Latent heat flux at the sea surface retrieved from combined TMI and VIRS measurements of TRMM

Kurzfassung

Two radiometers of the Tropical Rainfall Measuring Mission (TRMM) are used to retrieve parameters that are needed to determine the latent heat flux density at the sea surface. The Visible and Infrared Radiometer System (VIRS) is used to measure sea surface temperature. The TRMM Microwave Imager (TMI) measures near-surface wind speed and air specific humidity. The retrieval schemes for these parameters are derived theoretically by means of radiative transfer simulations and are validated by TRMM data matched with buoy measurements. The validation study reveals deficiencies in the description of the infrared water-vapour absorption continuum and in the TMI calibration. Both effects are corrected for so that the desired parameters can be retrieved with adequate accuracy. A global application of the retrieval method to TRMM data of April 1998 is shown.