Sensitivity of Satellite Retrievals of Temperature to Errors in Estimates of Tropospheric Water Vapor

A priori estimates of the vertical distribution of tropospheric water vapor are needed to solve the radiative transfer equation in the 15 μm CO2 band to derive tropospheric temperatures from radiances measured at orbiting satellites. This paper shows how errors in estimates of water vapor mixing ratio propagate into these solutions for temperature, and in simulation establishes the sensitivity of the rms errors in a collection of temperature soundings from the NOAA 2 satellite to errors in mixing ratio. The simulations predict that errors found in available estimates of mixing ratio degrade the solutions for temperature in the low troposphere so that they provide little new information over that already in the forecasts of the National Meteorological Center.