Arid Zone Research ›› 2024, Vol. 41 ›› Issue (1): 1-12.doi: 10.13866/j.azr.2024.01.01

• Weather and Climate • Previous Articles     Next Articles

Diurnal variation characteristics of warm season precipitation in Gansu Province

ZHOU Zihan1(),WANG Jixin1,2(),LIU Weicheng1,WANG Yong1,3,4,ZHANG Junxia1,GUO Runxia1   

  1. 1. Lanzhou Central Meteorological Observatory, Lanzhou 730020, Gansu, China
    2. School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, Anhui, China
    3. College of Atmospheric Science, Lanzhou University, Lanzhou 730000, Gansu, China
    4. Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, Gansu, China
  • Received:2023-05-27 Revised:2023-08-08 Online:2024-01-15 Published:2024-01-24

Abstract:

Based on hourly precipitation observation data from 340 meteorological stations in Gansu Province from April to October 2013 to 2022, the refined evolution characteristics of warm season precipitation in Gansu Province on a diurnal variation scale were revealed. Discussions and analyses were conducted in different regions, providing a scientific reference for the study of extreme precipitation events in Gansu. The results show the following: (1) the daily peak of precipitation and precipitation intensity in the warm season in Gansu mainly occurs between 10:00 and 13:00, the daily peak of precipitation frequency primarily occurs between 22:00 and 01:00 at night, and the daily precipitation variation has obvious seasonal differences. There is a relatively concentrated distribution of autumn rain in the central and southern parts of Gansu. (2) The diurnal variation of precipitation has distinct regional characteristics. Precipitation in the Qilian Mountains and the plateau slopes of central Gansu mainly occurs during the day, with intense precipitation dominating around noon, marking the peak of daytime precipitation. Conversely, in western Hexi, the peak and frequency of daily precipitation generally occur at night, with occasional sudden heavy rainfall between 18:00 and 21:00. In southeast and eastern Gansu, the precipitation is nonuniformly distributed; nighttime rain is common due to the frequency of precipitation peaks during the night, but strong precipitation periods tend to occur in the afternoon and morning, respectively. (3) The precipitation characteristics of different durations are different. For short-term precipitation events with a duration of 6 h and below, the daily variation of precipitation is mostly “bimodal type.” Long-term precipitation events lasting more than 6 h are “unimodal type” and primarily begin in the evening, reach their peak at night, and end at noon.

Key words: diurnal variation, warm season precipitation, different regions, different durations, Gansu Province