Journal of Hydrology: Regional Studies (Dec 2024)
Characteristics and discrepant responses of rainfall erosivity to El Niño-southern oscillation under varied rainfall intensity in a Karst Hilly region, China
Abstract
Study regions: The Guizhou Province (GZP) in southwestern China, where mainly comprises Karst regions. Study focus: The rainfall records were collected from 45 rain gauges within GZP during 1960–2019 to calculate the Rainfall Erosivity (RE). In addition, the spatio-temporal characteristics of RE were analyzed using statistical analysis methods, and the effect of El Niño-Southern Oscillation (ENSO) on RE under different rainfall intensities was also explored for the first time. New hydrological insights for the region: The annual average RE was 4774 MJ·mm·hm−2·h−1, exhibiting a persistent increasing trend. RE demonstrated an increasing trend in most months, except for April and May, and the trend would continue in the future. The southern region of the GZP exhibited higher RE values, while the northern region displayed lower values. The spatial distribution varied across different seasons and months. On an annual scale, RE was significantly (P < 0.01) negatively correlated with elevation, indicating a decrease in erosive precipitation with increasing elevation. On a monthly scale, except for June to September, RE showed a significant (P < 0.001) negative correlation with elevation. Additionally, the study revealed a significant positive correlation (P < 0.05) with a lag time of 1 year between the total RE and RE under rainfall intensities exceeding 40 mm/day and the Multivariate ENSO Index (MEI). This finding provides a possibility for predicting high-intensity RE with one year ahead.
