The rainstorm weather from July 15,2010 to July 18,2010 is researched by diagnosis analysis method.The results suggest that in the strong and lasting period,the upward air current in the basin is prevail and is above 300 hPa.The convergence layer during strong rainstorm period is not thick.The convergence movement of air current is under 500 hPa.In this rainstorm process,the positive vortex maximum value center of the lower layer of convection layer is perfectly corresponding to rainstorm zone.The air current convergence and divergence intensity is one magnitude larger than the turning intensity.Flux plays a leading role in the system changes process;the non-equilibrium value of the low layer of convection layer during the strong rainstorm period U<0.Strong non-equilibrium is favorable for the movement of convergence.The non-equilibrium value of the high layer of convection layer U>0,and it stimulates the divergence movement of high layer.The divergence of high layer pushes the convergence of the lower layer and thus forms strong upward movement.
By using the ground climate observation data of Chengdu from 1951 to 2009,the time variation sequence of mean temperature,total rainfall,seasonal mean temperature and precipitation were studied.The results showed that there was a trend of decreasing-increasing with the temperature and a trend of decreasing with the rainfall in Chengdu.The main temperature increasing occurred in spring and main rainfall decreasing occurred in summer.With the M-K method analysis,the spring temperature change time was in 1968,and the summer rainfall change time was in 1977 in Chengdu.With the temperature increasing in spring,the accumulated temperature would be higher,and it was beneficial to the agriculture.With the rainfall decreasing in summer,there was more summer drought.We needed to build more water facilities to protect agriculture production in Chengdu.