Origin and variability of resource-grade marine ferromanganese nodules and crusts in the Pacific Ocean: A review of biogeochemical and physical controls

Marine ferromanganese nodules and crusts containing Mn, Cu, Ni and Co in the most promising resource-grade concentrations and quantities, together with Fe and Zn (all elements of biogeochemical importance) are found far from land on the deep seafloor of the Pacific Ocean. The biogeochemical, chemical and physical mechanisms contributing to their formation, distribution, abundance and – for these six elements – variability in their concentrations in these deposits, are the main focus of the present review. The mechanisms addressed include biological productivity, sedimentation types and rates, bottom water characteristics, the Calcium Carbonate Compensation Depth, the depth and intensity of the oxygen minimum zone, and biogeochemical characteristics of the six focal elements. Particular attention is given to comparisons between the deposits found in the north and the south Pacific, in order to present an overarching view of our current understanding of the mechanisms that apply to both nodules and crusts in both oceanic hemispheres, including examination of the possible existence of a marine ferromanganese oxide continuum. The renewed interest in the commercial exploitation of these deposits has stimulated a welcome increase in scientific research that is essential to informing the public discourse on seabed mining. We briefly reflect on the work addressed in this review in that context.     

气候系统模式FGOALS-s2对南半球气候的模拟和预估

针对参加“国际耦合模式比较计划”(CMIP5)的IAP/LASG气候系统模式FGOALS-s2,评估了其对南半球气候平均态的模拟能力,在此基础上,预估了未来不同“典型浓度路径”(RCPs)情景下南半球气候的变化特征.对20世纪历史气候模拟结果的分析表明,模式能够合理再现南半球大气环流气候态分布特征,包括6～8月平均(JJA)南半球双西风急流现象,只是模拟的北支急流偏弱、南支急流偏强.未来气候预估试验中,不同RCPs情景下南半球温度变化以增暖为主要特征,陆地增温大于海洋,只有南大西洋—印度洋海盆存在局部变冷.综合四种不同情景,未来随着温室气体浓度的增加,南半球中纬度高压带将显著加强,绕极低压带将加深.降水呈现出增多的特征,12月到来年2月平均(DJF)强于JJA,海洋强于陆地,只有南印度洋和南太平洋中部局部降水减少.未来不同RCPs情景下,马斯克林高压表现出先减弱后增强的特征,而澳大利亚高压则呈现出先增强后减弱的特征.南极涛动(AAO)的变化表现为:RCP2.6和RCP4.5情景下AAO都表现为先增强后减弱,RCP6.0和RCP8.5情景下都为一致的增强趋势,这主要与四种情景中模拟的未来温度变化结构不同有关.例如在RCP6.0和RCP8.5情景下,南半球高纬高层温度增暖趋势小于中纬地区,使得经向温度梯度增大,中纬度西风加强,60°S以南位势高度减小,最终令AAO增强.     

Study on changes of plasmalemma permeability and some primary inorganic ions of Antarctic ice microalgae （Chlamydomonas sp. ICE-L） in the low-temperature stress

The changes of plasmalemma permeability and some primary inorganic ions of Antarctic ice microalgae （ Chlamydomonas sp. ICE-L） in the low-temperature stress were examined. The plasmalemma of 1CE-L could maintain the stability at the freezing condition of -6 ℃. That signifies that it could maintain the proper function of plasmalemma and stability of the intracellular environment during sea ice formation. The function of inorganic ions on low-temperature adaptation of ICE-L was investigated by using the X-ray microanalysis method. Low temperature （0 - -6 ℃ ） induces Ca^2 ＋ concentration increment of cytoplasm, but after 24 h the content decrease quickly to normal value. As a matter of fact, Ca^2 ＋ plays an important role as the second messenger in the low temperature adaptation of ICE-L. In addition, low temperature also influences on the other primary inorganic ions transfer and the cell maintains activity by keeping ratio balance among different ions. Above all, it is necessary for Antarctic ice microalgae to survive and breed by maintaining the stability of K^ ＋ content and the balance of Na^ ＋/Cl^ -.     

南极长城站地区气象要素的中期振荡特征

本文用多维谱分析的方法研究了1985年1月-1987年12月南极长城站地面气象要素的谱特征。该地区的气象要素与北半球一样,也普遍存在3-5天、准一周、准二周和3-4周振荡周期。在长城站所在的乔治王岛地区,从地面到平流层中下部,气压系统都存在着显著的准二周振荡,这种振荡是由上往下传播的。无论冬、夏季,准二周和准一周振荡都是由西往东传播的,而扰动的南北传播方向则与季节及振荡周期长度有关。南极地区的中期振荡特征与500hPa极地涡旋的活动和强度变化有密切关系。     

GPS-derived horizontal ice flow velocities along the traverse route from Zhongshan Station to Dome-A, East Antarctica

1　IntroductionFromitsoriginalformulationin 1 990 ,theInternationalTrans AntarcticScientificExpedition (ITASE)hashadasitsprimaryaimthecollectionandinterpretationofacon tinental widearrayofenvironmentalparametersassembledthroughthecoordinatedeffortsofscientistsfromseveralnations(Mayewskietal.1 996) .AsaconsequenceITASEhasbeenfocusedtoaddresstwokeyscientificobjectives:1 )Todeterminethespatialvariabil ityofAntarcticclimate (eg.accumulation,airtemperature,atmosphericcirculation)overthelast2…     

南大洋海冰影像地图投影变换与瓦片切割应用研究

南大洋海冰分布是南极考察过程中影响破冰船航行的重要因素,也是南极研究的重要内容之一。目前国际上不同机构发布的南大洋海冰分布图,大多是球面投影,不能直接用于主流的瓦片地图发布。将极方位立体投影海冰图转换为目前主流的网络墨卡托投影地图,并利用合适的图像重采样方法,按照不同级别比例尺进行瓦片切割和编号存储,最终实现海冰影像地图的发布共享是本文的主要研究内容。笔者对不同的图像重采样方法进行了比较,分析了最邻近点采样方法、双线性内插和双三次卷积重采样方法的优劣,针对本文的研究优选双线性内插方法进行影像地图瓦片的切割,并最终叠加融合在Google地图上,实现了Google底图、准实时海冰影像图与破冰船走航位置的集成显示,为雪龙船的冰区航行提供了重要的数据支撑。     

北大西洋飓风频次与西半球的南极涛动的联系

To examine the zonal asymmetry of the Antarctic oscillation （AAO）, different portions of the AAO from June to October （JJASO） in the interannual variability of the Atlantic tropical hurricanes number （ATHN） are documented in this research. It follows that the AAO in the Western Hemisphere （AAOWH） is positively correlated with the ATHN, at 0.36 during the period of 1871-1998 and 0.42 during the period of 1949-98. After removing the linear regressions on the Southern Oscillation Index （SOI） in all time series, the above correlation coefficients are 0.25 and 0.30, respectively. The underlying mechanisms are studied through analyses of the atmospheric general circulation variability associated with the AAOWH. It turns out that the positive （negative） phase of JJASO AAOWH corresponds with several factors： decreased （increased） vertical zonal wind shear magnitude, low-level anomalous convergence （divergence）, high-level anomalous divergence （convergence）, and warmed （cooled） sea surface temperature in the tropical Atlantic. Therefore, the positive （negative） phase of JJASO AAOWH is favorable （unfavorable） to the tropical hurricane genesis.     

The Arctic and Antarctic Oscillations in the IPCC AR4 Coupled Models

This study evaluates the fidelity of Arctic and Antarctic oscillations (AO and AAO for short,respectively) in the coupled general circulation models participating in the Fourth Assessment Report of Intergovernmental Panel on Climate Change (IPCC AR4).The AO and AAO during 1970-1999 in 24 models are analyzed and compared with that in ERA-40 and NCEP-1.Models'performance is seasonally dependent,with best reproducibility of both spatial structure and trend in winter.In most models,the spatial pattern and temporal trend of AAO during this period are more delicately simulated than AO.After picking out models with better performance according to the Taylor diagram,we find that their ensemble mean can obviously improve models'reproducibility.The AO and AAO in the Special Report on Emission Scenarios (SRES) A1B Projection during the 21st century are also briefly analyzed.The results reveal that both the AO and AAO indices keep increasing during 1970-2099,with a steadier pace of AO than AAO.The spatial difference of sea level pressure between 2060 2089 and 1970-1999 shows decreased values in polar regions,and increased values in midlatitudes.The results manifest that the ozone recovery during the mid 21st century may not weaken such a trend.     

The Role of Southern High Latitude Wind Stress in Global Climate

In this paper, the role of westerly winds at southern high latitudes in global climate is investigated in a fully coupled ocean-atmosphere general circulation model. In the model, the wind stress south of 40°S is turned off with ocean and atmosphere fully coupled both locally and elsewhere. The coupled model explicitly demonstrates that a shutdown of southern high latitude wind stress induces a general cooling over the Antarctic Circumpolar Current (ACC) region, with surface Ekman flow and vertical mixing p...     

春季南极涛动对北美夏季风的影响

This study examined the relationship between the boreal spring(April?May) Antarctic Oscillation(AAO) and the North American summer monsoon(NASM)(July?September) for the period of 1979?2008.The results show that these two systems are closely related.When the spring AAO was stronger than normal,the NASM tended to be weaker,and there was less rainfall over the monsoon region.The opposite NASM situation corresponded to a weaker spring AAO.Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM.It was found that the tropical Atlantic sea surface temperature(SST) plays an important role in the connection between the two phenomena.The variability of the boreal spring AAO can produce anomalous SSTs over the tropical Atlantic.These SST anomalies can persist from spring to summer and can influence the Bermuda High,affecting water vapor transportation to the monsoon region.Through these processes,the boreal spring AAO exerts a significantly delayed impact on the amount of NASM precipitation.Thus,information about the boreal spring AAO is valuable for the prediction of the NASM.