Arctic Radiation Fluxes--The Long Wave Radiation Transfer in ARctic Stratus Clouds.
Final rept. 1 Jan 76-30 Sep 77,
ALASKA UNIV COLLEGE GEOPHYSICAL INST
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Stratus cloud cover over Barrow, AIDJEX camp Big Bear and over the Beaufort Sea was derived for 1975 using surface and satellite observations. Contrary to the reported value of the consistently high long term summer mean cloudiness, the values for 1975 showed a period of complete lack of cloudiness. Comparison with the wind field suggests that a southerly component in the 700 mb winds corresponds to an increase in cloudiness and a northerly component corresponds to a decrease. The unusual northerly 700 mb flow during this year may explain both the low summer cloudiness and the severe ice conditions in the Beaufort Sea. The temperature and emissivity profiles measured using unstrumented aircrafts indicated that within a few days of formation fo stratus cloud overcast the emissivity at the top part of cloud becomes low and the temperature inversion drops down to the middle part of the cloud. Continuous solar heating and the effect of scattering in the long wave may be responsible for these changes. Author