| 1 | Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation显示文摘Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method. | Ge Yong Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences & Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Cheng Qiuming Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Earth Systems and Mineral Resource Engineering Lab, China University of Geosciences, Wuhan 430074, China Zhang Shenyuan Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Department of Resource and Earth Science, China University of Mining & Technology, Beijing 100083, China | 2004 | Journal of China University of Geosciences2004，15，4： | 28 |
| 2 | CHANGES OF PRECIPITATION IN CHINA DUE TO THE ENHANCED GREENHOUSE EFFECT显示文摘We mainly discuss changes of precipitation in China due to growinggreenhouse gases using GCM1 model assuming the IPCC 'Business-as-Usual'Scenario. An increasing greenhouse effect will lead to precipitation increasesmostly in north of 30°N for winter, and strongly increases alap a slant belt fromNortheast China to Bay of Bangal for summer in China. The mp of increasingprecipitation are about 7.9, -0.7 and 13.6 percent for winter, and 6.4, 12.9 and 8.4percent for summer m China, Changjinang and Huanghe river valleys, respectively.The model results are also shown to imply that an increasing greenhouse effectenhances chanas of intense storms and shown for winter and summer in China. | Ge Quansheng(Institute of Geography, CAS, Beijing 100101People’s Republic of China)Wei-Chyung Wang(Atmospheric Sciences Research Center, State University of New York, Albany, New York 12205. U.S.A.) | 1995 | Journal of Geographical Sciences1995，5，2： | 1 |
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