MEAN GLOBAL SURFACE PRESSURE SERIES EVALUATED FROM ECMWF REANALYSIS DATA

Time series (1979-93) of the global mean surface pressure are determin ed using data provided by the ECMWF ReAnalysis (ERA) project. Total pr essure, water vapour pressure and dry-air pressure are evaluated. It i s shown that a trend of only 0.01 hPa per decade exists for the total surface pressure whereas that of the water vapour surface pressure is 0.05 hPa per decade. This underlines the homogeneous character of the time series of ERA data, at least for the integral quantities surface pressure and water vapour surface pressure.