Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited ...Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited precipitation, and where human activities have greatly transformed natural desert system by clearing natural vegetation, expanding oases and even building dams on inland rivers. However, the current studies on land use patterns are still characterized by field investigations and case studies, with almost no solid scientific basis. This paper holds that land types and their combination patterns are the principal basis for designing sustainable land use patterns, and that GIS and RS-based large-scale land type mapping and the study of their spatial combination structures should be coordinated with the demand of social development. The existing environmental problems induced by irrational land use mostly result from their deviation from the natural properties of land types. Taking the northern slope of the Tianshan Mountains （NSTM） as an example and considering land type patterns as the basis of land use patterns, this paper improves the vertical oa- sis-and-mid-mountain two-belts development model and the sustainable mountain land use model for arid lands put forward in recent years; and in terms of oases patterns, it outlines oasis development models, including intensive land use pattern in alluvial-diluvial fans, moderate agricultural development pattern in alluvial plains, and ecological land use pattern in river-end oases.展开更多
The estimation of peak discharge from a catchment due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately, it may lead to serious problem in hydraulic structure...The estimation of peak discharge from a catchment due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately, it may lead to serious problem in hydraulic structure design like bridge, culvert across a river and drainage system. The main parameter which affects the peak flow is runoff coefficient of the catchment which directly depends on the soil type, its slope and land use pattern with vegetation covers. For the purpose, this study was carried out to estimate maximum runoff coefficients for different land profiles and soil types in hill slope model developed in 10 degree with the horizontal to the rainfall simulator rig (Basic Hydrology system-S12) experimentally which can give more reliable value than the real field test method as it is easier than field test especially in hill slope. The soil slope preparation was made of sand, silt and clay separately and the experiments were carried out in a controlled system. The slope prepared represented a small catchment on a plot of 2.02 meter length, 1 meter wide and 0.15 m depth soil plots (at the slope of 10° to the horizontal plane). From the experiment in different soil plots, the rainfall runoff coefficients were observed as 0.428 - 0.53 for sand soil slope, 0.46 - 0.55 for silt soil slope and 0.42 - 0.51 for clay soil slope under uniform rainfall rate of 4 lpm to 13 lpm in each soil slope. Rainfall runoff correlation equation was found with the values of R above 90% in each soil slope. The value observed is within the range of rational value of 0.05 to 0.95 as standard which concluded that the performance of simulator was found good to deal with rational values. And the runoff coefficients for these soil types can be taken within the range obtained to estimate peak discharge in any small catchment area depending on the soil types.展开更多
Based on the chromatograms of oils and saturated hydrocarbons, biomarkers and stable carbon isotope analyses, the geochemical characteristics and oil family Classification of crude oils from the Markit Slope in the so...Based on the chromatograms of oils and saturated hydrocarbons, biomarkers and stable carbon isotope analyses, the geochemical characteristics and oil family Classification of crude oils from the Markit Slope in the southwest of the Tarim Basin were investigated. The results showed that crude oils from the Markit Slope are divided into two oil family Classification. Oils collected from the Bashituo oilfield in the western part of the Markit Slope are characterized by high contents of tricyclic terpanes, pregnane, and homopregnane, low contents of garmmacerane (G/H<0.20), dibenzofuran, and methyl cyclohexane, and light stable carbon isotopic values (the δ13C values of satu-rated hydrocarbons and aromatic components are less than -34‰ and -32‰, respectively), with the distribution type of steranes being C27>>C28<C29. Condensate oils collected from the Hetian River gasfield in the eastern part of the Markit Slope are characterized by low contents of tricyclic terpanes, pregnane, and homopregnane, high contents of garmmacerane (0.20<G/H<0.36), dibenzofuran, and methyl cyclohexane, and relatively heavy carbon isotopic values (δ13C of saturated hydrocarbons and aromatic components (> -32‰ and -30.6‰, respectively), with the distribution type of steranes being C27>C28<<C29. In addition, oils from Well Qu 1 have some characteristics similar to those of the above oils, with some special characteristics including high contents of β-carotenes and special distribution of steranes (C27<C28 <C29).展开更多
基金National Basic Research Program of China, No.2009CB825105National Natural Science Foundation of China, No.40671015
文摘Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited precipitation, and where human activities have greatly transformed natural desert system by clearing natural vegetation, expanding oases and even building dams on inland rivers. However, the current studies on land use patterns are still characterized by field investigations and case studies, with almost no solid scientific basis. This paper holds that land types and their combination patterns are the principal basis for designing sustainable land use patterns, and that GIS and RS-based large-scale land type mapping and the study of their spatial combination structures should be coordinated with the demand of social development. The existing environmental problems induced by irrational land use mostly result from their deviation from the natural properties of land types. Taking the northern slope of the Tianshan Mountains （NSTM） as an example and considering land type patterns as the basis of land use patterns, this paper improves the vertical oa- sis-and-mid-mountain two-belts development model and the sustainable mountain land use model for arid lands put forward in recent years; and in terms of oases patterns, it outlines oasis development models, including intensive land use pattern in alluvial-diluvial fans, moderate agricultural development pattern in alluvial plains, and ecological land use pattern in river-end oases.
文摘The estimation of peak discharge from a catchment due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately, it may lead to serious problem in hydraulic structure design like bridge, culvert across a river and drainage system. The main parameter which affects the peak flow is runoff coefficient of the catchment which directly depends on the soil type, its slope and land use pattern with vegetation covers. For the purpose, this study was carried out to estimate maximum runoff coefficients for different land profiles and soil types in hill slope model developed in 10 degree with the horizontal to the rainfall simulator rig (Basic Hydrology system-S12) experimentally which can give more reliable value than the real field test method as it is easier than field test especially in hill slope. The soil slope preparation was made of sand, silt and clay separately and the experiments were carried out in a controlled system. The slope prepared represented a small catchment on a plot of 2.02 meter length, 1 meter wide and 0.15 m depth soil plots (at the slope of 10° to the horizontal plane). From the experiment in different soil plots, the rainfall runoff coefficients were observed as 0.428 - 0.53 for sand soil slope, 0.46 - 0.55 for silt soil slope and 0.42 - 0.51 for clay soil slope under uniform rainfall rate of 4 lpm to 13 lpm in each soil slope. Rainfall runoff correlation equation was found with the values of R above 90% in each soil slope. The value observed is within the range of rational value of 0.05 to 0.95 as standard which concluded that the performance of simulator was found good to deal with rational values. And the runoff coefficients for these soil types can be taken within the range obtained to estimate peak discharge in any small catchment area depending on the soil types.
文摘Based on the chromatograms of oils and saturated hydrocarbons, biomarkers and stable carbon isotope analyses, the geochemical characteristics and oil family Classification of crude oils from the Markit Slope in the southwest of the Tarim Basin were investigated. The results showed that crude oils from the Markit Slope are divided into two oil family Classification. Oils collected from the Bashituo oilfield in the western part of the Markit Slope are characterized by high contents of tricyclic terpanes, pregnane, and homopregnane, low contents of garmmacerane (G/H<0.20), dibenzofuran, and methyl cyclohexane, and light stable carbon isotopic values (the δ13C values of satu-rated hydrocarbons and aromatic components are less than -34‰ and -32‰, respectively), with the distribution type of steranes being C27>>C28<C29. Condensate oils collected from the Hetian River gasfield in the eastern part of the Markit Slope are characterized by low contents of tricyclic terpanes, pregnane, and homopregnane, high contents of garmmacerane (0.20<G/H<0.36), dibenzofuran, and methyl cyclohexane, and relatively heavy carbon isotopic values (δ13C of saturated hydrocarbons and aromatic components (> -32‰ and -30.6‰, respectively), with the distribution type of steranes being C27>C28<<C29. In addition, oils from Well Qu 1 have some characteristics similar to those of the above oils, with some special characteristics including high contents of β-carotenes and special distribution of steranes (C27<C28 <C29).
