河南省北部一次大雾天气过程分析   总被引：1，自引：1，他引：0  

张永涛  谷秀杰  王友贺  高媛媛   《气象与环境科学》2009,32(3):29-31

利用地面观测和探空资料以及NCEP1°×1°再分析资料,分析了2007年12A25-27日河南省北部大雾的成因,结果表明：由于降水后低层相对湿度较大,大气层结稳定,地面处在均压场里,风速较小,且大气低层为弱的上升运动、中高层为强的下沉运动,有利于低层水汽聚集,使湿层达到一定的厚度,从而使垂直能见度变差,雾的浓度变大。  相似文献   

2010年6月大气环流和天气分析   总被引：3，自引：0，他引：3  

孔期 《气象》2010,36(9):120-125

2010年6月大气环流主要特征如下:极涡呈两个中心分布并偏离极地;北支锋区偏北,冷空气偏北偏弱;欧亚中高纬度位势高度偏高;低纬度地区多波动;副热带高压偏西,强度偏强。2010年6月,全国平均降水量为95.0 mm接近常年同期,全国平均气温为20.5℃,较常年同期偏高1.0℃。月内南方地区出现持续性强降水过程,共有7次暴雨过程。东北、新疆部分地区出现罕见高温天气。河北、辽宁、山东、江苏等地遭受风雹灾害。  相似文献   

2010年8月大气环流和天气分析   总被引：2，自引：0，他引：2  

赵伟 《气象》2010,36(11):109-114

2010年8月大气环流主要特征如下:极涡呈单极型,中心略偏于东半球。北半球高纬度环流呈4波型分布,欧洲西北部、新地岛附近为低于-40 gpm负距平所控制。西北太平洋副热带高压面积较常年同期偏大,强度显著偏强,位置异常偏西。2010年8月,全国平均气温为21.4℃,比常年同期(20.3℃)偏高1.1℃。全国平均降水量为108.1 mm,比常年同期(102.6 mm)偏多5.5 mm。月内出现了14次降水过程,共有5个热带风暴生成,其中1008号热带风暴南川在福建登陆。江淮、江南、华南北部、重庆、四川东部及新疆南部等地高温日数异常偏多。  相似文献   

FY2卫星云图分析系统在热带气旋北冕过程中的应用   总被引：1，自引：0，他引：1  

何立  覃丹宇  黄小燕  徐建文 《气象》2010,36(9):21-28

利用FY2卫星云图分析系统的各项分析功能,结合常规观测资料对热带气旋北冕的天气形势、云图演变以及路径变化、风雨情况等进行了分析。结果表明,副热带高压摆动,中纬度西风小槽东移,低层西南气流加强和减弱是"北冕"出现两次北抬和一次南折的直接原因;对流云团的发展和减弱对应低层西南气流的加强和减弱;强降水与云顶亮温的最低值中心及强度密切相关,而云团面积和云顶亮温与强降水也有很好的对应关系,其中发展的云系是强降水发生的信号。FY2卫星云图分析系统较好地分析了"北冕"整个过程的变化特点,对于短时临近预报有较好的辅助作用。  相似文献   

Radar Data Assimilation for the Simulation of Mesoscale Convective Systems     

Jo-Han LEE  Dong-Kyou LEE  Hyun-Ha LEE  Yonghan CHOI  Hyung-Woo KIM 《大气科学进展》2010,27(5):1025-1042

A heavy rainfall case related to Mesoscale Convective Systems (MCSs) over the Korean Peninsula was selected to investigate the impact of radar data assimilation on a heavy rainfall forecast. The Weather Research and Forecasting (WRF) three-dimensional variational (3DVAR) data assimilation system with tuning of the length scale of the background error covariance and observation error parameters was used to assimilate radar radial velocity and reflectivity data. The radar data used in the assimilation experiments were preprocessed using quality-control procedures and interpolated/thinned into Cartesian coordinates by the SPRINT/CEDRIC packages. Sensitivity experiments were carried out in order to determine the optimal values of the assimilation window length and the update frequency used for the rapid update cycle and incremental analysis update experiments. The assimilation of radar data has a positive influence on the heavy rainfall forecast. Quantitative features of the heavy rainfall case, such as the maximum rainfall amount and Root Mean Squared Differences (RMSDs) of zonal/meridional wind components, were improved by tuning of the length scale and observation error parameters. Qualitative features of the case, such as the maximum rainfall position and time series of hourly rainfall, were enhanced by an incremental analysis update technique. The positive effects of the radar data assimilation and the tuning of the length scale and observation error parameters were clearly shown by the 3DVAR increment.  相似文献   

ATOVS资料在淮河暴雨预报中的同化应用研究   总被引：2，自引：1，他引：1  

郭锐  李泽椿  张国平 《气象》2010,36(2):1-12

ATOVS资料的获取弥补了测站稀少地区常规观测资料的不足,尤其是有云条件下的温湿资料,这两种资料对于模式的降水预报极为重要。采用T213-SSI业务系统,对全球NOAA16、17的ATOVS资料进行同化试验,分析了ATOVS资料在极端暴雨天气预报中的应用效果。对2007年7月7—9日发生在淮河流域的一次暴雨过程进行数值模拟研究,设计3种同化方案,对比分析了不同方案的同化模拟结果。试验表明:长期同化AMSU资料,可以改善降水预报,尤其是降水强度的改善明显。通过连续同化,卫星资料能改进大尺度环境场、温湿场和动力场。剔除AMSU-A地面通道及低层700 hPa通道资料的同化效果要优于全部同化,对于暴雨中心的模拟位置、强度有较明显改进,中高层形势场的降水直接影响系统也更加接近实况,温湿场、风场的调整作用尤其明显。  相似文献   

AREM模式中引入MYJ边界层方案介绍及其试验     

蒋兴文  何光碧  李跃清 《四川气象》2010,(4):1-7

业务实践表明,AREM模式对中国暴雨有较好的模拟能力。当前AREM模式中可供选择的边界层参数化方案比较单一,而不同边界层方案对暴雨的模拟差异较大,所以在AREM中引入一种新的边界层方案是提高其性能的一个重要方面。本文介绍了在AREM模式中引入Mellor-Yamada-Janjic′（MYJ）边界层方案的关键技术与流程,并对MYJ方案的模拟能力进行了评估。模式对2008年四川暴雨的模拟结果表明,MYJ方案有助于改善模式预报的降雨落区位置。  相似文献   

苏尼特左旗春季一次大雨天气诊断分析     

郑晓艳  胡敬华  鲁双宁 《内蒙古气象》2010,(5):15-17

应用常规气象资料、卫星云图,对2009年4月23日苏尼特左旗对流性大雨天气的成因进行了诊断。分析了产生大雨的天气系统特征,大气垂直稳定度,产生大雨的水汽条件和动力触发机制。给出了产生大雨的对流云团演变特征。研究结果表明：对流性大雨是由高空冷涡、蒙古气旋共同影响产生的。低层强盛的偏南气流建立起水汽通道,把水汽源源不断地向大雨区输送。低涡槽结构和低层增温增湿气流侧向汇合,垂直涡度增大,辐合上升运动增强,对流不稳定能量释放,继而产生对流性大雨天气。  相似文献   

一次暴雨过程的动力诊断   总被引：3，自引：2，他引：1  

吴启树  郑颖青  林金凎  赖绍钧  龚振彬 《气象科技》2010,38(1):21-25

应用常规观测资料及NCEP再分析资料,对2008年5月21日福建中部地区暴雨成因进行诊断分析。结果表明:此次强降水位于水汽通量散度平流项与散度项辐合配置较好区域;高层较强涡度平流促进福建中部地区上升运动;差动假相当位温平流增强大气不稳定度,促进垂直上升运动;低层水平运动锋生中心的位置和强度与未来6h降水中心位置和强度较为一致。  相似文献   

A Study on a Heavy Rainfall Event Triggered by an Inverted Typhoon Trough in Shandong Province   总被引：2，自引：0，他引：2       下载免费PDF全文

ZHAO Yu  CUI Xiaopeng  WANG Jianguo 《Acta Meteorologica Sinica》2009,23(4):468-484

A heavy rainfall event that occurred in Shandong Province in 26 28 August 2004 was caused mainly by Typhoon Acre and cold air activities related to a westerly trough. The event was triggered by an inverted typhoon trough, which was closely associated with the intensification of the low-level southeasterly flow and the northward transport of heat and momentum in the periphery of the typhoon low. A numerical simulation of this event is performed using the nonhydrostatic mesoscale model MM5 with two-way interactive and triply-nested grids, and the structure of the inverted typhoon trough is studied. Furthermore, the formation and development mechanism of the inverted typhoon trough and a mesoscale vortex are discussed through a vorticity budget analysis. The results show that the heavy rainfall was induced by the strong convergence between the strong and weak winds within the inverted typhoon trough. Dynamic effects of the low-level jet and the diabatic heating of precipitation played an important role in the development of the inverted typhoon trough and the formation of the mesoscale vortex. The vorticity budget analysis suggests that the divergence term in the low troposphere, the horizontal advection term, and the convection term in the middle troposphere were main contributors to positive vorticity. Nonetheless, at the same pressure level, the effect of the divergence term and that of the adveetion term were opposite to each other. In the middle troposphere, the vertical transport term made a positive contribution while the tilting term made a negative contribution, and the total vorticity tendency was the net result of their counteractions. It is found that the change tendency of the relative vorticity was not uniform horizontally. A strong positive vorticity tendency occurred in the southeast of the mesoscale vortex, which is why the heavy rainfall was concentrated there. The increase of positive vorticity in the low （upper） troposphere was caused by horizontal convergence （upward transport of vorticity from the lower troposphere）. Therefore, the development of the inverted typhoon trough and the formation of the mesoscale vortex were mainly attributed to the vorticity generated in the low troposphere, and also the vertical transport of vorticity from the low and middle troposphere.  相似文献