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891.
Wang Yuan Niu Shengjie Lu Chunsong Lv Jingjing Zhang Jing Zhang Hongwei Zhang Sirui Shao Naifu Sun Wei Jin Yuchen Song Qinghai 《中国科学:地球科学(英文版)》2021,64(11):1982-1995
Science China Earth Sciences - We conducted a three-month field experiment focusing on the physical and chemical characteristics of fog in a tropical rainforest in Xishuangbanna, Southwest China,... 相似文献
892.
893.
土壤碳蓄积量变化的影响因素研究现状 总被引:37,自引:2,他引:37
土壤碳库的动态平衡影响作物产量和土壤肥力的高低,是土壤肥力保持和提高的重要研究内容。简要评述了土壤理化特性、温度和降水变化、大气CO2浓度上升、人类的农业活动对土壤有机碳蓄积量的影响,介绍了当前对土壤碳蓄积量动态变化的研究进展,认为应加强气候变化和土地利用/土地覆被变化与土壤碳循环研究的结合,提高对陆地生态系统碳循环变化的认识,并需要从生态环境保护的利益和可持续发展的理论出发,进一步加强土地管理方式的改变,促进土壤有机质的积累,提高土壤对碳的固定。 相似文献
894.
从板块理论看辽宁大地构造轮廓 总被引:2,自引:0,他引:2
据近十年来1:5万区域地质调查及有关科研成果资料,应用板块构造理论对辽宁境内板块构造进行了轮廓性的讨论。划分出天山-赤峰陆缘活动带和华北陆块两个二级构造单元;辽东地块,辽西地块,泛河微地块,浑河构造接合带,下辽河裂陷等五个三级单元及清源绿岩带,辽吉夭蜇裂谷带两个可能存在的四级单元。 相似文献
895.
Methods for feature detection in laser scanning data have been studied for decades ever since the emergence of the technology.However,it is still one of the unsolved problems in LiDAR data processing due to difficulty of texture and structure information extraction in unevenly sampled points.The paper analyzes the characteristics of Laplacian of Gaussian(LoG) Filter and its potential use for structure detection in LiDAR data.A feature detection method based on LoG filtering is presented and ex-perimented on the unstructured points.The method filters the elevation value(namely,z coordinate value) of each point by convo-lution using LoG kernel within its local area and derives patterns suggesting the existence of certain types of ground ob-jects/features.The experiments are carried on a point cloud dataset acquired from a neighborhood area.The results demonstrate patterns detected at different scales and the relationship between standard deviation that defines LoG kernel and neighborhood size,which specifies the local area that is analyzed. 相似文献
896.
As the basic problems in seismology, fluid, heat and energy distribution near earthquake sources during earthquake generation have been the leading subjects of concern to seismologists. Currently, more and more research shows fluid around earthquake source areas, which plays an important role in the process of earthquake preparation and generation. However, there is considerable controversy over the source of fluid in the deep crust. As for the problem of heat around earthquake source areas, different models have been proposed to explain the stress heat flow paradox. Among them, the dynamic weakening model has been thought to be the key to solving the heat flow paradox issue. After large earthquakes, energy distribution is directly related to friction heat. It is of timely and important practical significance to immediately implement deep drilling in-site surveying to gain understanding of fluid, friction heat and energy distribution during earthquake generation. The latest international progress in fluid, heat and energy distribution research has been reviewed in this paper which will bring important inspiration for the understanding of earthquake preparation and occurrence. 相似文献
897.
关于震源附近流体、热和能量分配问题的研究进展 总被引:1,自引:0,他引:1
作为地震学的基本问题,地震发生过程中震源附近流体、热与能量的分配问题一直是地震学家关注的前沿课题.目前,越来越多的研究表明震源附近存在流体,且流体在地震的孕育、发生过程中起重要作用,但对深部流体的来源尚存较大争议.对于震源区的热问题,自应力热流佯谬提出以来,不同的模型被用于解释热流佯谬相关问题,其中动态弱化被认为可能是解决热流佯谬的关键.摩擦产生的热能与能量分配问题直接相关,大地震发生后,立即进行深钻现场测量对认识地震发生过程中震源附近的流体、摩擦热能及能量分配问题具有时效性和重要现实意义.本文回顾了国际上有关震源附近流体、热及能量分配问题的最新研究进展,这些问题的研究将对认识地震的孕育和发生过程带来重要启示. 相似文献
898.
899.
“0814”号强台风发展维持的环境场分析 总被引:4,自引:3,他引:1
应用中国台风网提供的“黑格比”台风定位及强度资料、NCAR/NCEP再分析资料及DISCOVER项目组的卫星遥感数据对0814号强台风“黑格比”的发展、维持阶段进行了诊断分析。结果表明:西北太平洋中部异常偏高的SST为“黑格比”的生成提供了有利的背景条件,浙闽沿海及海南岛沿海异常偏高的SST为“黑格比”的发展和维持提供了有利的环境条件;西太副高断裂为东西两个单体,“黑格比”移经这两个单体之间使其强度迅速增强;南亚高压东侧的强东北气流将高位涡向台风环流输送,使得台风得以增强发展;强劲的西南季风为“黑格比”提供了充足的水汽来源,并向台风环流输送了气旋性相对涡度带,使其得以快速发展并维持强度。 相似文献
900.
Characteristics of water circulation and balance of typical vegetations at plot scale on the Loess plateau of China 总被引:1,自引:1,他引:0
Large-scale artificial afforestation has aggravated the water scarcity and resulted in the severe soil desiccation in the Loess plateau of China. Understanding the water circulation processes and the water balance characteristics of typical vegetations is of great significance to the vegetation restoration in the Loess plateau of China. Based on field observation from May to October in 2004, the soil desiccation under five vegetations was investigated in the Liudaogou watershed on the Loess plateau of China. Moreover, the water circulation and balance of them at plot scale were also studied. The results showed that among these five vegetations, the degree of soil desiccation under alfalfa and caragana was more severe than that under defarming grassland, millet and soybean, and there existed the dried soil layers under caragana and alfalfa. The dynamic of the soil water storage under five vegetations was quite similar and the soil water storage in the five runoff plots followed the order: defarming grass > millet > soybean > caragana > alfalfa. The order of runoff amount in the five plots was soybean > millet > defarming grass > alfalfa > caragana. The water consumption (ET) of five vegetations followed the order: caragana > alfalfa > defarming grass > soybean > millet. The results indicated that the greater the evapotranspiration of one vegetation, the higher the possibility to develop the soil desiccation under it. The findings provided helpful reference for the vegetation restoration and environment improvement programs in the Loess plateau of China. 相似文献