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

Two radiometers of the Tropical Rainfall Measuring Mission (TRMM) were used to retrieve parameters that were necessary to determine the latent heat fl ux density at the sea surface. The Visible and Infrared Radiometer System ( VIRS) was used to measure sea surface temperature. The TRMM Microwave Image r (TMI) measured near-surface wind speed and air-specific humidity. The ret rieval schemes for these parameters were derived theoretically by means of radiative transfer simulations and were validated by TRMM data matched with buoy measurements. The validation study revealed deficiencies in the descr iption of the infrared water vapour absorption continuum and in the TMI cal ibration. Both effects were corrected for so that the desired parameters co uld be retrieved with adequate accuracy. A global application of the retrie val method to TRMM data for April 1998 is shown.