal mechanism of the event. Our results demonstrate that the Baltic-Bothnia Megashear is an important large-scale, reactivated tectonic structure that has to be taken into account when estimating seismic hazard.

Description: Experimental sand burial affects seedling survivorship, morphological traits, and biomass allocation of Ulmus pumila var. sabulosa in the Horqin Sandy Land, China Jiao Tang, Carlos Alberto Busso, Deming Jiang, Ala Musa, Dafu Wu, Yongcui Wang, and Chunping Miao Solid Earth, 7, 1085-1094, doi:10.5194/se-7-1085-2016, 2016 In order to test the tolerance of sandy elm after emergence, an experiment was conducted to evaluate the changes of survivorship, morphological traits and biomass allocation buried by various experimental burial depths. The results showed that partial sand burial did not influence survivorship but increased seedling height, diameter, taproot length, total biomass, and relative growth rates. It decreased total leaf area and changed biomass allocation, transferring more biomass to aboveground.

Description: Active faulting, 3-D basin architecture and Plio-Quaternary structural evolution of extensional basins: a 4-D perspective on the central Apennine chain evolution, Italy Stefano Gori, Emanuela Falcucci, Chiara Ladina, Simone Marzorati, and Fabrizio Galadini Solid Earth Discuss., doi:10.5194/se-2016-103,2016 Manuscript under review for SE (discussion: open, 0 comments) We perfomed geological field survey and seimic recordings of ambient noise to study the evolution of a portion of the central Apennines, in central Italy, over the past few million years. The adopted approach and the analysis of the available information allowed to decipher how the investigated areas evolved, in terms of activity of the faults present there. We also defined that some of the investigated faults are no more major faults, i.e. they are no more able to produce strong earthquakes.

Description: Comparison of the simulated upper-ocean vertical structure using 1-dimensional mixed-layer models Sonaljit Mukherjee and Amit Tandon Ocean Sci. Discuss., doi:10.5194/os-2016-45,2016 Manuscript under review for OS (discussion: open, 0 comments) Atmospheric fluxes influence the momentum and scalar properties in the upper-cean. Buoyancy fluxes result in a diurnal variability in the sea-surface temperature (SST), whereas the wind stress forms near-inertial currents in the mixed layer (ML). In this study, we investigate the contrasts between the simulated SST and the vertical structure of the temperature and shear by three different mixing models: the PWP bulk mixed-layer model, the KPP non-local boundary layer model and the κ−ϵ local mixing model. We choose two upper-ocean datasets for our studies, namely the SWAPP (1990) and the MLML (1991). The SWAPP dataset shows the presence of strong near-inertial shear below the ML and negligible near-inertial shear within the ML. The MLML dataset shows a negligible rise in the SST during the first 22 day mixing phase, which is followed by a steep rise by 6 °C during the subsequent 75 day restratification phase. Comparison with the SWAPP dataset shows that the KPP and κ−ϵ models form strong shear near the surface due to weak eddy viscosities, thus producing a thin shear layer over the entire range of frequencies in the wind stress. At the ML base, the models form an inertial and a diurnal maximum. The inertial maximum extends over a substantial range of depths, and is continuous for the κ−ϵ model but discontinuous for the KPP and PWP models. Comparison with the MLML dataset reveals that the KPP yields the largest SST amplitude over a 24-hour diurnal cycle, and is followed by the κ−ϵ and PWP. However, the net warming of SST at the end of the diurnal cycle is stronger for the PWP compared to κ−ϵ and KPP. The PWP also forms stronger temperature gradients at the ML base compared to κ−ϵ and KPP. Over multiple diurnal cycles, the shallowing and deepening of the mixed layer results in multiple sharp temperature gradients in PWP, thus forming a serrated vertical profile that remains unaffected during the restratification phase of the MLML dataset.

Description: Arrested development – a comparative analysis of multilayer corona textures in metamorphic rocks Paula P. Ogilvie and Roger Lawrence R. L. Gibson Solid Earth Discuss., doi:10.5194/se-2016-97,2016 Manuscript under review for SE (discussion: open, 0 comments) Coronas are vital clues to the presence of arrested reaction in metamorphic rocks. We review formation mechanisms of coronas and approaches utilised to model their evolution in P - T - X space. Forward modelling employing calculated chemical potential gradients allows a far more nuanced understanding of the intricacies that govern metamorphic reaction. These models have critical implications for the limitations and opportunities coronas afford in interpreting the evolution of metamorphic terranes.

Description: Aragonite saturation states and pH in western Norwegian fjords: seasonal cycles and controlling factors, 2005–2009 Abdirahman M. Omar, Ingunn Skjelvan, Svein Rune Erga, and Are Olsen Ocean Sci., 12, 937-951, doi:10.5194/os-12-937-2016, 2016 We have determined, for the first time, the seasonal changes and controlling processes of ocean acidification parameters across western Norwegian fjords, based on data obtained mainly with sensors on board a commercial ship, MS Trans Carrier , in 2005–2009. The study fills an important gap in our knowledge on ocean acidification in western Norwegian fjords, which are important ecosystems: important recreation areas, marine pathways, spawning grounds for different fish species, etc.

Description: Observed and simulated full-depth ocean heat-content changes for 1970–2005 Lijing Cheng, Kevin E. Trenberth, Matthew D. Palmer, Jiang Zhu, and John P. Abraham Ocean Sci., 12, 925-935, doi:10.5194/os-12-925-2016, 2016 A new method of observing ocean heat content throughout the entire ocean depth is provided. The new method is compared with simulated ocean heat content changes from climate models. The comparisons are carried out in various depth layers of the ocean waters. It is found that there is excellent agreement between the models and the observations. Furthermore, we propose that changes to ocean heat content be used as a fundamental metric to evaluate climate models.

Description: Accessing diverse data comprehensively – CODM, the COSYNA data portal Gisbert Breitbach, Hajo Krasemann, Daniel Behr, Steffen Beringer, Uwe Lange, Nhan Vo, and Friedhelm Schroeder Ocean Sci., 12, 909-923, doi:10.5194/os-12-909-2016, 2016 The coastal observation system COSYNA aims to describe the physical and biogeochemical state of a regional coastal system. The COSYNA data management (CODM) is the link between observations, model results and data usage. The challenge for CODM is the integration of diverse data sources in terms of parameters, dimensionality and observation methods to gain a comprehensive view of the observations. How this is achieved is described in the paper.

Description: Freshening of Antarctic Intermediate Water in the South Atlantic Ocean in 2005–2014 Wenjun Yao and Jiuxin Shi Ocean Sci. Discuss., doi:10.5194/os-2016-54,2016 Manuscript under review for OS (discussion: open, 0 comments) Antarctic Intermediate Water (AAIW) in the South Atlantic Ocean has experienced basin-scaled freshening from 2005 to 2014, reflected by the Argo gridded products. Two zonal sections of WOCE observation also revealed a similar quasi-decadal signal. Our analysis revealed that such freshening was induced by the contemporaneous freshwater input in the AAIW ventilation region and the reduced more saline water carried by Agulhas Leakage.

Description: Changes in extreme regional sea level under global warming S.-E. Brunnabend, H. A. Dijkstra, M. A. Kliphuis, H. E. Bal, F. Seinstra, B. van Werkhoven, J. Maassen, and M. van Meersbergen Ocean Sci. Discuss., doi:10.5194/os-2016-57,2016 Manuscript under review for OS (discussion: open, 0 comments) An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a strongly eddying version of the Parallel Ocean Program. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways.

Description: X-ray computed tomography investigation of structures in Opalinus Clay from large-scale to small-scale after mechanical testing Annette Kaufhold, Matthias Halisch, Gerhard Zacher, and Stephan Kaufhold Solid Earth, 7, 1171-1183, doi:10.5194/se-7-1171-2016, 2016 The OPA material has been intensively studied by a variety of multiple scale and non-destructive 3-D X-ray CT investigations, following a consequent top-down approach to identify specific regions of interest. According to the mechanical experiment, it has been observed that the shear failure is located in a clay-rich area. Within the intersecting area of the two main fractures, a so called mylonitic zone with a particle reduction was observed on the open shear failure using CT and SEM techniques.

Description: A stable Faroe Bank Channel overflow 1995–2015 Bogi Hansen, Karin Margretha Húsgarð Larsen, Hjálmar Hátún, and Svein Østerhus Ocean Sci. Discuss., doi:10.5194/os-2016-56,2016 Manuscript under review for OS (discussion: open, 0 comments) The Faroe Bank Channel is one of the main passages for the flow of cold dense water from the Arctic into the depths of the World Ocean where it feeds the deep branch of the AMOC transporting heat and carbon dioxide from the atmosphere into the deep ocean. Based on in situ measurements we show that the volume transport of this flow has been stable from 1995 to 2015. The water has warmed, but has not become less dense. Thus, this branch of the AMOC did not weaken during the last two decades.

Description: Digital carbonate rock physics Erik H. Saenger, Stephanie Vialle, Maxim Lebedev, David Uribe, Maria Osorno, Mandy Duda, and Holger Steeb Solid Earth, 7, 1185-1197, doi:10.5194/se-7-1185-2016, 2016 Modern estimation of rock properties combines imaging with advanced numerical simulations, an approach known as digital rock physics (DRP). In this paper we suggest a specific segmentation procedure of X-ray micro-computed tomography data with two different resolutions for two sets of carbonate rock samples. These carbonates were already characterized in detail in a previous laboratory study, which we complement with nanoindentation experiments.

Description: GEM: A Dynamic Tracking Model for Mesoscale Eddies in the Ocean Qiu-Yang Li, Liang Sun, and Sheng-Fu Lin Ocean Sci. Discuss., doi:10.5194/os-2016-49,2016 Manuscript under review for OS (discussion: open, 0 comments) Genealogical Evolution Model (GEM) is an efficient logical model used to track dynamic evolution of mesoscale eddies in the ocean. It can distinguish different dynamic processes (e.g., merging and splitting) within a dynamic evolution pattern with a two-dimensional vector. All of the computational steps are linear and do not include iteration. It is very fast and is potentially useful for studying dynamic processes in other related fields, e.g., the dynamics of cyclones in meteorology.

Description: Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of southwestern China Yecui Hu, Zhangliu Du, Qibing Wang, and Guichun Li Solid Earth, 7, 1075-1084, doi:10.5194/se-7-1075-2016, 2016 We quantified the SOC and TN losses induced by land-use changes in a typical karst region of southwestern China. Converting from natural forest to croplands greatly led to SOC and TN losses (as higher as 37.8 %), but the magnitude depended on sampling depth and calculation method. We recommend to account for SOC and TN stocks on equivalent soil mass basis together with deep sampling. This study has significant implications on the projected land management in the degraded karst areas.

Description: Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data Tobias Kling, Da Huo, Jens-Oliver Schwarz, Frieder Enzmann, Sally Benson, and Philipp Blum Solid Earth, 7, 1109-1124, doi:10.5194/se-7-1109-2016, 2016 A method is introduced to implement medical CT data of a fractured sandstone under varying confining pressures into fluid flow simulations to reproduce experimental permeabilities. The simulation results reproduce plausible fracture flow features (e.g. flow channeling, fracture closing/opening) and approximate the actual permeabilities, which are affected by the CT resolution and compositional matrix heterogeneities. Additionally, some recommendations are presented concerning future studies.

Description: Phase segmentation of X-ray computer tomography rock images using machine learning techniques: an accuracy and performance study Swarup Chauhan, Wolfram Rühaak, Hauke Anbergen, Alen Kabdenov, Marcus Freise, Thorsten Wille, and Ingo Sass Solid Earth, 7, 1125-1139, doi:10.5194/se-7-1125-2016, 2016 Machine learning techniques are a promising alternative for processing (phase segmentation) of 3-D X-ray computer tomographic rock images. Here the performance and accuracy of different machine learning techniques are tested. The aim is to classify pore space, rock grains and matrix of four distinct rock samples. The porosity obtained based on the segmented XCT images is cross-validated with laboratory measurements. Accuracies of the different methods are discussed and recommendations proposed.

Description: Effects of topsoil treatments on afforestation in a dry-Mediterranean climate (southern Spain) P. Hueso-González, J. F. Martínez-Murillo, and J. D. Ruiz-Sinoga Solid Earth Discuss., doi:10.5194/se-2016-98,2016 Manuscript under review for SE (discussion: open, 0 comments) The development of alternative low cost and low environmental impact revegetation methods is necessary for the effective management of Mediterranean forest environments. This research assessed the effects of five types of soil amendment on the success of afforestation processes. In terms of land management, the study shows that the addition of mulch or hydroabsorbent polymer can reduce transplanting stress, and improve the success of afforestation programs.

Description: Archie's law – a reappraisal Paul W. J. Glover Solid Earth, 7, 1157-1169, doi:10.5194/se-7-1157-2016, 2016 In 1942 Archie discovered equations which have been used ever since to calculate reserves of oil and gas around the world. Two equations exist, one which is theoretically justified, and one which is not. Unfortunately it is the one which is not justified that often gives the best results. This research examines the extent to which the two approaches give differing results, concluding that the Winsauer et al. form of Archie's equations is better for use with data containing systematic errors.

Description: Sub-basin scale sea level budgets from satellite altimetry, Argo floats and satellite gravimetry in the North Atlantic Marcel Kleinherenbrink, Riccardo Riva, and Yu Sun Ocean Sci. Discuss., doi:10.5194/os-2016-50,2016 Manuscript under review for OS (discussion: open, 0 comments) Satellite altimetry measures changes in sea level, while satellite gravimetry measures mass changes and from Argo temperature and salinity profiles one can infer steric sea level. For the first time it is shown that the mass and steric components match in most cases the total sea level measured by altimetry on a sub-basin scale in terms of trend, annual amplitude and interannual variability. We also find that the choice of gravity field filter is essential to close the budget.

Description: Technical note: GODESS – a profiling mooring in the Gotland Basin Ralf D. Prien and Detlef E. Schulz-Bull Ocean Sci., 12, 899-907, doi:10.5194/os-12-899-2016, 2016 A profiling mooring with an interdisciplinary suite of sensors for water depths up to 300 m is described in this note. It can be programmed to take profiles through the water column at set times or intervals and with the standard set of batteries is able to profile about 34 km in total (e.g. 200 profiles of 170 m profiling each). The mooring was designed to observe the dynamics of the redoxcline in the Gotland Basin over periods of up to 3 months.

Description: Evaluation of Peaks-Over-Threshold Method Soheil Saeed Far and Ahmad Khairi Abd. Wahab Ocean Sci. Discuss., doi:10.5194/os-2016-47,2016 Manuscript under review for OS (discussion: open, 0 comments) In this paper, two commonly used extreme value analysis models have been developed (POT and GPD models). Both models use threshold values to censor a range of data. The results of this study show the two models are very sensitive to any changes in threshold value. Moreover, the POT model has shown some imperfections in determining true threshold value and a best fitting distribution function. Two methods were proposed by this paper to deal with the limitations in order to improve the model.

Description: Seiche excitation in a highly stratified fjord of southern Chile: the Reloncaví fjord Manuel I. Castillo, Oscar Pizarro, Nadin Ramirez, and Mario Caceres Ocean Sci. Discuss., doi:10.5194/os-2016-42,2016 Manuscript under review for OS (discussion: open, 0 comments) Here we present the results of an intensive physical oceanography study on the Reloncavi fjord (41.5º S, 72.5º W) focused on the subinertial time-scale. The along-fjord currents presented 3 days oscillations which were consistent with the natural internal period of oscillation of the fjord basin (internal seiche). This oscillation could exexplain more than 44 % of the 3 days variability and contributed levels of kinetic energy as large as the tidal currents.

Description: Seismic structure beneath the Gulf of Aqaba and adjacent areas based on the tomographic inversion of regional earthquake data Sami El Khrepy, Ivan Koulakov, Nassir Al-Arifi, and Alexey G. Petrunin Solid Earth, 7, 965-978, doi:10.5194/se-7-965-2016, 2016 Three-dimensional seismic structures beneath the Gulf of Aqaba are presented for the first time for the southern part of the Dead Sea. A regional earthquake tomography method is applied to P and S waves data. The new results indicate new perspectives suggesting an oceanic nature of the crust in the northern part of the Red Sea, disagreeing with the hypothesis of a gradual stretching of the continental crust.

Description: Marine mammal tracks from two-hydrophone acoustic recordings made with a glider Elizabeth T. Küsel, Tessa Munoz, Martin Siderius, David K. Mellinger, and Sara Heimlich Ocean Sci. Discuss., doi:10.5194/os-2016-48,2016 Manuscript under review for OS (discussion: open, 0 comments) An ocean glider was tested during the REP14-MED experiment off the western coast of the Island of Sardinia as a platform for recording sounds produced by whales and dolphins using two sensors. Sperm whale clicks as well as dolphin clicks and whistles were identified in the recordings. Automatically detected sperm whale clicks were used to estimate animal tracks. Such information is useful for marine mammal density estimation studies that use passive acoustics.

Description: 3D GPS velocity field and its implications on the present-day postorogenic deformation of the Western Alps and Pyrenees Hai Ninh Nguyen, Philippe Vernant, Stephane Mazzotti, Giorgi Khazaradze, and Eva Asensio Solid Earth Discuss., doi:10.5194/se-2016-78,2016 Manuscript under review for SE (discussion: open, 0 comments) We present a new 3D GPS velocity solution for 182 sites for the region encompassing the Western Alps, Pyrenees. The only significant horizontal deformation (0.2 mm yr −1 over a distance of 50 km) is a NNE-SSW extension in the western Pyrenees. In contrast, significant uplift rates up to 2 mm yr −1 occur in the Western Alps but not in the Pyrenees. A correlation between site elevations and fast uplift rates in the Western Alps suggests that part of this uplift is induced by postglacial rebound.

Description: The importance of external climate forcing for the variability and trends of coastal upwelling in past and future climate Nele Tim, Eduardo Zorita, Birgit Hünicke, Xing Yi, and Kay-Christian Emeis Ocean Sci., 12, 807-823, doi:10.5194/os-12-807-2016, 2016 The impact of external climate forcing on the four eastern boundary upwelling systems is investigated for the recent past and future. Under increased radiative forcing, upwelling-favourable winds should strengthen due to unequal heating of land and oceans. However, coastal upwelling simulated in ensembles of climate simulations do not show any imprint of external forcing neither for the past millennium nor for the future, with the exception of the strongest future scenario.

Description: Seasonal, Spring-Neap and Tidal Variation of Hydrodynamics and Water Constituents in the Mouth of the Elbe Estuary, Germany Jens Kappenberg, Michael Berendt, Nino Ohle, Rolf Riethmüller, Dagmar Schuster, and Thomas Strotmann Ocean Sci. Discuss., doi:10.5194/os-2016-7,2016 Manuscript under review for OS (discussion: open, 0 comments) Results of long-term measurements of CTD, current velocity, turbidity, and dissolved oxygen from three stations in the mouth of the Elbe Estuary in northern Germany are presented for the period of 2012 and 2013. The focus is on a station named HPA-Elbe 1, which is part of the COSYNA coastal observing system for northern and arctic seas, but data from two neighbouring stations are also presented for comparison and to bridge gaps in the time-series of HPA-Elbe 1. The variations of the variables exhibit distinct tidal patterns related to the longitudinal estuarine gradients of the water constituents and local sediment dynamics. On longer time-scales, spring-neap variability is observed, most prominently in the hydrodynamics. On the seasonal scale, the water temperature influences the degradation processes, which deplete the dissolved oxygen on the one hand and increase the oxygen contents by biological respiration on the other hand. Freshwater events from the catchment play an important role for sediment dynamics and mixing of riverine and coastal waters in the brackish water reach of the estuary. The periods of the deployment of the stations comprise the severest river flood observed so far in the Elbe in June 2013. The effects of the flood at the stations and along the estuary consist of a rapid flushing of the mixing zone and the turbidity maximum to the outer estuary and the transition to freshwater conditions from Hamburg to the mouth at Cuxhaven. The impact of the river flood at the stations is more pronounced in changes in salinity than in turbidity. The restoration of estuarine salinity and turbidity values comparable to those before the river flood took several months.

Description: Defining a Mid-Holocene earthquake through speleoseismological and independent data: constraints for the outer Central Apennines (Italy) seismotectonic framework Alessandra Di Domenica and Alberto Pizzi Solid Earth Discuss., doi:10.5194/se-2016-77,2016 Manuscript under review for SE (discussion: open, 0 comments) Speleoseismological investigations have been adopted to characterize a complex tectonically active area in the easternmost sector of the Central Apennines. Evidence of earthquake damages have been recognized in the analyzed cave. Radiocarbon dating and the correspondence with independent data collected outside the cave, provide constraints for the individuation of a M~7 Mid-Holocene earthquake and for the identification of the nearby Sulmona normal fault as the most likely causative structure.

Description: Spatial variability of some soil properties varies in oil palm ( Elaeis guineensis Jacq.) plantations of west coastal area of India Sanjib Kumar Behera, Kancherla Suresh, Bezawada Narsimha Rao, Ravi Kumar Mathur, Arvind Kumar Shukla, Kamireddy Manorama, Kummari Ramachandrudu, Parasa Harinarayana, and Chandra Prakash Solid Earth, 7, 979-993, doi:10.5194/se-7-979-2016, 2016 This study analyzed the spatial variability of some soil properties in surface and subsurface soil layers of oil palm plantations in the south Goa district of Goa situated in western coastal area of India. The studied soil properties in surface and subsurface layers varied widely. Geostatistical analysis revealed different spatial distribution patterns for the soil properties. The generated prediction maps are useful for site-specific soil nutrient management in the area.

Description: Development of a numerical workflow based on μ -CT imaging for the determination of capillary pressure–saturation-specific interfacial area relationship in 2-phase flow pore-scale porous-media systems: a case study on Heletz sandstone Aaron Peche, Matthias Halisch, Alexandru Bogdan Tatomir, and Martin Sauter Solid Earth, 7, 727-739, doi:10.5194/se-7-727-2016, 2016 In this case study, we compute georeservoir specific capillary pressure-saturation- interfacial area relationships by implementing a FEM-based two-phase flow model on μ-CT-based modelling domains. We propose a recommended practice for deriving a model and model setup for the successful modelling of such types of problems on micro-CT obtained geometries.

Description: Ocean Forecasting: From Regional to Coastal Scales Emil V. Stanev, Johannes Schulz-Stellenfleth, Joanna Staneva, Sebastian Grayek, Sebastian Grashorn, Arno Behrens, Wolfgang Koch, and Johannes Pein Ocean Sci. Discuss., doi:10.5194/os-2016-25,2016 Manuscript under review for OS (discussion: open, 0 comments) This paper describes coastal ocean forecasting practices exemplified for the North and Baltic Sea. It identifies new challenges, most of which are associated with the non-linear behavior of coastal ocean. It describes assimilation of remote sensing, in situ and HF radar data, prediction of wind waves and storm surges, as well as possible applications to search and rescue operations, and modelling support for assessing the environmental impact of wind parks. Concepts for seamless approaches to li

Description: Geopotential field anomalies and regional tectonic features – two case studies: southern Africa and Germany Monika Korte and Mioara Mandea Solid Earth, 7, 751-768, doi:10.5194/se-7-751-2016, 2016 We investigated characteristics of magnetic anomalies over southern Africa (South Africa, Namibia, and Botswana) and Germany on different scales and also compared them to gravity gradient anomalies. Such anomalies provide information relevant to understanding geological and tectonic structures. Our results indicate a better agreement between anomalies caused by shallow and deeper structures in the southern African area than in the German area.

Description: Discussing the genesis of karst rocky desertification research based on the correlations between cropland and settlements in typical peak-cluster depressions Yang Bing Li, Qiong Yao Li, Guang Jie Luo, Xiao Yong Bai, Yong Yan Wang, Shi Jie Wang, Jing Xie, and Guang Bin Yang Solid Earth, 7, 741-750, doi:10.5194/se-7-741-2016, 2016 In karst mountainous areas in Southwest China, sloping land is overly reclaimed. Why are farmers doing this? Through typical case studies of peak-cluster depression areas, we found that low land carrying capacity and high population pressure where farmers carry out extreme steep reclamation activities are the main reasons for desert-like landscapes; this is a kind of land degradation which occurs in vulnerable karst dryland socioecological systems.

Description: A possibility of large scale intrusions generation in the Arctic Ocean under stable-stable stratification: an analytical consideration Natalia Kuzmina Ocean Sci. Discuss., doi:10.5194/os-2016-15,2016 Manuscript under review for OS (discussion: open, 0 comments) Some analytical solutions are found for the problem of three-dimensional instability of a weak geostrophic flow with linear velocity shear taking into account vertical diffusion of buoyancy. The analysis is based on the potential vorticity equation in a long-wave approximation when the horizontal scale of disturbances is taken to be much larger than the local baroclinic Rossby radius. It is hypothesized that the solutions found can be applied to describe stable and unstable disturbances on a planetary scale with respect, especially, to the Arctic Basin, where weak baroclinic fronts with typical temporal variability periods of the order of several years or more are observed and the beta-effect is negligible. Stable (decaying with time) solutions describe disturbances that, in contrast to the Rossby waves, can propagate to both the west and east, depending on the sign of the linear shear of geostrophic velocity. The unstable (growing with time) solutions are applied to describe large-scale intrusions at baroclinic fronts under the stable–stable thermohaline stratification observed in the upper layer of the Polar Deep Water in the Eurasian Basin. The proposed description of intrusive layering can be considered as a possible alternative to the mechanism of interleaving due to the differential mixing.

Description: Current temporal asymmetry and the role of tides: Nan-Wan Bay vs. the Gulf of Elat Yosef Ashkenazy, Erick Fredj, Hezi Gildor, Gwo-Ching Gong, and Hung-Jen Lee Ocean Sci., 12, 733-742, doi:10.5194/os-12-733-2016, 2016 Nan-Wan Bay in Taiwan and the Gulf of Elat in Israel are two different coastal environments, and as such, their currents are expected to have different statistical properties. We find that in spite of these differences, the statistical properties of the surface currents are similar in both basins. Still, surface currents are temporally asymmetric in Nan-Wan but not in Elat; we attribute this difference to the strong tides that exist in Nan-Wan but not in Elat.

Description: The Pollino 2012 seismic sequence: clues from continuous radon monitoring Antonio Piersanti, Valentina Cannelli, and Gianfranco Galli Solid Earth Discuss., doi:10.5194/se-2016-72,2016 Manuscript under review for SE (discussion: open, 0 comments) We investigate in an innovative way the dynamics of radon emanation in a seismically active area. We analyzed three years of data, collected during a long term radon monitoring experiment. The complexity of the relationships among the investigated variables led us to consider the problem both from a phenomenological point of view and by means of original numerical analyses. Different approaches converge on the existence of a physical relation between soil radon emanation and seismicity.

Description: Effect of polluted water on soil and plant contamination by heavy metals in El-Mahla El-Kobra, Egypt Esawy Kasem Mahmoud and Adel Mohamed Ghoneim Solid Earth, 7, 703-711, doi:10.5194/se-7-703-2016, 2016 Delta drains receive high concentrations of organic and inorganic pollutants from industrial, domestic as well as diffuse agricultural waste water. High priority should be given to Zefta and drain no.5 sites which receive high loads of pollutants. This was confirmed by the lower water quality and polluted soils, especially by heavy metals in the El-Mahla El-Kobra area.

Description: Soil wind erosion in ecological olive trees in the Tabernas desert (S.E. Spain): a wind tunnel experiment Carlos Asensio, Francisco Javier Lozano, Pedro Gallardo, and Antonio Giménez Solid Earth Discuss., doi:10.5194/se-2016-65,2016 Manuscript under review for SE (discussion: open, 0 comments) Climate and soil surface conditions influence the erosive capacity of the wind, causing loss of soil productivity. Wind erosion leads soil drying and its loss of nutrients, and this in turn is conditioned by soil surface compaction. The impact of management on most of soil properties and on its wind erodibility determines agricultural productivity and sustainability. We used a new wind tunnel to evaluate all these acts.

Description: Nitrogen and Warming Control the Vegetation in Inner Mongolia Tourist Area Qiong Sun, Xiaobing Hu, and Chi Zhang Solid Earth Discuss., doi:10.5194/se-2016-52,2016 Manuscript under review for SE (discussion: open, 0 comments) The global warming and atmospheric nitrogen deposition problem has become more and more serious under the influence of human activities, and it has become one of the hot issues in this field, which will have far-reaching impact on all kinds of vegetation, thus the functioning of the ecosystem will be changed, which will be reflected in climate warming process. Inner Mongolia Autonomous Region is mainly composed of desert grasslands, so the development and protection of vegetation has considerable significance on the region. However, in the current environment of global warming, few studies have been carried out on desert grassland plants. In this paper, an in-depth study was carried out on the impact of warming and nitrogen addition on soil temperature, vegetation reproductive phenology and vegetation community seed rain under natural conditions during five-year period from 2011 to 2015. During the experimental period, we found that soil temperature and soil moisture decreased with the increase of soil layer, and warming obviously shortened the time of budding, flowering and fruiting of vegetation. However, no significant effect was found on nitrogen addition. Meanwhile, the impact of interaction effect of warming and nitrogen addition on seed rain was not obvious, but the year difference of all relevant indicators was significant.

Description: Tectonothermal evolution in the core of an arcuate fold and thrust belt: the south-eastern sector of the Cantabrian Zone (Variscan belt, north-western Spain) María Luz Valín, Susana García-López, Covadonga Brime, Fernando Bastida, and Jesús Aller Solid Earth, 7, 1003-1022, doi:10.5194/se-7-1003-2016, 2016 The tectonothermal evolution of an area located in the core of the Ibero-Armorican Arc (Variscan belt) has been determined by using the conodont colour alteration index (CAI), Kübler index of illite (KI), the Árkai index of chlorite (AI) and the analysis of clay minerals and rock cleavage. The area is part of the Cantabrian Zone (CZ), which represents the foreland fold and thrust belt of the orogen. It has been thrust by several large units of the CZ, what resulted in the generation of a large number of synorogenic Carboniferous sediments. CAI, KI and AI values show an irregular distribution of metamorphic grade, independent of stratigraphic position. Two tectonothermal events have been distinguished in the area. The first one, poorly defined, is mainly located in the northern part. It gave rise to very-low-grade metamorphism in some areas and it was associated with a deformation event that resulted in the emplacement of the last large thrust unit and development of upright folds and associated cleavage ( S 1 ). The second tectonothermal event gave rise to low-grade metamorphism and cleavage ( S 2 ) crosscutting earlier upright folds in the central, western and southern parts of the study area. The event continued with the intrusion of small igneous rock bodies, which gave rise to contact metamorphism and hydrothermal alteration. This event was linked to an extensional episode due to a gravitational instability at the end of the Variscan deformation. This tectonothermal evolution occurred during the Gzhelian–Sakmarian. Subsequently, several hydrothermal episodes took place and local crenulation cleavage developed during the Alpine deformation.

Description: 4-D imaging of sub-second dynamics in pore-scale processes using real-time synchrotron X-ray tomography Katherine J. Dobson, Sophia B. Coban, Samuel A. McDonald, Joanna N. Walsh, Robert C. Atwood, and Philip J. Withers Solid Earth, 7, 1059-1073, doi:10.5194/se-7-1059-2016, 2016 State-of-the-art synchrotron x-ray imaging was used to observe micron scale transport processes in real time. The 20 Hz 3-D image acquisition rates give experimental data free from motion artefacts, and suitable for detailed quantitative analysis of the dynamic fluid distribution, flow pathways and processes. The method marks a major breakthrough in our ability to capture both sub-second and lower frequency non-equilibrium process in many geological or engineering systems.

Description: Pore-scale tomography and imaging: applications, techniques and recommended practice Matthias Halisch, Holger Steeb, Steven Henkel, and Charlotte M. Krawczyk Solid Earth, 7, 1141-1143, doi:10.5194/se-7-1141-2016, 2016 No abstract available.

Description: Stepwise drying of Lake Turkana at the end of the African Humid Period: an example of forced regression modulated by solar activity? Alexis Nutz and Mathieu Schuster Solid Earth Discuss., doi:10.5194/se-2016-95,2016 Manuscript under review for SE (discussion: open, 0 comments) From the geomorphology of a paleo-delta complex of Lake Turkana (Kenya), we explore the end of the Holocene African Humid Period (AHP) that corresponded to a major change in climate of Africa and that had important environmental impacts. Here, we propose that the transition from a wet to a dry period at the end of the AHP is stepwise, discussing a potential control by short-term evolution of solar activity. Understanding of this climate event is crucial to anticipate a future climate change.

Description: Porosity and permeability determination of organic-rich Posidonia shales based on 3-D analyses by FIB-SEM microscopy Georg H. Grathoff, Markus Peltz, Frieder Enzmann, and Stephan Kaufhold Solid Earth, 7, 1145-1156, doi:10.5194/se-7-1145-2016, 2016 This study improves our understanding of the evolution of pores in shales for modelling transport properties. 3-D microscopy on early and postmature Posidonia Shales showed similar porosities and pore size distributions. Large isolated pore clusters are within carbonates and clay minerals. Pores form during maturation in the postmature-matrix-filling organic matter. Modelled permeabilities are lowest perpendicular to bedding. They decrease with increasing maturity and are comparable to experimental data.

Description: Developing European operational oceanography for Blue Growth, climate change adaptation and mitigation, and ecosystem-based management Jun She, Icarus Allen, Erik Buch, Alessandro Crise, Johnny A. Johannessen, Pierre-Yves Le Traon, Urmas Lips, Glenn Nolan, Nadia Pinardi, Jan H. Reißmann, John Siddorn, Emil Stanev, and Henning Wehde Ocean Sci., 12, 953-976, doi:10.5194/os-12-953-2016, 2016 This white paper addresses key scientific challenges and research priorities for the development of operational oceanography in Europe for the next 5–10 years. Knowledge gaps and deficiencies are identified in relation to common scientific challenges in four EuroGOOS knowledge areas: European ocean observations, modelling and forecasting technology, coastal operational oceanography, and operational ecology.

Description: Livestock redistribute runoff and sediments in semi-arid rangeland areas Solid Earth, 6, 433-443, 2015 Author(s): P. Sarah and M. Zonana Semi-arid areas where grazing is the main land use exhibit a "three-phase-mosaic" pattern of dominant surface patches: shrubs, trampling routes, and intershrub areas. This pattern differs from the "two-phase mosaic" seen in grazing-free semi-arid areas. The patches might create a positive feedback process in which enhanced infiltration beneath shrubs minimizes overland flow from under their canopies, thereby strengthening the sink–source mechanism by which overland flow generated between shrubs rapidly infiltrates into the soil beneath them, where it deposits soil particles, litter, nutrients and organic matter, thereby enhancing infiltration by changing the local microtopography, and improving soil properties. To analyze sink–source relationships among the patches in grazed areas in rangelands of the semi-arid northern Negev region of Israel, we constructed small runoff plots, 0.25–1.0 m 2 in area, of five types: shrub ( Sarcopoterium spinosum ), intershrub, route, route–shrub combination, and intershrub–shrub combination. The shrubs always occupied the downslope part of the plot. Overland flow and sediment deposits were measured in all plots during 2007/8 and 2008/9. The combined plots yielded much less overland flow and sediments than intershrub, routes and shrub ones, indicating that the shrubs absorbed almost all the yields of the upper part of their plots. The shrubs generated less runoff and sediments than routes and intershrubs; runoff flows from the routes and intershrubs were similar; sediment yield was highest in the intershrubs. Thus, runoff yield exhibited a two-phase mosaic pattern, and sediment yield, i.e., soil erosion, a three-phase mosaic pattern.

Description: Accelerated sea level rise and Florida Current transport Ocean Science Discussions, 12, 551-572, 2015 Author(s): J. Park and W. Sweet The Florida Current is the headwater of the Gulf Stream and is a component of the North Atlantic western boundary current from which a geostrophic balance between sea surface height and mass transport directly influence coastal sea levels along the Florida Straits. A linear regression of daily Florida Current transport estimates does not find a significant change in transport over the last decade, however, a nonlinear trend extracted from empirical mode decomposition suggests a 3 Sv decline in mean transport. This decline is consistent with observed tide gauge records in Florida Bay and the Straits, all exhibiting an acceleration of mean sea level rise over the decade. It is not known whether this recent change represents natural variability or the onset of the anticipated secular decline in Atlantic meridional overturning circulation, nonetheless, such changes have direct impacts on the sensitive ecological systems of the Everglades as well as the climate of western Europe and eastern North America.

Description: Simulation of tsunami generation, propagation and coastal inundation in the Eastern Mediterranean Ocean Science Discussions, 12, 673-699, 2015 Author(s): A. G. Samaras, T. V. Karambas, and R. Archetti In the present work, an advanced tsunami generation, propagation and coastal inundation 2-DH model (i.e. 2-D Horizontal model) based on the higher-order Boussinesq equations – developed by the authors – is applied to simulate representative earthquake-induced tsunami scenarios in the Eastern Mediterranean. Two areas of interest were selected after evaluating tsunamigenic zones and possible sources in the region: one at the Southwest of the island of Crete in Greece and one at the East of the island of Sicily in Italy. Model results are presented in the form of extreme water elevation maps, sequences of snapshots of water elevation during the propagation of the tsunamis, and inundation maps of the studied low-lying coastal areas. This work marks one of the first successful applications of a fully nonlinear model for the 2-DH simulation of tsunami-induced coastal inundation; acquired results are indicative of the model's capabilities, as well of how areas in the Eastern Mediterranean would be affected by eventual larger events.

Description: Tectonic evolution and high-pressure rock exhumation in the Qiangtang terrane, central Tibet Solid Earth, 6, 457-473, 2015 Author(s): Z. Zhao, P. D. Bons, G. Wang, A. Soesoo, and Y. Liu Conflicting interpretations of the 〉 500 km long, east–west-trending Qiangtang metamorphic belt have led to very different and contradicting models for the Permo–Triassic tectonic evolution of central Tibet. We define two metamorphic events, one that only affected pre-Ordovician basement rocks and one subduction-related Triassic high-pressure metamorphism event. Detailed mapping and structural analysis allowed us to define three main units that were juxtaposed due to collision of the north and south Qiangtang terranes after closure of the Ordovician–Triassic ocean that separated them. The base is formed by the Precambrian–Carboniferous basement, followed by non-metamorphic ophiolitic mélange containing mafic rocks that range in age from the Ordovician to Middle Triassic. The top of the sequence is formed by strongly deformed sedimentary mélange that contains up to 〉 10 km size rafts of both unmetamorphosed Permian sediments and high-pressure blueschists. We propose that the high-pressure rocks were exhumed from underneath the south Qiangtang terrane in an extensional setting caused by the pull of the northward subducting slab of the Shuanghu–Tethys. High-pressure rocks, sedimentary mélange and margin sediments were thrust on top of the ophiolitic mélange that was scraped off the subducting plate. Both units were subsequently thrust on top of the south Qiantang terrane continental basement. Onset of Late Triassic sedimentation marked the end of the amalgamation of both Qiangtang terranes and the beginning of spreading between Qiantang and north Lhasa to the south, leading to the deposition of thick flysch deposits in the Jurassic.

Description: The RADMED monitoring program: towards an ecosystem approach Ocean Science Discussions, 12, 645-671, 2015 Author(s): J. L. López-Jurado, R. Balbín, B. Amengual, A. Aparicio-González, M. L. Fernández de Puelles, M. C. García-Martínez, M. Gazá, J. Jansá, A. Morillas-Kieffer, F. Moyá, R. Santiago, M. Serra, M. Vargas-Yáñez, and L. Vicente In the Western Mediterranean, the IEO-RADMED monitoring program is already conducting many of the evaluations required under the Marine Strategy Framework Directive (MFSD) along the Spanish Mediterranean coast. The different aspects of the ecosystem that are regularly sampled under this monitoring program are the physical environment and the chemical and biological variables of the water column, together with the planktonic communities, biomass and structure. Moreover, determinations of some anthropogenic stressors on the marine environment, as contaminants and microplastics, are under develop. Data are managed and stored at the IEO Data Center that works under the SeaDataNet infrastructure and are also stored under the IBAMar database. In combination with remote sensing data they are used to address open questions on the ecosystem in the Western Mediterranean sea.

Description: Carbon-based phytoplankton size classes retrieved via ocean color estimates of the particle size distribution Ocean Science Discussions, 12, 573-644, 2015 Author(s): T. S. Kostadinov, S. Milutinović, I. Marinov, and A. Cabré Owing to their important roles in biogeochemical cycles, phytoplankton functional types (PFTs) have been the aim of an increasing number of ocean color algorithms. Yet, none of the existing methods are based on phytoplankton carbon (C) biomass, which is a fundamental biogeochemical and ecological variable and the "unit of accounting" in Earth System models. We present a novel bio-optical algorithm to retrieve size-partitioned phytoplankton carbon from ocean color satellite data. The algorithm is based on existing algorithms to estimate particle volume from a power-law particle size distribution (PSD). Volume is converted to carbon concentrations using a compilation of allometric relationships. We quantify absolute and fractional biomass in three PFTs based on size – picophytoplankton (0.5–2 μm in diameter), nanophytoplankton (2–20 μm) and microphytoplankton (20–50 μm). The mean spatial distributions of total phytoplankton C biomass and individual PFTs, derived from global SeaWiFS monthly ocean color data, are consistent with current understanding of oceanic ecosystems, i.e. oligotrophic regions are characterized by low biomass and dominance of picoplankton, whereas eutrophic regions have large biomass to which nanoplankton and microplankton contribute relatively larger fractions. Global spatially integrated phytoplankton carbon biomass standing stock estimates using our PSD-based approach yield on average ~0.2–0.3 Gt of C, consistent with analogous estimates from two other ocean color algorithms, and several state-of-the-art Earth System models. However, the range of phytoplankton C biomass spatial variability globally is larger than estimated by any other models considered here, because the PSD-based algorithm is not a priori empirically constrained and introduces improvement over the assumptions of the other approaches. Satisfactory in situ closure observed between PSD and POC measurements lends support to the theoretical basis of the PSD-based algorithm. Uncertainty budget analyses indicate that absolute carbon concentration uncertainties are driven by the PSD parameter N o which determines particle number concentration to first order, while uncertainties in PFTs' fractional contributions to total C biomass are mostly due to the allometric coefficients.

Description: An evaluation of different measures of dynamically recrystallized grain size for paleopiezometry or paleowattometry studies Solid Earth, 6, 475-495, 2015 Author(s): M. A. Lopez-Sanchez and S. Llana-Fúnez Paleopiezometry and paleowattometry studies are essential to validate models of lithospheric deformation and therefore increasingly common in structural geology. These studies require a single measure of dynamically recrystallized grain size in natural mylonites to estimate the magnitude of differential paleostress (or the rate of mechanical work). This contribution tests the various measures of grain size used in the literature and proposes the frequency peak of a grain size distribution as the most robust estimator for paleopiezometry or paleowattometry studies. The novelty of the approach resides in the use of the Gaussian kernel density estimator as an alternative to the classical histograms, which improves reproducibility. A free, open-source, easy-to-handle script named GrainSizeTools ( http://www.TEOS-10.org ) was developed with the aim of facilitating the adoption of this measure of grain size in paleopiezometry or paleowattometry studies. The major advantage of the script over other programs is that by using the Gaussian kernel density estimator and by avoiding manual steps in the estimation of the frequency peak, the reproducibility of results is improved.

Description: Sea level budget over 2005–2013: missing contributions and data errors Ocean Science Discussions, 12, 701-734, 2015 Author(s): H. B. Dieng, A. Cazenave, K. von Schuckmann, M. Ablain, and B. Meyssignac Based on the sea level budget closure approach, this study investigates the residuals between observed global mean sea level (GMSL) and the sum of components (steric sea level and ocean mass) for the period January 2005 to December 2013. The objective is to identify the impact of errors in one or several components of the sea level budget on the residual time series. This is a key issue if we want to constrain missing contributions such as the contribution to sea level rise from the deep ocean (〉 2000m). For that purpose, we use several data sets as processed by different groups: six altimetry products for the GMSL, four Argo products plus the ORAS4 ocean reanalysis for the steric sea level and three GRACE-based ocean mass products. We find that over the study time span, the observed trend differences in the residuals of the sea level budget can be as large as ~0.55mm yr −1 . These trend differences essentially result from the processing of the altimetry data (e.g., choice the geophysical corrections and method of averaging the along-track altimetry data). At short time scale (from sub-seasonal to multi-annual), residual anomalies are significantly correlated with ocean mass and steric sea level anomalies (depending on the time span), indicating that the residual anomalies are related to errors in both GRACE-based ocean mass and Argo-based steric data. Efforts are needed to reduce these various sources of errors before using the sea level budget approach to estimate missing contributions such as the deep ocean heat content.

Description: Litter contribution to soil organic carbon in the processes of agriculture abandon Solid Earth, 6, 425-432, 2015 Author(s): A. Novara, J. Rühl, T. La Mantia, L. Gristina, S. La Bella, and T. Tuttolomondo The mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in the functioning of the ecosystem, as they regulate the cycle of soil organic matter (SOM) and CO 2 emission into the atmosphere. In this study the contribution of litters of different stages of Mediterranean secondary succession on carbon sequestration was investigated, analyzing the role of earthworms in the translocation of SOM into the soil profile. For this purpose the δ 13 C difference between meadow C 4 -C soil and C 3 -C litter was used in a field experiment. Four undisturbed litters of different stages of succession (45, 70, 100 and 120 since agriculture abandon) were collected and placed on the top of isolated C4 soil cores. The litter contribution to C stock was affected by plant species and it increased with the age of the stage of secondary succession. One year after the litter position, the soil organic carbon increased up to 40% in comparison to soils not treated with litter after 120 years of abandon. The new carbon derived from C 3 litter was decomposed and transferred into soil profile thanks to earthworms and the leaching of dissolved organic carbon. After 1 year the carbon increase attributed to earthworm activity was 6 and 13% in the soils under litter of fields abandoned for 120 and 45 years, respectively.

Description: Spatial variability of soil properties and soil erodibility in the Alqueva reservoir watershed Solid Earth, 6, 383-392, 2015 Author(s): V. Ferreira, T. Panagopoulos, R. Andrade, C. Guerrero, and L. Loures The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility ($K$ factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.

Description: Soil aggregation, erodibility, and erosion rates in mountain soils (NW Alps, Italy) Solid Earth, 6, 403-414, 2015 Author(s): S. Stanchi, G. Falsone, and E. Bonifacio Erosion is a relevant soil degradation factor in mountain agrosilvopastoral ecosystems that can be enhanced by the abandonment of agricultural land and pastures left to natural evolution. The on-site and off-site consequences of soil erosion at the catchment and landscape scale are particularly relevant and may affect settlements at the interface with mountain ecosystems. RUSLE (Revised Universal Soil Loss Equation) estimates of soil erosion consider, among others, the soil erodibility factor ( K ), which depends on properties involved in structure and aggregation. A relationship between soil erodibility and aggregation should therefore be expected. However, erosion may limit the development of soil structure; hence aggregates should not only be related to erodibility but also partially mirror soil erosion rates. The aim of the research was to evaluate the agreement between aggregate stability and erosion-related variables and to discuss the possible reasons for discrepancies in the two kinds of land use considered (forest and pasture). Topsoil horizons were sampled in a mountain catchment under two vegetation covers (pasture vs. forest) and analyzed for total organic carbon, total extractable carbon, pH, and texture. Soil erodibility was computed, RUSLE erosion rate was estimated, and aggregate stability was determined by wet sieving. Aggregation and RUSLE-related parameters for the two vegetation covers were investigated through statistical tests such as ANOVA, correlation, and regression. Soil erodibility was in agreement with the aggregate stability parameters; i.e., the most erodible soils in terms of K values also displayed weaker aggregation. Despite this general observation, when estimating K from aggregate losses the ANOVA conducted on the regression residuals showed land-use-dependent trends (negative average residuals for forest soils, positive for pastures). Therefore, soil aggregation seemed to mirror the actual topsoil conditions better than soil erodibility. Several hypotheses for this behavior were discussed. A relevant effect of the physical protection of the organic matter by the aggregates that cannot be considered in $K$ computation was finally hypothesized in the case of pastures, while in forests soil erodibility seemed to keep trace of past erosion and depletion of finer particles. A good relationship between RUSLE soil erosion rates and aggregate stability occurred in pastures, while no relationship was visible in forests. Therefore, soil aggregation seemed to capture aspects of actual vulnerability that are not visible through the erodibility estimate. Considering the relevance and extension of agrosilvopastoral ecosystems partly left to natural colonization, further studies on litter and humus protective action might improve the understanding of the relationship among erosion, erodibility, and structure.

Description: Effects of surface current/wind interaction in an eddy-rich general ocean circulation simulation of the Baltic Sea H. Dietze and U. Löptien Ocean Sci. Discuss., doi:10.5194/os-2016-12,2016 Manuscript under review for OS (discussion: open, 0 comments) Winds blowing over the ocean drive ocean currents. The oceanic response to winds is, in turn, influenced by ocean currents. Theoretical considerations suggest that the latter effect is especially pronounced in the Baltic Sea where the spatial scale of current variability is much smaller than in the open ocean. The study presented here puts theses theoretical considerations in a high-resolution ocean circulation model of the Baltic Sea to the test.

Description: POLENET/LAPNET teleseismic P wave travel time tomography model of the upper mantle beneath northern Fennoscandia Hanna Silvennoinen, Elena Kozlovskaya, and Eduard Kissling Solid Earth, 7, 425-439, doi:10.5194/se-7-425-2016, 2016 POLENET/LAPNET broadband seismic network was deployed in northern Fennoscandia 2007–2009. In our study we estimate the 3D architecture of the upper mantle beneath the network using high-resolution teleseismic P-wave tomography. Our study reveals a highly heterogeneous lithospheric mantle. The most significant feature seen in the obtained velocity model is a large elongated low-velocity anomaly beneath the crust, separating the three cratonic units that formed the region in the early Proterozoic.

Description: Calculating structural and geometrical parameters by laboratory measurements and X-ray microtomography: a comparative study applied to a limestone sample before and after a dissolution experiment Linda Luquot, Vanessa Hebert, and Olivier Rodriguez Solid Earth, 7, 441-456, doi:10.5194/se-7-441-2016, 2016 To evaluate oil and gas production, accurate characterization (usually based on laboratory experiments) of reservoir rock properties needs to be performed. X-ray scanning samples enable obtaining 3-D images of the rock inner structure from which those properties can be obtained using images processing. This article shows that these two approaches are complementary and yield consistent results. Moreover, image-based calculations allow to save a huge amount of time compared to lab-based measures.

Description: Experimental sand burial affects seedling survivorship, morphological traits and biomass allocation of Ulmus pumila var. sabulosa in Horqin Sandy Land Jiao Tang, Carlos Alberto Busso, Deming Jiang, Ala Musa, Dafu Wu, Yongcui Wang, and Chunping Miao Solid Earth Discuss., doi:10.5194/se-2016-55,2016 Manuscript under review for SE (discussion: open, 0 comments) In order to test the tolerance of sandy elm after emergence, an experiment was conducted to evaluate the changes of survivorship, morphological traits and biomass allocation buried by various experimental burial depths. The results showed that partial sand burial did not influence survivorship and increased seedling height, diameter, taproot length, total biomass and relative growth rates. But it decreased total leaf area and changed biomass allocation, transferring more biomass to aboveground.

Description: Phase Segmentation of X-Ray Computer Tomography Rock Images using Machine Learning Techniques: an Accuracy and Performance Study Swarup Chauhan, Wolfram Rühaak, Hauke Anbergen, Alen Kabdenov, Marcus Freise, Thorsten Wille, and Ingo Sass Solid Earth Discuss., doi:10.5194/se-2016-44,2016 Manuscript under review for SE (discussion: open, 0 comments) Machine learning techniques are a promising alternative for processing (phase segmentation) of 3D X-Ray computer tomographic (XCT) rock images. Here, the performance and accuracy of different machine learning techniques is tested. Aim is to classify pore space, rock grains and matrix of four distinct rock samples. The porosity obtained based on the segmented XCT images is cross-validated with laboratory measurements. Accuracies of the different methods are discussed and recommendation proposed.

Description: Feathery and network-like filamentous textures as indicators for the crystallization of quartz from a silica gel precursor at the Rusey Fault, Cornwall, UK Tim I. Yilmaz, Florian Duschl, and Danilo Di Genova Solid Earth Discuss., doi:10.5194/se-2016-61,2016 Manuscript under review for SE (discussion: open, 1 comment) Quartz crystals from a hydrothermal shear-zone-hosted quartz deposit (Rusey Fault, Cornwall, UK) show feathery textures and network-like filamentous textures. Optical hot-cathodoluminescence (CL) analysis and LA-ICP-MS investigations on quartz samples revealed that positions exhibiting feathery textures (violet luminescence) incorporate higher amounts of Ca, As, Na, Mg, and K than quartz positions without feathery textures (blue luminescence). Raman spectroscopy investigations revealed the presence of a weak peak ("shoulder") at 507–509 cm −1 in quartz affected by feathery textures, which we attribute to the presence of moganite, a microcrystalline silica variety. The combined occurrence of feathery textures and network-like filamentous textures in quartz samples from the Rusey fault zone points to the presence of a silica gel precursor before or during the crystallization.

Description: Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of Southwestern China Yecui Hu, Zhangliu Du, Qibing Wang, and Guichun Li Solid Earth Discuss., doi:10.5194/se-2016-57,2016 Manuscript under review for SE (discussion: open, 0 comments) We quantified the SOC and TN losses induced by land-use changes in a typical karst region of southwestern China. Converting from natural forest to croplands greatly led to SOC and TN losses (as higher as 37.8 %), but the magnitude depended on sampling depth and calculation method. We recommend to account for SOC and TN stocks on equivalent soil mass basis together with deep sampling. This study has significant implications on the projected land management in the degraded karst areas.

Description: Turbulent heat transfer as a control of platelet ice growth in supercooled under-ice ocean boundary layers Miles G. McPhee, Craig L. Stevens, Inga J. Smith, and Natalie J. Robinson Ocean Sci., 12, 507-515, doi:10.5194/os-12-507-2016, 2016 Measurements of turbulent heat fluxes in tidally modulated flow of supercool seawater under Antarctic land-fast sea ice show that turbulent heat exchange at the ocean–ice boundary is characterized by the product of friction velocity and (negative) water temperature departure from freezing. Also, the conditions cause platelet ice growth to form on the underside of the sea ice which increases the hydraulic roughness (drag) of fast ice compared to ice without platelets.