translate Chinese into English 2评估了流域水安全状况。流域蓝水短缺程度为低蓝水短缺224绿水短缺程度为低绿水短缺414超过80的区域人均可用水量超过1700 m3 capita-1 a-1。流域蓝水短缺度以03 a-1的速率缓慢上升绿水短缺度以-004 a-1的速率显著下降。流域年尺度上发生蓝绿水短缺的风险较小但年内发生了中度蓝绿水短缺蓝水短缺峰值多出现在10月到次

(2) The water security status of the basin was evaluated. The degree of blue water shortage in the basin was low (22.4%), and the degree of green water shortage was also low (41.4%). Over 80% of the region had a per capita available water volume of more than 1700 m3 capita-1 a-1. The degree of blue water shortage in the basin slowly increased at a rate of 0.3% a-1, while the degree of green water shortage significantly decreased at a rate of -0.04% a-1. The risk of blue and green water shortage at an annual scale was relatively low in the basin, but moderate blue and green water shortages occurred during the year. The peak of blue water shortage occurred from October to March of the following year, and the downstream area had a higher frequency of blue water shortage than other regions. Moderate green water shortage occurred throughout the basin from May to September.

(3) The response mechanisms of blue and green water resources and their distribution to climate and land use changes were explored. For every 10% increase in precipitation (potential evapotranspiration), the blue water in the basin increased by 12.8% (decreased by 21%), the green water flow decreased by 0.04% (increased by 4.2%), and the green water storage increased by 1.2% (decreased by 5.2%). Precipitation, potential evapotranspiration, and extreme precipitation were the main meteorological factors affecting the green water coefficient, with relative contributions of 57.5%, 11%, and 31.4%, respectively. Land use conversion changed the spatial and temporal distribution of blue and green water in the basin. For every 10% increase in cropland-forest land (cropland-construction land, forest land-construction land, and forest land-cropland), the blue water decreased by 0.3% (increased by 0.26%, 0.3%, and 0.3%), the green water flow increased by 2% (decreased by 1.6%, 3%, and 1.7%), the green water storage increased by 1.2% (decreased by 1.2%, 1.5%, and 0.6%), and the green water coefficient increased by 0.8% (decreased by 0.69%, 1.3%, and 1.2%). Based on the Budyko water-heat coupling equilibrium framework, the response of green water flow and runoff to underlying surface factors was quantitatively analyzed. The average relative contributions of climatic seasonality, precipitation seasonality, total vegetation cover, tree canopy cover, and shrub cover to changes in green water flow and runoff in the basin were 6.8%, 14.1%, 5.6%, 11.5%, 11.1%, and 2.9%, 6.6%, 2.4%, 5%, and 5.5%, respectively. The effect of increasing tree canopy cover on reducing runoff and increasing green water flow was offset by the effect of decreasing shrub cover on increasing runoff and decreasing green water flow.

(4) The coupling driving effects of climate and land use changes on blue and green water and their shortage were explored. The response of blue and green water to climate and land use changes differed significantly. Climate change had a relative contribution of 88.01%, 88.54%, and 39.44% to the change in blue water, green water flow, and green water storage, respectively, in the Dongjiang River Basin. Changes in precipitation and population had relative contributions of 57.7% and 42.3%, respectively, to changes in blue water shortage. Climate and land use changes had relative contributions of 96.7% and 3.3%, respectively, to changes in green water shortage. Blue and green water were more sensitive to land use changes at the sub-basin scale, and integrating the changes in blue and green water at the basin scale may result in the effects of land use being offset. The coupling driving effects of climate and land use on blue water and green water storage were additive, while their effects on green water flow and green water shortage were negatively synergistic.

(5) The future changes in climate, blue and green water, and land use in the Dongjiang River Basin from 2022 to 2100 were predicted. The distribution of basin precipitation during the year was more concentrated under the SSP126 and SSP585 scenarios compared to the baseline period (1970-2017), with an increase in precipitation of 112.9 and 133.1 mm, respectively, under the two scenarios. The maximum daily temperature increased by 2.1 and 3.2°C, and the minimum daily temperature increased by 1.2 and 2.2°C, respectively. Under the SSP126 scenario, blue water decreased by 5.6% (increased by 0.8%) compared to the baseline period in the near future (distant future), while green water flow increased by 14.6% (18.7%), and green water storage decreased by 8% (8.4%). Under the SSP585 scenario, blue water decreased by 5.8% (increased by 6.2%) compared to the baseline period in the near future (distant future), while green water flow increased by 9.1% (13.8%), and green water storage decreased by 5.8% (9.8%). Overall, this study scientifically understood the water and heat conditions and evolution characteristics of blue and green water resources under land use change in the Dongjiang River Basin, evaluated the water resource security status of the basin, and provided a theoretical basis for the comprehensive planning and management of blue and green water resources in the basin and the optimization of upstream and downstream blue and green water resource allocation. The study also quantified the impact of climate and land use changes on blue and green water and their shortage, revealed the response mechanisms of changes in blue and green water, distribution, and shortage to climate and land use changes, and had significant implications for further understanding the evolution laws of blue and green water.