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1.
利用2006-2017年黑龙江省闪电定位资料和日平均地面相对湿度资料,采用数理统计、Pearson相关分析、GIS空间分析技术,研究了闪电密度和强度对地面相对湿度(RH)的响应关系。结果表明:地面RH过小或过大都不利于闪电活动产生;当RH < 25%时,几乎无闪电发生,当RH < 77%时,RH增加有利于闪电活动发生,当RH>79%时,随着RH增加,闪电活动减少;当RH < 77%时,闪电密度与之呈正相关,闪电强度与之呈负相关;当RH>79%时,闪电密度与之呈负相关,闪电强度与之呈正相关;地面RH的临界值域约为77%-79%;70%≤ RH ≤ 90%区间为闪电易发湿度区间,在闪电密度与湿度相关度高的区域,闪电更趋于集中发生在闪电易发湿度区间。  相似文献   
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桂北-湘南中生代玄武质岩石中含有丰富的深源包体,它们分别为橄榄岩、变形的辉长岩和中酸性片麻岩三大类,本文在论述上述岩石地球化学性质的基础上,探讨了它们之间的成因关系;寄主的中生代玄武质岩石为地幔楣榄岩部分熔融的产物,与辉长岩和中酸性片麻岩并无成因联系,后者属偶然包体,值得注意的是,深源包体中的变形辉长岩与片麻岩之间为分离结晶的成因关系,它们均为元古宙壳、幔间底侵玄武质岩浆的演化产物,其中辉长岩为底侵岩浆的堆积相,而片麻岩则为底侵岩浆经历分离结晶的堆积作用之后所剩下的残余岩浆的变质产物。  相似文献   
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"A modification of the population potential model is used to analyze the structure of the potential of population for cities of the Moscow region, to develop a relationship between population potential and city size, and to use this procedure to forecast future population change in Moscow Oblast cities." Cities in the region with a population of 50,000 or more at the censuses of 1959, 1970, and 1979 are included.  相似文献   
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Long-term biological data supported by physicochemical parameters were evaluated to investigate the biodiversity of the Golden Horn Estuary from the past to the present. Limited observations dating back to 60 years ago indicated the existence of a diverse community in this small estuary. Unfortunately, in parallel with the increase in unplanned settlements and industry around the Golden Horn, pollution stress increased since the 1960s. Preliminary studies in the 1990s indicated survival of only a couple of pollution-resistant species, in the relatively cleaner lower estuary. Following the intensification of rehabilitation studies in 1998 and particularly after the opening of the floating bridge at the mid estuary; a remarkable day-by-day recovery in marine life has begun with the improving water quality. Nutrient concentrations decreased markedly; while water clarity significantly increased. Fecal coliform values decreased 10(3) fold. Phytoplankton composition changed and dense blooms of eukaryotic phytoplankters frequently occurred. Hydrogen sulfide almost completely disappeared even during the warmest periods of the year and dissolved oxygen concentrations increased. All results clearly depicted that the Golden Horn ecosystem shifted to eutrophic conditions from an anoxic environment. SCUBA dives in 2002, documented the level of diversification of life in the Golden Horn. All appropriate substratums were intensely covered by macrobenthic forms until the Halic Bridge and filter feeders dominated the plankton-rich ecosystem. Achieving the diversity of 1940s is not possible since the Black and Marmara seas, influencing water quality of the Golden Horn, are also suffering from anthropogenic impacts and are far less diverse than their rich diversity in 1940s. However, the Golden Horn is a good example that even the most polluted ecosystems can recover when appropriate measures are taken.  相似文献   
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对高频NORESS台阵接收的人工爆破和天然地震的短周期记录进行f-k分析的结果表明,续至波来自于接近国西南约25~30km处。应用从台阵记录中减去波束形成而得到的残差地震记录,改进了识别相同散射的效果。将针对后面波至的窗口与针对初动P波窗口相对于慢度值的f-k功率相减(归-化以后)而得到的f-k功率差图,提供了几乎相同的结果。续至波源好象是短周期的面波Rg,它是由f-k功率差图,提供了几乎相同的结  相似文献   
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ANALYSIS OF FOLDS SOUTH OF MALAKAND AND ADJOINING AREAS, NORTH PAKISTAN1 Can啨rotJ,QuG .CuadernosdeGeologiaiberica ,1998,2 4:311~ 331. 2 DebelmasJ,MascleG .EnsSciencesdelaTerre[M ].Masson ,ed .1991.2 99.3 GaetaniM ,GarzantiE .AAPGBull ,1991,75 (9) :142 7~ 144 6 . 4 HendrixMS ,GrahamSA ,CarrollAR ,etal.GeolSocAmBull,1992 ,10 4:5 3~ 79.. 5 Jia ,Coll.PetroleumIndustryPress,Beijing .1997,2 95 . 6 JiaD ,LuHCaiD ,etal.AAPGBull ,8…  相似文献   
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1 引言 随着气象科技业务技术现代化建设的深入发展,一些气象台站陆续开展了"CTL-713C型天气雷达"气象观测业务.七台河市气象局"CTL-713C型天气雷达"于2006年11月开始运行至今,在灾害性天气预报、定量估测降水和人工影响天气作业指挥等气象预报和气象应用服务工作中发挥了重要作用. 2008年7月,七台河市气象局"CTL-713C型天气雷达"出现回波失真现象,需要对雷达重新进行标定.现将具体操作方法做一总结.  相似文献   
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