The characteristics of the permafrost along National Highway No. 214(G214) in Qinghai province(between kilometer markers K310 and K670),including the distribution patterns of permafrost and seasonally frozen ground(SF...The characteristics of the permafrost along National Highway No. 214(G214) in Qinghai province(between kilometer markers K310 and K670),including the distribution patterns of permafrost and seasonally frozen ground(SFG), ground ice content and mean annual ground temperature(MAGT), were analyzed using a large quantity of drilling and measured ground temperature data. Three topographic units can be distinguished along the highway: the northern mountains, including Ela Mountain and Longstone Mountain; the medial alluvial plain and the southern Bayan Har Mountains.The horizontal distribution patterns of permafrost can be divided into four sections, from north to south: the northern continuous permafrost zone(K310-K460),the island permafrost zone(K460-K560), the southern continuous permafrost zone(K560-K630),and the discontinuous permafrost zone(K630-K670).Vertically, the permafrost lower limits(PLLs) of the discontinuous zone were 4200/4325 m, 4230/4350 m,and 4350/4450 m on the north-facing/south-facing slopes of Ela Mountain, Longstone Mountain and Bayan Har Mountains, respectively. The permafrost was generally warm, with MAGTs between-1.0°C and0°C in the northern continuous permafrost zone,approximately-0.5°C in the island permafrost zone,between-1.5°C and 0°C in the southern continuous permafrost zone, and higher than-0.5°C in the discontinuous permafrost zone. In contrast, the spatial variations in ground ice content were mainly controlled by the local soil water content and lithology.The relationships between the mean annual air temperature(MAAT) and the PLLs indicated that the PLLs varied between-3.3°C and-4.1°C for the northern Ela and Longstone Mountains and between-4.1°C and-4.6°C in the southern Bayan Har Mountains.展开更多
As the highest and most extensive plateau on earth, the Tibetan Plateau has strong thermo- dynamic effect, which not only affects regional climate around the plateau but precipitation patterns of scattered meteorologi...As the highest and most extensive plateau on earth, the Tibetan Plateau has strong thermo- dynamic effect, which not only affects regional climate around the plateau but precipitation patterns of scattered meteorological also temperature and itself. However, due to stations, its spatial precipitation pattern and, especially, the mechanism behind are poorly understood. The availability of spatially consistent satellite-derived precipitation data makes it possible to get accurate precipitation pattern in the plateau, which could help quantitatively explore the effect and mechanism of mass elevation effect on precipitation pattern. This paper made full use of TMPA 3B43 V7 monthly precipitation data to track the trajectory of precipitation and identified four routes （east, southeast, south, west directions） along which moisture-laden air masses move into the plateau. We made the assumption that precipitation pattern is the result interplay of these four moisture- laden air masses transportation routes against the distances from moisture sources and the topographic barriers along the routes. To do so, we developed a multivariate linear regression model with the spatial distribution of annual mean precipitation as the dependent variable and the topographical barriers to these four moisture sources as independent variables. The result shows that our model could explain about 7o% of spatial variation of mean annual precipitation pattern in the plateau; the regression analysis also shows that the southeast moisture source （the Bay of Bengal） contributes the most （32.56%） to the rainfall pattern of the plateau; the east and the south sources have nearly the same contribution, 23.59% and 23.48%, respectively; while the west source contributes the least, only 2o.37%. The findings of this study can greatly improve our understanding of mass elevation effect on spatial precipitation pattern.展开更多
Fluid flow and mixing phenomenon have a significant impact on coagulation and flocculation processes. Particles dissipating the turbulent kinetic energy increase the efficiency of collision, grow in size and incorpora...Fluid flow and mixing phenomenon have a significant impact on coagulation and flocculation processes. Particles dissipating the turbulent kinetic energy increase the efficiency of collision, grow in size and incorporate phosphate from the wastewater Only certain flocks can be separated depending on their stability, size, density, etc.. According to the literature the velocity gradient of the flow （G-value） is the main design parameter of the flocculators, but there is a need to take into account at least the flocks age, too. In this paper, it presents a novel approach to determine the efficiency of flocculators using local mean age theory, residence time distribution and dimensional analysis. Calculations were performed for two constructions of cascade reactors---one with small baffles and one without these; hydraulical performance and the achievable conversion were compared. As a result, the flocculator with small baffles proved to be more efficient than the traditional construction.展开更多
基金supported financially by the Chinese Academy of Sciences (CAS) Key Research Program (Grant No. KZZD-EW-13)the Major State Basic Research Development Program of China (Grant No. 2013CBA01803)+2 种基金the National Natural Science Foundation of China (Grant No. 41271084)the Research Program of State Key Laboratory of Frozen Soil Engineering of Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences (Grant No. SKLFSE-ZT-10)the Natural Science Foundation of Gansu Province (Grant No. 145RJY304)
文摘The characteristics of the permafrost along National Highway No. 214(G214) in Qinghai province(between kilometer markers K310 and K670),including the distribution patterns of permafrost and seasonally frozen ground(SFG), ground ice content and mean annual ground temperature(MAGT), were analyzed using a large quantity of drilling and measured ground temperature data. Three topographic units can be distinguished along the highway: the northern mountains, including Ela Mountain and Longstone Mountain; the medial alluvial plain and the southern Bayan Har Mountains.The horizontal distribution patterns of permafrost can be divided into four sections, from north to south: the northern continuous permafrost zone(K310-K460),the island permafrost zone(K460-K560), the southern continuous permafrost zone(K560-K630),and the discontinuous permafrost zone(K630-K670).Vertically, the permafrost lower limits(PLLs) of the discontinuous zone were 4200/4325 m, 4230/4350 m,and 4350/4450 m on the north-facing/south-facing slopes of Ela Mountain, Longstone Mountain and Bayan Har Mountains, respectively. The permafrost was generally warm, with MAGTs between-1.0°C and0°C in the northern continuous permafrost zone,approximately-0.5°C in the island permafrost zone,between-1.5°C and 0°C in the southern continuous permafrost zone, and higher than-0.5°C in the discontinuous permafrost zone. In contrast, the spatial variations in ground ice content were mainly controlled by the local soil water content and lithology.The relationships between the mean annual air temperature(MAAT) and the PLLs indicated that the PLLs varied between-3.3°C and-4.1°C for the northern Ela and Longstone Mountains and between-4.1°C and-4.6°C in the southern Bayan Har Mountains.
基金funded by the National Natural Science Foundation of China(Grant Nos.41421001 and 41030528)
文摘As the highest and most extensive plateau on earth, the Tibetan Plateau has strong thermo- dynamic effect, which not only affects regional climate around the plateau but precipitation patterns of scattered meteorological also temperature and itself. However, due to stations, its spatial precipitation pattern and, especially, the mechanism behind are poorly understood. The availability of spatially consistent satellite-derived precipitation data makes it possible to get accurate precipitation pattern in the plateau, which could help quantitatively explore the effect and mechanism of mass elevation effect on precipitation pattern. This paper made full use of TMPA 3B43 V7 monthly precipitation data to track the trajectory of precipitation and identified four routes （east, southeast, south, west directions） along which moisture-laden air masses move into the plateau. We made the assumption that precipitation pattern is the result interplay of these four moisture- laden air masses transportation routes against the distances from moisture sources and the topographic barriers along the routes. To do so, we developed a multivariate linear regression model with the spatial distribution of annual mean precipitation as the dependent variable and the topographical barriers to these four moisture sources as independent variables. The result shows that our model could explain about 7o% of spatial variation of mean annual precipitation pattern in the plateau; the regression analysis also shows that the southeast moisture source （the Bay of Bengal） contributes the most （32.56%） to the rainfall pattern of the plateau; the east and the south sources have nearly the same contribution, 23.59% and 23.48%, respectively; while the west source contributes the least, only 2o.37%. The findings of this study can greatly improve our understanding of mass elevation effect on spatial precipitation pattern.
文摘Fluid flow and mixing phenomenon have a significant impact on coagulation and flocculation processes. Particles dissipating the turbulent kinetic energy increase the efficiency of collision, grow in size and incorporate phosphate from the wastewater Only certain flocks can be separated depending on their stability, size, density, etc.. According to the literature the velocity gradient of the flow （G-value） is the main design parameter of the flocculators, but there is a need to take into account at least the flocks age, too. In this paper, it presents a novel approach to determine the efficiency of flocculators using local mean age theory, residence time distribution and dimensional analysis. Calculations were performed for two constructions of cascade reactors---one with small baffles and one without these; hydraulical performance and the achievable conversion were compared. As a result, the flocculator with small baffles proved to be more efficient than the traditional construction.
