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961.
Cold water in the deep Pacific can be drawn up to the surface (or west warm water drifts eastwards) because strong tide increases the mixing of seawater both in vertical and horizontal. In this way greenhouse effect is decreased or in-creased by means of absorbing (or releasing) CO2. Therefore, La Nina cold event (or El Nino warm event) may occur, which is caused by wanning - up or cooling - down air above the ocean. Volcanic action at sea bottom is also controlled by strong tide. 相似文献
962.
Based on investigations of the Zhongwei Nanshan aeolian section situated in the southeastern margin of Tengger Desert, carbon-14 and TL (thermoluminescence) dating results and paleoclimatie proxies such as magnetic susceptibility and grain size, we inferred that the northwestern margin of East Asian monsoon region experienced abrupt climatic changes during the last deglaciation. Six oscillation events were identified: Oldest Dryas, Bφlling, Older Dryas, Allerφd, Intra-Allerφd Cold Period (IACP) and Younger Dryas (YD). The summer monsoon was weaker during Oldest Dryas and Younger Dryas when the winter monsoon was stronger. However, during the B/A (Bφlling/Allerφd) period, the summer monsoon strengthened, reflected by magnetic susceptibility, when the winter monsoon also became strong, which is different from the paleoclimatic pattern established in the East Asian monsoon region. Furthermore, the summer monsoon was nearly in phase with the climate changes inferred from the oxygen isotopic records of 相似文献
963.
964.
LU La-chang 《中国地理科学(英文版)》2001,(2)
1 INTRODUCTION China is a country with many nationalities. The western China includes Zhuang Autonomous Region of Guangxi, Guizhou Province, Yunnan Province, Chongqing City, Sichuan Province, Xizang(Tibet) Autonomous Region, Uygur Autonomous Region of Xijiang, Qinghai Province, Hui Autonomous Region of Ningxia, Gansu Province, Shaanxi Province and the Inner Mongolia Autonomous Region, these places are densely populated with 46 minorities out of a total of 55 minorities of C… 相似文献
965.
1 INTRODUCTIONAccording to historical records, there has existed the large-area desert in the northwest of China for a long time, which formed in the geologic age and historical periods, and continuously evolved because of climate changes and human activities. Although a certain amount of achievement has been obtained since the 1950s, land desertification went on expanding quickly. For desertification by wind erosion, the average expansion speed was 1560km2 per year from the late 1950s … 相似文献
966.
人类和每一种生物的生理生存都依赖于水,而许多人类食品的生产却又破坏了水质(如灌溉、鱼类产卵场的维护等)。要想评价地表水水质是比较困难的。与海水相比,它的离子含量变化非常大,海水是很均一的。 相似文献
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969.
In our previous work on the 3-dimensional dynamical structure of planetary nebulae the effect of magnetic field was not considered. Recently Jordan et al. have directly detected magnetic fields in the central stars of some planetary nebulae. This discovery supports the hypothesis that the non-spherical shape of most planetary nebulae is caused by magnetic fields in AGB stars. In this study we focus on the role of initially weak toroidal magnetic fields embedded in a stellar wind in altering the shape of the PN. We found that magnetic pressure is probably influential on the observed shape of most PNe. 相似文献
970.
1IntroductionEarthvisionsoftwareintroducedfromU .S .DGIcompanycanplayanimportantpartinbothspatialgeo logicmodelingandcompilingdifferentmaps .Ontheba sisofrealizingsandbodymodelinganddatainterfacebe tweenDaqingblack -oilandEarthvision ,theFaciestractmodelhas… 相似文献