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Rainfall erosivity is an important indicator for quantitatively representing the erosive power of rainfall. This study expanded three satellite-based precipitation products (SPPs) for estimating and mapping rainfall erosivity in a subtropical basin in China and evaluated their performance at different rainfall erosivity intensities, seasons, and spaces. The results showed that the rainfall erosivity data from GPM-IMERG had the smallest errors compared to the estimates from rain gauge data on monthly and seasonal scales, while data from PERSIANN-CDR and TRMM 3B42 significantly underestimated and slightly overestimated rainfall erosivity, respectively. The three SPPs generally presented different strengths and weaknesses in different seasons. TRMM 3B42 performed best in summer, with small biases, but its performance was less satisfactory in winter. The precision of estimates from GPM-IMERG was higher than that from TRMM 3B42; the biases, especially in winter, were significantly reduced. For different intensities, PERSIANN-CDR overestimated light rainfall erosivity but underestimated heavy rainfall erosivity. In terms of space, TRMM 3B42 and GPM-IMERG correctly presented the spatial pattern of rainfall erosivity. However, PERSIANN-CDR tended to be less skillful in describing its spatial maps. Outcomes of the study provide an insight into the suitability of the SPPs for estimating and mapping rainfall erosivity and suggest possible directions for further improving these products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water release from local reservoirs significantly raised the lake level in dry season. • Release of local reservoirs decreased the duration and severity/intensity of drought. • Exposure duration of wetland was shortened and the area with long duration decreased. • Joint operation of local reservoirs and the TGR has further alleviated the droughts. Lake is an important component of the Earth's surface water bodies. Frequent and serious drought events in lakes have affected the security of regional water resources and caused the degradation of the lake ecosystem. Poyang Lake, the largest freshwater lake in China, has been suffering from increasingly severe hydrological droughts. This study simulated and investigated the effects of water release from local reservoirs in dry season on hydrological droughts in Poyang Lake based on a hydrodynamic model MIKE 21, and quantified the effectiveness of the joint operation of local reservoirs and the Three Gorges Reservoir (TGR). Major results showed that the water level of Poyang Lake during the dry period was significantly raised by the water release from local reservoirs, especially in the northern lake area. The average and the lowest lake level increased from 10.99 m to 11.18–11.59 m and from 9.97 m to 10.14–10.50 m at Xingzi station, respectively. Meanwhile, both the duration of low water and the drought severity/intensity (DS/DI) decreased significantly, with the duration decreasing from 128 days to 105–115 days for typical threshold lake level of 12.0 m, and the DS and DI decreasing from 176.6 m and 1.38 m/day to 117.6–155.3 m and 1.12–1.35 m/day, respectively. Moreover, the release of local reservoirs shortened the exposure duration of beach wetland, from nearly 3 months to about 1.5–2.5 months at the northern channel of Poyang Lake. The area with long exposure duration (>120 days) was also significantly reduced. In addition, the hydrodynamic simulations revealed that the joint operation of local reservoirs and the TGR further raised the average and the lowest lake level and decreased the duration of low water and drought severity and intensity. Outcomes of the study provided valuable references for mitigating lake droughts in complex river-lake-catchment system. [ABSTRACT FROM AUTHOR]

• 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]