The moist potential vorticity is uesd to conduct a diagnostic analysis for the heavy rain events in Northeastern China when the blocking high covered the middle and high latitudes in July, 1998.

The results show that the high potential vorticity,dry air from the upper level of troposphere extended downwards and southwards,which increased the vertical component of the vorticity on the steep iso-entropy plane and promoted the rapid development of the low level cyclone,resulted in a low level jet and the intensive convergence in .

Based on the reanalysis data of NCEP 1°×1°,the diagnostic analysis on potential vorticity,dry intrusion and vertical helicity of a sand-dust storm process occurred in the west of Gansu and Inner Mongolia and the south of Mongolia during period from Oct.

An extraordinary ozone enhancement event is observed at Lin-An (30 30°N, 119 75°E) from March 25 to 31 in the spring of 2001, especially on March 29 and 30 The cause of the ozone enhancement is studied utilizing synoptic meteorology diagnosis from conventional weather data and the NCEP data, as well as potential vorticity (PV).

An Analysis of Moist Potential Vorticity for Early Typhoon Rainstorm;

Diagnostic analysis of moist potential vorticity for local heavy rain

Based on the analysis of moist potential vorticity(mpv) for the typhoon "Haitang" inverted trough which caused rainstorm in Henan province,the results show that slantwise vorticity development is one of the important mechanisms of the rainstorm occurrence and intensification.