Low-lying prairie wetland, which has characteristics of both grassland and wetland, has irreplaceable ecological functions in inland river basins of Northwest China. Owing to its small-scale distribution, so far, the ...Low-lying prairie wetland, which has characteristics of both grassland and wetland, has irreplaceable ecological functions in inland river basins of Northwest China. Owing to its small-scale distribution, so far, the observation and research on it are rare. The estimation of evapotranspiration is significant to ecological and environmental construction, scientific management of pasture and protection of wetland. For studying the evapotranspiration （ET） of low-lying prairie wetland in the middle reaches of the Heihe River, an inland river, in Northwest China, the automatic weather station in Linze Ecological Experimental Station of Lanzhou University （39°15′ 3″N, 100°03′ 52″ E）, Linze, Gansu Province, was selected as a case study. Based on meteorological data collected, Bowen-Ratio Energy Balance （BREB） method was used to calculate the evapotranspiration （ET） of low-lying prairie wetland. The analysis results showed that in a whole year （September 2003 -August 2004）, the total ET was 611.5mm and mean daily 1.67mm/d. The ET varied with different growing stages. In non-growing stage （NGS）, initial growing stage （IGS）, middle growing stage （MGS） and end growing stage （EGS）, the ET was 0.57, 2.01, 3.82 and 1.49mrrdd, with a percentage of total ET of 18.26%, 9.20%, 61.83% and 10.71% respectively. In March, ET began to increase. But in April, the ET increased most. After that, it increased gradually and got the maximal value in July. From then on, the ET decreased gradually. In September, the ET decreased rapidly. With the ending of growing and the freezing of soil, the ET stopped from the middle of November to February in next year. Hourly ET analysis showed that at 8：00 a.m. （during MGS at 7：00 a.m.）, the evapotranspiration began, at 13：00 p.m. got its maximal value and at 19：00 p.m. （during MGS at 20：00 p.m.）, the evapotranspiration stopped. The intensity of ET in sunny day was much larger than that in cloudy day in the same growing stage.展开更多
Abstract： Because of the complex topography in southwest region of China, the water level of the inland river has a large amplitude of variation which causes a frequent diversification of water content in the river s...Abstract： Because of the complex topography in southwest region of China, the water level of the inland river has a large amplitude of variation which causes a frequent diversification of water content in the river slope. The flow caused by the infiltration of the terminal slope stability will induce a great impact on the slope stability of wharf.. This paper uses an ideal elastic-plastic model and the Moore Coulomb yield criterion for numerical simulation. Through the b an k slop e stability of the overhead-type terminal s under the changes of water, we obtained the impact of all factors on the bank slope in the course of water lowering. It was found out that the impact from the cohesion of the geo-materials of the bank slope on the slope stability is greater than that from the internal friction angle.展开更多
基金Underthe auspicesofthe Sino-Japan Cooperation Projectand the SpecialFund ofC hina M etrologicalA dm inistration(N o.C CSF-2005-2-Q H 39)
文摘Low-lying prairie wetland, which has characteristics of both grassland and wetland, has irreplaceable ecological functions in inland river basins of Northwest China. Owing to its small-scale distribution, so far, the observation and research on it are rare. The estimation of evapotranspiration is significant to ecological and environmental construction, scientific management of pasture and protection of wetland. For studying the evapotranspiration （ET） of low-lying prairie wetland in the middle reaches of the Heihe River, an inland river, in Northwest China, the automatic weather station in Linze Ecological Experimental Station of Lanzhou University （39°15′ 3″N, 100°03′ 52″ E）, Linze, Gansu Province, was selected as a case study. Based on meteorological data collected, Bowen-Ratio Energy Balance （BREB） method was used to calculate the evapotranspiration （ET） of low-lying prairie wetland. The analysis results showed that in a whole year （September 2003 -August 2004）, the total ET was 611.5mm and mean daily 1.67mm/d. The ET varied with different growing stages. In non-growing stage （NGS）, initial growing stage （IGS）, middle growing stage （MGS） and end growing stage （EGS）, the ET was 0.57, 2.01, 3.82 and 1.49mrrdd, with a percentage of total ET of 18.26%, 9.20%, 61.83% and 10.71% respectively. In March, ET began to increase. But in April, the ET increased most. After that, it increased gradually and got the maximal value in July. From then on, the ET decreased gradually. In September, the ET decreased rapidly. With the ending of growing and the freezing of soil, the ET stopped from the middle of November to February in next year. Hourly ET analysis showed that at 8：00 a.m. （during MGS at 7：00 a.m.）, the evapotranspiration began, at 13：00 p.m. got its maximal value and at 19：00 p.m. （during MGS at 20：00 p.m.）, the evapotranspiration stopped. The intensity of ET in sunny day was much larger than that in cloudy day in the same growing stage.
文摘Abstract： Because of the complex topography in southwest region of China, the water level of the inland river has a large amplitude of variation which causes a frequent diversification of water content in the river slope. The flow caused by the infiltration of the terminal slope stability will induce a great impact on the slope stability of wharf.. This paper uses an ideal elastic-plastic model and the Moore Coulomb yield criterion for numerical simulation. Through the b an k slop e stability of the overhead-type terminal s under the changes of water, we obtained the impact of all factors on the bank slope in the course of water lowering. It was found out that the impact from the cohesion of the geo-materials of the bank slope on the slope stability is greater than that from the internal friction angle.
