干旱气象
榦旱氣象
간한기상
Journal of Arid Meteorology
2015年
4期
644-650
,共7页
长波调整%垂直温度梯度%垂直风切变%地形作用
長波調整%垂直溫度梯度%垂直風切變%地形作用
장파조정%수직온도제도%수직풍절변%지형작용
long-wave adjustment%vertical temperature gradient%vertical wind shear%terrain effect
利用常规高空和地面观测资料、FY-2E卫星云图资料、多普勒天气雷达及地面加密气象站资料,对2014年7月1日发生在陕西渭南的一次强对流天气过程进行分析。结果表明:本次强对流天气过程是在500 hPa长波调整过程中,冷空气不断从切断低压底部扩散南下,与中纬度中尺度切变线相互作用所致;垂直温度梯度大对渭南市强对流天气有较好的潜势预报意义;地形作用导致中低层风向垂直切变增强和地面小尺度辐合线形成。其中,垂直风切变的增强致使中层干空气卷入对流云团中,新鲜空气补充了云凝结核源,经过渭河之后,近地面气温升高、相对湿度增大,有利于冰雹转成短时暴雨。地面小尺度辐合线触发了不稳定能量进一步释放;强的垂直风切变和低层辐合共同作用,使对流云团增强,降雨强度增大。
利用常規高空和地麵觀測資料、FY-2E衛星雲圖資料、多普勒天氣雷達及地麵加密氣象站資料,對2014年7月1日髮生在陝西渭南的一次彊對流天氣過程進行分析。結果錶明:本次彊對流天氣過程是在500 hPa長波調整過程中,冷空氣不斷從切斷低壓底部擴散南下,與中緯度中呎度切變線相互作用所緻;垂直溫度梯度大對渭南市彊對流天氣有較好的潛勢預報意義;地形作用導緻中低層風嚮垂直切變增彊和地麵小呎度輻閤線形成。其中,垂直風切變的增彊緻使中層榦空氣捲入對流雲糰中,新鮮空氣補充瞭雲凝結覈源,經過渭河之後,近地麵氣溫升高、相對濕度增大,有利于冰雹轉成短時暴雨。地麵小呎度輻閤線觸髮瞭不穩定能量進一步釋放;彊的垂直風切變和低層輻閤共同作用,使對流雲糰增彊,降雨彊度增大。
이용상규고공화지면관측자료、FY-2E위성운도자료、다보륵천기뢰체급지면가밀기상참자료,대2014년7월1일발생재협서위남적일차강대류천기과정진행분석。결과표명:본차강대류천기과정시재500 hPa장파조정과정중,랭공기불단종절단저압저부확산남하,여중위도중척도절변선상호작용소치;수직온도제도대대위남시강대류천기유교호적잠세예보의의;지형작용도치중저층풍향수직절변증강화지면소척도복합선형성。기중,수직풍절변적증강치사중층간공기권입대류운단중,신선공기보충료운응결핵원,경과위하지후,근지면기온승고、상대습도증대,유리우빙박전성단시폭우。지면소척도복합선촉발료불은정능량진일보석방;강적수직풍절변화저층복합공동작용,사대류운단증강,강우강도증대。
Based on the conventional and intensive meteorological data,FY-2E satellite images and Doppler radar data,a severe con-vective weather which occurred during the evening of July 1,2014 in Weinan of Shaanxi was analyzed. The results indicated that the severe convective weather was caused by the interaction of cold air which spread to the south constantly from the bottom of the cut-off low and mesoscale shear line in mid-latitude region during the process of 500 hPa long-wave adjustment. Large vertical temperature gradient had good guiding significance to the potential forecast of severe convective weather in Weinan. Terrain effect caused the en-hancement of the lower vertical wind shear and the formation of ground small-scale convergence line. The dry air in middle level was involved into the convective clouds owe to the enhancement of vertical wind shear,which led to the increase of cloud condensation nu-clei. The surface temperature rose and the humid increased after the airflow passing through Weihe river,which was beneficial to the transformation of weather phenomenon from hail to short-term rainstorm. In addition,the small scale ground convergence line further triggered off convective instability energy. Therefore,the strong vertical wind shear and the low-level convergence acted together to cause the enhancement of the convective clouds and rainfall intensity.