Spatiotemporal Patterns and Driving Factors of Growing Season Drought on the Loess Plateau

Loess Plateau is a crucial agricultural region in China that plays a vital role in national food production. This study employs the Vegetation Condition Index (VCI) as the drought indicator and combines it with the Enhanced Vegetation Index (EVI) phenology extraction method to analyze the spatiotemporal dynamics of growing season drought on the Loess Plateau from 2018 to 2023. Additionally, the geographical detector method is applied to quantitatively assess the driving effects of various factors, including climate, topography, and human activities, on vegetation growing season drought. The results reveal that (1) the phenology of the growing season on the Loess Plateau exhibits significant regional differences and inter-annual fluctuations, with an overall trend of delayed Start of Season (SOS) and shortened Length of Season (LOS), and the growing season is concentrated from May to September; (2) the occurrence frequency of growing season drought on the Loess Plateau has tended to increase over the past five years, and the proportion of areas affected by severe and extreme drought has increased annually, particularly in northern Shaanxi and Ningxia; (3) climate change is the dominant factor influencing drought, with precipitation and temperature contributing the most, while topography and human activities further impact the drought process through interactions with climatic factors.