Abstract: This study investigated the evolving microphysical characteristics of a stratiform cloud precipitation event over Tianjin on November 25,2024,which was induced by an upper-level trough. Multi-source observational datasets,including weather radar,millimeter-wave cloud radar,microwave radiometer,and wind profiler radar,were utilized to analyze the variation laws of microphysical characteristics affecting this stratiform cloud precipitation. The results indicated that the eastward progression of the upper-level trough led to enhanced positive vorticity advection ahead of the 500 hPa trough,coupled with convergent ascending motion in the low-level airflow at 850 hPa,thereby providing a robust dynamic lifting mechanism to sustain adequate water vapor supply for precipitation. Vertically,the stratiform cloud exhibited a distinct cold-upper and warm-lower structure. Retrievals from the microwave radiometer revealed that increased water vapor content furnished sufficient moisture conditions for precipitation,with variations in liquid water content showing consistency with changes in radar echo reflectivity and radial velocity. In terms of wind field structure,strong cold advection prevailed in the upper levels,while the lower levels facilitated water vapor transport to the surface; significant vertical wind shear in the middle levels contributed to maintaining the ascending motion. These findings can serve as an observational basis for artificial precipitation enhancement operations targeting stratiform clouds in the Tianjin region.

Key words: stratiform cloud precipitation, vertical structure, liquid water content, microphysical characteristics