近50年华南沿海SST热事件变化的时空特征          下载免费PDF全文

郑兆勇  周雄  江四义  蔺明霞  游大伟  吕柏明 《热带海洋学报》2010,29(4)

根据华南沿海10个海洋站1960-2009年实测海表温度(SST)资料统计分析了近50年华南沿海SST热事件时空变化特点,得出如下结论:华南沿海SST热事件主要出现在6-8月份,SST热事件出现的频率以北部湾东北部海域最高,粤东沿海最低;导致SST热事件海区差异的原因是上升流及热带气旋存在海区差异;受全球气候变暖的影响,华南沿海年均SST有上升趋势,近50年来气候变化可划分为冷、暖两个时期,其相对暖期SST热事件的年频数、累计天数、每次SST热事件持续天数较相对冷期均有增加趋势.  相似文献   

一种遥感信息服务分类本体构建方法     

詹勤  李德仁  眭海刚  张霞 《武汉大学学报(信息科学版)》2010,(3)

在分析遥感信息服务的领域特征及其概念的事件名词特点的基础上,结合框架语义学理论,提出了基于事件框架提取遥感信息服务概念的语义特征并在此基础上利用形式概念分析构建遥感信息服务分类本体的方法。实验结果表明了此方法的有效性。  相似文献   

50年来十大测绘科技事件发布     

《测绘学报》2010,(1)

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主编手记     

屠强 《海洋世界》2012,(10):5-5

最近一个月以来,海洋的热度突然急剧增温。虽然这主要拜日本对我钓鱼岛掀风作浪所赐,但由此引起公众对海洋事务更为广泛的关注也未尝不是一件好事。不过,在钓鱼岛事件过程中引发的诸多社会反应,也揭示了一些平时被掩盖的问题——并不完全是海洋问题。《海洋世界》杂志很少就海洋以外的社会问题展开评述,但是目睹这些发生在我们身边  相似文献   

基层、网络、“马锡五”应对信访的衡阳模式     

《湖南地质》2010,(6):23-24

随着中国城市化迅猛推进，针对土地而引发的上访事件愈来愈多，其涉及的情况也越来越复杂。衡阳市正开始新一轮城镇化建设浪潮，也同样遇到了土地信访难题，在工农和城乡争地的大背景下，信访新政成为突破瓶颈的现实路径。  相似文献   

7·23事件赔偿法律依据存疑     

陈云良 《湖南地质》2011,(8):16-16

在《中华人民共和国侵权责任法》已经出台的今日,沿用这样一个行政法规本身就是没有任何法律依据的。  相似文献   

欺骗攻击下一类神经网络的自适应事件触发H_∞滤波     

王锦霞  高金凤  谭天 《南京气象学院学报》2021,13(1):102-110

本文主要研究了在欺骗攻击下的离散时间神经网络的H_∞滤波器设计问题.考虑到被控系统和滤波器在一个易受外部网络攻击且带宽有限的共享通信网络上进行信息交换,本文提出了自适应事件触发机制来减轻数据传输的通信负担.此外,由于通信网络的开放性和互通互联,通过共享通信网络传输到滤波器的实际输入信息可能会被攻击者注入的虚假信息所改变.在此基础上,利用构造Lyapunov-Krasovskii泛函、线性矩阵不等式等处理技术,本文给出了滤波误差系统渐近稳定的充分条件,并且设计了满足预设性能的H_∞滤波器,最后通过一个仿真实例验证了所提方法的有效性.  相似文献   

Possible Linkage Between Tropical Indian Ocean SST Anomalies and the Date ofFirst and Last Tropical Cyclones Landfalling in the Chinese Mainland     

周群  魏立新  李敏 《热带气象学报(英文版)》2022,28(1):71-81

Bases on the NCEP / NCAR reanalysis products, HadISST dataset, and data of tropical cyclone (TC)landfalling in the Chinese mainland during 1960-2019, the possible impacts of Indian Ocean Dipole (IOD) mode andIndian Ocean basin (IOB) mode on the last-TC-landfall date (LLD) and first-TC-landfall date (FLD), respectively, areinvestigated in this study. The LLD is in significantly negative correlation with autumn IOD on the interannual time-scale and their association is independent of El Ni?o-Southern Oscillation (ENSO). The LLD tends to be earlier when theIOD is positive while becomes later when the IOD is negative. An anomalous lower-level anticyclone is located aroundthe Philippines during October-November, resulting from the change of Walker circulation over the tropical Indo-westPacific Ocean forced by sea surface temperature (SST) anomalies related to a positive IOD event. The Philippinesanticyclone anomaly suppresses TCs formation there and prevents TCs from landfalling in the Chinese mainland due tothe anomalous westerly steering flows over southeast China during October-November, agreeing well with the earlierLLD. However, the robust connection between spring IOB and FLD depends on ENSO episodes in preceding winter.There is an anticyclonic anomaly around the Philippines caused by the tropical SST anomalies through modulating theWalker circulation during May-June when the IOB is warming in the El Ni?o decaying phase. Correspondingly, the TCsgenesis is less frequent near the Philippines and the mid-level steering flows associated with the expanded westernPacific subtropical high are disadvantageous for TCs moving towards southeast China and making landfall during May-June, in accordance with the later FLD. By contrast, cooling IOB condition in spring of a La Ni?a decaying year andnegative IOD cases during autumn could produce a completely reversed atmospheric circulation response, leading to anearlier FLD and a later LLD over the Chinese mainland, respectively.  相似文献   

Interdecadal Change in the Interannual Variation of the Western Edge of theWestern North Pacific Subtropical High During Early Summer and the Influenceof Tropical Sea Surface Temperature     

詹鸿宇  陈锐丹  蓝铭 《热带气象学报(英文版)》2022,28(1):57-70

This study reveals that the interannual variability of the western edge of the western North Pacific (WNP) subtropical high (WNPSH) in early summer experienced an interdecadal decrease around 1990. Correspondingly, the zonal movement of the WNPSH and the zonal extension of the high-pressure anomaly over the WNP (WNPHA) in abnormal years possess smaller ranges after 1990. The different influences of the tropical SSTAs are important for this interdecadal change, which exhibit slow El Ni?o decaying pattern before 1990 while rapid transformation from El Ni?o to La Ni?a after 1990. The early summer tropical SSTAs and the relevant atmospheric circulation anomalies present obvious interdecadal differences. Before 1990, the warm SSTAs over the northern Indian Ocean and southern South China Sea favor the WNPHA through eastward-propagating Kelvin wave and meridional-vertical circulation, respectively. Meanwhile, the warm SSTA over the tropical central Pacific induces anomalous ascent to its northwest through the Gill response, which could strengthen the anomalous descent over the WNP through meridional-vertical circulation and further favor the eastward extension of the WNPHA to central Pacific. After 1990, the warm SSTAs over the Maritime Continent and northern Indian Ocean cause the WNPHA through meridional-vertical and zonal-vertical circulation, respectively. Overall, the anomalous warm SSTs and ascent and the resultant anomalous descent over the WNP are located more westward and southward after 1990 than before 1990. Consequently, the WNPHA features narrower zonal range and less eastward extension after 1990, corresponding to the interdecadal decease in the interannual variability of the western edge of the WNPSH. On the other hand, the dominant oscillation period of ENSO experienced an interdecadal reduction around 1990, contributing to the change of the El Ni?o SSTA associated with the anomalous WNPSH from slow decaying type to rapid transformation type.  相似文献   

热带大西洋海温异常季节内演变对中国江南地区夏季持续性高温事件影响的初步研究     

王慧美  刘舸  彭京备  纪立人 《大气科学》2021,45(2):300-314

中国江南地区是高温热浪灾害的高影响区。以往的一些研究发现了不同海域海温异常在年际或年代际尺度上的变化对中国南方夏季平均温度异常的影响效应。但是,关于这些关键海域海温季节内尺度变化对江南地区高温事件发生和维持影响的研究尚不多见。为此,本文利用中国站点观测、美国气象环境预报中心和美国国家大气研究中心（NCEP/NCAR）再分析以及美国国家海洋大气管理局（NOAA）海温等资料,首先以2016年江南地区夏季2次高温事件为例（分别发生在7月21日至31日和8月15日至25日）,重点探讨了热带大西洋海温季节内变化的可能贡献。在此基础上,基于1981～2016年多高温事件合成结果,进一步分析了热带大西洋海温季节内变化影响江南高温事件的可能链接过程。研究发现,热带西大西洋暖海温异常在季节内尺度上的发展与维持有利于在欧亚大陆激发出较为稳定的Rossby波列结构,使东亚及其沿海地区为深厚的高压系统控制,进而引发江南地区持续性高温事件。这种热带大西洋暖海温的阶段性增强与维持及其相应的稳定Rossby波列结构超前于持续性高温事件:在热带大西洋海温显著升高1个月之内,江南地区可能出现持续性高温事件。在季节内尺度上,热带大西洋显著暖海温异常出现明显的阶段性增强之后10天左右,北印度洋暖海温也出现了阶段性增强。这暗示热带大西洋热力异常除通过直接激发欧亚大陆Rossby波列之外,还有可能通过影响热带印度洋海温的阶段性异常,进而对江南地区高温事件的发生和维持产生一定影响。另外,在厄尔尼诺衰减并向拉尼娜转变阶段,热带中东太平洋冷海温异常和北印度洋暖海温异常在季节内的协同阶段性变化可能也对持续性高温事件有贡献。上述关键区海温的季节内变化对中国江南地区高温事件具有一定的前期指示意义,但它们的具体影响过程,特别是在季节内尺度上的协同影响效应和物理过程,尚需未来进一步研究。  相似文献