Anomaly of the Ozone Low Center over the Tibetan Plateau in 1998 and the Surrounding Flow Field
1998年青藏高原臭氧低值中心异常及其背景环流场的分析

Based on the data sets from TOMS and SAGE II,the anomaly of ozone low center over the Tibetan Plateau in 1998 has been analyzed both in its variation process and in its vertical distribution.In order to investigate the cause for the anomaly,the variation of the flow field and the vertical motion in 1998 over the plateau was analyzed through the changes of the geopotential height and potential temperature by using the NCEP/NCAR monthly mean reanalysis data.The result shows that the tropopause over the plateau in November 1998 was much higher than normal and the ascend motion over the plateau both in the upper troposphere and in the lower stratosphere was stronger than the normal in November 1998;In the same period,the South Asian High was also stronger than the normal.These are the reason for the strong ozone low center over the plateau in 1998 maintained to November.