水文模拟精度决定着流域水资源丰枯状态,开展水文模型不确定性研究可有效降低模拟结果的不确定性,从而提高径流组成成分模拟精度。为此,本文以汉江上游的子午河流域为例,提出一种改进的第二代非支配排序算法(Non-dominated Sorting Gene...水文模拟精度决定着流域水资源丰枯状态,开展水文模型不确定性研究可有效降低模拟结果的不确定性,从而提高径流组成成分模拟精度。为此,本文以汉江上游的子午河流域为例,提出一种改进的第二代非支配排序算法(Non-dominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)多目标算法校准分布式SWAT(Soil and Water Assessment Tool)模型,并将其与基于SWAT-CUP软件下SUFI-2算法的模拟结果进行对比分析。同时,采用Mann-Kendall趋势检验方法研究分析各子流域径流组成的趋势性演变特征。结果表明,改进的NSGA-Ⅱ算法能够较好地模拟子午河流域的水文过程,且模拟精度优于SUFI-2算法;其模拟的流域实际蒸发量、土壤蓄水量、总产水量和地下径流量精度均优于后者,而后者低估了各子流域的土壤蓄水量,尤其是地下径流量。研究结果对于流域水资源量的精准预估具有重要的指导意义。展开更多
Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluat...Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluating water and soil quality within watersheds.The latest version,SWAT+,introduces advanced encoding capabilities and improved performance,making it better suited for addressing complex watershed modeling challenges.This study implemented the SWAT+model to quantify soil erosion rates within the Chehelchay watershed in northern Iran.The foundational dataset comprises a 30-meter resolution Digital Elevation Model(DEM),land use classification,soil,and weather data.Model performance was evaluated using Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R^(2)),root mean square error(RMSE),and percent bias(PBIAS).The SWAT+simulation revealed substantial spatial variation in erosion patterns across the watershed,with annual sediment yields in critical HRUs,reflecting diverse erosion intensities driven by variations in land use,soil characteristics,and slope.Among the Hydrological Response Units(HRUs),50 critical units,representing approximately 9%of the total watershed area,generate sediment yields exceeding 5 tons per hectare per year.The most severe erosion occurs predominantly in the central zone of the watershed.Downstream regions exhibit minimal soil loss due to gentle topography while upstream areas maintain soil stability through protective forest cover,resulting in negligible erosion rates.Best Management Practices(BMPs)were designed to safeguard water and soil resources at a watershed level.The study evaluated three strategic conservation interventions:alfalfa cultivation,agroforestry implementation,and garden development.When applied in combination,these measures achieved approximately 30%reduction in sediment yield at the HRU level.This integrated approach demonstrates the potential of combining multiple land management strategies to combat erosion effectively.展开更多
The story of a man in China who had to have his left eyeball removed because of an infection caused by him swatting an insect on his face has trended on social media.The man,surnamed Wu,from Shenzhen in the southern p...The story of a man in China who had to have his left eyeball removed because of an infection caused by him swatting an insect on his face has trended on social media.The man,surnamed Wu,from Shenzhen in the southern province of Guangdong,killed the fly that was buzzing around him after it landed on him,according to the report.展开更多
文摘水文模拟精度决定着流域水资源丰枯状态,开展水文模型不确定性研究可有效降低模拟结果的不确定性,从而提高径流组成成分模拟精度。为此,本文以汉江上游的子午河流域为例,提出一种改进的第二代非支配排序算法(Non-dominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)多目标算法校准分布式SWAT(Soil and Water Assessment Tool)模型,并将其与基于SWAT-CUP软件下SUFI-2算法的模拟结果进行对比分析。同时,采用Mann-Kendall趋势检验方法研究分析各子流域径流组成的趋势性演变特征。结果表明,改进的NSGA-Ⅱ算法能够较好地模拟子午河流域的水文过程,且模拟精度优于SUFI-2算法;其模拟的流域实际蒸发量、土壤蓄水量、总产水量和地下径流量精度均优于后者,而后者低估了各子流域的土壤蓄水量,尤其是地下径流量。研究结果对于流域水资源量的精准预估具有重要的指导意义。
文摘Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluating water and soil quality within watersheds.The latest version,SWAT+,introduces advanced encoding capabilities and improved performance,making it better suited for addressing complex watershed modeling challenges.This study implemented the SWAT+model to quantify soil erosion rates within the Chehelchay watershed in northern Iran.The foundational dataset comprises a 30-meter resolution Digital Elevation Model(DEM),land use classification,soil,and weather data.Model performance was evaluated using Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R^(2)),root mean square error(RMSE),and percent bias(PBIAS).The SWAT+simulation revealed substantial spatial variation in erosion patterns across the watershed,with annual sediment yields in critical HRUs,reflecting diverse erosion intensities driven by variations in land use,soil characteristics,and slope.Among the Hydrological Response Units(HRUs),50 critical units,representing approximately 9%of the total watershed area,generate sediment yields exceeding 5 tons per hectare per year.The most severe erosion occurs predominantly in the central zone of the watershed.Downstream regions exhibit minimal soil loss due to gentle topography while upstream areas maintain soil stability through protective forest cover,resulting in negligible erosion rates.Best Management Practices(BMPs)were designed to safeguard water and soil resources at a watershed level.The study evaluated three strategic conservation interventions:alfalfa cultivation,agroforestry implementation,and garden development.When applied in combination,these measures achieved approximately 30%reduction in sediment yield at the HRU level.This integrated approach demonstrates the potential of combining multiple land management strategies to combat erosion effectively.
文摘The story of a man in China who had to have his left eyeball removed because of an infection caused by him swatting an insect on his face has trended on social media.The man,surnamed Wu,from Shenzhen in the southern province of Guangdong,killed the fly that was buzzing around him after it landed on him,according to the report.
