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11

Electronic Resource

Transport and storage of CO2 in the ocean ——an inorganic ocean-circulation carbon cycle model (1987)

Maier-Reimer, E. ; Hasselmann, K.

Springer

Climate dynamics 2 (1987), S. 63-90

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ISSN: 1432-0894

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract Inorganic carbon in the ocean is modelled as a passive tracer advected by a three-dimensional current field computed from a dynamical global ocean circulation model. The carbon exchange between the ocean and atmosphere is determined directly from the (temperature-dependent) chemical interaction rates in the mixed layer, using a standard CO2 flux relation at the air-sea interface. The carbon cycle is closed by coupling the ocean to a one-layer, horizontally diffusive atmosphere. Biological sources and sinks are not included. In this form the ocean carbon model contains essentially no free tuning parameters. The model may be regarded as a reference for interpreting numerical experiments with extended versions of the model including biological processes in the ocean (Bacastow R and Maier-Reimer E in prep.) and on land (Esser G et al in prep.). Qualitatively, the model reproduces the principal features of the observed CO2 distribution bution in the surface ocean. However, the amplitudes of surface pCO2 are underestimated in upwelling regions by a factor of the order of 1.5 due to the missing biological pump. The model without biota may, nevertheless, be applied to compute the storage capacity of the ocean to first order for anthropogenic CO2 emissions. In the linear regime, the response of the model may be represented by an impulse response function which can be approximated by a superposition of exponentials with different amplitudes and time constants. This provides a simple reference for comparison with box models. The largest-amplitude (∼0.35) exponential has a time constant of 300 years. The effective storage capacity of the oceans is strongly dependent on the time history of the anthropogenic input, as found also in earlier box model studies.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01054491

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12

Electronic Resource

Monte Carlo climate change forecasts with a global coupled ocean-atmosphere model (1994)

Cubasch, U. ; Santer, B. D. ; Hellbach, A. ; [et al.]

Springer

Climate dynamics 10 (1994), S. 1-19

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ISSN: 1432-0894

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract. Four time-dependent greenhouse warming experiments were performed with the same global coupled atmosphere-ocean model, but with each simulation using initial conditions from different ”snapshots" of the control run climate. The radiative forcing – the increase in equivalent CO2 concentrations from 1985–2035 specified in the Intergovernmental Panel on Climate Change (IPCC) scenario A – was identical in all four 50-year integrations. This approach to climate change experiments is called the Monte Carlo technique and is analogous to a similar experimental set-up used in the field of extended range weather forecasting. Despite the limitation of a very small sample size, this approach enables the estimation of both a mean response and the ”between-experiment" variability, information which is not available from a single integration. The use of multiple realizations provides insights into the stability of the response, both spatially, seasonally and in terms of different climate variables. The results indicate that the time evolution of the global mean warming signal is strongly dependent on the initial state of the climate system. While the individual members of the ensemble show considerable variation in the pattern and amplitude of near-surface temperature change after 50 years, the ensemble mean climate change pattern closely resembles that obtained in a 100-year integration performed with the same model. In global mean terms, the climate change signals for near surface temperature, the hydrological cycle and sea level significantly exceed the variability among the members of the ensemble. Due to the high internal variability of the modelled climate system, the estimated detection time of the global mean temperature change signal is uncertain by at least one decade. While the ensemble mean surface temperature and sea level fields show regionally significant responses to greenhouse-gas forcing, it is not possible to identify a significant response in the precipitation and soil moisture fields, variables which are spatially noisy and characterized by large variability between the individual integrations.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s003820050032

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13

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Ocean-circulation model of the carbon cycle (1990)

Bacastow, R ; Maier-Reimer, E

Springer

Climate dynamics 4 (1990), S. 95-125

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ISSN: 1432-0894

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract A three-dimensional model of the natural carbon cycle in the oceans is described. The model is an extension of the inorganic ocean-circulation carbon cycle model of Maier-Reimer and Hasselmann (1987) to include the effect of the ocean biota. It is based on a dynamic, general circulation model of the world oceans. Chemical species important to the carbon cycle are advected by the current field of the general circulation model. Mixing occurs through numerical diffusivity (related to finite box size), a small explicit horizontal diffusivity, and a convective adjustment. An atmospheric box exchanges CO2 with the surface ocean. There is no land biota provided in the present version of the model. The effect of the ocean biota on ocean chemistry is represented in a simple way and model distributions of chemical species are compared with distributions observed during the GEOSECS and other expeditions.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00208905

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14

Electronic Resource

The seasonal variation of the angular momentum of the oceans (1990)

Brosche, P. ; Wünsch, J. ; Frische, A. ; [et al.]

Springer

Naturwissenschaften 77 (1990), S. 185-186

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ISSN: 1432-1904

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01131164

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15

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A Study of Ozone Laminae Using Diabatic Trajectories, Contour Advection and Photochemical Trajectory Model Simulations. (1998)

Reid, S. J. ; Rex, M. ; Von Der Gathen, P. ; [et al.]

Springer

Journal of atmospheric chemistry 30 (1998), S. 187-207

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ISSN: 1573-0662

Keywords: Ozone laminae ; mid-latitudes ; ozone depletion

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Geosciences

Notes: Abstract In this paper, we show that the rate of ozone loss in both polar and mid-latitudes, derived from ozonesonde and satellite data, has almost the same vertical distribution (although opposite sense) to that of ozone laminae abundance. Ozone laminae appear in the lower stratosphere soon after the polar vortex is established in autumn, increase in number throughout the winter and reach a maximum abundance in late winter or spring. We indicate a possible coupling between mid-winter, sudden stratospheric warmings (when the vortex is weakened or disrupted) and the abundance of ozone laminae using a 23-year record of ozonesonde data from the World Ozone Data Center in Canada combined with monthly-mean January polar temperatures at 30 hPa. Results are presented from an experiment conducted during the winter of 1994/95, in phase II of the Second European Stratospheric And Mid-latitude Experiment (SESAME), in which 93 ozone-enhanced laminae of polar origin observed by ozonesondes at different time and locations are linked by diabatic trajectories, enabling them to be probed twice or more. It is shown that, in general, ozone concentrations inside laminae fall progressively with time, mixing irreversibly with mid-latitude air on time-scales of a few weeks. A particular set of laminae which advected across Europe during mid February 1995 are examined in detail. These laminae were observed almost simultaneously at seven ozonesonde stations, providing information on their spatial scales. The development of these laminae has been modelled using the Contour Advection algorithm of Norton (1994), adding support to the concept that many laminae are extrusions of vortex air. Finally, a photochemical trajectory model is used to show that, if the air in the laminae is chemically activated, it will impact on mid-latitude ozone concentrations. An estimate is made of the potential number of ozone molecules lost each winter via this mechanism.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1005836212979

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16

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Chemical Ozone Loss in the Arctic Winter 1994/95 as Determined by the Match Technique (1999)

Rex, M. ; Von Der Gathen, P. ; Braathen, G.O. ; [et al.]

Springer

Journal of atmospheric chemistry 32 (1999), S. 35-59

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ISSN: 1573-0662

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Geosciences

Notes: Abstract The chemically induced ozone loss inside the Arctic vortex during the winter 1994/95 has been quantified by coordinated launches of over 1000 ozonesondes from 35 stations within the Match 94/95 campaign. Trajectory calculations, which allow diabatic heating or cooling, were used to trigger the balloon launches so that the ozone concentrations in a large number of air parcels are each measured twice a few days apart. The difference in ozone concentration is calculated for each pair and is interpreted as a change caused by chemistry. The data analysis has been carried out for January to March between 370 K and 600 K potential temperature. Ozone loss along these trajectories occurred exclusively during sunlit periods, and the periods of ozone loss coincided with, but slightly lagged, periods where stratospheric temperatures were low enough for polar stratospheric clouds to exist. Two clearly separated periods of ozone loss show up. Ozone loss rates first peaked in late January with a maximum value of 53 ppbv per day (1.6 % per day) at 475 K and faster losses higher up. Then, in mid-March ozone loss rates at 475 K reached 34 ppbv per day (1.3 % per day), faster losses were observed lower down and no ozone loss was found above 480 K during that period. The ozone loss in hypothetical air parcels with average diabetic descent rates has been integrated to give an accumulated loss through the winter. The most severe depletion of 2.0 ppmv (60 %) took place in air that was at 515 K on 1 January and at 450 K on 20 March. Vertical integration over the levels from 370 K to 600 K gives a column loss rate, which reached a maximum value of 2.7 Dobson Units per day in mid-March. The accumulated column loss between 1 January and 31 March was found to be 127 DU (∼36 %).

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1006093826861

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17

Electronic Resource

The genetic basis of scald resistance in western Canadian barley cultivars (1995)

Penner, G. A. ; Tekauz, A. ; Reimer, E. ; [et al.]

Springer

Euphytica 92 (1995), S. 367-374

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ISSN: 1573-5060

Keywords: marker-assisted selection ; genetics ; barley ; Hordeum vulgare ; scald ; Rhynchosporium secalis ; Canada

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Summary The genetic basis of resistance to scald (Rhynchosporium secalis) within barley breeding populations is poorly understood. The design of effective genetically based resistance strategies is predicated on knowledge of the identity of the resistance genes carried by potential parents. The resistance exhibited by a broad selection of western Canadian barley lines was investigated by evaluating their reactions to five R. secalis isolates. Results were compared to the resistance exhibited by previously characterized lines. This comparison, combined with pedigree analysis indicated that there are two different resistance genes present inwwestern Canadian cultivars. These genes were shown to be independent through analysis of a segregating population derived from a cross between Falcon and CDC Silky. This evidence, along with observed linkage of the gene in CDC Silky with an allele specific amplicon developed for a Rhynchosporium secalis resistance locus on chromosome 3, provides evidence that the gene in Falcon is the Rh2 gene derived from Atlas, and the gene (s) in CDC Silky is located within the Rh/Rh3/Rh4 cluster and is similar to the Rh gene in Hudson.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00037121

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18

Electronic Resource

Zum Einfluß eines mittleren Windschubes auf die Restströme der Nordsee (1975)

Maier-Reimer, E.

Springer

Ocean dynamics 28 (1975), S. 253-262

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ISSN: 1616-7228

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Description / Table of Contents: Summary On a simple model, residual currents of the North Sea, resulting from M2-tide and a wind stress constant in time and space, have been calculated. The results are compared with the measured propagation of Cs137. The measurements are reproduced qualitatively with a mean wind stress of 0,3 dyn/cm2 for all wind directions between West and South. The model permits to estimate a mean isotropic exchange coefficient in the coastal regions of the southern part of the North Sea. It is within the order of magnitude of 10 to 50 m2/s.

Abstract: Résumé On a calculé sur un modèle simple les courants résiduels de la Mer du Nord résultant de l'onde M2 et d'une poussée du vent, constante dans le temps et dans l'espace. Les résultats ont été comparés avec la mesure de la propagation du Cs137. Les mesures ont été reproduites d'une manière qualitative pour une poussée moyenne du vent de 0,3 dyne par centimètre carré à toutes les directions du vent entre l'Ouest et le Sud. Le modèle permet d'évaluer un coefficient de diffusion moyen isotrope pour les régions côtières de la partie Sud de la mer du Nord. Son ordre de grandeur est de 10 à 50 m2/s.

Notes: Zusammenfassung In einem einfachen Modell werden Restströme der Nordsee, resultierend aus M2-Gezeit und einem räumlich und zeitlich konstanten Windschub, berechnet. Die Ergebnisse werden verglichen mit der gemessenen Ausbreitung von Cs137. Die Messungen werden qualitativ reproduziert mit einem mittleren Windschub von 0,3 dyn/cm2 bei allen Windrichtungen zwischen West bis Süd. Das Modell erlaubt eine Abschätzung für einen mittleren isotropen Austauschkoeffizienten in den küstennahen Bereichen der südlichen Nordsee. Er liegt in der Größenordnung 10 bis 50 m2/s.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02225969

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