Proportion and Distribution of Rain and Snow in China from 1960 to 2018

Rainfall and snowfall have different effects on energy balance calculations and land-air interactions in terrestrial models. The identification of precipitation types is crucial to understand climate change dynamics and the utilization of water resources. However, information regarding precipitation types is not generally available. The precipitation obtained from meteorological stations across China recorded types only before 1979. This study parameterized precipitation types with air temperature, relative humidity, and atmospheric pressure from 1960 to 1979, and then identified precipitation types after 1980. Results show that the main type of precipitation in China was rainfall, and the average annual rainfall days (amounts) across China accounted for 83.08% (92.55%) of the total annual precipitation days (amounts). The average annual snowfall days (amounts) in the northwestern region accounted for 32.27% (19.31%) of the total annual precipitation days (amounts), which is considerably higher than the national average. The average annual number of rainfall and snowfall days both displayed a downward trend while the average annual amounts of these two precipitation types showed an upward trend, but without significance at 0.1 levels. The annual number of rainfall and snowfall days in the southwestern region decreased significantly (-2.27 and -0.31 day decade(-1), p < 0.01). The annual rainfall amounts in the Jianghuai region increased significantly (40.70 mm decade(-1), p < 0.01), and the areas with the most significant increase in snowfall amounts were the northwestern (3.64 mm decade(-1), p < 0.01). These results can inform our understanding of the distribution and variation of precipitation with different types in China.

Automated summary

This study successfully identified precipitation types in China through parameterizing data such as air temperature and humidity. The results showed that rainfall was the main precipitation type in China, and the snowfall in the northwestern region was significantly higher than the national average. The average annual number of rainfall and snowfall days exhibited a downward trend, while the amounts of these two precipitation types showed an upward trend without significance.