Analysis on characteristics of abrupt intensification of heavy rainfall associated with tropical cyclones in Fujian province

Threshold standard of abrupt intensification of tropical cyclone rainstorm was given, and temporal and spatial distribution of rainstorm abrupt intensification and its relationship with tropical cyclones were analyzed, using data of hourly precipitation of regional automatic weather stations and basic weather stations in Fujian province, from 2007 to 2013. The results showed that the tropical cyclones which had abrupt intensification of rainstorm for 1h, 3h, 6h, decreased as time resolution reduced. The tropical cyclones which had abrupt intensification of rainstorm for 3h mainly occurred from June to October, and, the number and the times of abrupt intensification of rainstorm both increased year by year. The diurnal variation of the times of abrupt intensification of rainstorm was the triple-peak type, and the high value region occurred from 17:00 to 20:00.Most of the tropical cyclones which had abrupt intensification of rainstorm made a landfall on the middle and south coast of Fujian province.Among various tropical cyclones, the weaker the intensity, the more times of abrupt rainfall intensification, and the higher amplification of rainfall intensity. The abrupt intensification of heavy rainfall mainly occurred within 24h after the tropical cyclone landed, in the southwest, and within 400 km of the center, related to the landing track of the tropical cyclone. Characteristics of abrupt intensification of heavy rainfall before and after the tropical cyclones landed in Fujian province were analyzed contrastively. The results showed that there were the most tropical cyclones landing on the middle coast, and also the most times of abrupt intensification of heavy rainfall. The times of abrupt intensification of heavy rainfall after the landfall were obviously more than that before the landfall of the tropical cyclones.