Contrast Tests of GRAPES Prediction with T213 and T639 as Initial Field and Boundary Condition
Using global model T213L31 and T639L60's product as initial field and boundary condition,and using the same physical processes and programs to drive GRAPES-Meso,we contrasted and tested forecasting ability of rainfall and temperature in Xinjiang during April to September 2009,the results showed the follows:(1)Using T639's product as initial field and boundary condition,Ts skill score of 24 hour precipitation for 103 stations increased about 5 points than that of T213,and rainy/sunny forecasting accurate rate increased 20 points,but error rate also increased.For the distribution of the stations rainfall forecasting score,different initial field showed same situation: west of north Xinjiang,Tianshan Mountain area were the best,south of Xinjiang was the worst.(2)Using T639's product as initial field and boundary condition,hourly 1 ℃ and 2 ℃ temperature forecasting accurate rate for 103 stations increased 15 and 28 points respectively than that of T213,the average forecasting error was negative.Accuracy increased mostly in Tianshan Mountains area and both sides of Tianshan Mountain,the increased accuracy in south Xinjiang was greater than that of north Xiniang,and the increase of 2 ℃ forecasting accurate rate was greater than that of 1 ℃.