Double cores of the Ozone Low in the vertical direction over the Asian continent in satellite data sets

Using four satellite data sets(TOMS/SBUV, OMI, MLS, and HALOE), we analyze the seasonal variations of the total column ozone(TCO) and its zonal deviation(TCO*), and reveal the vertical structure of the Ozone Low(OV) over the Asian continent. Our principal findings are:(1) The TCO over the Asian continent reaches its maximum in the spring and its minimum in the autumn. The Ozone Low exists from May to September.(2) The Ozone Low has two negative cores, located in the lower and the upper stratosphere. The lower core is near 30 hPa in the winter and 70 hPa in the other seasons. The upper core varies from 10 hPa to 1 hPa among the four seasons.(3)The position of the Ozone Low in the lower and the upper stratosphere over the Asian continent shows seasonal variability.

Evaluation of the Trend Uncertainty in Summer Ozone Valley over the Tibetan Plateau in Three Reanalysis Datasets

Trend uncertainty in the ozone valley over the Tibetan Plateau（OVTP）and the South Asian high（SAH）during1979–2009 in ERA-Interim（interim reanalysis data from the ECMWF）,JRA-55（55-yr reanalysis data from the Japan Meteorological Agency）,and NCEP-CFSR（Climate Forecast System Reanalysis）datasets was evaluated.The results showed that the NCEP-CFSR OVTP became strong in the summers of 1979–2009,whereas it became weak according to ERA-Interim and JRA-55.Satellite data merged with TOMS（Total Ozone Mapping Spectrometer）and OMI（Ozone Monitoring Instrument）agreed with the OVTP trend of NCEP-CFSR.The OVTP strengthening in NCEP-CFSR may have been caused by SAH intensification,a rising tropopause,and increasing ozone over non-TP（non-Tibetan Plateau）areas（27°–37°N,〈75°E and〉105°E）.Analogously,the OVTP weakening in ERA-Interim and JRA-55 may have been affected by weakening SAH,descending tropopause,and decreasing non-TP ozone.