Remote sensing parameterization of the processes of energy and water cycle over desertification areas     

Yaoming Ma  Osamu Tsukamoto  Hirohiko Ishikawa 《中国科学D辑(英文版)》2002,45(1):47-53

In order to understand the processes of land surface-atmosphere interaction over desertification area, it is indispensable to utilize of satellite remote sensing. Two scenes of Landsat TM were used to produce a set of maps of surface reflectance, MSAVI, vegetation coverage, surface temperature, net radiation, soil heat flux, sensible heat flux and latent heat flux. Statistical analysis based on these maps revealed some quantitative significant land surface characteristics. Future developments of the method are also discussed.  相似文献   

Remote sensing analysis of desert vegetation and its landscape changes: The case in middle reaches of Tarim River Basin,Xinjiang, China     

Ranghui Wang  Zili Fan  Huizhi Zhang  Yaping Chen  Yingjun Ma 《中国科学D辑(英文版)》2002,45(1):54-58

Based on remote sensing information sources including B/W aerial photos of 1983, pseudo-color aerial photos of 1992 and JERS-1/OPS VNIR image of 1996, vegetation types of Yingbazha, in the middle reaches of the Tarim River Basin in Xinjiang, China are mapped using ARC/INFO and related software. The changes in vegetation areas and distribution conditions are analyzed. As a result of natural and human influences, vegetation changes have temporal and spatial characteristics. According to the principles of landscape ecology and geographical information science, the landscape changes are indicated. Moreover, the remote sensing and GIS techniques are integrated to study vegetation and its landscape.  相似文献   

Utilization of water resources,ecological balance and land desertification in the Tarim Basin,Xinjiang     

Zili Fan  Xuncheng Xia  Yuling Shen  Kurban Alishir  Ranghui Wang  Shengyu Li  Yingjun Ma 《中国科学D辑(英文版)》2002,45(1):102-108

Because of the human exploitation and utilization of water resources in the Tarim Basin, the water resources consumption has changed from mainly natural ecosystem to artificial oasis ecosystem, and the environment has changed correspondingly. The basic changes are: desertification and oasis development coexist, both “the human being advance and the desert retreat” and “the desert advance and the human being retreat” coexist, but the latter is dominant. In the upper reaches, water volume drawing to irrigated agricultural areas has increased, artificial oases have been enlarging and moving from the deltas in the lower reaches of many rivers to the piedmont plains. In the middle and lower reaches of the Tarim River, the stream flow has decreased, old oases have declined, natural vegetations have been degenerating, desertification has been enlarging, and the environment has deteriorated. The transition regions, which consist of forestlands, grasslands and waters between the desert and the oases, have been decreasing continuously, their shelter function to the oases has been weakened, and the desert is threatening the oases seriously.  相似文献   

地震前兆时空非均匀性指标Cv值的实验检验   总被引：1，自引：1，他引：1  

王凯英  马胜利  刘力强  马瑾 《地震学报》2002,24(1):82-89

在双向加载条件下，对两种构造和介质不同的岩石标本进行变形实验，测量了标本表面不同部位的应变．在此基础上，利用王晓青和陈学忠等提出的描述地震前兆非均匀分布的参量————Cv值，分析了标本变形失稳过程中应变异常的分布，以期从实验角度检验Cv值方法并探讨其物理意义．研究表明，Cv值的变化与岩石变形特征的变化有关，是描述前兆分布非均匀性的一种有效指标；Cv值在失稳发生前先异常上升，然后下降，并在Cv值恢复过程中或恢复后伴随着失稳事件的发生．因此，Cv值是一种有效的预报指标．   相似文献   

用应变积累释放模型研究中国大陆地块分区地震活动   总被引：11，自引：1，他引：11       下载免费PDF全文

马宏生  刘杰  张国民  李丽 《地震学报》2002,24(6):569-578

依据活动地块假说及活动边界的划分，对中国大陆地震活动进行分区．在此基础上，应用应变积累释放模型，通过地震应变积累释放的计算，研究了中国大陆各活动地块分区的地震活动性，初步探讨了各地块的地震活动阶段划分．此外，还对应变积累释放模型的应用前提条件进行了必要的讨论，并对模型结果中可能出现的问题给予一定分析．   相似文献   

Study on the characteristics of rock failure strain and acoustic emission field for two parallelling faults with the same slip direction including asperities     

焦明若  张国民  马胜利  马宏生 《地震学报(英文版)》2002,15(4):374-382

Introduction Concerning about research on grouped-earthquake seismogenic and occurrence, at present it is only limited on the stage of the theoretical analysis and numerical model. For instance, ZHANG (1987) simulated the grouped-earthquake generation and physical mechanism making use of spring-block principle. Applying for non-linear dynamic model, referring to Chinese continental plate as object, LI, et al (1997) performed the numerical simulation on the seismogenic and occurring of group…  相似文献   

Extracting coseismic deformation of the 1997 Mani earthquake with differential interferometric SAR   总被引：2，自引：0，他引：2  

单新建  马瑾  王长林  柳稼航 《地震学报(英文版)》2002,15(4):431-438

Introduction The development and application of Interferometric Synthetic Aperture Radar (InSAR) have a close relationship with the sensors development of Synthetic Aperture Radar (SAR). The conception of SAR is proposed comparatively to the real aperture radar antenna. It is well known that the longer the antenna is, the higher the observation resolution will be. Just limited by the length of the antenna, the resolution of real aperture radar is generally very low and cannot meet the r…  相似文献   

江西白垩纪—新近纪陆相红色盆地的盆缘类型划分与盆地充填样式   总被引：8，自引：1，他引：8  

廖瑞君衷存堤  肖晓林 《地质通报》2003,22(9):680-685

根据在江西白垩纪—新近纪陆相红盆地中1：50000地质填图对盆地的盆缘类型和盆地充填样式研究的新认识，以及陆相红盆地的形成、发展机制与盆地边缘岩石的成生性质，将盆缘划分为基底盆缘和新生盆缘2类；又依据盆缘的原始自然坡度和形态特征划分为缓坡型、折坡型、陡坡型(或断坡型)和新缓坡型、新折坡型、新陡坡型等6型。根据陆相红盆地中不同构造期(幕)不同沉积环境沉积的沉积体的空间展布特征及其各种有序叠置组合形式，厘定了辫状河—湖三角洲—浅湖型、冲积扇—辫状河—湖三角洲—浅湖型、冲积扇—浅湖型、近岸水下扇—浅湖型、冲积扇—辫状河型和河流—沼泽(湿地)型等6种盆地充埴样式。  相似文献   

The Paleo－Environmental Significance of Sr and Ca Contained in Acid－Soluble Fraction of Plateau Loess Deposits in Xining Basin     

谭红兵  马海州  鹿化煜  张西营  魏海珍 《中国地球化学学报》2003,22(2):156-163

The Xining Basin,located on northeastern Qinghai-Xizang Plateau,is adjacent to the Qaidam Bsim and Gobi-desert.Therefore,thick,integrated deposits of loess or paleo-sol sequence were well developed.As is well known,there is much paleo-environmental information recorded in loess and plaeo-sol.So if we deal with paleo-environmental index from different an gles ,especially from loess geochemistry,some important and detailed paleo-environmental evolutional information will be acquired.Based on this,the authors determined the contents of Sr and Ca contained in acid-soluble fraction from the bottom to the top of the Panzishan section.This section was obtained through making a well about 17 m in depth,including S1 paleo-sol that was developed during the last interglacial period.According to the results,it is found that variations in contents of Sr and Ca are well correlated with conversion of loess and paleo-sol.In loess deposits,the contents of Sr and Ca are higher than those in paleo-sol deposits.It is known that loess was deposited under cold-dry climate conditions and paleo-sol was developed during warm-humid climate episodes.It is concluded that due to their mobile behaviors,under cold-dry climate conditions,Sr and Ca are stagnant during weak weathering,but under warm-humid climate conditions,Sr and Ca are easily leached and transported in aqueous solution.Therefore,they can be utilized as indicatiors of climate changes.Moreover,variations in contents of Sr and Ca are more sensitive than susceptibility.The mobile behaviors of Sr and Ca contained in acid-soluble fraction can serve as a new quantitative index to evaluate paleo-environmental changes on the plateau.  相似文献   

湖泊纹层状沉积物的同生期变化研究述评     

王冠民  钟建华  马在平 《世界地质》2003,22(3):231-236

湖泊纹层状沉积物是在湖水分层的条件下缓慢沉积的。这些沉积物在沉积以后可能会发生一些同生期的改造作用，如季节性湖流的微弱冲刷、湖水中溶解氧对有机质的氧化、硫酸盐还原作用对有机质的氧化和硫化物的形成、有机质分解形成的偏酸性底层湖水对碳酸盐的溶解和磷的迁移造成的藻类勃发等，使纹层在成分、结构和构造方面发生一些变化。在对纹层进行古气候、古环境恢复的时候，这些同生期的变化不能被忽视。对这些变化的研究有助于对古气候、古湖水沉积环境的正确认识。  相似文献