Impacts of Assimilated Data on Reanalysis Climatology

Impacts of the observing systems and meteorological parameters on a reanalyzed climatology are investigated using an assimilation algorithm based on the National Centers for Environmental Prediction/Department of Energy (NCEP/DOE) reanalysis system. The one-year analyzed climatology is generated in a standard analysis using all of the observations, which is named the control run. Additional climatology data sets are produced by selectively choosing observational systems or meteorological variables in the reanalysis system. It is found that the radiosonde-only observation is sufficient for reproducing the reanalysis climatology. Satellite observations have no significant contribution to the large-scale fields. The importance of meteorological variables on the analyzed climatology is temperature, wind, and moisture in that order, where the mass observation is found to have a greater impact on the analyzed climatology than wind. It is, however, noted that the moisture field demonstrates a profound influence on the surface hydroclimate such as cloud cover, radiation flux, and land surface temperature.