The Relation between Tectonic Movement and Climatic Change     

Xuexiang Yang  Qiyuan Qiao  Dianyou Chen 《东北亚地学研究》2003,(1)

1SeesawphenomenonofoceaniccrustSince 1996, Yoshino etal.(2002) have been us-ing the space geodetic techniques to observe crustal deformation at four sites in Tokyo metropolitan area. It is called Keystone project (KSP). At the end of June in 2000, volcanic and seismic events star-ted at Izu islands, south of Tokyo. Following the ev-ent, extraordinary crustal deformation was observed not only around the Izu islands, but also at the Key-stone network, where the closest site is over 100…  相似文献   

北太平洋东部风暴轴的时空演变特征   总被引：6，自引：2，他引：4  

朱伟军  袁凯  陈懿妮 《大气科学》2013,37(1):65-80

本文利用欧洲中期天气预报中心(ECMWF)逐日再分析资料(ERA-40),以500 hPa位势高度滤波方差为代表,对1957年12月～2001年11月期间44年528个月北太平洋区域(30°N～60°N,120°E～120°W)月平均风暴轴的多中心数目和最强中心位置进行了客观统计,在此基础上,对北太平洋区域进行了分区,通过对比各区域风暴轴的时间演变和结构变化,重点揭示了北太平洋东部地区风暴轴的时空演变特征.主要结论如下:(1)逐月来看,北太平洋风暴轴“多中心”现象普遍存在,概率高达94.7%,最典型的分布呈2～3个中心分布;从季节上来看,春季是“多中心”现象最容易出现的季节,秋季和冬季相对较少,而4个及以上的“多中心”现象则更容易出现在夏季.(2)若把最强中心出现在160°W以东地区的北太平洋风暴轴定义为东部型风暴轴,那么从月份上来看,7月相对最容易出现东部型风暴轴,1月和2月最难;从季节上来看,夏季相对最容易出现东部型风暴轴,冬季最难;总的来看,出现东部型风暴轴的频数大约占总频数的三分之一.(3)从垂直结构上看,在北太平洋160°W以东地区,风暴轴的强度可以最强,但与斜压性密切联系的涡动向极和向上热量通量的最大值却并不是最强.(4)经验正交函数分解(EOF)分析的结果表明,在不同季节、不同区域以及是否单独考虑东部型风暴轴的情况下,风暴轴的变化虽然表现出了一定的差异,但都反映出在北太平洋东部区域风暴轴的变化特征有其独特特点,如在该区域风暴轴的主要变化模态并不一定时时与其他区域的主要变化模态一一对应.北太平洋东部区域风暴轴变化的原因和机制值得进一步深入探讨.  相似文献   

Comparing the terrain reversal effect in satellite images and in shaded relief maps: an examination of the effects of color and texture on 3D shape perception from shading     

Arzu Çöltekin  Julien Biland 《International Journal of Digital Earth》2019,12(4):442-459

Terrain reversal effect (TRE) causes reversed 3D shape perception in satellite images and shaded relief maps (SRMs), and introduces difficulties in identifying landforms such as valleys and ridges. With this paper, in a controlled laboratory experiment, we compare how well 27 participants could identify valleys and ridges over 33 locations using SRMs, color satellite images and grayscale satellite images. The main depth cue is shadow both in vertical-view images and SRMs. However, the presence of texture and color in images also affect 3D shape perception. All our participants experience the illusion strongly: with the SRMs, it is very severe (2% accuracy), with grayscale images low but considerably better than SRMs (17.6% accuracy), and slightly worse with color imagery (15.3% accuracy). These differences between SRMs and imagery suggest that the participants who are able to bypass the illusion consciously or subconsciously interpret the photographic information. We support this observation further with a cue-strength analysis. Furthermore, we provide exploratory analyses of the effects of expertise, global convexity bias, and bistable perception. Our original empirical observations serve towards a better understanding of this visual illusion, and contribute towards nuanced and appropriate solutions to correcting for TRE differently for satellite images and SRMs.  相似文献   

Quantifying the Degree of Water Resource Utilization Polarization: A Case Study of the Yellow River Basin     

GU Shijie  LU Chunxia  QIU Jingen 《资源与生态学报(英文版)》2019,10(1):21-28

The overexploitation of water resources has a substantial influence on their sustainable utilization and the ecological environment in a river basin. Quantification of the development and utilization of water resources plays an important role in guiding the rational utilization of water resources. Based on this, this paper develops the concept of water resource utilization polarization (WRUP) in order to qualitatively analyze whether water resources are being overexploited in the process of utilization. An index model of WRUP was built to quantify the degree of water resources overexploitation. In addition, taking seven secondary basins of the Yellow River as examples, the available quantity, overdraft and polarization indexes of surface water and groundwater resources were calculated. The results show that there are 34.49×10⁸ m³ of surface water available, which accounts for 56.21% of the total surface water volume. A total of 5.84×10⁸ m³ of groundwater is available, which is 58.74% of the total groundwater resources. We also found that the water resources are heavily overexploited and that there is extensive polarization in the middle and lower reaches of the Yellow River. The highest polarization of water resources occurs from Lanzhou to Toudaoguai where the polarization index is 19.88 and from Longmen to Sanmenxia where it is 11.81. There is no polarization above Longyangxia or from Toudaoguai to Longmen. Overall, the polarization of water resources is 7.95 over the entire Yellow River area. These results provide a reference for the availability of water resources that can be used to determine the degree of overexploitation of the water resources in the Yellow River.  相似文献   

龙岩台VS型垂直摆倾斜仪标定异常问题分析     

刘其寿  杨佩琴  郑建志  陈懿德  陈传昌  王绍然  赖福霖 《华南地震》2012,32(1):49-53

通过对龙岩台VS型垂直摆倾斜仪防雷改造后,日常观测资料正常,但标定时出现幅度异常增大的问题进行分析,经多次试验,发现标定异常现象是由信号线路问题造成的而非安装了防雷器。  相似文献   

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宋传峰  党亚民  秘金钟  薛树强 《大地测量与地球动力学》2014,34(3):108-110

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辽宁地区地震的时空分布特征及未来地震趋势的预测     

刘佳丽  崔震 《防灾减灾学报》2014,(2):62-65

简要论述了辽宁地区地震的时空分布特征,阐述了目前辽宁地震活动处在活跃期的活跃时段,未来17年发生中强地震的可能性较大,应加强防范。  相似文献   

河池边界层逆温现象变化特征及影响   总被引：3，自引：0，他引：3  

韦肖林  周慧僚  唐新 《气象研究与应用》2012,33(1):30-34

利用河池近5a来GFE(L)型雷达探测的高空气象资料,对河池边界层逆温现象变化特征和强度进行分析,寻找河池边界层逆温现象的变化特征及规律,进而利用这些规律进一步阐述逆温现象对人民生活的影响以及如何减少逆温现象带来的危害。  相似文献   

Hydrochemical characteristics and seasonal variations in groundwater quality of an alluvial aquifer in parts of Central Ganga Plain,Western Uttar Pradesh,India   总被引：1，自引：0，他引：1  

Rashid Umar  Izrar Ahmed  Fakhre Alam  Mohammad Muqtada Khan 《Environmental Geology》2009,58(6):1295-1300

The present study was undertaken to assess major ion chemistry of groundwater in parts of the Central Ganga Plain and observe seasonal variations in its chemical quality. Systematic sampling was carried out during November 2005 and June 2006. The major ion chemistry of groundwater shows large variations, so much so that at times the meteoric signature seems to be completely obliterated. In many samples the concentrations of SO₄, NO₃ and F are above the permissible limit for human consumption. The graphical treatment of major ion chemistry helps in identifying four types of groundwater. All possible ionic species such as NaCl, KCl, NaHCO₃, NaSO₄, KNO₃, NaNO₃, CaHCO₃, MgHCO₃, MgSO₄ are likely to occur in groundwater system. The observed chemical variations may be attributed to sediment water interaction, ion exchange, dissolution mechanisms and anthropogenic influences such as application of fertilizers and effluents from sugar factories and paper mills. A general increase in TDS is observed in samples during June 2006. The increase in salinity is attributed to evaporation from water table, irrigation return flows, anthropogenic activities and below average rainfall in 2005 and 2006. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

非均匀下垫面边界层的观测和数值模拟研究(I):冷岛效应和逆湿现象的完整物理图像   总被引：11，自引：4，他引：7  

左洪超  吕世华  胡隐樵  马耀明 《高原气象》2004,23(2):155-162

利用HEIFE、DHEX和GAME/Tibet 3个观测试验和部分常规气象站观测资料,分析了下垫面非均匀条件下产生的冷岛效应和逆湿现象的完整物理图像以及它们对地表能量和五水转化的影响.分析结果表明,下垫面非均匀特征对五水转化有着明显的影响;冷岛效应和逆湿现象是下垫面非均匀性的必然结果,它们在自然界普遍存在;现有陆面过程模式很难刻画冷岛效应和逆湿现象,通常现有陆面过程模式很难将冷岛效应中的热量平流转化成蒸发潜热,同时陆面过程模式也混淆了逆湿现象和发生在下垫面上的大气水的冷却凝结.这些评述将有助于今后非均匀陆面过程的进一步研究.  相似文献