Study On The Precipitation In Heilongjiang Province In Spring Sowing Period (April-may)

By using the stational precipitation dataset of82stations in1973-2008during the spring sowing period (mainly in April and May) from Meteorological Information Center of Heilongjiang Meteorological Administration,the NCEP/NCAR daily reanalysis data, and the daily observation dataset of the northern hemisphere from National Meteorological Information Center of China Meteorological Administration, the climatic distribution, weather system characteristics, atmospheric circulation characteristics etc. of precipitation during the spring sowing period are analysed in Heilongjiang province, and forecasting models and forecast objectives are researched. At last, the example analysis of precipitation during the spring sowing period in Heilongjiang province is also analysed and samed up.The major conclusions are as follows:(1) The precipitation during the spring sowing period in Heilongjiang province has each rules on climatic characteristics, the starting time of the precipitation during the spring sowing period happened on18-22April and25-29April in time;the precipitation during April happened in center area of Heilongjiang province,and the precipitation during May in south-west and north-east regions in space.(2) There are six kinds of synoptic systems for the precipitation during the spring sowing period in Heilongjiang province,Mongolia cyclone,North China cyclone,Changjiang-Huaihe cyclone, northeast cyclone etc.(3) The weather system characteristics of atmospheric circulation which effect precipitation during the spring sowing period in Heilongjiang province are low trough precipitation and vortex precipitation.The former involves precipitation which located in the nearby of the temperature advection zero line, precipitation caused by wind shear which located in north of low trough, warm front frontogenesis precipitation etc. The latter involves cold front precipitation, warm front precipitation, occluded front precipitation etc.(4) There are four forecasting models can be concluded by analysing precipitation during the spring sowing period in Heilongjiang province:Mongolia cyclone-type, northeast cyclone-type, Changjiang-Huaihe cyclone-tyoe and North China cyclone-type. Moreover,by analysing forecast objectives,the conclusions above will be good for forecasting the precipitation during the spring sowing period and analyzing typical examples.(5) When conducting a study on analysis of precipitation during the spring sowing period,we can use kinds of methods just as conventional data analysis, physical diagnosis analysis,mesoscale synoptic analysis, satellite cloud image analysis etc. As a result, the examples of precipitation and snowfall during the spring sowing period are the typical Changjiang-Huaihe cyclone-type and northeast cyclone-type.