Gerrity, Joseph P.

Office note (National Meteorological Center (U.S.)) ; 151

National Weather Service (NWS)

"When cold dry air flows over a warmer water body, one observes a significant transfer of sensible heat and water vapor to the air. In the present LFM model this process is modeled by transferring heat to the boundary layer at a rate proportional to the difference between the sea surface temperature TS and the boundary layer potential temperature TB, and by constraining the relative humidity of the air not to become less than 30%. In some cases, the modified air moves back over the land. It is sometimes found that the limit RH 2 30% has been an inadequate parameterization of the moistening of the air in its passage over the sea. A feasible scheme to correct this deficiency of the model is proposed in this note"--Introduction.