An annual sediment yield indicator based on precipitation − vegetation unmatched-degree developed in the Huangfu River basin

• It is not necessarily that the larger the precipitation, the greater the sediment yield. • A new index (ASYI) is proposed to reflect the sediment yield status of the basin. • The temporal matching relationship of “precipitation-vegetation” and its impact on sediment yield is revealed. • An efficient simulation method for sediment yield has been discovered in the Huangfu River basin. Revealing the matching relationship of “precipitation − vegetation” and its impact on sediment yield is of great scientific significance for controlling soil erosion and promoting coordinated environmental development. Based on GPM precipitation data and MODIS 250 m NDVI, the temporal distribution pattern and matching relationship between precipitation and vegetation within a year are analyzed, and the annual sediment yield index (ASYI) is constructed to reflect the sediment yield status of the basin. Furthermore, multiple regression analysis is conducted using precipitation, NDVI and its distribution parameters, as well as ASYI and actual sediment yield. The results show that (1) the inhibitory effect of vegetation on erosion varies little between years, while the fluctuation of precipitation distribution is more pronounced than that of vegetation; (2) the correlation between the constructed ASYI index and the actual sediment yield reaches 0.877, indicating that the index can well reflect the sediment yield; when fitting ASYI to sediment yield using a quadratic function, R 2 reaches 0.9193; (3) there is a positive correlation between precipitation and sediment yield, but it is not necessarily that the larger the precipitation, the greater the sediment yield, and the annual distribution pattern of precipitation is the dominant factor affecting sediment yield; (4) the model which considering precipitation, NDVI, distribution parameters and ASYI, can achieve the best fit, and R 2 reached 0.9129. In summary, the matching pattern of “precipitation − vegetation” within a year has a significant impact on sediment yield. When ASYI is greater than 1.63, the sediment yield will increase sharply. This paper provides a new perspective for studying the relationship and quantitative expression between precipitation and sediment yield. The proposed index can be easily applied to other regions due to its good operability.