Relationship between the western Pacific subtropical high′s characteristic index and summer precipitation over Guizhou

Based on the summer daily and monthly precipitation data in Guizhou province from 1979 to 2015, the subtropical high index provided by National Climate Center and the re-analysis data from NCEP/NCAR, the relationship between the summer precipitation and the western Pacific subtropical high was analyzed, and the rain storms´ position was analyzed when the subtropical high position changed. The results are as follows: (1) The summer precipitation and the subtropical high intensity/area index are positively correlated, and the summer precipitation and ridge line/west ridge point are negatively correlated. When the size and strength of the subtropical high are enhanced, rainfall is increased. In positive precipitation anomaly years, the position of subtropical high is either to the west or closed to the average. In negative precipitation anomaly years, the position of subtropical high is either to east or closed to the average. In either cases, it tends to gradually be pushed back to northeast. (2) Area index, intensity index and precipitation have condensed resonance relations in 2-4 years, and the change of the subtropical high area (intensity) is behind the change of precipitation. The subtropical high ridge line and west ridge point with precipitation have 2 years of coherence resonance, and the ridge line stretch (west ridge point) of changes is significantly ahead of the change of precipitation. (3) The average location of subtropical high ridge line is gradually pushed to the north, and so is the Guizhou rain belt. Heavy rain days first increases then decreases. West ridge point is pushed to the west gradually. Guizhou storm days is reduced gradually, when the ridge line is located in 25°-29°N. When the west ridge point is located in 90°-100°E, Guizhou heavy rain days are the most.