西北高寒干旱区哈尔腾河流域植被覆盖变化及其对全球气候变化的响应     

何红  牛叔文  齐敬辉 《冰川冻土》2015,37(4):963-972

基于ArcGIS软件, 对哈尔腾河流域1990年、 2000年、 2010年3期Landsat5-TM遥感影像分6种土地覆盖类型进行解译. 结果表明: 近20 a来, 研究区无植被区面积呈净减少趋势, 减少 2 192.37 km²; 上游高海拔地区草地面积增加明显, 新增1 938.15 km², 新增面积约占流域总面积的10%, 哈尔腾河流域呈显著绿化趋势; 冰雪面积增加210.39 km², 主要是沿原有冰雪的前缘延伸. 各种覆盖类型之间的转换主要表现为无植被区向其他5种类型的转变, 反向转换则比较少; 三种草地之间的转换主要表现为由低向中、 高覆盖类型的转换. 气温的升高与降雨量的增加是该流域土地覆盖变化的主要影响因素. 气候变化明显改善了流域上游的植被覆盖, 但“引哈济党”工程调水1.0×10⁸ m³后将对流域下游大苏干湖的生态系统产生一定影响. 应未雨绸缪, 加强监测和评估.  相似文献   

风积沙对青藏铁路块碎石路基降温效果的影响   总被引：4，自引：4，他引：0  

陈琳  喻文兵  韩风雷  刘伟博  易鑫 《冰川冻土》2015,37(1):147-155

风沙危害正在威胁着青藏铁路的安全营运. 通过数值方法研究了风积沙填堵和覆盖青藏铁路块碎石路基后, 块碎石层降温机理以及降温效果的变化特征. 结果表明:开放条件下块石路基具有较强的强迫对流效应; 风积沙填堵后, 块碎石层降温效果减弱. 封闭条件下, 冷季路基坡脚处自然对流较强, 冻土上限抬升; 路基内部自然对流较弱, 由于路基填土作用, 路基中心处冻土上限抬升较大, 但随时间增长而降低; 沙层覆盖后, 块碎石层降温效果减弱, 路基下部冻土上限下降. 在气候变暖背景条件下, 封闭块碎石层自然对流减弱, 冻土上限下降, 不利于冻土路基的热稳定. 因此, 建议对沙害路段的块碎石路基采取补强措施.  相似文献   

Integrating hydrodynamic analysis of flow systems and induced-pressure decline at the Otway CO2 storage site to improve reservoir history matching     

《Marine and Petroleum Geology》2013

The CO2CRC Otway Project is the first demonstration scale project for geosequestration of CO₂ in Australia. The storage site is located in the depleted Waarre reservoir of the Naylor gas field contained within a single fault block, in the onshore Otway Basin of Victoria. During 2009, approximately 65,000 tonnes of a mixture of CO₂ and CH₄ (∼80%/20%) was injected into the reservoir, accumulating at the top of the structure.To fully understand the pressure response of a depleted reservoir to CO₂ injection all of the mechanisms that may impact the reservoir pressure, prior to injection, must be identified. In the case of the Otway Project there were five possible mechanisms with potential for impacting the Naylor Field pressure. These are (1) the rate of recovery due to gas production from the Naylor Field; (2) depletion from the nearby Boggy Creek CO₂ production field; (3) depletion from the nearby Buttress CO₂ Field, the source of the CO₂ for injection into the Naylor Field; (4) depletion from the regional Waarre Formation reservoir which has been producing gas (and water) since 1986; and (5) hydraulic potentiometric disequilibrium via connection to other active aquifers.These mechanisms were examined through a regional conceptual hydrodynamic model as part of the pre-injection site characterisation. The reservoir pressure measured at the Naylor-1 well, prior to production, was lower than predicted by the hydrodynamic model. Examination of regional drawdown demonstrated that the reservoir is experiencing pressure decline which could have extended to the Naylor Field at this time.Ongoing monitoring of the Naylor-1 well, prior to injection, showed the depleted reservoir recovering faster than predicted by the reservoir simulation model matched to the production history. Connecting the target fault block to the regional aquifer using a dual aquifer model supported by the hydrodynamic model significantly improved the predicted recovery of the depleted reservoir.  相似文献   

Early Stage Characteristics of Macro Engineering and Suggestions for the Taiwan Strait Tunnel Project     

《Marine Georesources & Geotechnology》2013,31(3-4):279-288

Taiwan Strait Tunnel (TST) is a Macro Engineering Project (MEP). Countries all over the world have accumulated much experience on MEPs. To study the early stage characteristics of MEPs would be significant for advancing the progress of TST project. This article summarizes some common characteristics in early stage of MEPs, such as Three Gorges, South-to-North Water Diversion, The Channel Tunnel, Confederation Bridge projects, and so on. Some suggestions on early stage development are given to TST project for reference.  相似文献   

MODIS大气产品的光合有效辐射估算研究   总被引：2，自引：0，他引：2  

陈卓奇  邵全琴  刘纪远  王军邦 《遥感学报》2012,16(1):25-37

利用气溶胶、水汽、云以及臭氧等MODIS标准大气产品,在简单辐射传输模型基础上估算青藏高原光合有效辐射,经验证估算的光合有效辐射与实测数据存在显著的线性相关,相关系数在0.8—0.9之间,最大误差为13%。经过敏感性分析发现云层厚度、气溶胶含量以及大气压力对光合有效辐射的影响大。臭氧和水汽含量的变化不敏感。云层厚度、Angstrom浑浊度系数和大气压力分别变化30%、25%和15%时,光合有效辐射变化分别为20%、5%和5%。  相似文献   

Future Teachers of Geography: Whose Opportunity?     

《The Journal of geography》2012,111(5):487-494

Abstract

Although geography is being revived in the K-12 curriculum, preservice teachers—candidates for the teaching profession—now in our universities are not universally reaping the benefits of cooperative efforts of geography and college of education faculty. Reform is appropriate in both camps. Colleges of education, influenced by many agents, including Certificate/licensing regulations, accrediting agencies, professional organizations, and a stream of reform movements, are bringing education to the level of a true profession. The dimensions of the reform underway and several key players offer great opportunities for geography education and for improving the general climate for teaching excellence in institutions of higher learning. Candidates for the new teaching profession and their education faculty are teaching and learning collaboratively, and conducting research in diverse school districts. Geographers have new reasons and new opportunities to participate in the education of the geography teachers of tomorrow.  相似文献   

青藏高原少数民族地区特色城镇化动力机制分析——以环青海湖地区为例   总被引：1，自引：0，他引：1  

丁生喜  王晓鹏 《地域研究与开发》2012,31(1):65-69

通过调查青藏高原环青海湖少数民族地区城镇化发展现状,揭示西部大开发以来该区域城镇化的动力机制的多元性、独特性:特色产业发展是城镇化的重要推动力量;农牧民改善生活方式、改变就业现状、提高受教育水平的意愿是该区域城镇化的新动因;政府的相关政策对城镇化有明显的推动作用;生态环境对该地区城镇化发展也有特殊要求.结合环青海湖少数民族地区城镇化开发的环境分析,阐明该区域城镇化发展的优势与劣势,以及城镇化面临的机遇与威胁.针对特有的城镇化动力机制,提出环青海湖少数民族地区城镇化发展思路.  相似文献   

青藏高原东北侧雷电气候特征     

黄涛  王让会  王润元 《南京气象学院学报》2012,4(2):151-156

选取了青藏高原东北侧临夏站1980—2010年的雷暴观测资料和陇中地区闪电定位仪2006—2010年的闪电观测资料,利用统计学手段对该地区雷电的年际变化、年变化、日变化、首次发生雷暴方向、地闪密度等进行了分析.基本揭示了该地区雷电的发生特征,发现一年中雷电主要发生在夏季,一天中雷电主要发生在下午及傍晚,地闪密度高于中国平均密度.对该地区雷电灾害防灾减灾工作有一定的促进意义.  相似文献   

青藏高原草地生态系统碳收支研究进展   总被引：7，自引：3，他引：4  

王军邦  黄玫  林小惠 《地理科学进展》2012,31(1):123-128

陆地生态系统碳收支仍然是当前全球气候变化研究的重要内容,青藏高原作为全球气候变化的敏感区,使青藏高原草地生态系统在区域碳收支平衡中占有主导地位,但研究方法等不同使得碳收支估算结果存在很大的不确定性。气候变暖在一定程度上提高了高寒草地生态系统的植被初级生产力和生物量,由此补偿了气候变暖导致的土壤有机碳分解释量,使青藏高原草地植被仍然发挥着碳汇的功能。而人类放牧活动对草地生态系统的影响较为复杂。因此,如何区分气候变化和人类活动对生态系统的影响机制,定量评价未来气候变化和人类活动影响下,青藏高原生态系统碳源/汇格局的可能变化,是一个非常重要的研究方向,也是一个极大的挑战。  相似文献   

Influence of the Three Gorges Project on saltwater intrusion in the Yangtze River Estuary   总被引：3，自引：0，他引：3  

Qiang An  Yanqing Wu  Shauna Taylor  Bin Zhao 《Environmental Geology》2009,56(8):1679-1686

The Three Gorges Project (TGP) is a transcentury project that has aroused world attention. It is expected that the flow velocity and runoff of the Yangtze River will be changed after the project has been accomplished. Consequently, however, the ecological environment in the Yangtze River Basin, particularly in the estuary region, will be affected. Salinity intrusion into the Yangtze River estuary, in general, is mostly affected by the Yangtze River discharge and its external tidal level. This paper focuses on examining the influence of changes in runoff on salinity value. The question, to which should be paid attention is: how is the interaction between changes in runoff of the Yangtze River and salinity distribution in the Yangtze River estuary, China? In this research, a three-dimensional model has been used to identify the effects of runoff change on salinity distribution. The drawn conclusion is that the change of salinity is influenced by discharge variation. Positive and negative impacts of TGP would both turn up but in different period. In sum, TGP is in favor of restraining saltwater intrusion. Nevertheless a suitable method should be found to resolve its negative influences.  相似文献