Comparison Of Geopotential Heights And Wind Velocity Between Reanalysis Datasets And Radiosonde Datasets Over The Area Of China

Using the radiosonde data and reanalysis data from NCEP/NCAR, ERA-interim, JRA and MERRA, the applicability evaluation of the atmospheric geopotential heights and wind velocities in the area of China are conducted in this paper. The results are as follows:(1)The annual mean geopotential heights show an upward trend in the troposphere over the north part of China while a downward trend in the tropopause and lower stratosphere. An in-phase variation in geopopential heights over the whole tropospheric layer on interannual time scale and an anti-phase change over the north and south part of China on decadal time scale are also characterized, respectively. In general, the geoptential heights of the three reanalysis datasets are lower than that of observation. Compared to the other two reanalysis datasets, the NCEP/NCAR geopotential height is much closer to observed one.(2)In terms of seasonal mean field, geopotential heights experience an upward trend in the troposphere in winter, while the trend in other seasons is consistent with that of annual mean field. In additions, the smallest deviation between radiosonde and reanalysis datasets appears in winter. Overall, NCEP/NCAR geopotential heights agree well with the observed geopotential heights in spring, summer and winter, while ERA geopotential heights show much better performance in autumn.(3)The annual mean wind velocity shows a downward trend in the middle and upper troposphere while a downward trend in the lower troposphere over the east and south part of China, the ERA-interim and MERRA wind velocities are much closer to the observed one. In general, the wind velocities of the three reanalysis datasets are lower than observations. In the upper troposphere, ERA-interim is much closer to the observed one in the1980s and1990s, while NCEP/NCAR is much better in the21st century. In the middle and lower troposphere, NCEP/NCAR wind velocity agrees well with the observed one.(4) In terms of seasonal mean field, wind velocity experiences an upward trend in the middle and upper troposphere in winter, while a downward trend in spring, summer and autumn. The smallest deviation between radiosonde and reanalysis datasets appears in winter, and the largest one appears in the summer. In the middle and lower troposphere, NCEP/NCAR and MERRA wind velocities are much closer to the observed one in winter, while MERRA is much better in summer. In the tropopause and lower stratosphere, ERA-interim and MERRA wind velocities show much better performance in the four seasons.