| With the development of social economy and the continuous growth of population,the contradiction between supply and demand of water resources has become increasingly conspicuous.The shortage of water resources is getting more and more serious,which has become one of the main factors restricting social and economic development.Global warming has a profound impact on the hydrological process,which leads to serious problems of regional water shortage.The quantitative evaluation of the spatial and temporal variations of blue water and green water resources can provide a more reliable basis for regional water resources management and water protection.Taking the Shanmei Reservoir watershed as the research area,the watershed distributed hydrological model(SWAT),was applied to simulate the spatial and temporal distribution of blue water and green water resources during the baseline period from 1991 to 2010.The variation characteristics of blue water and green water resources with different land use types at typical years were analyzed and the influence of climate change and land use on the spatial and temporal distribution of blue water and green water in Shanmei Reservoir watershed were discussed.Based on precipitation and temperature data from two GCM models(Had GEM2-ES and Noer ESM1-M)and two RCP scenarios(RCP4.5 and RCP8.5)during the 2031-2090,the spatial and temporal distributions of blue water and green water were simulated.Furthermore,the impact of future climate change on blue water and green water resources were quantitatively evaluated.The main conclusions of the study are as follows:(1)From 1991 to 2010,the annual average amount of blue water and green water resources were 1334.90 mm and 717.18 mm respectively in Shanmei Reservoir watershed.The spatial distribution of blue water and green water resources in Shanmei Reservoir watershed showed a certain degree of similarity,with the amount of water resources in upstream sub-basins larger than that in downstream sub-basins.In different land use types,the blue water and green water storage per unit area were the largest in forestland,while the green water flow storage is the largest in agricultural land.The green water flow of paddy field is the larger that of dry land and orchard.The blue water and green water in wet year were significantly greater than that in dry year,the amount of blue water in a wet year was 2.3 times that in a dry year,while the amount of green water resources showed little difference during the study period.(2)At temporal scale,climate change has a significant impact on the amount of blue water and green water in the Shanmei Reservoir watershed.Precipitation is significantly correlated with the temporal distribution of blue water resource(r=0.96,p<0.01),while the temperature is directly correlated with the green water resource.At spatial scale,precipitation is the key factor to the spatial distribution of blue water resource(r=0.72,p<0.01).Land use type has a great impact on the distribution of green water flow in some subbasins and the agricultural land directly affects the spatial distribution of green water resource(r=0.81,p<0.01).(3)In the next 60 years,the annual average precipitation is predicted to vary in the range of-0.43% ～ 7.16%,and the average temperature will increase from 1.72℃ to5.43℃.Compared with the baseline period,the amount of blue water resources in the RCP4.5 scenario will decrease by 12.81% to 33.41%,and the amount of green water resources will increase by 28.45% to 33.33% during 2031-2090.The amount of blue water resources will decrease by 14.17% ～ 35.28%,and the amount of green water resources will increase by 32.21%～36.12% under the RCP8.5 scenario.It indicates that with the increase of total emission intensity of greenhouse gases,the magnitude of change in blue water and green water resources will further increase. |
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