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排序方式: 共有365条查询结果,搜索用时 46 毫秒
31.
Michael H. Cosh Jery R. Stedinger Steve C. Ou Kuo-Nan Liou Wilfried Brutsaert 《Advances in water resources》2007
This study focuses on how the variability of land surface temperature and vegetation density at the SGP ARM-CART site changes over episodic (day to day) and seasonal time scales using AVHRR satellite data. Four drying periods throughout the year are analyzed. Land surface temperature had an erratic relationship with time exhibiting no deterministic pattern from day-to-day or season-to-season. Furthermore, it did not exhibit spatial pattern persistence. On the other hand, vegetation density had a consistent spatial pattern and temporal decay during average length drying periods (less than 7 days) as well as within a season. However, there were distinct differences in the seasonal pattern of variation between winter and growing seasons. In addition, the paper highlights a methodology to quantify the relationships that exist at the land surface between the primary parameter of interest and the controlling variables. 相似文献
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H.J Bauer 《Geoforum》1971,2(4):31-41
The lignite mining area of the Rhineland provides an excellent example for planned recultivation of large open-works. In order to properly carry out recultivation measures, it is necessary to conduct basic research on the ecological factors which compose a balanced landscape. The problems involved in reconstructing a landscape, which has been pitted by large-scale open-cut mines, are discussed from the aspects of: planning and construction of a new landscape-relief, proposed agricultural and forestry use, nature preserves and resort areas. The aim of recultivation, from the ecological point of view, is to renew the natural biological potential and to reform the landscape, so as to provide the healthiest environment for Man. 相似文献
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36.
Günter Bauer 《International Journal of Earth Sciences》1955,44(1):193-208
Zusammenfassung Feintektonische Untersuchungen, ergänzt durch stratigraphische Profilaufnahme, erbrachten den Nachweis eines Hönningen-Seifener-Sattels aus Schichten des Unteren Siegen, Im NW wie SE wird dieser Sattel von flachwelligen Muldenzonen begleitet, deren südöstliche in Richtung auf die Siegerländer Hauptüberschiebung einen zunehmenden Schuppenbau zeigt. 相似文献
37.
Wilfried Philipp 《International Journal of Earth Sciences》1955,44(1):345-375
Zusammenfassung Die Bildung des Spateisensteinganges von Grube Neue Haardt schließt an die Hauptfaltung an. Der Gang ist aus einer Abschiebung entstanden und wird von der Geisweider Überschiebung abgeschnitten.Es wird nachgewiesen, daß auf dieser Überschiebung nach Zeit und Richtung unterschiedliche Bewegungen stattgefunden haben. 相似文献
38.
This study uses a numerical model to investigate the groundwater flow and salt transport mechanisms below islands in the Okavango Delta. Continuous evapotranspiration on the islands results in accumulation of solutes and the formation of a saline boundary layer, which may eventually become unstable. A novel Lagrangian method is employed in this study and compared to other numerical methods. The numerical results support the geophysical observations of density fingering on Thata Island. However, the process is slow and it takes some hundreds of years until density fingering is triggered. The results are sensitive to changes of the hydraulic gradient and the evapotranspiration rate. Small changes may lead to different plume developments. Results further demonstrate that density effects may be entirely overridden by lateral flow on islands embedded in a sufficiently high regional hydraulic gradient. 相似文献
39.
基于地理信息系统的太阳直接辐射与冰川物质平衡的关系 总被引:4,自引:1,他引:3
基于冰川微地形对冰川物质平衡重要影响的认识,在考虑朝向、坡度、地形遮蔽等因素的条件下,以地理信息系统为手段,对乌鲁木齐河源1号冰川冰面太阳可能直接辐射进行了理论计算.在此基础上,建立了计算冰面任意一点物质平衡的B=f(T,R)(气温-辐射)模型.比较了该模型与B=f(T)(气温)模型、B=f(P,T)(降水-气温)模型及B=f(Q)(能量平衡)模型之间的优缺点,表明该模型具有物理意义明确、计算精度较高、参数易于获得等优点,从而为计算冰川物质平衡提供了新的途径. 相似文献
40.
Wilfried Heller 《GeoJournal》1998,46(3):199-205
This study evaluates some aspects of the socio-economic transformation of rural Romania with reference to the views of representative
organisations (at national, regional and local levels) and other experts. Interviews conducted in ten communes of nine Romanian
counties (‘judete’) focus attention on the advantages and disadvantages of system change experienced since 1989; the most
important problems and constraints for future socio-economic change; and appropriate policies and perspectives for development
in the immediate future. Wherever appropriate the claims of interviewees are substantiated through reference to statistics,
drawn in many cases from Chambers of Commerce & Industry (CCI). Local level representatives presented much more negative views
on recent change than their national and regional level counterparts, but all agreed on the crucial problem of capital shortage.
Thus while specific programmes to assist rural areas are justified, they cannot fully succeed until the national economy is
able to grow more rapidly and attract greater foreign investment.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献