基于拉格朗日方法的气流轨迹模式在判定南海夏季风爆发时间中的应用分析  

ANALYSIS ON APPLICATION OF AN AIRFLOW TRAJECTORY MODEL BASED ON LAGRANGIAN METHOD IN DETERMINATION OF THE ONSET DATE OF THE SOUTH CHINA SEA SUMMER MONSOON

作　　者：梁卓然[1,2] 江志红[1] 刘征宇[3,1] 顾婷婷[4] 

机构地区：[1]气象灾害省部共建教育部重点实验室/南京信息工程大学,江苏南京210044 [2]上海市气候中心,上海200030 [3]Center for Climatic Research,University of Wisconsin-Madison,美国 [4]浙江省气象服务中心,浙江杭州310017

出　　处：《热带气象学报》2011年第3期357-364,共8页Journal of Tropical Meteorology

基　　金：公益性行业(气象)科研专项(GYHY200906016);江苏省高校自然科学重大基础(07KJA7020)共同资助

摘　　要：利用NCEP再分析资料,驱动基于拉格朗日方法的气流轨迹模式(HYSPLITv4.9),模拟追踪南海区域850 hPa 4—6月逐日的气流后向轨迹,根据模拟出的南海监测区低层气流来源,定义1948—2009年南海夏季风的爆发日期,通过分析62年南海夏季风爆发日期的时间序列,得出南海季风爆发早年占13%,正常年占73%,爆发晚年占14%。将拉格朗日方法与两种利用风场并结合温湿指标的方法定义南海夏季风爆发时间对比发现,一些年份在南海季风爆发之前,南海监测区低空形成的西南气流来源于副热带,从而可以排除副热带气流对定义南海夏季风爆发时间的影响。由轨迹模式模拟的结果还发现在个别年份南海季风爆发时,南海区域低空盛行东南风而非通常认为的西南气流。Using U.S.National Centers for Environmental Prediction（NCEP） reanalysis data and an airflow trajectory model based on the Lagrangian method（HYSPLITv4.9）,we simulated the daily backward trajectories on the 850 hPa level above the South China Sea（SCS） area from April to June.The onset date of the South China Sea summer monsoon from 1948–2009 is determinated according to the simulated source of airflow in the monitored area of the South China Sea.With analysis of 62-year South China Sea monsoon onset dates,we found that the number of early onset years accounted for 13%,late onset years accounted for 14%,and normal onset years accounted for 73%,of the total.Comparative analyses with the Lagrangian method and two other methods were performed,which combined wind and potential pseudo-equivalent temperature in determination of the onset date of the monsoon.In some years,the southwest airflow in the monitoring area of the South China Sea originates from the subtropical region prior to the onset of the monsoon,so that the subtropical airflow can be distinguished from the tropical airflow by using the Lagrangian method.The simulation results of the trajectory model show that in some years,after the onset date of the monsoon,the South China Sea is controlled by the southeast wind instead of the southeast wind in usual time.

关 键 词：气候学 南海夏季风 拉格朗日方法 轨迹模式 

分 类 号：P426.42[天文地球—大气科学及气象学]