Comparitive Studies Between in-Situ Observations and Reanalysis Products in Tibetan Plateau

Abstract:

Due to the high altitude, severe weather, and tough environment, few in-situ observations (In particular, with altitude > 5000 m a.s.l) have been conducted in the TP. In this data sparse areas, reanalysis products are arguably the best available source of infromation on the four dimensional structure of the atmosphere. Here in-suit observations at 12 weather stations (AWS) with altitude > 5000 m a.s.l from the Tibetan Observation and Research Platform (TORP) have been collected since 2005. These data are used for a comprehensive comparison with 10 reanalysis products including 20thC, CFSR, ERA-Int, FNL, HAR, JRA25, JRA55, MERRA, NCEP1, and NCEP2. The variables include six hour, daily and monthly temperature, relative humidity and wind speed. Statistical results show that all reanalysis products can capture much of the synoptic-scale variability of in-situ observations although reanalysis values are systematically higher than the observations. With the increase of time scale, the performance of all reanalysis products get better. Compararison with in-situ observtion verifies the best overall performance of ERA-Int in temperature, relative humidity and wind speed, and the second best performance of JRA55.