Observation of clouds and solar radiation over the Pacific Ocean as relation to global climate

During a research cruise over the Pacific Ocean in 1989, solar irradiance was measured with a broad-band pyranometer along the cruise track.Cloud cover was photographed with an all-sky time-lapse camera.Cloud types were observed and recorded.The data show that both the types and the amounts of clouds affeet radiation fluxes on the sea surface.For low-level and middle-level clouds, the correlations (r) between measured irradiance (in percent of calculated maximum irradiance) and cloud amount (in fraction of sky) were significant:r=-0.79 and -0.66, respectively.For high-level clouds, the correlation was not significant;r=-0.21.The results indicate that cloud shortwave forcing is a major modifier of the earth's surface insulation and change of cloud amount may affect global climate.