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• Projected runoff will increase during 2020–2099, and peak flow will be delayed from June to July. • The range of time distribution will become wide for DTFEs, while narrow for FTDEs in the future. • Projected DFAAEs are mainly mild, and the moderate and extreme DFAAEs will be reduced. • The intensity of Projected DFAAE will be stronger in the future. Drought-flood abrupt alternation events (DFAAEs) bring about detrimental impacts on economics and environment. Projection of the future change in the DFAAEs is a challenging issue. Incorporated with the datasets of the Coupled Model Intercomparison Project Phase 5 under two Representative Concentration Pathway scenarios (RCP4.5 and RCP8.5), we applied the Soil and Water Assessment Tool model and the drought-flood abrupt alternation index (DFAAI) to detect climate change impacts on the DFAAEs in the Poyang Lake Basin for the period from 2020 to 2099. Our results demonstrated that the projected DFAAEs would become more frequent and be mainly distributed from January to October. Among them, the drought-to-flood events mainly occur from January to July, while the flood-to-drought events mainly occur from July to October. The occurrence of the DFAAEs is more frequent, and the occurrence frequency of DFAAEs under RCP4.5 is 75. The mild DFAAEs would be the dominated events in the Poyang Lake Basin, while the moderate and extreme DFAAEs are spatially unevenly distributed. The annual maximum and minimum of DFAAI would increase, and the frequency and intensity of the DFAAEs tend to increase. The projected runoff tends to increase but spatially homogenous. The projected peak flow would delay leading to a change in the transition time of the DFAAEs' type. This study provides a future projection on DFAAEs, valuable for policy makers to mitigate flood disasters at a basin scale. [ABSTRACT FROM AUTHOR]

• High spatial–temporal resolution of drought monitoring dataset was constructed. • Composite index of anthropogenic influence was constructed using multi-source data. • Human contribution to drought increases exponentially with social development level. • Effects of human activities on drought can be spatially opposite. 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 ≥ 50%) in the PYLB is the highest, followed by regional drought (33%≤DIS < 50%), partial local drought (25%≤DIS < 33%), and local drought (10%≤DIS < 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. [ABSTRACT FROM AUTHOR]

Climate change and human activities have impacted the Poyang Lake Basin (PLB) greatly over the past decades, and have significantly changed the local ecological environment and hydrological cycle. Based on the daily records from 16 meteorological stations and 7 gauging stations in the Poyang Lake Basin from 1960 to 2015, the contributions of climate change and human activities to runoff variations under different timescales (annual, flood season, and non-flood season) were explored using the Mann-Kendall, Moving-T test, and a linear regression model. The results showed that on annual timescale, climate change accounted for 91.88% of the increased runoff depth. However, intensive human activities in the subbasins would have reduced the runoff depth in the Poyang Lake Basin. The impact of climate change on the variation of runoff depth increased during the flood season. Climate change and human activities contributed ~57% and ~42%, respectively. Both climate change and human activities could increase the runoff depth during the non-flood season. • Effect of precipitation on annual runoff depth is significant. • Climate change contributes greater to runoff depth from 1960 to 2015. • Human activities could increase the runoff depth during the non-flood season. [ABSTRACT FROM AUTHOR]