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1.
气候系统中存在着各种各样的气候反馈机制,而气候模式对这些反馈机制描述的差异,正是造成不同模式对同一直接辐射强迫(如二氧化碳加倍)的响应不同的主要原因。因此,只有正确描述气候系统中的各种反馈作用,气候模式才可能用来对未来的气候变化进行预测。为此,本文首先介绍了气候系统及模式反馈机制分析研究时所常用的一些概念,如气候敏感性参数、云辐射强迫等,随后概述了气候模式反馈机制比较分析时常用的各种方法,并指出了这些方法各自的优缺点。而详细的有关气候系统及模式中反馈作用及其机制的分析则在文章的第II部分给出。  相似文献   
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The Chi Chi earthquake (Mw7.6) occurred at 17:47 UTC on Sept. 20,1999 (01:47 September 21, 1999, local time) in central Taiwan. CWB located the epi- center at (120.82°E; 23.85°N) and the focal depth 8 km. Chi Chi earthquake is the best documented earth- quake ever recorded. The abundance and quality of its near-source observations present an unparalleled op- portunity for studying the rupture history from a close distance. More than 400 free field digital accelerome- ters with 3-compon…  相似文献   
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一次冷涡过程降水的微物理机制分析   总被引:6,自引:0,他引:6  
该文分析了一次冷涡天气过程中云微物理量的分布特征、降水粒子的增长机制及云下雨滴的蒸发效应。主要结果为:云系由低层暖性Sc云和冷性主体As云组成。As云底高2 km,云顶高大于5 km,云中存在比较大的过冷水区,–11.2 ℃时的过冷水含量0.21 g·m-3,但过冷水的含量分布极不均匀,大于0.05 g·m-3的过冷水区连续分布的宽度87%小于2.4 km,不利于云中冰晶的连续凇附增长;同时云下雨滴的蒸发效应大,直径小于1.0 mm的雨滴难以落到地面,因此本次过程只产生弱的降水。  相似文献   
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Various measures including material experiments, centrifuge modeling tests and FEM numerical analyses were performed to study systematically the action mechanism of the geotextile-reinforced cushion under breakwater on soft ground and the effects of the strata characterization and the reinforcement condition on the stability of the breakwater-ground system. In the aspect of controlling the deformation, the geotextile-reinforced cushion under breakwater constrains the lateral displacement of both the embankment and the ground. From the viewpoint of stress, the reinforcement suppressed the range of high stress level in the system. In general, the weaker the ground is and the greater the modulus of the geotextile is, the more effective the reinforcement is. The tensile force in the geotextile is greater in the range of the main part of the embankment.  相似文献   
6.
随着环境的改变,水质成分日趋复杂,水-土作用对土体性能的影响越来越明显。针对这一情况,考察了不同种类、不同浓度及不同pH值溶液对土体渗透系数的影响。结果表明,水-土作用对土体渗透系数存在正负两个方向的影响,且影响显著,对土体SEM照片分析后发现,水土之间通过阳离子交替吸附作用和溶蚀及结晶沉淀作用,使土体微观形貌及孔隙特征发生变化,最终导致其渗透性发生改变。  相似文献   
7.
Systematic researches to the clastic reservoirs in various types and various geological ages basins in China indicate that the present burial depth of deep buried clastic eureservoir ranges from 3000 to 6000 m,and its geological ages from Paleozoic,Mesozoic to Cenozoic. It mainly deposited in delta (including braid delta,fan delta,normal delta),river,also shore,shallow lake,gravity flow channel and turbidity fan facies. The quartzose sandstone is the main reservoir rock of deep-buried clastic eureservoir in the shore facies in Paleozoic,but the arenite and arkose sandstones are the main reservoir rock types in delta,river,shallow lake and gravity flow facies in Mesozoic and Cenozoic. The porosity of most of deep-buried clastic eureservoir is more than 10% and permeability more than 10×10?3 μm2. The forma-tion of the deep-buried eureservoir was related to the paleotectonics,paleotemperature,sedimentary environment,the deep dissolution caused by organic acid or carbonic acid,burial style,the abnormal high pore fluid pressure,early hydrocarbon charging,gyprock sealing,hot convective fluid flow and the mode of sand-mud interbedded,etc. The paleotectonics controls the burial style of sandstones,and the paleotemperature controls the diagenesis process. The sedimentary environment is the precondi-tion and foundation,the dissolution is the direct reason to generate the deep buried clastic eureservoir. The abnormal high pore fluid pressure,gyprock sealing,the mode of sand-mud interbedded,early hy-drocarbon charging and the structure fractures were the assistant factors of generating the deep buried clastic eureservoir.  相似文献   
8.
边缘型旅游地的开发建设是中国旅游业转型升级时代面临的重要命题。随着区域经济一体化的推进和消费者消费理念的转变,一些边缘型旅游地开始逐渐成长为区域旅游发展的"潜力区",研究空间与研究意义日益凸显。以具有典型边缘性特征的宣城市为实证,从区位空间、旅游资源、旅游形象、旅游交通和旅游经济等角度剖析其多重边缘化特征,探讨边缘化形成的主要机制。地处省际交界区、地域特征典型性不足是边缘化形成的自然诱因,周边核心旅游地遮蔽效应显著是边缘化形成的空间致因,经济支撑能力薄弱是边缘化形成的经济制因,政策惠及偏少是边缘化形成的人为促因。边缘型旅游地应实施多元比附、突出个性差异、完善要素建设的发展路径。  相似文献   
9.
To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea (ECS) shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector (BSR) occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural "anomalies" are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation:to help gather enough methane into a small area and to modulate the thermal regime.  相似文献   
10.
Onthespatialcharacteristicoftheshort┐termandimminentanomaliesofundergroundwaterbehaviorsbeforestrongearthquakeXUE-BINDU(杜学彬)...  相似文献   
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