Research On Vertical Structure Of Cloud And Precipitation Feature Of Cloudsat Data In HuaBei And JiangHuai

Cloud vertical structure is associated with cloud radiation characteristic, precipitation physical process, precipitation mechanism, precipitation efficiency and the artificial precipitation conditions. The intraction between cloud and radiation is impact on global weather and climate change process. Different height of clouds has different cloud radiative forcing, obtaining the vertical distribution of cloud is important for changing the general circulation models. The different structure of precipitation clouds is the object of artificial precipitation enhancement Fully understanding the macro micro feature of vertical structure in precipitation cloud is important for deepening basic scientific understanding of artificial precipitation, choosing the rainfall enhancement conditions, estimating affected by artificial precipitation. Strengthening the understanding of different properties cloud structure from different places will be of important significance to improve climate prediction accuracy, the ability of forecasting precipitation refinement and scientific standards of artificially seeding clouds and catalytic.Cloudsat is the first satellitet for the research of cloud specially. Use the Cloudsat products information from March 2008 to February 2009, combining surface data, to study cloud vertical structure statistical characteristics, identification method of precipitation cloud and vertical structure characteristics of precipitation cloud in HuaBei and JiangHuai where is the representative region for rainfall enhancement. The results reported here show that:1. Cloud statistical characteristics in HuaBei and JiangHuai area. The vertical distributions of monthly cloud fraction displays the significant seasonal variation both in HuaBei and JiangHuai. The hydrometeor amounts in Spring and Summer is more than Autumn and Winter, which is mainly of 20%-60% in Spring and Summer, of 10%-30% in Autumn and Winter. The amounts of high-level cloud is the most, middle-level cloud is second, low-level cloud is the least. The frequency of single layer cloud is larger than the multi-layers in both HuaBei and JiangHuai, and lots of double-layer cloud in the the multi-layer cloud. The frequency of double-layer displays the significant seasonal variation, the frequency in Spring and Summer is more than Autumn and Winter, The average height of layer top and layer base also display the significant seasonal variation, the layer top and layer base in summer half year is higher than winter half, so do the highest level of double-layer cloud, and the lowest level does not display significant seasonal variation.2. Study precipitation identification method with Cloudsat. Firstly, analyze the ability to detect cloud and precipitation particles with 94GHz cloud radar. Secondly, analyze the rationality of identification precipitation method and analyze with several different thresholds comparatively to identify the difference of precipitation. Finally, precipitation identification by Cloudsat is compared to identification by surface data, with a lot of example analysis, verify the precipitation identification method with Cloudsat is reasonable.3. Precipitation cloud statistical characteristics in HuaBei and JiangHuai area. The studies have been carried out by statistical analysis of monthly total rainfall frequency distribution,cloud layer proportion in precipitation cloud, height of layer base and cloud thickness,average height cloud top and cloud base in precipitation and non-precipitation,the thickness of multilayer cloud except interlayer in precipitation cloud. The results reported here show that:Precipitation mainly caused by a single cloud and the frequency is 78.1% in HuaBei,69.7% in JiangHuai. The precipitation frequency caused by multi-layer is 21.9% in HuaBei and 30.3% in JiangHuai. Double-layer cloud precipitation is most in April, JiangHuai is more than HuaBei, the frequency of double-layer cloud precipitation is 50% in JiangHuai. Through the compared of macro micro structure in precipitation cloud, the cloud base height of precipitation cloud is below 2km,cloud thickness is mainly of 2-4km, in which the single-layer cloud thickness more than 6km has a rather high proportion, the thickness of multilayer cloud except interlayer is of 1-3km in precipitation cloud. Comparatively, the cloud base height of non-precipitation cloud is mainly above 2km, cloud thickness is mainly less than 2km, the thickness of multilayer cloud except interlayer is almost higher than 4km. Judging from the representative region for rainfall enhancement, there is no significant distinction on the height of cloud base and cloud thickness in HuaBei and JiangHuai. However, the thickness of multilayer cloud except interlayer which is important for double-layer cloud precipitation conditions has some distinction, with a value of 1-2km,frequency is 32.2% in JiangHuai, with a value 2-3km,frequency is 26.4% in HuaBei.From the research in this paper, we have a preliminary understanding about cloud vertical structure in HuaBei and JiangHuai and study precipitation identification method with Cloudsat. Then analyze and verify the rationality of identification precipitation method. Finally, we do a statistical analysis to study vertical structure of precipitation and non-precipetation cloud in HuaBei and JiangHuai, which is helpful to study the interaction between cloud and radiation, choose weather modification conditions accurately, design scientific standards of artificially seeding clouds and catalytic.