Analysis on an extreme torrential rainfall in arid northwest China area with remote sensing data

Using remote sensing data of satellite and the new generation weather radar, together with NWP products and conventional observation, a study on an extreme torrential rainfall in the arid area of northwest China was conducted. The results show that 1. The extreme torrential rainfall happened under a unique circulation background of west stretching subtropical high pressure in the medium latitude which is caused by landing tropical cyclone. 2. The data of radar indicated the train-effect caused by the low centroid strong echoes lead to severe precipitation. 3. The meso-γ scale gust nucleus, corresponding convergence-divergence, and vertical motion are major affect systems. 4. High efficient vapor transportation of southwest jet at low altitude indicated by VWP of radar and satellite image was the key factor of the extreme torrential rainfall. 5. The cold air invasion at med-high altitude and the moist air coming from the mid-low altitude revealed by satellite provided favorable condition for the heavy precipitation.