Long-term trends of precipitation and erosivity over Northeast China during 1961–2020

Abstract

Northeast China (NEC) is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection. To determine long-term trends of precipitation and rainfall erosivity over NEC during the latest decades, daily precipitation for the entire year during 1961–2020 and hourly precipitation for the warm season (May to September) during 1971–2020 were collected for 192 and 126 stations, respectively. Three seasons, including the cold season (October to April), early warm season (May to June), and late warm season (July to September) were divided according to the combination of precipitation and vegetation. Results demonstrate: (1) Daily precipitation reveals total precipitation and rainfall erosivity in the cold season and early warm season increase significantly at relative rates of 3.1% ∼ 6.1% compared with the average during 1961–2020, and those in the late warm season decrease insignificantly. (2) Hourly precipitation reveals storms occurring in the early and late warm seasons have undergone significant increasing changes, which shift towards longer storm duration, larger amount, peak intensity, kinetic energy, and rainfall erosivity during 1971–2020. Moreover, the frequency of extreme storms increased. (3) Rainfall erosivities estimated from daily precipitation during 1971–2020 increase insignificantly for the early and late warm season, whereas those from hourly precipitation increase significantly (6.1% and 5.5%, respectively), which indicates daily precipitation may not be able to capture the trend fully under the warming background, and precipitation at higher resolutions than the daily scale is necessary to detect trends of rainfall erosivity more accurately.