Correcting satellite Doppler data for tropospheric effects


  • H. D. Black,

  • A. Eisner


Using a simple geometrical model, and one fitted parameter, tropospheric effects can be effectively removed from satellite Doppler data at microwave frequencies. Both the wet and the dry parts of the tropospheric refraction effect are removed. The technique works best for low (say, 1200 km or less) altitude satellites. For these satellites, the pass (transit) duration limits the required atmospheric correlation time to about 20 min. The effective thickness of the neutral atmosphere (10 km for the wet and 45 km for the dry) limits the required correlation distance to a few degrees in latitude and longitude. These conditions are satisfied often enough to make the fitting technique highly useful. The fitted parameter together with minimal dependence on model structure appears to skirt a difficult problem, modeling the water vapor distribution in a poorly mixed atmosphere. Experimental results (for a limited time period) confirm that the approach is valid on a global basis. In another context, this technique can be used to intensively sample the precipitable water vapor in the atmosphere without using balloons.