Spatial and Temporal Variability in a Vertical Section Across the Alaskan Stream and Subarctic Current   总被引：1，自引：0，他引：1  

Hiroji Onishi 《Journal of Oceanography》2001,57(1):79-91

In the central North Pacific Subarctic Gyre, CTD hydrographic measurements were carried out yearly in late June from 1990 to 1998 at 9 stations along 180° meridian from 48°N to 51.2°N. Vertical sections of 9-year means, anomalies for each year and others of potential temperature, salinity, potential density and geostrophic velocity (referred to 3000 m) were calculated based on this data set. Empirical Orthogonal Function (EOF) analysis was adopted in the investigation of spatial characteristics and its temporal variation in vertical sections. The spatial distribution of the 1st mode EOF of velocity shows the westward Alaskan Stream and the eastward Subarctic Current. This mode explains 37.6% of the total variance. Two positive maxims appear in its amplitude in 1991 and 1997, which is similar to the variation in volume transport of the eastward Subarctic Current. These variations are closely related to the vertical movement of Ridge Domain deep water.  相似文献   

利用GAM模型分析表温和时空因子对西北太平洋海域柔鱼资源状况的影响   总被引：9，自引：0，他引：9  

陈新军  田思泉 《海洋湖沼通报》2007,(2):104-113

根据1996～2001年6～11月西北太平洋海城柔鱼生产统计及其表温数据,利用GAM模型分析了表温、月份、经玮度等因子对柔鱼资源状况的影响。分析结果认为,经纬度、月份和表温对CPUE都有较大的影响。160°E以西海域CPUE高,而165°E以东海域CPUE低,并主要集中在40°N～43°N海域。一般在8～10月的CPUE最大。柔鱼分布的各海域其表温不相同,150°E以西海域表温为13～18℃;150°E～165°E海域为14～18℃,165°E-180°E海域为11～14℃。  相似文献   

基于多源降水数据的洞庭湖流域夏季降水与西太平洋副热带高压的关系   总被引：2，自引：1，他引：1  

孙葭  章新平  黄一民  张新主 《地理科学》2016,36(7):1115-1124

基于中国气象科学数据共享服务网提供的1979~2012年夏季6~8月降水实测数据（CMD）和3种不同来源的再分析降水数据,研究和比较副高特征指数与洞庭湖流域夏季降水的关系及空间差异。结果表明：① 6、7月副热带高压（副高）脊线位置偏北,洞庭湖流域大部分区域降水偏多,8月偏少;6、7月北界位置偏北使流域东南降水偏少、西北降水偏多,8月大部分地区降水偏多;6~8月西伸脊点位置东移使降水偏多范围自东向西增大;6月份副高强度增强使东部和南部降水偏多、西部和北部降水偏少,7和8月大部分地区降水减少。② 再分析降水数据大体上能反映出7月份脊线指数、6和7月北界指数、6~8月西伸脊点指数和副高强度指数对相应月份CMD降水的影响。③ 副高特征指数对CMD降水的拟合能力存在区域差异。  相似文献   

基于GIS的西北太平洋热带气旋影响研究     

张伟  罗向欣  邵德民  王远飞 《测绘科学》2008,33(5)

本文结合自主研发的《西北太平洋热带气旋检索系统》,利用西北太平洋热带气旋与全国主要气象站点的空间关系,对1949年至2005年的热带气旋数据资料进行分析和挖掘,结合G IS技术表现和分析热带气旋对我国主要站点产生影响的概率分布情况。这不仅有利于气象部门从宏观上把握易受热带气旋影响的地区分布现状,也可以为防灾减灾提供参考信息。  相似文献   

华南前汛期极端降水气候变化特征及其与太平洋海温相关关系研究   总被引：3，自引：0，他引：3       下载免费PDF全文

章开美  李丽平  项连东  朱珍 《气象与减灾研究》2015,38(1):1-7

利用国家气象信息中心提供的89个华南代表气象站的1969—2013年逐日降水资料及NOAA重构延长的逐月海表温度(SST)资料,研究了华南前汛期极端降水的时间变化特征,以及太平洋海表温度与华南前汛期极端降水年际异常的相关关系,并定义了对华南前汛期极端降水具有指示意义的海表温度异常指数。主要结论:1)华南前汛期极端降水存在显著的年际变化以及年代际变化。20世纪90年代以来,华南前汛期发生极端旱涝的情况增多,此外,华南前汛期极端降水存在2个显著的突变年份。除降水强度外,其他各个极端降水指数在1977年存在一个突变,极端降水由多变少;在21世纪初存在另外一个极端降水由少到多的突变(除总降水量外)。2)定义的前冬太平洋海温异常指数与华南前汛期极端降水具有显著相关关系,该指数与El Ni觡o事件关系密切,当前冬该指数为正(负)或者发生El Ni觡o(La Ni觡a)现象时,则可预测次年华南前汛期极端降水异常也偏强(弱)。  相似文献   

热带次表层海温对中国东部夏季气候的影响     

李晓婧  肖天贵  唐毅 《成都信息工程学院学报》2011,26(1):29-36

热带海洋热状况是影响中国气候变化的主要因子之一,为了研究热带次表层海温如何影响中国气候,通过相关计算和合成分析等方法讨论了热带太平洋至印度洋次表层海温异常对中国东部夏季降水和温度的影响。结果表明:当冬季赤道东印度洋至西太平洋次表层海温偏暖(偏冷),中印度洋和东太平洋次表层海温偏冷(偏暖),夏季,长江中下游地区降水偏少(偏多),华南、华北和东北大部地区降水偏多(偏少);中国东部大范围高温(低温)。其可能的影响途径为,东亚夏季风环流对热带次表层海温异常的响应导致了其年际变化,进而引起中国东部夏季气候的异常分布。  相似文献   

2013年夏季西太平洋副高异常特征及其对湖南高温干旱的影响   总被引：2，自引：0，他引：2  

彭莉莉  戴泽军  罗伯良  孙佳庆  黄晚华 《干旱气象》2015,33(2)

利用湖南96个测站的逐日降水、日最高气温和NCEP/NCAR再分析资料、海温资料,分析了2013年夏季西太平洋副热带高压异常活动特征、成因及其对湖南高温干旱的影响。结果表明,2013年夏季西太平洋副高异常偏西、偏强,使得湖南一直处在高压下沉气流控制下,形成持续高温干旱天气。造成副高变异的原因主要有:(1)2012年冬季至2013年春季,赤道东太平洋海表温度持续偏低,印度洋—赤道西太平洋海表温度持续偏高,使得Walker环流和Hadley环流的上升和下沉运动得到加强,西太平洋副高西伸、加强;(2)南亚高压一次次东伸,通过强烈高空负涡度平流的动力强迫,造成西太平洋副高区内的下沉运动,导致副高稳定维持,天气晴热高温;(3)西风急流较常年偏北,纬向环流偏强,导致副热带高压在偏北位置稳定维持,200 h Pa高空辐合增强,辐合中心位于30°N以北,造成500 h Pa副高下沉运动区位置偏北、偏强。  相似文献   

Research into fisheries equity and fairness—addressing conservation burden concerns in transboundary fisheries     

《Marine Policy》2015

Conservation and management of transboundary fisheries must account for diverse national interests while adopting compromises necessary to develop and implement robust conservation and management measures. The United Nations Fish Stocks Agreement requires states to ensure that conservation and management measures for straddling and highly migratory fisheries do not transfer a disproportionate burden of conservation action onto developing states. However, fulfilling this obligation in transboundary fisheries is undermined by the lack of agreed transparent frameworks for assessing the impact of alternative conservation and management measures, and distributive decision making processes for adopting measures that meet scientific and equity obligations. A new informal and multi-disciplinary research partnership, the Fisheries Equity Research Network, has been established to encourage international research into the equitable distribution of conservation limits in trans-boundary oceanic fisheries. The Fisheries Equity Research Network will research transparent and equitable rules and frameworks for assessing and distributing conservation burdens in transboundary fisheries.  相似文献   

地球圈层相互作用中的深海过程和深海记录（II）：气候变化的热带驱动与碳循环   总被引：1，自引：3，他引：1  

汪品先  翦知湣  刘志飞 《地球科学进展》2006,21(4):338-345

地球轨道变化驱动冰期旋回的理论是气候演变研究在20世纪的最大突破。然而以65°N太阳辐射量为准的传统轨道理论，忽视了低纬区和碳循环的作用。本项目以“西太平洋暖池”为重点，通过地质资料和气候数值模拟的结合，揭示了“西太平洋暖池”和东亚季风发育的阶段性，发现了暖池海区冰消期表层水升温超前于北半球冰盖的融化。在南沙海区发现了碳同位素有40~50万年长周期，经过全球对比和对意大利上新世地层的实测与分析，证明这是世界大洋碳储库对于地球运行轨道偏心率长周期的响应，并推测是通过浮游植物群改变有机碳在海洋碳沉积中的比例所致。研究表明热带驱动和碳循环在气候演变中重要性，其正确认识是预测气候长期演变趋势的前提。是“深海973”项目总结报道之后的续篇，对上述成果作专题讨论。  相似文献   

Holocene environmental history in northwest Finnish Lapland reflected in the multi-proxy record of a small subarctic lake     

Krystyna Szeroczyńska  Andrzej Tatur  Jan Weckström  Michał Gąsiorowski  Agnieszka M. Noryśkiewicz  Elwira Sienkiewicz 《Journal of Paleolimnology》2007,38(1):25-47

A 2.5-m-long sediment core was retrieved from Lake Somaslampi, a small lake located in a kame field on the north slope of the Scandes Mountains in Finnish Lapland. Holocene environmental changes were inferred from the lithological, geochemical, pollen, diatom and Cladocera records stored in the lake sediment. The chronology was based on six radiocarbon AMS dates supported by a palynological control chronology. The sediment profile consists of a glacial sedimentary sequence truncated by a lacustrine one. A hiatus, tentatively correlated with climate cooling and advances of glaciers during the 8.2 ka yrs BP “Finse cooling Event”, occurs between these sequences. The glacial sequence was composed of fluvioglacial clastics, smoothly changing into glacio-lacustrine diatomaceous ooze deposited in a meromictic proglacial lake that covered the kame field. The meromixis was probably caused by the greater depth of the lake, the extended ice-cover, and the microbial mats covering large areas of the lake bottom. A distinct change in the biota of the glacio-lacustrine sediments indicates higher trophic conditions than during deposition of the fluvioglacial clastics. The late-Pleistocene vegetation was characterised by subarctic birch tundra vegetation (Betula–Salix–Ericaceae) with low biodiversity gradually changing to Betula–Pinus dominance in the early Holocene. The lake was deep and had a diatom inferred pH ~ 7 indicated also by the dominance of planktonic Cladocera. The base of the lacustrine sediment sequence (6,650–6,300 cal. BP) consisted of loess-rich sediment indicating an increase in eolian activity. This is also supported by the pollen record, which is dominated by more long-distant taxa such as Alnus and Pinus, and by the increased C/N ratio of the sediment. After the initial meromictic phase of the lake, an abrupt lowering of the water level occurred. Lake Somaslampi was isolated from the larger Pre-Lake Somas basin and became holomictic, shallow, much warmer and more productive, until the deterioration of climate around 3,000 yr BP and the increased input of clastics from the tundra soils. The vegetation followed the general climatic trend by gradually changing from the dominance of Betula and Pinus to the dominance of more tundra-related vegetation like Poaceae and Cyperaceae. However, the higher frequencies of planktonic Cladocera and centric diatoms in the most recent sediments indicates higher trophic conditions, increased turbulence and a prolonged ice-free period, which can possibly be linked to the recent climate warming especially in areas of higher altitude and latitude.  相似文献