A note on some early radiosonde temperature observations in the Antarctic lower stratosphere     

H. R. Phillpot 《Pure and Applied Geophysics》1989,130(2-3):171-180

The behaviour of the Southern Hemisphere stratosphere has attracted considerable interest, and been compared with the Northern Hemisphere, since the International Geophysical Year (1957–58) when the sudden (explosive or accelerated) springtime warming phenomenon in the Antarctic was first observed. Over the years studies of upper air temperature and wind observations have been made, principally through the spring months when the polar vortex breakdown occurs, utilising both ground-based (rawinsonde, rocket) and more recently, satellite-derived data. Although the radiosonde-derived temperature data are limited both by the number of reporting stations, and the practical difficulty of securing observations much above the 100 hPa level, useful records exist from 1956 or 1957. These have shown that in the 1959 southern spring, the lower stratosphere was relatively colder, and the warming rate through the season was essentially more regular, with little evidence of the marked but short-lived temperature fluctuations usually found. Similar, but not quite such wide-spread conditions occurred again in the 1961 spring. In another study, 30 hPa temperature fields over the Antarctic continent, which could be drawn for the 1967 spring, showed the complexity of the polar vortex breakdown. These features are recalled because extension of the 100 hPa springtime temperature series for the Australian Antarctic station at Casey (66.3°S, 110.5°E) shows that in 1985 and part of 1986, the temperature behaviour there was similar to, but not quite so extreme as that which occurred at Mirny (66.5°S, 93.0°E) in 1959.  相似文献   

Late Quaternary record of sea-level changes in the Antarctic     

H. Grobe  P. Huybrechts  D. K. Fütterer 《International Journal of Earth Sciences》1993,82(2):263-275

The Late Quaternary sediment sequence of the continental margin in the eastern Weddell Sea is well suited for palaeoenvironmental reconstructions. Two cores from the upper slope, which contain the sedimentary record of the last 300 ky, have been sedimentologically investigated. Age models are based on lithostratigraphy and are correlated with the stable isotope record. As a result of a detailed analysis of the clay mineral composition, grain size distributions and structures, this sedimentary record provides the first marine evidence that the Antarctic ice sheet extended to the shelf edge during the last glacial.The variations in volume and size of the ice sheet were also simulated in numerical models. Changes in accumulation rate and ice temperature are of some importance, but the model revealed that fluctuations are primarily driven by changes in eustatic sea-level and that the ice edge extended to the shelf edge during the last glacial maximum. This causal relationship implies that the maximum ice extension strongly depends on the magnitude and duration of the sea-level depression during a glacial period. The results of the sedimentological investigations and of the numerical models show that the Antarctic ice sheet follows glacial events in the northern hemisphere by teleconnections of sea level. Correspondence to: H. Grobe  相似文献   

A　Diagnostic　Study　of　Explosive　Development　of　Extratropical　Cyclone　over　East　Asia　and　West　Pacific　Ocean   总被引：9，自引：0，他引：9  

Jia Yiqin  Zhao Sixiong 《大气科学进展》1994,11(3):251-270

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我国热带气旋灾害的分析研究   总被引：2，自引：1，他引：2  

蔡则怡  徐良炎  徐元太 《大气科学》1994,18(Z1):826-836

本文对１９４９—１９９１年４３年的热带气旋资料，以及１９５６—１９９２年３７年的热带气旋灾情资料进行了分析，说明了热带气旋灾害的主要特征和发展趋势。提出了关于热带气旋灾情评估的３项指标，表明灾情与热带气旋系统强度、大小、天气，登陆率，预报准确率，热带气旋系统影响地区社会经济活动的发达程度，物质财富积累水平，以及防抗措施的水平等有密切的关系，为我国今后防台减灾提供了依据。  相似文献   

南北两极海冰的涛动关系          下载免费PDF全文

解思梅  包澄澜  郝春江 《极地研究》1994,6(3):41-55

本文将南极海冰分为４个区：ＳＰＩ１（０°－１２０°Ｅ），东南极海冰；ＳＰＩ２（１２０°Ｅ－１２０°Ｗ），以罗斯海为主体的海冰区；ＳＰＩ３（１２０°Ｗ－０°），以威德尔海为主体的海冰区；ＳＰＩ４，全南极海冰区。北极海冰区分为３个区：ＮＰＩ１（９０°Ｅ－１８０°－９０°Ｗ），太平洋侧冰区；ＮＰＩ２（９０°Ｗ－０°－９０°Ｅ），大西洋侧冰区；ＮＰＩ３，全北极冰区。本文使用了ＷＤＣ－Ａ的ＳＩＧＲＩＤ海冰资料，以分析南极和北极各冰区之间的相互关系。发现两极各冰区之间存在着非常复杂的相互作用。其中最突出的特征是：两极海冰之间相互作用的振源是ＮＰＩ２。ＳＰＩ３是影响南极海冰的正反馈中心。ＳＰＩ２则是南北两极海冰的负反馈中心。ＮＰＩ２，ＳＰＩ３和ＳＰＩ２之间的相互作用最强，形成涛动关系。这种涛动关系不是同时期的，而是有较长的滞后时间差。两极海冰形成周期变化，其周期为５－６年，正与ＮＰＩ２和ＳＰＩ３自身变化周期一致。另外还有更长的循环周期９－１１年  相似文献   

Radiometric dating of lake sediments from Signy Island (maritime Antarctic): evidence of recent climatic change   总被引：4，自引：0，他引：4  

P. G. Appleby  V. J. Jones  J. C. Ellis-Evans 《Journal of Paleolimnology》1995,13(2):179-191

Sediment cores from three lakes (Moss, Sombre and Heywood) in the maritime Antarctic (Signy Island, South Orkney Islands) have been successfully dated radiometrically by²¹⁰Pb and¹³⁷Cs. The core inventories of both fallout radionuclides are an order of magnitude higher than that which can be supported by the direct atmospheric flux at this latitude. The elevated values may be explained by fallout onto the catchment during the winter being delivered directly to the lakes during the annual thaw. Two of the lakes (Sombre and Heywood) show marked increases in sediment accumulation afterc. 1950. This appears to be associated with a documented rise in temperature in the South Orkney Islands, which has caused extensive deglaciation at Signy Island.This is the tenth of a series of papers to be published by this journal following the 20 ^th anniversary of the first application of²¹⁰Pb dating of lake sediments. Dr P.G. Appleby is guest editing this series.  相似文献   

南极地区小象幅航测内业成图          下载免费PDF全文

肖应华  王茜 《极地研究》1995,7(3):95-100

本文阐述了用１２０型非量测相机对南极中山站地区所摄制的１４００００小象幅航片制作１５０００地形图、正射像片图及１１００００地形图的原理、方法和精度。在外定向中适当增加控制点及考虑到加入适当的权的情况下，其外定向最大对点误差平面为２．２ｍ，高程为１．２ｍ。所制作的正射像片图和相应的地形图套合中误差为０．１４ｍｍ。其结果完全可满足南极科研、考察的要求  相似文献   

一次地中海气旋发展的分析和诊断   总被引：2，自引：2，他引：2  

彭新东  丑纪范 《高原气象》1993,12(3):274-282

  相似文献   

北上热带气旋发展与不发展的对比分析   总被引：2，自引：0，他引：2       下载免费PDF全文

孙力  郑秀雅  王琪 《热带气象学报》1993,9(4):326-334

重点分析了一个北上热带气旋（８５０９号台风）变性发展过程中扰动能和扰动有效有效位能的收支平衡关系及其与中纬地区高空环境场、Ｑ矢量散度、旋度特征和锋生锋消现象的联系，并和与此台风前期路径及强度相似、但进入西风带后很快消失了的８４０６号台风的诊断结是要 进行了对比。结果表明：有利的大尺度环境是台风变性发展的主要因子和先决条件，斜压过程是否能有效和大量地制造扰动动能以抵消台风北上过程中的能量耗散是其能否  相似文献   

南极地区冰雪消失对全球大气环流和气候影响的数值模拟   总被引：1，自引：0，他引：1  

杨修群  谢倩 《地理学报》1993,48(5):394-402

本文利用全球大气环流模式通过数值模拟研究了北半球夏季南极地区冰雪覆盖的消失对大气环流和全球气候影响的过程。结果表明南极冰雪消失不仅影响南半球大气环流异常,而且通过引起热带环流异常如增强东亚季风环流和减弱Walker环流等引起北半球大气环流和我国夏季气候的异常。南极冰雪覆盖的消失将给全球气候带来严重后果。文中也对南极冰雪气候效应的动力学机制进行了讨论。  相似文献