Evapotranspiration (ET) process of plants is controlled by several factors. Besides the physiological factors of plants, height, density, LAI (leaf area index), etc., the change of meteorological factors, such as radi...Evapotranspiration (ET) process of plants is controlled by several factors. Besides the physiological factors of plants, height, density, LAI (leaf area index), etc., the change of meteorological factors, such as radiation, temperature, wind and precipitation, can influence ET process evidently, thus remodeling the spatial and temporal distribution of ET. In order to illuminate the effects of meteorological factors on wetland ET, the ET of Zhalong Wetland was calculated from 1961 to 2000, the statistical relationships (models) between ET and maximum temperature (Tmax), minimum temperature (Tmin), precipitation (P) and wind speed at 2m height (U2) were established, and the sensitivity analysis of the variables in the model was performed. The results show that Tmax and Tmin are two dominating factors that influence ET markedly, and the difference of rising rate between Tmax and Tmin determines the change trend of ET. With the climatic scenarios of four General Circulation Models (GCMs), the ET from 2001 to 2060 was predicted by the statistical model. Compared to the period of 1961-2000, the water consumption by ET will increase greatly in the future. According to the scenarios, the rise of Tmax (about 1.5℃ to 3.3℃) and Tmin (about 1.7℃ to 3.5℃) will cause an additional water con- sumption of 14.0%-17.8% for reed swamp. The ecological water demand in Zhalong Wetland will become more severe.展开更多
A series of ice freezing-thawing experiments are performed under different nitro- benzene concentrations of 1.7, 8, 17, 170, and 1700 μg/L. A special flume, made of stainless steel and glass, is built to simulate the...A series of ice freezing-thawing experiments are performed under different nitro- benzene concentrations of 1.7, 8, 17, 170, and 1700 μg/L. A special flume, made of stainless steel and glass, is built to simulate the flowing water for the experiments. The ice frozen in cold room has similar crystal structure of natural ice, therefore the behaviors of nitrobenzene in the ice frozen in cold room is also believed to be similar to that in natural ice. The results of the experiments reveal that the freezing rate of ice decreases with the increase of nitrobenzene concentration in water, and that the nitrobenzene ratio in water-ice system becomes higher with the increase of freezing rate. In addition, the nitrobenzene in ice does not move and is only re- leased into water after melt.展开更多
This paper proposes an on-site monitoring system for evaporation(Ew) and evapotranspiration(ET) in wetlands called the Compensation Evapotranspiration Observation System.Considering the characteristics of wetlands env...This paper proposes an on-site monitoring system for evaporation(Ew) and evapotranspiration(ET) in wetlands called the Compensation Evapotranspiration Observation System.Considering the characteristics of wetlands environment and emergent plants,the vertical flux of water loss in wetlands can be separated using the system based on compensation principle.A comparison research on water loss through ET in reed(Phragmites australis) stands between Zhalong wetland and Baiyangdian wetland was carried out in 2004-2009.In Baiyangdian wetland,the ET rates from three reed stands with different leaf area indexes were measured.The results show that annual ET in Zhalong wetland was 739-886 mm during study period.Comparatively,annual ET of the three reed stands in Baiyangdian wetland was 970-1117 mm,1261-1452 mm and 1759-2035 mm,respectively.The ET rates in Baiyangdian were stronger than in Zhalong because of the effects of geography and climate characteristics.Moreover,seasonal dynamic changes and influence factors of transpiration-acting factor from the two wetlands were also analyzed.It is indicated that the transpiration-acting factor can be affected by geographic location,aboveground biomass,plant growth and climate conditions.展开更多
Objectives, principles, classification system, zoning method and procedure of river function region-alization were investigated systematically based on the present status of modern river regulation and function requir...Objectives, principles, classification system, zoning method and procedure of river function region-alization were investigated systematically based on the present status of modern river regulation and function requirement. Considering the ecosystem continuity and river function integrality, a river is suggested to be divided into five function zones: ecological protection zone, habitat restoration zone, exploitation and utilization zone, buffer zone,and transition zone, based on the developed intensity and the function characteristics of the river. In this paper, not only the five function zones were described qualitatively, but also the quantitative examination method on how to identify their function zone types was given. A double-criterion partitioning scheme was proposed according to the functional zoning diagram constructed by the evaluation of the social and ecological function of rivers. Finally, the procedures of river function regionalization were shown.展开更多
基金Under the auspices of the National Natural Science Foundation of China (No. 50139020)
文摘Evapotranspiration (ET) process of plants is controlled by several factors. Besides the physiological factors of plants, height, density, LAI (leaf area index), etc., the change of meteorological factors, such as radiation, temperature, wind and precipitation, can influence ET process evidently, thus remodeling the spatial and temporal distribution of ET. In order to illuminate the effects of meteorological factors on wetland ET, the ET of Zhalong Wetland was calculated from 1961 to 2000, the statistical relationships (models) between ET and maximum temperature (Tmax), minimum temperature (Tmin), precipitation (P) and wind speed at 2m height (U2) were established, and the sensitivity analysis of the variables in the model was performed. The results show that Tmax and Tmin are two dominating factors that influence ET markedly, and the difference of rising rate between Tmax and Tmin determines the change trend of ET. With the climatic scenarios of four General Circulation Models (GCMs), the ET from 2001 to 2060 was predicted by the statistical model. Compared to the period of 1961-2000, the water consumption by ET will increase greatly in the future. According to the scenarios, the rise of Tmax (about 1.5℃ to 3.3℃) and Tmin (about 1.7℃ to 3.5℃) will cause an additional water con- sumption of 14.0%-17.8% for reed swamp. The ecological water demand in Zhalong Wetland will become more severe.
基金Changjiang River Scholar and Innovative Team Developing Plan (Grant No. IRT0420) the National Natural Science Foundation of China (Grant No. 40676001)
文摘A series of ice freezing-thawing experiments are performed under different nitro- benzene concentrations of 1.7, 8, 17, 170, and 1700 μg/L. A special flume, made of stainless steel and glass, is built to simulate the flowing water for the experiments. The ice frozen in cold room has similar crystal structure of natural ice, therefore the behaviors of nitrobenzene in the ice frozen in cold room is also believed to be similar to that in natural ice. The results of the experiments reveal that the freezing rate of ice decreases with the increase of nitrobenzene concentration in water, and that the nitrobenzene ratio in water-ice system becomes higher with the increase of freezing rate. In addition, the nitrobenzene in ice does not move and is only re- leased into water after melt.
基金supported by the National Natural Science Foundation of China (Grant No. 50139020)the National Basic Research Program of China ("973" Program) (Grant No. 2006CB403405)
文摘This paper proposes an on-site monitoring system for evaporation(Ew) and evapotranspiration(ET) in wetlands called the Compensation Evapotranspiration Observation System.Considering the characteristics of wetlands environment and emergent plants,the vertical flux of water loss in wetlands can be separated using the system based on compensation principle.A comparison research on water loss through ET in reed(Phragmites australis) stands between Zhalong wetland and Baiyangdian wetland was carried out in 2004-2009.In Baiyangdian wetland,the ET rates from three reed stands with different leaf area indexes were measured.The results show that annual ET in Zhalong wetland was 739-886 mm during study period.Comparatively,annual ET of the three reed stands in Baiyangdian wetland was 970-1117 mm,1261-1452 mm and 1759-2035 mm,respectively.The ET rates in Baiyangdian were stronger than in Zhalong because of the effects of geography and climate characteristics.Moreover,seasonal dynamic changes and influence factors of transpiration-acting factor from the two wetlands were also analyzed.It is indicated that the transpiration-acting factor can be affected by geographic location,aboveground biomass,plant growth and climate conditions.
基金Supported by the Natural Science Foundation of Liaoning Province (Grant No. 20052183)
文摘Objectives, principles, classification system, zoning method and procedure of river function region-alization were investigated systematically based on the present status of modern river regulation and function requirement. Considering the ecosystem continuity and river function integrality, a river is suggested to be divided into five function zones: ecological protection zone, habitat restoration zone, exploitation and utilization zone, buffer zone,and transition zone, based on the developed intensity and the function characteristics of the river. In this paper, not only the five function zones were described qualitatively, but also the quantitative examination method on how to identify their function zone types was given. A double-criterion partitioning scheme was proposed according to the functional zoning diagram constructed by the evaluation of the social and ecological function of rivers. Finally, the procedures of river function regionalization were shown.
