干旱气象
榦旱氣象
간한기상
GANSU METEOROLOGY
2015年
1期
138-143
,共6页
干侵入%水汽图像%位涡
榦侵入%水汽圖像%位渦
간침입%수기도상%위와
dry intrusion%water vapor image%potential vorticity
以2012年7月15日凌晨榆林地区一次短时强降水过程为研究对象，利用NCEP 1°×1°再分析资料、FY－2E卫星资料及常规气象观测资料，通过卫星水汽图像和大气动力场相结合的方法揭示冷涡影响下降水过程中干侵入的特征及其对短时强降水发生、发展的作用机制。结果表明：此次短时强降水过程中干侵入特征明显，卫星水汽图像上的黑体亮温高值区与干冷区相对应，干冷区的伸入使得对流云团边缘亮温梯度增大，同时对流云团发展；干侵入与对流层高层的下沉运动、高值位涡以及干冷区相对应，因干冷空气叠加在暖湿气流之上，在强降水区上空出现了对流不稳定层结，为短时强降水的发生创造了有利的环境条件。另外，此次降水过程水汽条件主要集中在对流层低层，风场辐合带来的短时间水汽辐合为短时强降水集聚了一定的水汽条件。在地面中尺度辐合线的触发作用下，将不稳定层结中包含水汽的气块抬升，从而形成降水。
以2012年7月15日凌晨榆林地區一次短時彊降水過程為研究對象，利用NCEP 1°×1°再分析資料、FY－2E衛星資料及常規氣象觀測資料，通過衛星水汽圖像和大氣動力場相結閤的方法揭示冷渦影響下降水過程中榦侵入的特徵及其對短時彊降水髮生、髮展的作用機製。結果錶明：此次短時彊降水過程中榦侵入特徵明顯，衛星水汽圖像上的黑體亮溫高值區與榦冷區相對應，榦冷區的伸入使得對流雲糰邊緣亮溫梯度增大，同時對流雲糰髮展；榦侵入與對流層高層的下沉運動、高值位渦以及榦冷區相對應，因榦冷空氣疊加在暖濕氣流之上，在彊降水區上空齣現瞭對流不穩定層結，為短時彊降水的髮生創造瞭有利的環境條件。另外，此次降水過程水汽條件主要集中在對流層低層，風場輻閤帶來的短時間水汽輻閤為短時彊降水集聚瞭一定的水汽條件。在地麵中呎度輻閤線的觸髮作用下，將不穩定層結中包含水汽的氣塊抬升，從而形成降水。
이2012년7월15일릉신유임지구일차단시강강수과정위연구대상，이용NCEP 1°×1°재분석자료、FY－2E위성자료급상규기상관측자료，통과위성수기도상화대기동력장상결합적방법게시랭와영향하강수과정중간침입적특정급기대단시강강수발생、발전적작용궤제。결과표명：차차단시강강수과정중간침입특정명현，위성수기도상상적흑체량온고치구여간랭구상대응，간랭구적신입사득대류운단변연량온제도증대，동시대류운단발전；간침입여대류층고층적하침운동、고치위와이급간랭구상대응，인간랭공기첩가재난습기류지상，재강강수구상공출현료대류불은정층결，위단시강강수적발생창조료유리적배경조건。령외，차차강수과정수기조건주요집중재대류층저층，풍장복합대래적단시간수기복합위단시강강수집취료일정적수기조건。재지면중척도복합선적촉발작용하，장불은정층결중포함수기적기괴태승，종이형성강수。
The NCEP 1° × 1° reanalysis data,FY-2E satellite images,conventional meteorological data,and the method of combining satellite cloud images with atmospheric dynamic field were used to analyze the dry intrusion characteristics under the influence of cold eddy and the role of the dry intrusion during the short-time strong rainfall which occurred in Yulin of Shaanxi Province on July 15, 2012. The results show that the characteristics of the dry intrusion was significant during the short-time strong rainfall process,the high value area of TBB on satellite water vapor images corresponded to the dry cold area of upper troposphere,while the stretching of the cold dry area made the TBB gradient on convective cloud edge increase,at the same time convective cloud developed. The dry in-trusion corresponded to the sinking motion,high value area of potential vorticity and dry cold areas in the upper troposphere,the insta-bility stratification appeared over the heavy rainfall region due to the dry cold air overlaying the warm wet air,which created favorable environmental conditions for the occurrence of the short-term heavy rainfall. In addition,water vapor of the rainfall process mainly concentrated in the lower troposphere,short-term moisture convergence caused by wind convergence created a favorable moisture con-dition for the short-term heavy rainfall. The lifting of air mass that contained water vapor caused by the trigger mechanism of mesoscale convergence line on the ground led to precipitation.
