Statistics of the Global Tropopause Pressure

Abstract

Statistics of the global tropopause pressure are evaluated for the period between 1979 and 1993. The analysis is based on gridded data as provided by the ECMWF reanalysis project. The thermal and dynamical definitions of the tropopause are applied in order to derive the surface separating the troposphere from the stratosphere. The dynamical tropopause is evaluated for threshhold values of potential vorticity of ±1.6, ±2.5, and ±3.5 potential vorticity units. Positive (negative) values are applied for the Northern (Southern) Hemisphere. The thermal tropopause is determined using the lapse-rate criteria. Frequency distributions of the tropopause pressure are shown above continental, ocean, polar, midlatitude, and tropical areas. Trends in the tropopause pressure are evaluated and compared with observed trends in total ozone.