| The China probability distribution of ice cloud occurrence frequency,ice water path?ice water content?ice cloud effective radius and ice cloud optical depth were presented,based on data DARDAR(raDAR/liDAR),from December 2012 to November 2016,the distribution and vertical sturctures was discussed.The results show that the ice cloud occurrence frequency distribution has obvious seasonal variation,the high concentration area in the northeastern part of the Tibetan Plateau,ice cloud occurrence frequency is relatively high in northwest area;The horizontal distribution of ice water path for general trend is big in Southeast and small in Northwest,and ice water path has obvious seasonal variation,it is bigger in summer than in winter,minimum in winter,the maximum value appeared in summer,apart from winter,the other three seasons showed changes in ice water path of Southeast China is bigger than the northwest,this phenomenon is the most obvious in summer and Autumn;the IWC is the biggest in summer,and the vertical height distribution higher than other seasons,the height distribution of IWC is the highest in plateau section and the lowest in northeast China;Ice cloud effective radius and ice water content had similar trend in the whole of China area and six different sections.There were slight declines in ice cloud effective radius with increase height of China.In the summer ice effective radius is generally larger;Ice cloud optical depth values is mostly below 10 in China,the overall trend in China is relatively small in northern region,and relatively large in south China.The Northwest China probability distribution of ice cloud occurrence frequency,ice water content and ice cloud effective radius and ice cloud optical depth were discussed and analyzed.The results show that,the occurrence frequency of ice cloud is 55.1%over the last four years and the occurrence frequency of ice cloud in spring is majority greater than 70%apart from the Midwest area of Hexi-Neimeng,it has obvious seasonal variation.The season amplitude of variation is bigger in 2015-2016 than the first two years,and ice cloud occurrence frequency generally small in the desert area.The high occurrence frequency of ice cloud area is in the northeastern part of the Tibetan Plateau because of it's special terrain;The occurrence frequency of ice cloud is both bigger in spring,autumn and winter but only smaller in summer at the northeastern of the Tibetan Plateau,it is because the warm and humid air from the Indian Ocean is blocked by the southern mountain of the plateau,which leads to a lower occurrence frequency of ice cloud in the northeastern of plateau in summer.The ice water content is almost has no ice water distribution above 13 km,ice water content in Northwest China is the biggest in summer and almost has no ice water distribution below 5 km because of the high temperature in summer make the lower floors are not easy to form ice cloud,and the ice water content is generally smaller in autumn and winter.The difference of ice water content between different regions in northwest of China is relatively large;Ice cloud effective radius and ice water content had a similar trend in the whole of Northwest China area and five different sections,bigger in spring and summer and smaller in winter and autumn;especially in the summer,ice effective radius is generally larger,but ice cloud effective radius is relatively small in the numerical value of ice water content area 37°N-39°N because of the summer has the higher temperature.The difference of the Ice cloud effective radius between different regions in northwest of China is relatively large,the Ice cloud effective radius is minimum in Northwest eastern seasonal wind areas and biggest in Northern Xinjiang and Midwest area of Qilian Mountain-Qinghai area;The most concentrated desert in the northwest area of China,ice cloud optical depth is obvious small,and the ice cloud optical depth has seasonal characteristics of high in summer and very small in winter. |
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