西南地区东部大官山山地降水梯度变化特征分析

基于2019年1月~2020年12月西南地区东部大官山降水观测数据，分析了降水随海拔高度的变化特征。结果表明:2019~2020年，大官山降水量总体随海拔升高而增大，多年平均梯度变化率为1.32%/100 m，最大降水高度在海拔1900 m左右。各季降水梯度变化率中，夏、秋季高，冬、春季低，夏季为3.31 mm/100 m，秋季为1.39 mm/100 m，冬季为0.50 mm/100 m，春季为0.67 mm/100 m。各月降水梯度变化率中，7月最高，达5.06 mm/100 m，1月和11月最低，分别为0.23 mm/100 m和0.29 mm/100 m。降水日数和小雨日数随高度的线性变化趋势较明显，平均上升率分别为2.86 d/100 m和2.56 d/100 m。大雨日数在海拔1900 m左右最大，暴雨日数在海拔2500 m左右最大。降水日变化表现出多峰值特征，降水量和降水强度均在06~09时达到最大，降水频率也随海拔高度升高而增大，其中，高海拔降水频率在15时左右达到最大。降水随海拔高度的变化与天气过程密切相关，持续阴雨天气过程降水量的梯度变化较为平缓，暴雨天气过程降水量随海拔的升高而升高，局地阵雨中单次过程降水量与海拔高度相关性不明显。 

Analysis on Precipitation Gradient Variations of Daguan Mountain in the East of Southwest China

Based on the precipitation observation data of Daguan Mountain in Wuxi, Chongqing, in the eastern mountainous area of Southwest China from January 2019 to December 2020, the gradient variation characteristics of precipitation with altitude were analyzed. The results showed that from 2019 to 2020, the precipitation generally increased with the increasing of altitude, and the average change rate of precipitation with altitude was 1.32% / 100 m, the maximum precipitation height was about 1900 m. The average change rate of precipitation with altitude was higher in summer and autumn, lower in winter and spring. The average change rate was 3.31 mm/100 m in summer, 1.39 mm/100 m in autumn, 0.50 mm/100 m in winter and 0.67 mm/100 m in spring. The average change rate of precipitation with altitude was the highest in July, up to 5.06 mm/100 m, and the lowest was in January and November , 0.23 mm/100 m and 0.29 mm/100 m respectively. The linear trend of total precipitation days and light rain days with altitude was obvious, the average rising rates were 2.86d/100 m and 2.56d/100 m respectively. The number of heavy rain days was the largest at about 1900 m above sea level, and the number of rainstorm days was the largest at about 2500 m above sea level. To the daily variation of precipitation, the precipitation and the precipitation intensity reached the maximum during 06:00 to 09:00. The precipitation frequency also increased with the increasing of altitude. The precipitation frequency at high altitude reached the highest at about 15:00. The variation of precipitation with altitude was closely related to the weather process. The precipitation in the process of continuous cloudy and rainy weather increased gradually with altitude. The precipitation in the rainstorm process increased with the increase of altitude. The correlation between single process precipitation and altitude in local shower was not obvious.