The Statistical Relationship of Lightning Activity and Short-Duration Rainfall Events over Guangzhou, China, in 2017

The Earth Networks Total Lightning Network (ENTLN) lightning observation and rainfall data from 270 automatic weather stations (AWS) over Guangzhou in 2017 are examined. The high spatiotemporal resolution data are used to analyze the relationship between lightning activity and precipitation in 14 758 short-duration rainfall (SDR) events. About 43% of the SDR events are reported to be accompanied by lightning activity (SDRWL). The rainfall intensity of SDRWL is significantly higher than that of SDR events with no lightning (SDRNL). Lightning activity is more likely to occur in SDR events with higher rainfall rates. A power-law relationship is found between lightning flash rate and rainfall rate, with a max correlation coefficient of 0.44. In about 55% of SDRWL, lightning flashes occur later than precipitation, and the opposite is found in about 35% of SDRWL. When lightning is delayed for 5–10 min, the lagged correlation coefficient between lightning and precipitation is the largest. The results also show that the lightning flash rate peak mostly occurs from −10 to 20 min after the rainfall rate peak, and this time lag is common in SDRWL with all intensities. The starting time of lightning is related to the rainfall intensity. In heavy SDRWL, lightning activity usually occurs from −10 to 20 min after the beginning of precipitation, while in weak SDRWL, the above time window expands to ±1 h. These results indicate that the quantity and time relationship between lightning and precipitation are more solid in heavy SDR events.