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71.
利用步长模拟对青藏高原涡度方差测量法的质量评价 总被引:1,自引:0,他引:1
利用痕迹模拟方法对青藏高原两处地方涡度方差的测量数据进行了质量分析,揭示了其空间和时间结构。分析表明高达1/3的测量没有达到必要的数据正确假设。尽管这样对潜热、CO2、动量通量的测量基本通过测试,可以适用于基础研究,但是经常发现特定的风矢量违背基本假设条件。感热通量的测量允许使用不间断的连续测量法,然而由于局地地形的影响少量评估指数未能合理解释,但能够指示出组织结构及用于导出边界层中尺度流体模型假说。 相似文献
72.
流域水文模型研究进展 总被引:7,自引:0,他引:7
本文介绍了流域水文模型的分类,论述了流域水文模型基础理论——产汇流理论的发展及其自身的研究进展,探讨了流域水文模型的研究趋势和发展困境,并对未来做出了展望,以期能推进流域水文模型的研究。 相似文献
73.
高山雷达站选址对估测降水的影响分析 总被引:1,自引:0,他引:1
高山雷达站天线高度对雷达的垂直探测范围影响较大,加之中小尺度灾害性天气演生、发展的关键区域在高度1500~4500 m左右,所以高山雷达站在选址时应考虑当地零度层平均高度和雷达的垂直探测范围。通过定量估测层状云降水的个例实践,发现探测高度会限制定量估测降水,探测高度对近距离降水估测影响较小,但对远距离降水估测影响较大,原因主要是雷达的垂直探测范围及当地零度层亮带高度的影响。故在高山雷达站选址中应考虑雷达的垂直探测范围及当地零度层亮带高度的影响,同时对已建设完成的高山天气雷达应考虑对高山雷达做0°仰角的观测可行性研究。 相似文献
74.
75.
岩溶断陷盆地不同海拔植物水分利用效率分析 总被引:1,自引:0,他引:1
为探讨不同海拔高度的养分、环境要素与植物水分利用效率变化的关系,以岩溶断陷盆地云南小江流域的乔木、灌木、草本为研究对象,分析水分利用效率和叶片养分浓度随海拔的变化情况。结果表明:(1)研究区内海拔2 000 m处的草本植物的叶片δ13C值最高,2 200 m处的乔木的叶片δ13C值最低;(2)海拔高度对乔木、灌木的植物水分利用效率影响大于草本植物,草本植物的水分利用效率随海拔高度的变化甚微,两者之间的拟合度较小;高值区出现在海拔为2 200 m处的乔木;低值区出现在海拔为2 000 m处的草本植物;(3)不同海拔水分利用效率与叶片N、P浓度的相关性较弱(与叶片的N浓度呈弱正相关,与叶片的P浓度呈弱负相关);(4)不同海拔水分利用效率与各气候因子的相关性较弱,与多年平均气温、多年平均降雨量、多年平均日照时数均呈弱正相关。 相似文献
76.
Delineation of potential groundwater zones based on multicriteria decision making technique
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Groundwater is the most prioritized water source in India and plays an indispensable role in India's economy. The groundwater potential mapping is key to the sustainable groundwater development and management. A hybrid methodology is applied to delineate potential groundwater zones based on remote sensing, geographical information systems(GIS) and analytic hierarchy process(AHP) as on multicriteria decision making. For the purpose of demonstrating field application, Chittar watershed, Tamilnadu, India is studied as an example. The important morphological characteristics considered in the study are lithology, geomorphology, lineament density, drainage density, slope, and Soil Conservation Service–Curve Number(SCS-CN). These six thematic layers are generated in a GIS platform. Based on intersecting the layers, AHP method, the values for adopting the pairwise comparison normalized weight and normalized subclasses weightage were given. The normalized subclass weightage is input into each layer subclass. Then, weighted linear combination method is used to add the data layers in GIS platform to generate groundwater potential Index(GWPI) map. The GWPI map is validated based on the net recharge computed from the differences of measured groundwater levels between the pre-monsoon and post-monsoon in the year 2018. The kappa statistics are used to measure level spatial consistency between the GWPI and net recharge map. The overall average spatial matching accuracy between the two data sets is 0.86, while the kappa coefficient for GWPI with net recharge, 0.78. The results show that in Chittar watershed about 870 km~2 area is divided into high potential zone(i.e. sum of very high and high potential zone), 667 km~2 area, as the moderate one and the rest 105 km~2 area, as the poor zone(i.e. sum of very poor and poor potential zone). 相似文献
77.
陕西神府矿区束鸡沟流域风蚀水蚀交互作用特征研究 总被引:6,自引:1,他引:5
以神府矿区束鸡沟为典型小流域,讨论了风蚀水蚀交互作用的时空分布及其特征。风蚀水蚀交互作用在沙质坡面,坡面切沟和沙质沟道区表现最为突出,并形成了风蚀水蚀交互作用特有的侵蚀形态。 相似文献
78.
CAI Qiangguo 《国际泥沙研究》1998,(2)
PHYSICALPROCESSBASEDSOILEROSIONMODELINASMALLWATERSHEDINTHEHILLYLOESSREGION1CAIQiangguo2ABSTRACTAphysicalprocesbasedperstorm... 相似文献
79.
Caldear Volcanic Group (CVG), a stratigraphically well defined, calc-alkaline rock complex within Sa de Gata in the eastern part of the Alpine Betic mountain chain, S Spain, consists of three distinct formations: Hernández pyroxene andesites, Bujo hornblende-bearing pyroxene andesites and Viuda hornblende-bearing pyroxene dacites–rhyolites. The letter rock formation may have developed through crystal fractionation of mainly plagioclase and pyroxenes, however there is no direct relation between two formations. CVG has a domainal structure with a northeastern domain where Hernández formation is overlain by Bujo formation while Viuda formation is absent, and a southwestern domain where Viuda formation forms the only fractionate after Hernández formation. Hernández parent magma is thought generated through crustal anatexis by dehydration melting of a predominantly amphibolitic source rock complex which was formed by metamorphism from c. 500 Ma volcano-sedimentary parent material. The domainal structure of CVG is explained by compositional variation within this protogenetic complex. Single crystal U–Pb ages of c. 500 Ma to 1800 Ma for inherited zircon support the presence of clastic material of Proterozoic derivation within the original volcano-sedimentary complex. Regional study of syn-collisional rock formations (Alpine nappe complexes) indicate that the collisional tectonic stage in the Betic-Rif orogenic belt took place rather early (25–30 Ma?) and was followed by a stage of rapid regional rock uplift, fast cooling (c. 500°C/my) and extensional tectonics in the period 22–17 Ma. This later tectonic stage was set into motion by slab break-off which set the stage for a high temperature regime in the overlying lithosphere, providing the framework for the crustal melting and magma production responsible for the calc-alkaline rocks of Alborán volcanic province. Miocene zircon with ages ranging from c. 17 to 11 Ma indicate a rather protracted magmatic development prior to eruption at c. 11 Ma. Post-collisional character of Caldear Volcanic Group thus seems well established. 相似文献
80.
Colin E. Thorn 《地球表面变化过程与地形》1979,4(3):211-228
Reduced major axis analysis is used to describe monthly temperature averages for daily maxima, minima, means and ranges at a sequence of bedrock microenvironments in the alpine zone of the Colorado Front Range. Seven thermistors buried at 1 cm in bedrock provide comparative data on easterly, southerly and westerly aspects, and also upon the impact of snow accumulation (?0.5m to ≥4.0m deep) against an east-facing rock wall. Intersite temperatures commonly differ by less than 5°C and, rarely, by more than 10°C. The freezing intensity of freeze-thaw cycles occurring within the confines of a seasonal snow patch rarely dropped to ?5°C, while at snowfree, vertical faces freezing dropped to ?5°C quite commonly. Comparison with laboratory established criteria for effective freeze-thaw weathering (abundant moisture and freezing to at least ?5°C) suggests that moisture rich microsites lack adequate freezing intensity, while adequately frozen sites lack moisture. Available data suggest that the overlap between freeze-thaw and hydration weathering requires careful re-evaluation. 相似文献