A number of very serious drough disasters occurred in many regions of Aftica during past 30 years. It is commonly considered that they are among the most serious disasters after the World War II. The basic situation o...A number of very serious drough disasters occurred in many regions of Aftica during past 30 years. It is commonly considered that they are among the most serious disasters after the World War II. The basic situation of the droughs and drough disasters are introduced briefly, and the main causes resulting 1i drought disasters are analysed in the paper. The lack of rainfall is one of the factors producing the drough disasters in Africa, but it is not the real one. From environmental viewpoints, the drough disasters in Africa resulted from unsuitable land use and management by man, and in essence they are the results of man-made environmental disturbance. Finally, the strategy for preventing drought disasters in Africa is suggested.展开更多
古溪沟流域是岷江上游汇入紫坪铺水库重要的补水单元,为研究极端干旱条件下流域内地下水-地表水化学特征和影响因素,探讨地下水资源战略储备选址适宜性,通过采集16个地下水样和2个地表水样,综合运用Gibbs图、离子比值、绝对主成分-多元...古溪沟流域是岷江上游汇入紫坪铺水库重要的补水单元,为研究极端干旱条件下流域内地下水-地表水化学特征和影响因素,探讨地下水资源战略储备选址适宜性,通过采集16个地下水样和2个地表水样,综合运用Gibbs图、离子比值、绝对主成分-多元线性回归模型(absolute principal component multiple linear regression model,APCS-MLR)等方法分析水化学及其影响因素;运用熵权水质指数(entropy weighted water quality index,EWQI)进行地下水水质评价;采用层次分析法(analytic hierarchy process,AHP)构建流域地下水资源战略储备选址适宜性指标评价体系,探讨地下水资源战略储备选址的适宜性。结果表明:古溪沟流域地下水-地表水中主要阳离子为Ca^(2+)、Mg^(2+)、Na^(+)、K^(+),主要阴离子为HCO_(3)^-、SO_(4)^(2-)、Cl^(-),地下水化学类型以HCO_(3)-Ca、HCO_(3)-Ca·Mg、HCO_(3)·SO_(4)-Ca为主;Gibbs图、离子比值、APCS-MLR模型等解译出水化学组分主要来源为水-岩作用(44.08%)、工业活动(12.17%)、原生地质环境叠加工业活动(11.83%)、农业活动叠加生活污染(9.04%),水-岩相互作用主导了地下水水质形成的水文地球化学过程的同时还受到人为活动因素和自然环境等其他因素的影响;EWQI评价地下水质量为Ⅰ级和Ⅱ级分别占比56.25%和18.75%,Ⅲ级的占比为6.25%,Ⅳ级和Ⅴ级分别占比12.50%和6.25%,地表水上游为Ⅰ级,下游为Ⅳ级,整体出现沿地下水径流途径,水质逐渐变差的现象,表明地下水-地表水已受到人类活动一定程度的影响;流域地下水资源战略储备选址综合适宜性指数AI介于1.0~9.8,适宜区面积占比48.57%,分布在流域中-东部下游区域,不适宜占比51.43%,不适宜区分布在流域上游区域,研究成果可在极端条件下为古溪沟流域-紫坪铺水库-都江堰的水资源安全开发利用及地下水资源战略储备选址布局提供参考。展开更多
Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and...Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.展开更多
Atmospheric water absorption by plants has been explored for more than two centuries, and the aerial parts of plants, particularly the leaves of certain species, have been demonstrated to have an ability to absorb and...Atmospheric water absorption by plants has been explored for more than two centuries, and the aerial parts of plants, particularly the leaves of certain species, have been demonstrated to have an ability to absorb and utilize saturated atmospheric water such as fog, dew and condensed water. So far, however, there have been few studies on the aerial parts of desert plants in their absorption of unsaturated water from the atmosphere. This study presents an ultrasonic humidification fluorescent tracing method of detecting unsaturated atmospheric water absorption by the aerial parts of desert plants. We constructed an organic glass room based on the sizes of field plants. Then, the aboveground parts of the plants were humidified in the sealed glasshouse using an ultrasonic humidifier containing fluorescent reagents. The humidity and wetting time were controlled by turning on or off the humidifier according to the reading of a thermo-hygrometer suspended in the glasshouse. Fluorescence microscopy was employed to observe these plant samples. This method can generate unsaturated atmospheric water vapor and incorporate other fluorescent reagents or water-soluble chemical reagents for gasified humidification. In addition, it can identify plant parts that absorb unsaturated atmospheric water from the air, detect water absorption sites on the surface of leaves or tender stems, and determine the ability of tissues or microstructure of aerial parts to absorb water. This method provides a direct visual evidence for the inspection of leaf or tender stem microstructure in response to unsaturated atmospheric water absorption. Moreover, this method shows that aqueous pores in the cuticles of leaves or tender stems of desert plants are large enough to allow the passage of ionic fluorescent brightener with a molecular weight of up to 917 g/mol. Thus, this paper provides an important approach that explores the mechanism by which desert plants utilize unsaturated atmospheric water.展开更多
文摘A number of very serious drough disasters occurred in many regions of Aftica during past 30 years. It is commonly considered that they are among the most serious disasters after the World War II. The basic situation of the droughs and drough disasters are introduced briefly, and the main causes resulting 1i drought disasters are analysed in the paper. The lack of rainfall is one of the factors producing the drough disasters in Africa, but it is not the real one. From environmental viewpoints, the drough disasters in Africa resulted from unsuitable land use and management by man, and in essence they are the results of man-made environmental disturbance. Finally, the strategy for preventing drought disasters in Africa is suggested.
文摘古溪沟流域是岷江上游汇入紫坪铺水库重要的补水单元,为研究极端干旱条件下流域内地下水-地表水化学特征和影响因素,探讨地下水资源战略储备选址适宜性,通过采集16个地下水样和2个地表水样,综合运用Gibbs图、离子比值、绝对主成分-多元线性回归模型(absolute principal component multiple linear regression model,APCS-MLR)等方法分析水化学及其影响因素;运用熵权水质指数(entropy weighted water quality index,EWQI)进行地下水水质评价;采用层次分析法(analytic hierarchy process,AHP)构建流域地下水资源战略储备选址适宜性指标评价体系,探讨地下水资源战略储备选址的适宜性。结果表明:古溪沟流域地下水-地表水中主要阳离子为Ca^(2+)、Mg^(2+)、Na^(+)、K^(+),主要阴离子为HCO_(3)^-、SO_(4)^(2-)、Cl^(-),地下水化学类型以HCO_(3)-Ca、HCO_(3)-Ca·Mg、HCO_(3)·SO_(4)-Ca为主;Gibbs图、离子比值、APCS-MLR模型等解译出水化学组分主要来源为水-岩作用(44.08%)、工业活动(12.17%)、原生地质环境叠加工业活动(11.83%)、农业活动叠加生活污染(9.04%),水-岩相互作用主导了地下水水质形成的水文地球化学过程的同时还受到人为活动因素和自然环境等其他因素的影响;EWQI评价地下水质量为Ⅰ级和Ⅱ级分别占比56.25%和18.75%,Ⅲ级的占比为6.25%,Ⅳ级和Ⅴ级分别占比12.50%和6.25%,地表水上游为Ⅰ级,下游为Ⅳ级,整体出现沿地下水径流途径,水质逐渐变差的现象,表明地下水-地表水已受到人类活动一定程度的影响;流域地下水资源战略储备选址综合适宜性指数AI介于1.0~9.8,适宜区面积占比48.57%,分布在流域中-东部下游区域,不适宜占比51.43%,不适宜区分布在流域上游区域,研究成果可在极端条件下为古溪沟流域-紫坪铺水库-都江堰的水资源安全开发利用及地下水资源战略储备选址布局提供参考。
文摘Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.
基金supported by the National Natural Science Foundation of China(9112502531400319)
文摘Atmospheric water absorption by plants has been explored for more than two centuries, and the aerial parts of plants, particularly the leaves of certain species, have been demonstrated to have an ability to absorb and utilize saturated atmospheric water such as fog, dew and condensed water. So far, however, there have been few studies on the aerial parts of desert plants in their absorption of unsaturated water from the atmosphere. This study presents an ultrasonic humidification fluorescent tracing method of detecting unsaturated atmospheric water absorption by the aerial parts of desert plants. We constructed an organic glass room based on the sizes of field plants. Then, the aboveground parts of the plants were humidified in the sealed glasshouse using an ultrasonic humidifier containing fluorescent reagents. The humidity and wetting time were controlled by turning on or off the humidifier according to the reading of a thermo-hygrometer suspended in the glasshouse. Fluorescence microscopy was employed to observe these plant samples. This method can generate unsaturated atmospheric water vapor and incorporate other fluorescent reagents or water-soluble chemical reagents for gasified humidification. In addition, it can identify plant parts that absorb unsaturated atmospheric water from the air, detect water absorption sites on the surface of leaves or tender stems, and determine the ability of tissues or microstructure of aerial parts to absorb water. This method provides a direct visual evidence for the inspection of leaf or tender stem microstructure in response to unsaturated atmospheric water absorption. Moreover, this method shows that aqueous pores in the cuticles of leaves or tender stems of desert plants are large enough to allow the passage of ionic fluorescent brightener with a molecular weight of up to 917 g/mol. Thus, this paper provides an important approach that explores the mechanism by which desert plants utilize unsaturated atmospheric water.
