南海登陆热带气旋与浙北山梅期     

孙彭龄 《海洋预报》1994,(2)

对１９５４年以来南海登陆的热带气旋与浙北地区出梅期进行了比较系统的分析，发现热带气旋登陆造成出梅的概率占登陆热带气旋总数的５４％，在南海的北部和西北部登陆的热带气旋，使浙北地区出梅的概率远高于南海其他区域登陆热带气旋的出梅概率。通过对出海和出梅热带气旋的环流型及前期环境流场特征的对比分析，揭示出两者在西太平洋副高和西风帝系统存在着明显的差异。  相似文献   

A Large-Scale Seasonal Modeling Study of the California Current System   总被引：1，自引：0，他引：1  

Mary L. Batteen  Nicholas J. Cipriano  James T. Monroe 《Journal of Oceanography》2003,59(5):545-562

A high-resolution, multi-level, primitive equation ocean model has been used to investigate the combined role of seasonal wind forcing, seasonal thermohaline gradients, and coastline irregularities on the formation of currents, meanders, eddies, and filaments in the entire California Current System (CCS) region, from Baja to the Washington-Canada border. Additional objectives are to further characterize the meandering jet south of Cape Blanco and the seasonal variability off Baja. Model results show the following: All of the major currents of the CCS (i.e., the California Current, the California Undercurrent, the Davidson Current, the Southern California Countercurrent, and the Southern California Eddy) as well as filaments, meanders and eddies are generated. The results are consistent with the generation of eddies from instabilities of the southward current and northward undercurrent via barotropic and baroclinic instability processes. The meandering southward jet, which divides coastally-influenced water from water of offshore origin, is a continuous feature in the CCS, and covers an alongshore distance of over 2000 km from south of Cape Blanco to Baja. Off Baja, the southward jet strengthens (weakens) during spring and summer (fall and winter). The area off southern Baja is a highly dynamic environment for meanders, filaments, and eddies, while the region off Point Eugenia, which represents the largest coastline perturbation along the Baja peninsula, is shown to be a persistent cyclonic eddy generation region. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Contribution of Mesoscale Eddies to the Subduction and Transport of North Pacific Eastern Subtropical Mode Water     

YANG Zhitong  LUO Yiyong 《中国海洋大学学报(英文版)》2020,19(1):36-46

This study investigates the contribution of mesoscale eddies to the subduction and transport of North Pacific Eastern Subtropical Mode Water(ESTMW)using the high-frequency output of an eddy-resolved ocean model spanning the period 1994–2010.Results show that the subduction induced by mesoscale eddies accounts for about 31%of the total subduction of ESTMW formation.The volume of ESTMW trapped by anticyclonic eddies is slightly larger than that trapped by cyclonic eddies.The ESTMW trapped by all eddies in May reaches up to about 2.8×1013m3,which is approximately 16%of the total ESTMW volume.The eddy-trapped ESTMW moves primarily westward,with its meridional integration at 18°–30°N reaching about 0.17Sv,which is approximately 18%of the total zonal ESTMW transport in this direction,at 140°W.This study highlights the important role of eddies in carrying ESTMW westward over the northeastern Pacific Ocean.  相似文献   

The Initial Mesoscale Vortexes Leading to the Formation of Tropical Cyclones in the Western North Pacific     

Shenglan WU  Juan FANG 《大气科学进展》2023,40(5):804-823

A statistical analysis of the initial vortexes leading to tropical cyclone(TC) formation in the western North Pacific(WNP) is conducted with the ECMWF ERA5 reanalysis data from 1999 to 2018. It is found that TCs in the WNP basically originate from three kinds of vortexes, i.e., a mid-level vortex(MV), a low-level vortex(LV), and a relatively deep vortex with notable vorticity in both the lower and middle troposphere(DV). Among them, LV and DV account for 47.9% and24.2% of tropical cyclogenesis e...  相似文献   

On the Key Dynamical Processes Supporting the 21.7 Zhengzhou Record-breaking Hourly Rainfall in China     

Peng WEI  Xin XU  Ming XUE  Chenyue ZHANG  Yuan WANG  Kun ZHAO  Ang ZHOU  Shushi ZHANG  Kefeng ZHU 《大气科学进展》2023,40(3):337-349

An extremely heavy rainfall event occurred in Zhengzhou, China, on 20 July 2021 and produced an hourly rainfall rate of 201.9 mm, which broke the station record for mainland China. Based on radar observations and a convection-permitting simulation using the WRF-ARW model, this paper investigates the multiscale processes, especially those at the mesoscale,that support the extreme observed hourly rainfall. Results show that the extreme rainfall occurred in an environment characteristic of warm-sec...  相似文献   

湖南一次暖区暴雨的Barnes滤波客观分析          下载免费PDF全文

蔡海朝  刘红武  邓梅  王萍 《中低纬山地气象》2018,42(3):51-57

利用ECMWF高分辨率0.25×0.25格点资料、逐小时加密雨量观测资料,基于Barnes滤波原理,设计了3套从格点资料中提取中α尺度气象信息的方案,对2017年4月8日湖南的一次暖区暴雨过程进行Barnes滤波对比客观分析。结果表明:此次强降水过程发生在高空槽南侧的西南暖湿气流中,中尺度扰动是造成此次暖区暴雨的重要原因;通过选取不同参数的Barnes带通滤波方案,能够有效分离出中α尺度天气系统,进而剖析其一致性和差异特征,对中尺度雨团落区预报有很好的指示作用,同时,也可以作为判断滤波过程中产生虚假系统的参考依据,在实际业务应用中意义重大。  相似文献   

北大西洋爆发性气旋的统计特征   总被引：1，自引：0，他引：1  

孙雅文  傅刚  张树钦 《气象学报》2018,76(2):169-181

利用National Centers for Environmental Prediction（NCEP）提供的Final Analysis（FNL）再分析资料,对2000-2015年冷季（10月至次年4月）北大西洋上的爆发性气旋进行了分析,综合考虑气旋中心位置经向分布特征和海面10 m高风场对爆发性气旋的定义进行了修订。根据气旋中心海表面气压最大加深率的空间分布,发现北大西洋爆发性气旋主要发生在4个区域,即:北美大陆区、西北大西洋区、北大西洋中央区和东北大西洋区。整个北大西洋区爆发性气旋个数随海表面中心气压最大加深率增大而减少,自西向东气旋强度增强,气旋移动路径呈西南-东北向。按气旋强度等级可分为4类:超强（≥ 2.15 Bergeron（Ber））、强（1.75-2.14 Ber）、中（1.45-1.74 Ber）、弱（1.00-1.44 Ber）爆发性气旋。在北大西洋海盆区,自西南向东北爆发性气旋的个数逐渐减少,爆发时长变短。西北大西洋区气旋中心气压加深率最大,爆发时长最长。东北大西洋区加深率最小,爆发时长最短。东北大西洋区爆发性气旋主要发生在12月,北大西洋中央区主要发生在12月-次年3月,西北大西洋区主要发生在1-2月。与海上相比,北美大陆区爆发性气旋发生个数少,强度弱,爆发时长短。   相似文献   

Locating Parent Lightning Strokes of Sprites Observed over a Mesoscale Convective System in Shandong Province,China     

Anjing HUANG  Gaopeng LU  Hongbo ZHANG  Feifan LIU  Yanfeng FAN  Baoyou ZHU  Jing YANG  Zhichao WANG 《大气科学进展》2018,35(11):1396-1414

In this paper, we report the location results for the parent lightning strokes of more than 30 red sprites observed over an asymmetric mesoscale convective system(MCS) on 30 July 2015 in Shandong Province, China, with a long-baseline lightning location network of very-low-frequency/low-frequency magnetic field sensors. The results show that almost all of these cloud-to-ground(CG) strokes are produced during the mature stage of the MCS, and are predominantly located in the trailing stratiform region, which is similar to analyses of sprite-productive MCSs in North America and Europe. Comparison between the location results for the sprite-producing CG strokes and those provided by the World Wide Lightning Location Network(WWLLN) indicates that the location accuracy of WWLLN for intense CG strokes in Shandong Province is typically within 10 km, which is consistent with the result based on analysis of 2838 sprite-producing CG strokes in the continental United States. Also, we analyze two cases where some minor lightning discharges in the parent flash of sprites can also be located, providing an approach to confine the thundercloud region tapped by the sprite-producing CG strokes.  相似文献   

山东省初秋一次大范围强对流过程落区和抬升触发机制分析   总被引：5，自引：3，他引：2  

侯淑梅  王秀明  尉英华  李婕  张骞  谷山青 《气象》2018,44(1):80-92

利用常规观测、加密自动站、多普勒天气雷达、风廓线雷达及NCEP再分析资料,对2016年9月11日山东省初秋大范围强对流天气的落区和抬升触发机制进行了分析。结果表明:受高空槽影响,有、无对流区上空大气层结均不稳定,大的对流有效位能(CAPE)与小的对流抑制能量(CIN)环境条件下,强对流云团呈现"遍地开花型",抬升触发成为强对流发生的关键因素。地面辐合线、干线、海风锋、冷池出流是主要的抬升触发系统。由于对流抑制小,抬升强迫一般不需要太强,不同区域雷暴的抬升机制不同,鲁西北地区强对流天气由地面辐合线抬升触发,山东半岛地区的对流是由海风锋与冷锋共同触发,而鲁中地区强对流则由老的雷暴的冷池前沿阵风锋抬升触发,鲁东南地区的对流是由干线与地面辐合线共同作用造成的。辐合线抬升强迫的大小很重要,其量化可通过边界层散度衡量。在同样具备地面辐合线的情况下,不同温湿性质气团的中尺度边界对雷暴触发起关键作用。预报落区的偏差主要是因为短期阶段无法获取低空东南风气流这一关键中尺度系统,不同起报时间模式预报的调整趋势、季节等因素是对流强度预报偏弱的主要原因。经验表明,通过对大量个例的分析研究,提高对数值模式的订正能力是提高预报准确率的有效方法。  相似文献   

Passage of Tropical Storm Allison (2001) over southeast Texas recorded in δO values of Ostracoda     

James R. Lawrence  Kiseong Hyeong  Kwang-Sik Lee 《Quaternary Research》2008,70(2):339-342

Freshwater Ostracoda collected in ephemeral pond-waters derived from Tropical Storm Allison (2001, Texas) recorded the unusually low oxygen-isotope values of that storm. Therefore, the potential clearly exists, in locations where tropical cyclones make landfall, to obtain a long-term record of tropical cyclone activity from fossil ostracode calcite.  相似文献