Diurnal variation of precipitation at the southern slope in Nanyue Mountain based on hourly rain dataset from gradient observation

Abstract

The hourly rain dataset from the three surface weather observation stations with different elevation in the southern slope of Nanyue Mountain between 1 September 2015 and 31 August 2018 are used to analyze the diurnal variation characteristics of precipitation in Nanyue Mountain area. The results show that the total precipitation amount increases with the height from the bottom to top of Nanyue Mountain. There are three diurnal precipitation amount peaks which appear in the early morning,afternoon and early evening,respectively. The precipitation amount peak in the early morning is mainly caused by the high frequency of precipitation in this period. The precipitation amount peaks in the afternoon and early evening are mainly associated with precipitation intensity in the same time. The difference of precipitation amount between the summit station and the foot station mainly presents in the afternoon and early evening. Hourly precipitation amount reaches maximum in the afternoon and early evening. The occurrence time of short-time strong precipitation at the summit and hillside stations is mainly in the afternoon and early evening,which is more centralized than that at the foot of mountain. Short-duration precipitation events lasting from 1 hour to 6 hours usually occur from afternoon to early evening,which has higher frequency than long-duration precipitation events lasting time longer than 6 hours. The latter usually occurs from wee hours to noon and contributes more to the total precipitation amount than the short-duration precipitation events.

Keywords

• precipitation
• diurnal variation
• gradient observation
• nanyue mountain