Drought monitoring based on temperature vegetation dryness index and its relationship with anthropogenic pressure in a subtropical humid watershed in China

Drought has serious impacts on agricultural production and ecological environment in China. Study on the causes of drought and drought monitoring technology is crucial for drought mitigation. This study conducts drought monitoring based on temperature vegetation dryness index (TVDI) and investigates with the impact of anthropogenic pressure in the Poyang Lake basin (PYLB). In the study, the MODIS normalized vegetation index (NDVI) and land surface temperature (LST) products from 2000 to 2021 were selected to construct NDVI-LST feature space processed with elevation correction, from which the monthly TVDI data was calculated. The land use data and nighttime light data were used to construct the anthropogenic pressure index (API). The results indicate that the frequency of drought in the PYLB is higher in the south and lower in the north. According to drought influence scope (DIS), the occurrence frequency of basin-wide drought (DIS & GE; 50%) in the PYLB is the highest, followed by regional drought (33%< 50%), partial local drought (25%< 33%), and local drought (10%< 25%). The basin as a whole showed an obvious wetting trend in spring and a drying trend in autumn. During the study period, API in the north of PYLB was obviously higher than that in the south, and showed a general increasing trend. The contribution of human activities to drought in the PYLB increased exponentially with the improvement of social development level. Meanwhile, the impact of human activities on drought shows spatial differentiation. Ecological protection and green development have been implemented in the northerly region of the PYLB, and anthropogenic pressure inhibited the degree of drought. Oppositely, extensive socioeconomic development in the central and southern parts of the PYLB has caused damage to the environment and indirectly aggravated regional drought. This study makes important contributions to exploring the response between remote sensing drought monitoring and anthropogenic pressure and promoting regional drought mitigation in humid areas.

Automated summary

Drought has serious impacts on agriculture and ecology in China. This study focuses on drought monitoring and the impact of human activities in the Poyang Lake basin. The results show spatial differentiation in drought frequency and the influence of human activities. The study also highlights the importance of ecological protection and green development in mitigating drought.