This paper selected the typical wind-water erosion crisscross region Xiliugou watershed for research to reveal the impact of the landscape pattern change of the underlying surface in wind-water erosion crisscross regi...This paper selected the typical wind-water erosion crisscross region Xiliugou watershed for research to reveal the impact of the landscape pattern change of the underlying surface in wind-water erosion crisscross region where soil erosion is most serious on rainfall and runoff as well as erosion and sediment.Based on the Landsat TM image data and measured data of runoff-sediment in that watershed,the paper analyzed the characteristics of watershed landscape pattern change and runoff-sediment and explored the relationship between landscape index and runoff-sediment yield by means of GIS and Fragstats.The results were included as follows.(1)Grassland was the dominant landscape.In terms of the number of patches and area change rate,from 1985 to 2010,cultivated land,forest land and construction land were most stable,followed by unused land.Unused land,grassland and cultivated land experienced the most dramatic conversion and maximally affected by human activities.(2)The inter-annual difference between annual runoff and annual sediment load was significant.Compared with the annual sediment load,the trend of decreasing runoff was more obvious.The correlation coefficient of runoff-sediment was 0.67,representing a significant correlation.(3)There was a significant correlation between the landscape index and runoff-sediment.The runoff was negatively correlated with the largest patch index,patch cohesion index,aggregation index and contagion index,but positively correlated with landscape morphology index and landscape division index.And the sediment was negatively correlated with the contagion index,aggregation index and plaque cohesion index,but positively correlated with other landscape indexes.The results indicate that with the increase of the largest patch index,patch cohesion index and aggregation index,the rainfall infiltration capacity increase obviously and the soil erosion reduce significantly.Therefore,increasing the largest patch index,patch cohesion and aggregation index of the watershed landscape can enhance the function of water storage and soil conservation as well as ecological optimization in the windwater erosion crisscross region.The results can provide theoretical support for the ecological environment construction and comprehensive utilization of water and soil resources.展开更多
Serious soil erosion is one of the major issues threatening sustainable land use in semiarid areas, especially in the Loess Plateau of China. Understanding the effects of land use on soil and water loss is important f...Serious soil erosion is one of the major issues threatening sustainable land use in semiarid areas, especially in the Loess Plateau of China. Understanding the effects of land use on soil and water loss is important for sustainable land use strategy. Two sub-catchments： catchment A （CA） and catchment B （CB） with distinct land uses were selected to measure soil moisture, runoff and soil nutrient loss in Da Nangou catchment of the Loess Plateau of China. The effects of land use patterns on runoff and nutrient losses were analyzed based on soil moisture pattern by kriging and soil nutrients using multiple regression model. The results indicated that there were significant differences in runoff yield and soil nutrient losses between the two sub-catchments. With similar land uses, the CA produced an average sediment yield of 49 kg ha^-1 and 22.27 kg ha^-1 during two storm events. Meanwhile, there was almost no runoff in the CB with dissimilar land uses during the same events. Buffer zones should be established to re-absorb runoff and to trap sediments in catchment with similar land use structure such as the CA. Moreover, land use management strategy aiming to increase the infiltration threshold of hydrological response units could decrease the frequency of runoff occurrence on a slope and catchment scale.展开更多
In this study, two types of E1 Nifio events are distinguished and the correlations between the respective precipitation, temperature, and runoff are analyzed by a 5-point moving average method. Also, changes of the te...In this study, two types of E1 Nifio events are distinguished and the correlations between the respective precipitation, temperature, and runoff are analyzed by a 5-point moving average method. Also, changes of the temperature, precipitation, and runoff from mountainous watersheds of the Hexi Corridor region caused by these two types of E1 Nifio events from 1959 to 2005 are studied by the anomaly analysis method. The results indicate that the Hexi Corridor region is strongly influenced by El Nifio： rising tem- peratures and decreasing precipitation and runoff are features of the first E1 Nifio pattern, while decreasing temperature and in- creasing precipitation and runoff characterise the second pattern. The responses of temperature to E1 Nifio events are stronger in plains than in mountain regions, but the responses of precipitation are obvious in both types of regions. The response of runoff to E1 Nifio events is lower than the precipitation and temperature response because runoff from mountainous watersheds has a com- plex generation and concenlration process.展开更多
基金Sponsored by National Program on Key Basic Research Project(2011CB403303)A Special Fund for Central Public Welfare Research Institutes(HKY-2011-15)
文摘This paper selected the typical wind-water erosion crisscross region Xiliugou watershed for research to reveal the impact of the landscape pattern change of the underlying surface in wind-water erosion crisscross region where soil erosion is most serious on rainfall and runoff as well as erosion and sediment.Based on the Landsat TM image data and measured data of runoff-sediment in that watershed,the paper analyzed the characteristics of watershed landscape pattern change and runoff-sediment and explored the relationship between landscape index and runoff-sediment yield by means of GIS and Fragstats.The results were included as follows.(1)Grassland was the dominant landscape.In terms of the number of patches and area change rate,from 1985 to 2010,cultivated land,forest land and construction land were most stable,followed by unused land.Unused land,grassland and cultivated land experienced the most dramatic conversion and maximally affected by human activities.(2)The inter-annual difference between annual runoff and annual sediment load was significant.Compared with the annual sediment load,the trend of decreasing runoff was more obvious.The correlation coefficient of runoff-sediment was 0.67,representing a significant correlation.(3)There was a significant correlation between the landscape index and runoff-sediment.The runoff was negatively correlated with the largest patch index,patch cohesion index,aggregation index and contagion index,but positively correlated with landscape morphology index and landscape division index.And the sediment was negatively correlated with the contagion index,aggregation index and plaque cohesion index,but positively correlated with other landscape indexes.The results indicate that with the increase of the largest patch index,patch cohesion index and aggregation index,the rainfall infiltration capacity increase obviously and the soil erosion reduce significantly.Therefore,increasing the largest patch index,patch cohesion and aggregation index of the watershed landscape can enhance the function of water storage and soil conservation as well as ecological optimization in the windwater erosion crisscross region.The results can provide theoretical support for the ecological environment construction and comprehensive utilization of water and soil resources.
基金National Natural Science Foundation of China, No.40401001 No.40201003 Programme of Excellent YoungScientistsoftheM inistry ofLand and Resources
文摘Serious soil erosion is one of the major issues threatening sustainable land use in semiarid areas, especially in the Loess Plateau of China. Understanding the effects of land use on soil and water loss is important for sustainable land use strategy. Two sub-catchments： catchment A （CA） and catchment B （CB） with distinct land uses were selected to measure soil moisture, runoff and soil nutrient loss in Da Nangou catchment of the Loess Plateau of China. The effects of land use patterns on runoff and nutrient losses were analyzed based on soil moisture pattern by kriging and soil nutrients using multiple regression model. The results indicated that there were significant differences in runoff yield and soil nutrient losses between the two sub-catchments. With similar land uses, the CA produced an average sediment yield of 49 kg ha^-1 and 22.27 kg ha^-1 during two storm events. Meanwhile, there was almost no runoff in the CB with dissimilar land uses during the same events. Buffer zones should be established to re-absorb runoff and to trap sediments in catchment with similar land use structure such as the CA. Moreover, land use management strategy aiming to increase the infiltration threshold of hydrological response units could decrease the frequency of runoff occurrence on a slope and catchment scale.
基金We gratefully acknowledge the funding from the National Natural Science Foundation of China (Grant Nos. 41130368,41030527)the Global Change Research Program of China(No. 2010CB951404)the Hundred Talents Program of the Chinese Academy of Sciences
文摘In this study, two types of E1 Nifio events are distinguished and the correlations between the respective precipitation, temperature, and runoff are analyzed by a 5-point moving average method. Also, changes of the temperature, precipitation, and runoff from mountainous watersheds of the Hexi Corridor region caused by these two types of E1 Nifio events from 1959 to 2005 are studied by the anomaly analysis method. The results indicate that the Hexi Corridor region is strongly influenced by El Nifio： rising tem- peratures and decreasing precipitation and runoff are features of the first E1 Nifio pattern, while decreasing temperature and in- creasing precipitation and runoff characterise the second pattern. The responses of temperature to E1 Nifio events are stronger in plains than in mountain regions, but the responses of precipitation are obvious in both types of regions. The response of runoff to E1 Nifio events is lower than the precipitation and temperature response because runoff from mountainous watersheds has a com- plex generation and concenlration process.
