进入渤海的热带气旋路径特点分析     

张晓慧  卢霞  陈金龙 《海洋预报》2003,20(4):1-4

热带气旋是夏季影响渤海的灾害性天气系统之一。其影响路径主要有三类，各类路径在影响时前期中高纬500hPa高空环流形势及夏季西太平洋副热带高压特征指数有显著差异。  相似文献   

台风活动对副热带高压位置和强度的影响   总被引：9，自引：7，他引：9  

李春虎  黄福均  罗哲贤 《高原气象》2002,21(6):576-582

利用一个浅水模式，实施了6组时间积分为4－5个模式日的试验，研究了台风对副热带高压中心位置及强度的影响。结果表明：台风和副热带高压的相互作用可以使高压中心位置西移,强度增加。据此讨论了台风活动和西北地区东部干旱之间统计联系的可能机制。  相似文献   

MTCLIM模型系列研究报告(4):辐射估算方法在我国南方亚热带山地的改进   总被引：2，自引：0，他引：2  

李海涛  夏军  沈文清  刘琪憬  于贵瑞 《山地学报》2003,21(5):542-551

以已有的数据、理论和模型为基础,在我国南方亚热带山地对MTCLIM模型的辐射估算方法进行了改进,对模型参数作了重新估计。经过改进后,辐射子模型中的参数B的变化不再用月平均温差表示,而是用月平均水汽压来表示。交互验证估计参数的方法能消除不良数据的影响,获得较好的模拟效果,最后估计的参数T0 nadir.dry、α、C、a和b分别为0 823、0 000039、1 7、0 0173和0 0000122。与用原来参数估计的结果相比,参数估计后预测的日总辐射结果有明显改善,相关系数R2从原来的0 55～0 73提高到0 65～0 82,总平均绝对误差从原来的3 81MJ/m·d-1降低为2 90MJ/m·d-1,减少了约1MJ/m·d-1。  相似文献   

孟加拉湾季风爆发对南海季风爆发的影响Ⅰ:个例分析   总被引：11，自引：4，他引：11       下载免费PDF全文

刘屹岷  陈仲良  毛江玉  吴国雄 《气象学报》2003,61(1):1-9

利用南海季风试验分析场和NCAR向外长波辐射通量(OLR)资料研究了1998年孟加拉湾季风和南海季风爆发期间副热带环流的大尺度和天气尺度特征,探讨了孟加拉湾季风爆发与南海季风爆发之间的物理联系及孟加拉湾季风气旋的对流凝结潜热释放对副热带高压“撤出”南海的影响。结果表明,1998年5月爆发的东亚季风展现出典型的从孟加拉湾地区东传发展到南海地区的过程。随着孟加拉湾季风爆发和对流活动增强、北移,南海北部出现了低层西风和对流活动,领先于副热带高压在南海地区减弱和撤退。结果还显示南海北部地区的对流凝结加热有助于该地区经向温度梯度的反转,在热成风关系的制约下南海上空副热带高压脊面的垂直倾斜由冬季型转向夏季型,季风爆发。  相似文献   

集合预报及其在中期天气预报中的应用   总被引：3，自引：1，他引：3       下载免费PDF全文

李小泉  刘金达  汪迎辉 《气象》1997,23(8):3-9

作者概述了集合预报的基本概念，集合预报中期天气预报中的意义与作用，现有的主要集合预报产品以及集合预报在美国美国国家气象中心和欧洲中期天气预报的业务运行。简要介绍了我国国家气象中心在动力延伸预报和集合预报方面的试验研究情况。  相似文献   

华北夏季旱涝的前期环流异常及其与北太平洋海温的关系   总被引：10，自引：1，他引：10  

朱平盛  张苏平 《应用气象学报》1997,8(4):437-444

文章分析了华北地区夏季旱涝的前期春季大气环流和北太平洋海温异常（ＳＳＴＡ）分布特征，探讨ＳＳＴＡ与异常环流的关系，并用ＯＳＵ－ＡＧＣＭ进行黑潮地区热源异常强迫的数值试验．结果表明，当春季北极低涡明显减弱，欧亚大陆中高纬度地区纬向环流加强，西太平洋副高位置偏北偏西，且存在负ＰＮＡ型异常环流时，华北地区夏季多雨涝；反之则少雨干旱．此时，西北太平洋和赤道东太平洋ＳＳＴ分别存在较大的正、负异常，它们与春季环流异常密切相关，黑潮区ＳＳＴＡ对北半球副热带及其以北的大气环流产生显著影响，正的ＳＳＴＡ是造成华北夏涝年的前期春季异常环流形势的重要因素．  相似文献   

北太平洋副热带模态水盐度的年代际变化     

胡睿坤  边志刚  刘子洲  刘聪  翟方国  顾艳镇 《中国海洋大学学报(自然科学版)》2020,(2):9-21

副热带模态水(Subtropical Mode Water;STMW)在气候变化中起着重要作用。本文利用全球高分辨率数值模拟结果,研究了北太平洋STMW核心层盐度(Core Layer Salinity;CLS)的年代际变化及其物理机制。结果表明,CLS存在显著的年代际变化,其空间分布则与背景流场分布特征有关。侵蚀区CLS滞后生成区CLS约1~2年,这主要是海流平流输运引起的。生成区内,STMW的季节循环一般可分为生成期(12-4月)、隔离期(5-6月)和侵蚀期(7-11月),生成期混合层盐度(Mixed Layer Salinity;MLS)决定着隔离期和侵蚀期的CLS,而MLS年代际变化则主要由同太平洋年代际涛动存在负相关性的海表面淡水通量的变化引起。  相似文献   

THERMAL FORCING IMPACTS OF THE EASTERLY VORTEX ON THE EAST-WEST SHIFT OF THE SUBTROPICAL ANTICYCLONE OVER WESTERN PACIFIC OCEAN     

姚秀萍  孙建元 《热带气象学报(英文版)》2016,22(1):51-56

By employing the NCEP/NCAR reanalysis data sets(1 000 to 10 hPa,2.5°× 2.5°),the thermal forcing impacts are analyzed of an easterly vortex(shortened as EV) over the tropical upper troposphere on the quasi-horizontal movement of the Western Pacific Subtropical Anticyclone(shortened as WPS A) during 22-25 June 2003.The relevant mechanisms are discussed as well.It is shown that the distribution and intensity of the non-adiabatic effect near the EV result in the anomalous eastward retreat of the WPSA.The WPSA prefers extending to the colder region,i.e.,it moves toward the region in which the non-adiabatic heating is weakening or the cooling is strengthening.During the WPSA retreat,the apparent changes of non-adiabatic heating illustrate the characteristics of enhanced cooling in the east side of the EV.Meanwhile,the cooling in the west side exhibits a weakened eastward trend,most prominently at 300 hPa in the troposphere.The evidence on the factors causing the change in thermal condition is found:the most important contribution to the heating-rate trend is the vertical transport term,followed in turn by the local change in the heating rate term and the horizontal advection term.As a result,the atmospheric non-adiabatic heating generated by the vertical transport and local change discussed above is mainly connected to the retreat of the WPSA.  相似文献   

The cause of the spring strengthening of the Antarctic polar vortex     

《Dynamics of Atmospheres and Oceans》2019

The stratospheric polar vortex strengthening from late winter to spring plays a crucial role in polar ozone depletion. The Arctic polar vortex reaches its peak intensity in mid-winter, whereas the Antarctic vortex usually strengthens in early spring. As a result, the strong ozone depletion is observed every year over the Antarctic, while over the Arctic short-term ozone loss occasionally occurs in late winter or early spring. However, the cause of such a difference in the life cycles of the Arctic and Antarctic polar vortices is still not completely clear. Based on the ERA-Interim reanalysis data, we show a high agreement between the seasonal variations of temperature in the subtropical lower stratosphere and zonal wind in the subpolar and polar lower stratosphere in the Southern Hemisphere. Thus, the spring strengthening of the Antarctic polar vortex can occur due to the seasonal temperature increase in the subtropical lower stratosphere in this period.  相似文献   

Synoptic analysis of sea level pressure patterns and Vertically Integrated Moisture Flux Convergence VIMFC during the occurrence of durable and pervasive rainfall in Iran     

《Dynamics of Atmospheres and Oceans》2019

To carry out this research, interpolated data of daily rainfall from Iran’s Asfazari data base during 1/1/1979–31/12/2013 is used. The day along with pervasive rainfall considered a day that at least 50% of Iran’s territory has received more than 1 mm for at least two consecutive days. Based on mentioned thresholds, 224 days selected for statistical analysis. The sea level pressure data, zonal and meridional wind components and specific humidity with spatial resolution of 0.25*0.25 Gaussian degree in spatial domain of 10 °N to 60 °N and 15 °E to 75 °E obtained from the European Center for Medium range Weather Forecasting (ECMWF) ERA-Interim for selected days. Then on the data matrix of sea level pressure, the cluster analysis by Ward linkage method done and 4 sea level pressure patterns with different configuration of synoptic systems were identified. The findings showed that in the sea level, the interaction between southern thermal low pressure systems (Arabia low pressure) with Europe and Siberia cold immigrant high pressure both by individual and integration and anticyclone circulation of Arab sea from the low level of 1000–500 hPa of troposphere have the most role on occurrence of durable and pervasive rainfall of Iran. The most Vertically Integrated Moisture Flux Convergence in the first layer of troposphere (1000–850 hPa) observed in low height regions, in the second layer of troposphere (775–700 hPa) on Zagros Mountains and in third layer of troposphere (600–500 hPa) is seen in mountains leeward of Iran. Also the results showed that the maximum rainfall cores has the most coordination with Vertically Integrated Moisture Flux Convergence (VIMFC) in the second layer of troposphere (775–700 hPa) on the Zagros heights in the southwest of Iran.  相似文献