Comparison of rainfall characteristics of two national reference stations in Yunnan-Guizhou plateau

To better understand the influence of small-scale terrain on precipitation, the temporal-spatial variation features of precipitation were statistically analyzed using hourly precipitation data from two adjacent Taihuashan and Kunming national reference stations in Yunnan-Guizhou Plateau during the rainy season of 2006-2018. The altitude difference between the two stations is about 500 m and the station distance is about 5km. Results show that their rainy season precipitation amounts are similar, but the fine-scale characteristics of hourly precipitation are significantly different. The hourly precipitation differences between the two stations are as follows. (1) There are no obvious differences in the interannual variations of rainfall amount and rainfall intensity, but the rainfall frequency at Taihuashan station is higher than that at Kunming station in most years. (2) For diurnal variations, the cumulative precipitation amounts at Taihuashan station during 11:00-20:00 BT are larger than that at Kunming station. The precipitation frequency exhibits double diurnal peaks in both stations. The precipitation frequency at Taihuashan station is higher than that at Kunming station during 03:00-09:00 BT and 11:00-17:00 BT while the precipitation intensity at Taihuashan station is weaker than that at Kunming station during 00:00-13:00 BT and 21:00-23:00 BT. (3) The characteristics of precipitation events at the two stations are different. The number of precipitation events and cumulative precipitation at Taihuashan station are significantly higher than those at Kunming station, which is mainly contributed by the rainfall events longer than 6 hours. (4) For most rainfall events, rainfall can be observed at both two stations. Their rainfall differences are mainly caused by these coexistent events. These events more easily start at Taihuashan station while they more easily end at Kunming station. The duration and precipitation frequency contributed by these events at Taihuanshan station is also longer than that at Kunming station. The average precipitation duration of Taihuashan station is 0.36 h, which is longer than that of Kunming station. (5) The proportion of rainfall events that are only observed at one station is 39.9%. The number of rainfall events only occurring at Taihuashan station is 1.83 times than that at Kunming station. The duration of individual-rainfall-event at Taihuashan station is longer than that at Kunming station.