Reanalysis Water Vapor Comparison
Assessment of reanalysis hydrology and energy budgets: water vapor and radiative fluxes
Richard J. Engelen, Ian L. Wittmeyer, and Graeme L. StephensDepartment of Atmospheric Science, Colorado State University
Proceedings of the First WCRP International Conference on Reanalyses
WCRP-104, WMO/TD-NO. 876, pp.175 - 178, February 1998
Summary
This paper addresses the differences in water vapor variability between the ECMWF and NCEP reanalyses and satellite observations from the NVAP data set. Main differences in variability are observed in the tropics. The ECMWF reanalysis is able to capture most of the variability in total precipitable water and upper-tropospheric humidity, as reflected by calculated TOVS channel 12 brightness temperatures, compared to NVAP and TOVS radiance measurements. The NCEP reanalysis, however, is not able to simulate the same variability as the satellite observations. This analysis shows, therefore, the importance of assimilating radiance data related to water vapor in the reanalysis, as done in the ECMWF reanalysis, in order to be able to model some of the very important hydrological cycles in the atmosphere.
Main figures from the paper
Figure 1. Daily time series for 1989 of model calculated and observed TOVS channel 12 brightness temperature deviations over Central Africa. Data are smoothed for clarity.
Figure 2. Daily time series for 1989 of model
calculated and observed TOVS channel 12 brightness temperature deviations over the
Western Pacific. Data are smoothed for clarity.
Figure 3. Modeled and observed TOVS channel
12 brightness temperature deviations averaged over three warm SST events
during 1989.
Richard J. Engelen
Richard.Engelen@atmos.colostate.edu