At the level of 700 hPa wind resource distribution analysis overhead Yunnan

Using the wind and temperature data provided by NCEP from Jan1948 to December 2010,the wind velocity,wind power density distribution,and wind direction frequency distribution of Yunnan were analyzed.The result shows that on 700 hPa level above Yunan,the interannual changes of the mean wind velocity and wind power density are steady and the two of them have a similar trend.Inter-month variation of the mean windspeed and wind power density show apparent monthly change with February being the maximum,followed by March,and the wind velocity and wind power density of different months are significantly different.The wind power density of all quarters in an descending order is winter,spring,autumn,summer,among which winter has the most significant fluctuation.The region(10°—30°N,87.5°—117.5°E) with Yunnan being its center shows that on 700 hPa level above Yunnan wind velocity and wind power density have significant spatial distribution characteristics:in the southeast wind velocity as well as wind power density is big/large/has a higher value,in the north wind velocity as well as wind power density is small.On 700 hPa level above Yunnan the wind direction has significant characteristics:west,south,southwest are the principal wind directions in different quarters and years,and the more frequent wind directions are accompanied by bigger wind velocity and wind power density.