Abstract:

Using hourly precipitation data from 84 national meteorological stations in Heilongjiang province from 1991 to 2021, we analyzed the spatiotemporal distribution of conventional precipitation and hourly heavy precipitation processes. The results show that the precipitation process in Heilongjiang province mainly occurred in the afternoon to evening. The spatial distribution of precipitation was closely related to the terrain. The precipitation center was located in the middle of the Lesser Khingan Mountains, the eastern Songnen Plain, and the western Sanjiang Plain. The hourly heavy precipitation process mainly occurred in the southwestern and central regions of Heilongjiang province, and the distribution of hourly heavy precipitation extreme values were consistent with the distribution of heavy precipitation frequency. The annual variation in hourly average precipitation and precipitation frequency in Heilongjiang province from 1991 to 2021 decreased first and then increased, and the average intensity of hourly precipitation first increased and then decreased. From 2006 to 2021, the average intensity of hourly precipitation decreased, whereas the precipitation frequency increased significantly, resulting in an increase in precipitation year by year. The monthly variations in hourly average precipitation, precipitation frequency, and average intensity of hourly precipitation all reached their peaks in July. The daily variation of hourly average precipitation and the average intensity of hourly precipitation were both largest in the afternoon. Hourly heavy precipitation mainly occurred in the afternoon, with the highest frequency at 15:00.

Key words: Precipitation frequency, Precipitation intensity, Hourly heavy precipitation