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91.
皖南蛇绿岩的初步研究   总被引:4,自引:0,他引:4  
叶德隆  邓晋福 《地球科学》1991,16(2):143-152,T001
  相似文献   
92.
黑河地区绿洲和戈壁小气候特征的季节变化及其对比分析   总被引:20,自引:23,他引:20  
左洪超  胡隐樵 《高原气象》1994,13(3):246-256
  相似文献   
93.
The characteristics of simulated air flow over Andaman Islands are studied with a two-dimensional version of the University of Virginia meso scale model (UVMM). Using the observed synoptic data as initial conditions, 24 hr simulations are obtained for a day each in April and November. These days are chosen to study the variations in the simulated flow pattern under different synoptic conditions including precipitation effects. A large scale condensation scheme is employed to consider the effect of latent heat release on the perturbations. The results show that the latent heat released by condensation strengthens the intensity of perturbations and the topography accelerates the arrival of sea breeze by about an hour. The model-simulated results, given in graphical form, are discussed and compared with available observations.  相似文献   
94.
内蒙古中西部多岛海构造演化   总被引:10,自引:0,他引:10  
内蒙古中西部大陆由一个微大陆、三条弧后盆地和三条火山岛弧,即华北微大陆、白云鄂 傅弧后盆地、白乃庙火山岛弧、温都尔庙弧后盆地、苏尼特左-锡林浩特火山岛弧、贺根山弧后盆 地和二连浩特-锡林郭勒火山岛弧组成。经过了长期而复杂的微大陆和火山弧的裂解、弧后盆地 的消减衰亡及弧-陆和弧-弧碰拉等构造演化,才最终形成今天所见到的这种构造样式。  相似文献   
95.
ABSTRACT. Being on the edge, being out of sight and so out of mind, exposes the weakness of mainstream ideas, orthodoxies, and paradigms and foments alternatives to the status quo. Islands are thus propelled as sites of innovative conceptualizations, whether of nature or human enterprise, whether virtual or real. They stand out as sites of novelty; they tend toward clairvoyance; they are disposed to act as advance indicators or extreme reproductions of what is present or future elsewhere. This article, which is essentially bibliographical, celebrates islands as the quintessential sites for experimentation, with reference to the physical sciences, the social sciences, and literature.  相似文献   
96.
Geochemical processes were identified as controlling factors of groundwater chemistry, including chemical weathering, salinization from seawater and dry sea-salt deposition, nitrate contamination, and rainfall recharge. These geochemical processes were identified using principal component analysis of major element chemistry of groundwater from basaltic aquifers in Jeju Island, South Korea, a volcanic island with intense agricultural activities. The contribution of the geochemical processes to groundwater chemistry was quantified by a simple mass-balance approach. The geochemical effects due to seawater were considered based on Cl contributions, whereas the effects due to natural chemical weathering were based on alkalinity. Nitrogenous fertilizers, and especially the associated nitrification processes, appear to significantly affect groundwater chemistry. A strong correlation was observed between Na, Mg, Ca, SO4 and Cl, and nitrate concentrations in groundwater. Correspondingly, the total major cations, Cl, and SO4 in groundwater were assessed to estimate relative effect of N-fertilizer use on groundwater chemistry. Cl originates more from nitrate sources than from seawater, whereas SO4 originates mostly from rainwater. N-fertilizer use has shown the greatest effect on groundwater chemistry, particularly when nitrate concentrations exceed 6–7 mg/L NO3–N. Nitrate contamination significantly affects groundwater quality and 18% of groundwater samples have contamination-dominated chemistry.  相似文献   
97.
南沙群岛岛礁地形地貌TM影像特征分析   总被引:3,自引:2,他引:3  
根据南沙海区的地形地貌特征,利用TM图像,对不同的珊瑚礁、珊瑚沙发育状况和岛礁的地质特征与生态特征进行了分析,研究了水下礁、滩的物质组份、发育程度及TM影像特征,提出了30m以浅岛礁分类方法,查清了南沙海域岛、礁、滩、沙的形态和分布,细化并完善了南沙群岛岛礁分类。  相似文献   
98.
从上海市热岛演变看城市绿化的重要意义   总被引:15,自引:6,他引:15  
丁金才  周红妹  叶其欣 《气象》2002,28(2):22-24
近40年来,上海城市热岛面积扩大了7-8倍,强度增强了一倍,导致了高温灾害的增加。上海热岛的迅速扩张和增强始于20世纪80年代,与上海城市的建设有明显的对应关系。如何合理规划城市建设,减缓热岛效应影响,以保证上海城市的健康和可持续发展,已成为一个迫切需要解决的问题。近几年来显示出的上海中心城区热岛强度减弱趋势表明,城市绿化建设对减缓城市热岛效应具有重要意义。  相似文献   
99.
从地名看开疆文化在海南岛的传播扩散   总被引:4,自引:4,他引:4  
朱竑 《地理科学》2001,21(1):89-93
开疆文化是一种开发,开拓边疆的文化,开疆文化的传播是通过众多文化要素的逐渐渗透,传输而实现整体状况改变的,开疆文化在海南的传播扩散及其历史影响则又可以从地名等文化要素的演变中得到反映,进而从一个侧面印证开疆文化在海南岛的传播,扩散及影响。  相似文献   
100.
The Maldives host a sophisticated and competitive international tourist industry which has replaced fishing as the dominant economic activity. With their rich tropical reef ecosystems and the abundant biodiversity of their marine environment, a total of 86 uninhabited islands had been converted into Resort Islands by the end of 2000. Resort Islands are equipped with comprehensive facilities for accommodation, food, recreation and leisure. They are also strictly reserved for foreign tourists and guarantee complete privacy. This gives the benefit of averting conflicts of acculturation with local islanders. In the arena of impacts on the physical environment, however, the consumptive leisure lifestyle of the tourists has been harmful to the Resort Islands as seen in sewage, garbage and waste pollution, as well as reef destruction and beach erosion. While the government of the Maldives takes great effort to harmonise tourism and the environment, the growth of mass tourism in the last 20 years has engendered grave environmental impacts. For future sustainable development of the Resort Islands, the tourists' environmental awareness must be increased to promote greater responsibility for the protection of the fragile coral and reef ecosystems of the Maldives.  相似文献   
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