Sensitivity of the thermohaline circulation in coupled oceanic GCM — atmospheric EBM experiments     

Gerrit Lohmann  Rüdiger Gerdes  Deliang Chen 《Climate Dynamics》1996,12(6):403-416

We analyze the sensitivity of the oceanic thermohaline circulation (THC) regarding perturbations in fresh water flux for a range of coupled oceanic general circulation — atmospheric energy balance models. The energy balance model (EBM) predicts surface air temperature and fresh water flux and contains the feedbacks due to meridional transports of sensible and latent heat. In the coupled system we examine a negative perturbation in run-off into the southern ocean and analyze the role of changed atmospheric heat transports and fresh water flux. With mixed boundary conditions (fixed air temperature and fixed surface fresh water fluxes) the response is characterized by a completely different oceanic heat transport than in the reference case. On the other hand, the surface heat flux remains roughly constant when the air temperature can adjust in a model where no anomalous atmospheric transports are allowed. This gives an artificially stable system with nearly unchanged oceanic heat transport. However, if meridional heat transports in the atmosphere are included, the sensitivity of the system lies between the two extreme cases. We find that changes in fresh water flux are unimportant for the THC in the coupled system.  相似文献   

An estimate of horse mackerel biomass in the North Sea, 1991-1997     

Ruckert  Chris; Floeter  Jens; Temming  Axel 《ICES Journal of Marine Science》2002,59(1):120-130

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Analysis of prey size preference of North Sea whiting, saithe, and grey gurnard   总被引：2，自引：0，他引：2  

Floeter  Jens; Temming  Axel 《ICES Journal of Marine Science》2005,62(5):897-907

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Bücher- und Zeitschriftenschau     

Bubnoff  Wilckens  Axel Born 《International Journal of Earth Sciences》1931,22(5):340-351

Ohne Zusammenfassung  相似文献   

Formation of sequences of cemented layers and hardpans within sulfide-bearing mine tailings (mine district Freiberg,Germany)     

Torsten Graupner  Andrea Kassahun  Dieter Rammlmair  Jeannet A. Meima  Dagmar Kock  Markus Furche  Adrian Fiege  Axel Schippers  Frank Melcher 《Applied Geochemistry》2007

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Reproductive characteristics of invasive gammarids in the Rhine-Main-Danube catchment, South Germany     

Axel Kley  Gerhard Maier   《Limnologica》2006,36(2):79-90

The gammarid composition at 25 sites in the rivers Danube, Main and the southern reaches of the Rhine were studied during the years 2002–2004. Dikerogammarus villosus and Echinogammarus ischnus were the most frequent species prevailing at 17 sites. Sympatric occurrence of D. villosus and E. ischnus was observed at 12 sites. Dikerogammarus haemobaphes was recorded at 7 sites; this species prevailed in the Danube, west of the Weltenburger Enge and in the Isar mouth where it co-existed with native species (Gammarus pulex and/or G. roeseli) at 6 sites. Dikerogammarus bispinosus and E. berilloni were found at only 1 site, where they co-existed with D. villosus and E. ischnus, and with D. villosus and native species, respectively. Investigation of reproductive characteristics at 3 sites showed that females of D. villosus and D. haemobaphes produced the biggest clutches with more than 100 eggs. Females of E. ischnus produced much smaller clutches (10–35 eggs on an average), but very big eggs. Clutch sizes and egg volumes of D. bispinosus and E. berilloni resembled those of native species. Our results suggest that the most successful invaders (D. villosus, D. haemobaphes and E. ischnus) display reproductive traits that facilitate their success. Both Dikerogammarus sp. allocate energy into production of many but small eggs, thus maximizing offspring number, while E. ischnus allocates its energy into production of fewer but large eggs which could be beneficial at sites where food is scarce.  相似文献   

Climatic change on the Tibetan Plateau: Potential Evapotranspiration Trends from 1961–2000     

Chen Shenbin  Liu Yunfeng  Axel Thomas 《Climatic change》2006,76(3-4):291-319

Time series (1961–2000) of Penman-Monteith potential evapotranspiration estimates for 101 stations on the Tibetan Plateau and surrounding areas are analyzed in this paper. For the Tibetan Plateau as a whole potential evapotranspiration (PET) has decreased in all seasons. The average annual evapotranspiration rate decreased by 13.1 mm/decade or 2.0% of the annual total. Superimposed on this general decline are fluctuations ranging from app. 600 to 700 mm with above average rates in the 1970s and 1980s. On a regional basis, spatial trend distributions remain stable throughout the year with similar seasonal variations. Decreasing PET rates are more pronounced in winter and spring (80% of all stations) as compared to summer and autumn (58% of all stations). Maximum negative (positive) annual rates were recorded at two stations in the southern Qaidam Basin with –79.5 mm/decade (84.8 mm/decade) even though in general negative rates tend to be noticeably higher than positive rates.Changes in wind speed and to a lesser degree relative humidity were found to be the most important meteorological variables affecting PET trends on the Tibetan Plateau while changes in sunshine duration played an insignificant role. Stable daytime temperatures on the Tibetan Plateau have limited the importance of temperature trends for changes of PET rates. Negative evapotranspiration trends are therefore thought to be linked to a general decrease in intensity of the regional monsoon circulation rather than to reductions in sunshine duration. Reduced PET rates appear to be in contrast to a predicted increased hydrological cycle under global warming scenarios.  相似文献   

Climate Change in the Mediterranean     

Axel Michaelowa 《Climatic change》2006,75(4):513-515

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Editorial     

Axel Michaelowa 《Climate Policy》2003,3(1):1

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Instruments for Climate Policy: Limited Versus Unlimited Flexibility: Albrecht Johan (Ed.), Edward Elgar, Cheltenham, 2002, 286 pp., £69.95, ISBN 1-84064-759-0     

Axel Michaelowa 《Climate Policy》2003,3(3):322-325

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