Comparative Analysis on Hourly Precipitation Features on the East and West Sides of Yunling Diancang Mountain in Hengduan Mountains
Based on the 2005-2012 hourly precipitation data from two national meteorological stations on the east and west sides of Diancang Mountain, a part of Hengduan Mountains’ ranges, precipitation characteristics on each side and differences between them have been analyzed in detail. The results show that the climate states of average precipitation, annual precipitation and seasonal evolution on both sides are similar, but there are visible differences of the diurnal variations of precipitation between the east and west sides. The diurnal variation of rainfall amount and rainfall frequency presents a single peak curve on the east side, but significant double peaks are clear on another side. The two sides’ rainfall amount and rainfall frequency show peaks in late night which are mainly caused by long duration rainfall events lasting over 6 hours. The peaks of west side’s rainfall amount and rainfall frequency appear from afternoon to dusk, which are always derived from the contribution of rainfall events lasting less than 6 hours in duration. The accumulated rainfall amount and rainfall frequency reach the maximum in early morning on each side, but the occurrence time on the east side lags behind about 3 hours to the west side. The minimum of the accumulated rainfall amount at dusk on the east side appears, but on the west side it always occurs at noon while the minimum of the accumulated rainfall frequency on each side happens at around noon. The diurnal variation of hourly rain intensity on the west side is bigger than the west side, especially at night. The hourly rain on the west has two intensive periods (21:00 and 03:00 04:00), but it has slow diurnal variation on the east, getting to the maximum from 07:00 to 08:00. The difference of hourly precipitation between two sides is undoubtedly affected by the geography of Diancang Mountain. Due to the topography, the difference of the surface radiation on the east and west sides reaches the maximum at dusk, leading to a peak about rainfall amount and rainfall frequency, and hourly rain intensity on the west side. The inhomogeneity of rainfall distribution in Diancang Mountain area makes it become a typical representative to study the regional differences of climate in Southwest China with complex topography.