South-north dipolar pattern around mid-1990s in Korean summer rainfall variability     

《Dynamics of Atmospheres and Oceans》2017

From the time series of rainfall in summer (June, July and August) in South and North Koreas for recent 28 years (1981–2008), rainfall has significantly increased in South Korea while it has significantly decreased in North Korea since 1996. In particular, the decreasing trend of summer rainfall in North Korea was more conspicuous during the second Changma (late August – mid-September). This characteristic was also found in the south-north dipolar pattern based on 1996 by empirical orthogonal function analysis using summer rainfall observed in all weather observation stations in South and North Korea.The decreasing rainfall trend in North Korea was found to be associated with the weakening of convection by anomalous northeasterlies from anomalous anticyclone centered on around Baikal Lake during summer. On the other hand, the increasing rainfall trend of South Korea was associated with the strengthened anomalous cyclone in the southern region of China, which in turn strengthened anomalous southwesterlies.  相似文献   

北半球平流层极涡崩溃早晚的环流特征及其对5月南亚降水的影响     

沈熙  徐海明  胡景高 《气象科学》2017,37(6):718-726

本文采用1979—2014年NCEP/NCAR月平均再分析资料、CMAP和GPCP月平均降水资料,分析了北半球平流层极涡崩溃早晚的环流特征及其与南亚降水的关系。结果表明,北半球平流层极涡崩溃时间存在明显的年际变化特征。极涡崩溃偏早(偏晚)年,自3月开始异常信号从平流层向下传播,之后的4月,从平流层到对流层高层极区温度异常偏高(偏低),极涡异常偏弱(偏强),极夜急流异常偏弱(偏强)。结果还表明,5月南亚降水异常与平流层极涡崩溃时间的早晚存在显著相关,5月南亚降水异常与平流层极涡崩溃早晚年平流层异常信号的下传有关。当平流层极涡崩溃偏晚年,4月平流层极区表现为位势高度异常偏低,而中纬度则位势高度场异常偏高,并伴随位势高度异常场的向下传播,5月该位势高度异常场下传至阿拉伯海北部大陆上空对流层顶,形成有利于降水的环流场,导致南亚降水偏多。反之,则相反。  相似文献   

INTERDECADAL VARIATION OF THE INTENSITY OF SOUTH ASIAN HIGH     

杨光  李崇银  谭言科 《热带气象学报(英文版)》2016,22(1):19-29

The characteristics and possible physical mechanism of interdecadal variation of the intensity of the South Asian High (SAH) in summer are analyzed using the NCEP/NCAR reanalysis data and NOAA extended reconstructed sea surface temperature (SST) data. The results indicate that a remarkable interdecadal transition occurred in the late 1970s that increased the intensity of SAH, or, an abrupt climate change was around 1978. A comparative analysis between the weak and strong period of the SAH intensity shows that the related anomalous patterns of the atmospheric circulation (including wind field, air temperature field and vertical velocity field) are nearly opposite to each other. The surface latent heat flux anomalies over the plateau (especially in the northwest of the plateau) in summer exert great influence on the interdecadal variation of the SAH intensity and the surface sensible heat flux anomalies play a more important role. Consistent with the interdecadal variation of the SAH intensity, the monopole mode of the tropical Indian Ocean SST in summer also experienced a low to high transition in the late 1970s. To some extent, this can reveal the impact of the anomalous monopole mode of the tropical Indian Ocean SST in summer on interdecadal variation of the SAH.  相似文献   

韩国南极国家行动:动因、举措及策略          下载免费PDF全文

吴伦 《极地研究》2016,28(3):381-389

南极地区位于地球的最南端,其独特的地理位置和自然环境一方面推迟了人类对其争夺和改造,另一方面也积累和形成了特殊的资源储量和战略价值。在物质资源日益匮乏的今天,南极作为尚待开发的新边疆,其战略意义日渐突显。韩国在南极有着广泛而特殊的利益,为了实现这些利益,改变后发参与的不利局面,韩国在南极科研、政治、经济等领域采取了诸多积极举措,并且形成了一套灵活务实的策略。随着国内外形势的发展,韩国未来将制定正式的南极政策文件,在原有实践基础上加大参与力度,并充分发挥企业的支援作用,实现国内优势向国家能力的转换,从而更好地推进其南极战略。  相似文献   

Numerical Simulation and Analysis of Storm Surges Under Different Extreme Weather Event and Typhoon Experiments in the South Yellow Sea     

ZHANG Mingzong  ZHOU Chunyan  ZHANG Jisheng  ZHANG Xinzhou  TANG Zihao 《中国海洋大学学报(英文版)》2022,21(1):1-14

In this study,a coupled tide-surge-wave model was developed and applied to the South Yellow Sea.The coupled model simulated the evolution of storm surges and waves caused by extreme weather events,such as tropical cyclones,cold waves,extratropical cyclones coupled with a cold wave,and tropical cyclones coupled with a cold wave.The modeled surge level and significant wave height matched the measured data well.Simulation results of the typhoon with different intensities revealed that the radius to the maximum wind speed of a typhoon with 1.5 times wind speed decreased,and its influence range was farther away from the Jiangsu coastal region;moreover,the impact on surge levels was weakened.Thereafter,eight hypothetical typhoons based on Typhoon Chan-hom were designed to investigate the effects of varying typhoon tracks on the extreme value and spatial distribution of storm surges in the offshore area of Jiangsu Province.The typhoon along path 2 mainly affected the Rudong coast,and the topography of the Rudong coast was conducive to the increase in surge level.Therefore,the typhoon along path 2 induced the largest surge level,which reached up to 2.91 m in the radial sand ridge area.The maximum surge levels in the Haizhou Bay area and the middle straight coastline area reached up to 2.37 and 2.08 m,respectively.In terms of typhoons active in offshore areas,the radial sand ridge area was most likely to be threatened by typhoon-induced storm surges.  相似文献   

The 'Grasses' of the Big Scrub District of North-eastern New South Wales: A sedimentary record of late Holocene grasslands in a subtropical forest landscape     

W.E. Boyd  B.J. Stubbs  C. Averill 《The Australian geographer》1999,30(3):331-336

This paper records sedimentary data which indicate that at least part of the Wilsons River floodplain, on the margins of the subtropical rainforest known as the 'Big Scrub', has a long and certainly pre-European history of relative treelessness. Despite a general presumption that this lowland subtropical region was completely forested prior to European settlement, recent historical research has indicated that certain areas were naturally open. While the historical information is clear, the data reported here-a fossil pollen record and one radiocarbon date- reinforces that information for one type of locality, providing an initial indication of time depth.  相似文献   

Exploitation or 'Wise Use' of the Coongie Lakes,South Australia: Issues arising from a petroleum exploration proposal     

Thomas Jenkin 《The Australian geographer》1999,30(3):355-371

The exploitation of natural resources within areas that are valued for their environmental qualities raises competing emotions. This paper considers a proposal to undertake petroleum exploration in an area of recognised environmental value, namely, the Coongie Lakes of far north-east South Australia. In development cases such as this, the level of inquiry needs to address environmental, social, cultural and economic issues from a range of interest groups; therefore, the process of assessment is a crucial factor in minimising conflict and meeting the wishes of the stakeholders. In the example of Coongie Lakes, the chosen method failed. This paper discusses the perspectives of the major stakeholders, the process of assessment undertaken, and the criticisms directed at this process. The apparent inadequacies of the assessment process undertaken are then highlighted, and an alternative assessment procedure suggested.  相似文献   

中国南方地区土地退化动态变化及人类活动影响   总被引：22，自引：3，他引：19  

卢金发 《地理科学进展》1999,18(3):215-221

中国南方典型研究区50 年代和80 年代土地退化的对比分析表明, 近几十年来, 不同人类活动地区土地退化变化呈现出各自不同的特点, 土地退化发展最严重的地区既不是人口密度较小和经济较落后的基岩山区,也不是人口密度大、经济发达和土地开垦程度高的低丘岗地区, 而是人口增长速度较快, 经济不够发达的低山丘陵地区。  相似文献   

海岸沙丘沙运动特征若干问题的研究——以闽江口南岸为例     

陈方  贺辉扬 《中国沙漠》1997,17(4):355-361

在海岸带,沙粒粒径和水分含量是决定沙粒起动风速的最主要因素。闽江口南岸海滩沙的平均粒径为2.0Φ,水分含量多在0.3%~1.0%之间。运用Johnson的经验公式,可计算出海滩沙的起动风速为6~7m/s。这一结果与实际观测值十分吻合。由于海岸环境因素的影响,使得同等条件下海岸带沙粒的起动风速明显大于内陆沙漠沙,而风沙流的输沙率明显小于内陆沙漠沙。海岸带是风速剧变带,在引用陆地气象台站的风速记录分析海岸风况和研究风沙运动规律时,必须对风速进行订正。  相似文献   

论华南喷流—沉积块状硫化物矿床   总被引：28，自引：1，他引：27  

徐克勤  王鹤年  周建平  朱金初 《高校地质学报》1996,2(3):241

现代海底喷流－沉积硫化物矿床的发现极大地推动了海底热液成矿理论的发展,也大大地提高了对古代海底喷流块充化物矿术的研究水平。本文指出喷流－沉积是重要的成矿作用,提出喷流－沉积矿床是华南Ｃｕ、Ｐｂ、Ｚｎ、Ｓｎ、Ａｇ、Ａｕ等矿产资源的重要来源,形成了一批超大型矿床,并将华南许多曾被认为属夕卡岩矿床重新确认为喷流－沉积岩床。文章还论述了华南喷流－沉积块状硫化物矿床的特征、分类、时空分布及其成矿特点等问题,提出断裂拗陷带型喷流－沉积块状硫化物矿床是华南具有特色的类型,而陆相断陷盆地中喷流－沉积矿床值得进一步深入研究。  相似文献