塔克拉玛干沙漠腹地气流轨迹模拟

Simulation of airflow trajectories in the center of Taklimakan Desert

文中采用NCEP 1°×1°再分析资料,利用美国NOAA空气资源实验室（ARL）研发的混合单粒子拉格朗日综合轨迹模式Hysplit,对2011--2012年春季到达塔中气象站上空近地面和海拔5000m两个高度上气流的3天后向轨迹进行了聚类分析。2011--2012年春季,气流轨迹主要有西北路径和西方路径两种。各个高度上两种路径均有出现,但均以西方路径为主,分别占轨迹总数的90、和81%。在2011年春季分别占93和91%,在2012年春季分别为65和88%。随着高度的升高,西方路径比重增大,而西北路径比重减小。本次轨迹模式聚类分析的结果进一步定量印证了气流在高空的纬向性传播特征,在近地面与寒潮高压的传输路径有关。

Based on the NCEP（ National Centers for Environment Prediction） reanalysis GDAS（ Global Data Assimilation System） from ARL（ ftp： / / arlftp. arlhq. noaa. gov / pub / archives / gdas1 /） with spatial resolution 1° ×1°,a cluster algorithm was implemented to analyze the backward trajectories arriving at the Tazhong meteorological station,located at the center of the Taklimakan Desert. 3- day kinematic back trajectories for springtime in2011 and 2012 that computed with version 4. 9 of the Hybrid Single- Particle Lagrangian Integrated Trajectory model（ HYSPLIT）,were clustered and classified in groups of similar length and curvature. To describe better the tropospheric circulations near Tazhong,backward trajectories arriving at 2,1500,3000,and 5500 m were analyzed and clustered during the target period. The main transport patterns were identified as two type： one was westerly flows,which is the major pattern which occupy 90%,87%,63% and 81% separately at each level of the concerning total situations,the other was northwesterly flows. An annual distribution of the transport patterns was described. During the springtime of 2011,percent of the westerly flows at these four levels were 93%,90%,89% and 91%,while 65%,81%,85% and 88% for 2012 spring separately. For the monthly cluster analysis,the percent of westerly flows were 84%,53% and 86% near land surface for March,April and May,while 88%,88% and 85% for 1500 m,87%,90% and 100% for 3000 m,100%,88% and 100% for elevation 5000 m. The difference from near land surface to the other three level was that,the mean cluster passed through the mountain gap of the middle part of the Tianshan Mountain before arrived the south Xinjiang. According the increasing of the altitude,the proportion of the westerly flows increased as well,and that of the northwesterly flows decreased.