Bacterial productivity in the Prydz Bay and its adjacent waters,Antarctic

1　IntroductionBacteriaandtheiractivitiesplayanimportantroleintheelementalbiogeochemicalcyclesandenergytransformingintheocean (Zhenetal.1 997) .DortchandPackard(1 989) proposedthatfoodwebsintheeutrophicwatersaredominatedbythebiomassofprimaryproducerswhilefoodwebsintheoligotrophicwatersaredominatedbythebiomassofmicrobes.Heterotrophicbacteriahadbeenshowntoplayanimportantroleinthedecompositionoflarge ,rapidlysinkingorganicparticleswithinandbelowtheeuphot iczone ,andfurthertoaffecttheelementaldyn…     

A dynamically consistent analysis of circulation and transports in the southwestern Weddell Sea

An inverse model is applied for the analysis of hydrographic and current meter data collected on the repeat WOCE section SR4 in the Weddell Sea in 1989–1992. The section crosses the Weddell Sea cyclonic gyre from Kapp Norvegia to the northern end of the Antarctic Peninsula. The concepts of geostrophy, conservation of planetary vorticity and hydrostatics are combined with advective balances of active and passive properties to provide a dynamically consistent circulation pattern. Our variational assimilation scheme allows the calculation of three-dimensional velocities in the section plane. Current speeds are small except along the coasts where they reach up to 12 cm/s. We diagnose a gyre transport of 34 Sverdrup which is associated with a poleward heat transport of 28 × 10¹² W corresponding to an average heat flux of 15 Wm^–2 in the Weddell Sea south of the transect. This exceeds the estimated local flux on the transect of 2 Wm^–2. As the transect is located mostly in the open ocean, we conclude that the shelf areas contribute significantly to the ocean-atmosphere exchange and are consequently key areas for the contribution of the Weddell Sea to global ocean ventilation. Conversion of water masses occuring south of the section transform 6.6 ± 1.1 Sv of the inflowing warm deep water into approximately equal amounts of Weddell Sea deep water and Weddell Sea bottom water. The volume transport of surface water equals in the in-and outflow. This means that almost all newly formed surface water is involved in the deep and bottom water formation. Comparison with the results obtained by pure velocity interpolation combined with a hydrographic data subset indicates major differences in the derived salt transports and the water mass conversion of the surface water. The differences can be explained by deviations in the structure of the upper ocean currents to which shelf areas contribute significantly. Additionally a rigorous variance analysis is performed. When only hydrographic data are used for the inversion both the gyre transport and the poleward heat transport are substantially lower. They amount to less than 40% of our best estimate while the standard deviations of both quantities are 6.5 Sv and 37 × 10¹² W, respectively. With the help of long-term current meter measurements these errors can be reduced to 2 Sv and 8 × 10¹² W. Our result underlines the importance of velocity data or equivalent information that helps to estimate the absolute velocities.     

Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations

High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation.     

南大洋氟的生物地球化学研究——Ⅰ.南极磷虾富氟异常的研究

本文通过对南极磷虾不同部位中氟含量的测定,结合氟在测区环境中的分布特征及南极磷虾体中其它元素的分析资料,讨论了氟在磷虾体内的分布和赋存形式,并对其可能的富集机理及与环境的关系作了初步的探讨。     

黄壁庄水库降水效应的分析

南极洲万达盐湖为饱和方解石湖水。计算出的方解石饱和指数随水深增加而变化。在Ca~(2+)及HCO_3~-活度值均一的上部氧化环境湖水中,pH及溶解氧(DO)是控制该变化的主要因素,在下部还原环境湖水中,Ca~(2+)及HCO_3~-的活度对方解石的饱和指数SI的变化起主要作用。这充分揭示了湖底部近代沉积物中分布较多方解石矿物的原因。     

基于星载激光测高估计南极冰盖高程变化

利用NSIDC公布的ICESat运行期间的19个任务期的观测数据, 采用重复轨迹分析方法估计近年来南极冰盖高程的时空变化。结果表明,南极大陆冰盖整体上呈现消融趋势,基于不同的GIA模型和ICESat激光测高数据的南极大陆冰盖高程变化的趋势约为 -1.17~-1 cm/a。     

Improved sea-ice radiative processes in a global coupled climate model

1Introduction Seaiceplaysanimportantroleinmoderating heatandmoistureexchangesbetweentheatmosphere andtheoceanathighlatitudes.Seaicealsointeracts withthebroaderclimatesystembythepositiveice albedofeedback(Curryetal.,1995),whichamplifies projectedclimatewarmingatthehighlatitudes,andby theoceanicfeedbackinvolvingicegrowthandmelt, whichinfluencesglobalthermohalinecirculation(i.e., theNorthAtlanticDeepWaterandtheAntarcticBot- tomWater)(Walsh,1983;Barryetal.,1993). Recently,theimplementationofas…     

Arctic oscillation and the antarcic oscillation modes in the atmospheric stratosphere

1IntroductionThompson and Wallace(1998)first found the AOin1998and according to their definition,the spatialpattern of AO from the first EOF mode for the sea lev-el air-pressure(SLP)was that around the North Poleregion there was an oscillation out-of-phase with thatat the mid-latitudes zone.This oscillation had verywide frequency range from interannual to interdecadaltime scales.The AO is similar to the North Atlantic oscilla-tion(NAO)over the Atlantic.As Wallace said,theNAO could be…     

NUMERICAL EXPERIMENTS FOR THE IMPACT OF ANTARCTIC ICE COVER AND SEA SURFACE TEMPERATURE ON CLIMATE VARIABILITY*

By using a three-level atmospheric general circulation model(AGCM),we have completed several numerical experiments to study the impacts of sea surface temperature anomaly(SSTA) and antarctic ice cover anomaly(AICA) during 1981-1983 on climate variability.The results show that during the El Nino period of 1982-1983 the impact of SSTA overrides that of AICA.SSTA mainly affects equatorial zonal circulation and produces PNA wave train,and SE-NW wave train in East Asia to influence the weather of China.AICA produces west-east anomalous vortex streets in the middle latitudes of both hemispheres and affects the intensity of the polar vortex of Southern Hemisphere.     

南极航线和航区环境概述

本文汇集了我国南极科学考察前十年（１９８４－１９９３年）的南极考察航线，根据航区和任务，对南极航线进行了分类：对各航区中影响航行的海洋环境状况－诸如低纬地区的热带气旋，中纬地区的温带气旋和高纬地区的绕极气旋等主要灾害性天气系统的生成源地，移动路么荼了介绍；文中还着得活冰的增，减期和浮冰边缘线进行了描述。以求达到对过去十年南极考察航线作出比较客观的评价。