A strong precipitation event caused by the southwest vortex（SWV）, which affected Sichuan Province and Chongqing municipality in Southwest China on 10–14 July 2012, is investigated. The SWV is examined using satelli...A strong precipitation event caused by the southwest vortex（SWV）, which affected Sichuan Province and Chongqing municipality in Southwest China on 10–14 July 2012, is investigated. The SWV is examined using satellite observations from AIRS（Atmospheric Infrared Sounder）, in situ measurements from the SWV intensive observation campaign, and MICAPS（Marine Interactive Computer-Aided Provisioning System） data. Analysis of this precipitation process revealed that：（1）heavy rain occurred during the development phase, and cloud water content increased significantly after the dissipation of the SWV;（2） the area with low outgoing longwave radiation values from AIRS correlated well with the SWV;（3） variation of the temperature of brightness blackbody（TBB） from AIRS reflected the evolution of the SWV, and the values of TBB reduced significantly during the SWV＇s development; and（4） strong temperature and water vapor inversions were noted during the development of the SWV. The moisture profile displayed large vertical variation during the SWV＇s puissant phase,with the moisture inversion occurring at low levels. The moisture content during the receding phase was significantly reduced compared with that during the developing and puissant phases. The vertical flux of vapor divergence explained the variation of the moisture profile. These results also indicate the potential for using AIRS products in studying severe weather over the Tibetan Plateau and its surroundings, where in situ measurements are sparse.展开更多
The present study solves a two-layer atmospheric wave equation model with a lower atmosphere concave wind profile and cold-air outbreak over sea, while simultaneously proving that such a wind shear may cause neutral b...The present study solves a two-layer atmospheric wave equation model with a lower atmosphere concave wind profile and cold-air outbreak over sea, while simultaneously proving that such a wind shear may cause neutral boundary layer roll vortices in the presence of disturbing sources upstream. Without thermal effects, the wind shear-induced waves have band structures at the top of the boundary layer that are similar to cloud street patterns observed over sea. This study proves that dynamic and thermal effects can act independently to initiate the roll vortices in the lower atmosphere. At the same time, a quantitative comparison shows that dynamic effects play a large role in the formation of roll vortices in the initial stage of cold-air outbreak and will be surpassed by thermal effects soon after surface heating commences.展开更多
基金supported by the Special Fund for Meteorological Research in the Public Interest(Grant No.GYHY201206042)the National Natural Science Foundation of China(Grant No.41675057,91337215)
文摘A strong precipitation event caused by the southwest vortex（SWV）, which affected Sichuan Province and Chongqing municipality in Southwest China on 10–14 July 2012, is investigated. The SWV is examined using satellite observations from AIRS（Atmospheric Infrared Sounder）, in situ measurements from the SWV intensive observation campaign, and MICAPS（Marine Interactive Computer-Aided Provisioning System） data. Analysis of this precipitation process revealed that：（1）heavy rain occurred during the development phase, and cloud water content increased significantly after the dissipation of the SWV;（2） the area with low outgoing longwave radiation values from AIRS correlated well with the SWV;（3） variation of the temperature of brightness blackbody（TBB） from AIRS reflected the evolution of the SWV, and the values of TBB reduced significantly during the SWV＇s development; and（4） strong temperature and water vapor inversions were noted during the development of the SWV. The moisture profile displayed large vertical variation during the SWV＇s puissant phase,with the moisture inversion occurring at low levels. The moisture content during the receding phase was significantly reduced compared with that during the developing and puissant phases. The vertical flux of vapor divergence explained the variation of the moisture profile. These results also indicate the potential for using AIRS products in studying severe weather over the Tibetan Plateau and its surroundings, where in situ measurements are sparse.
基金supported by the National Basic Research Program of China (973 Program) (Grant No. 2010CB951801)the National Natural Science Foundation of China (Key Program) (Grant No. 41030106)
文摘The present study solves a two-layer atmospheric wave equation model with a lower atmosphere concave wind profile and cold-air outbreak over sea, while simultaneously proving that such a wind shear may cause neutral boundary layer roll vortices in the presence of disturbing sources upstream. Without thermal effects, the wind shear-induced waves have band structures at the top of the boundary layer that are similar to cloud street patterns observed over sea. This study proves that dynamic and thermal effects can act independently to initiate the roll vortices in the lower atmosphere. At the same time, a quantitative comparison shows that dynamic effects play a large role in the formation of roll vortices in the initial stage of cold-air outbreak and will be surpassed by thermal effects soon after surface heating commences.
