Statistical model of cloud optical thickness in specific Yamal areas using satellite-based data
D.N. Troshkin, V.E. Pavlov
Institute for Water and Environmental Problems of the Siberian Branch of the RAS, 656038, Barnaul, 1, Molodezhnaya str. IWEP SB RAS
Keywords: полуостров Ямал, Обская, Гыданская и Байдарацкая губы, функции распределений оптических толщ облаков, Yamal Peninsula, the Gulf of Ob, Khalmyer Bay, Baidaratskaya Bay, probability density of clouds’ optical thickness
Abstract
The statistical analysis of summer cloud optical thickness over three geographically restricted zones in the region of the Ob Bay (dry and wet zones, coordinates are given) is performed with the use of ENVISAT-based experimental data on the cloud optical thickness obtained in 2008-2011. Type of functions of probability density of cloud optical thickness for each zone is determined. In logarithmic coordinates, each of these functions has several (3-4) maxima, indicating the occurrence of individual modes. The functions are approximated by a set of normal logarithmic distributions with certain parameters. The parameters prove to be well repetitive from year to year. There are three modes above the low-watered western zone, while in the eastern zones, where full-flowing rivers with relatively warm waters run from the south, they increase to four. On the authors’ opinion, water evaporation with subsequent condensation promotes the formation of an additional mode with low optical thickness. Anthropogenic emissions, which increase the number of condensation nuclei in the eastern zones, may also play a specific role in the process of enhanced condensation. Distribution function curves and tables with parameters are presented. Such data can be useful for calculations on radiation regime for small Yamal areas.
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