Remote Sensing of Near Surface Humidity over North Pacific

Humidity soundings at 12 mid-ocean stations of small islands and weather ships in north Pacific from N to N during a 9 years period from 1972 to 1980 were used to study the variation of columnar water vapor W (as measured by spaceborne sensors) in relation to the variation of surface level specific humidity Q (as required in the determination of air-sea moisture and latent heat exchanges). It was found that a simple regression can be used to specify monthly mean Q from W to an accuracy of about , corresponding to about 20 W/m²in latent heat flux. The regression aocounts for both temporal and spatial variations of Q and W. Better accuracy can be achieved by using regional regressions. The study affirms the potential of space-borne sensors in providing global monitoring of air-sea moisture and heat exchanges.