中尺度灾害天气分析与预报系统综合显示平台   总被引：1，自引：1，他引：0       下载免费PDF全文

高梅  倪允琪  张文华  李丰  接连淑  李红莉 《应用气象学报》2011,22(5):621-630

中尺度灾害天气分析与预报系统(Meso-Weather Analysis and Forecasting System,简称MWAFS)是集成了国家重大科研项目产出的有关中尺度灾害天气研究成果以及气象行业关键的业务产品,综合应用计算机网络、地理信息系统、数据库以及气象专业分析模型等信息处理技术建立的一个能快速、有效地监...  相似文献   

不同卫星遥感干旱指数在黑龙江的对比应用   总被引：3，自引：0，他引：3       下载免费PDF全文

于敏  王春丽 《应用气象学报》2011,22(2):221-231

采用MODIS的1 km×1 km分辨率数据,以我国黑龙江为研究区,对基于植被指数的植被状态指数 (I_VC)、基于地表温度的温度状态指数 (I_TC) 和基于植被指数-地表温度特征空间的植被温度状态指数 (I_VTC) 与10 cm,20 cm土壤相对湿度、降水量的关系、3种指数监测结果及其相互关系进行了对比分析。结果表明:I_VTC相对于I_TC,I_VC更适于反映土壤湿度的变化,对浅层土壤湿度更加敏感;I_VTC相对于I_TC,I_VC对降水更敏感,与监测时段的降水和前期总体降水都密切相关;在生长季早期,I_VTC和I_TC用于干旱监测的适用性明显优于I_VC;不同区域间,I_VTC的可比性较好,I_VC和I_TC则较差;I_VTC所反映的地表温度信息对干旱的直接指示作用最强,所反映的植被信息对干旱的直接指示作用较弱。  相似文献   

太湖水量平衡影响因素分析及误差控制措施研究   总被引：2，自引：1，他引：1  

申金玉  石亚东  高怡  莫李娟  陈润 《水文》2011,31(3):60-63

本文在搜集2001~2008年太湖水量平衡中各个计算要素的基础上,分析计算太湖水量平衡的绝对误差及相对误差。究其原因,误差产生的影响因素主要有测验手段、风浪、巡测线内的产流、农业用水等。根据对影响因素分析,本文有针对性地提出了误差控制措施,重点是要加强测验手段及频次,从而减小水量平衡误差,为太湖水量分配方案提供更加精准的数据基础和依据。  相似文献   

山洪灾害监测雨量站网密度分析探讨   总被引：1，自引：1，他引：0  

舒大兴  韩金山 《水文》2011,31(5):64-67

暴雨是诱发山洪的主要原因,雨量监测站网的布设至关重要。本文采用抽站法和流域水文模型法对江西遂川江流域雨量站网密度进行了分析研究,得出允许误差控制下的最少监测站数量。对比分析站网密度公式计算结果,大流域内的子流域区划对雨量站数量有很大影响。综合考虑流域特征、地形起伏及流域内人口密度、社会经济水平等因素修正的站网密度公式,为无资料地区山洪监测预警系统建设提供参考。  相似文献   

Conservation planning, boundary-making and border terrains: The desire for forest and order in the Gran Sabana, Venezuela     

Bjørn Sletto 《Geoforum》2011,42(2):197-210

Conflicts surrounding protected area management often emerge from contested processes of boundary-making. Such productions of bounded conservation spaces are contingent in part on processes of identity formation, where some social groups are legitimized as belonging to conservation units, while others are constructed as out-of-place. This article draws on the literature in postmodern geopolitics and the political ecology of fire to interrogate processes of boundary-making and identity formation in the savanna landscape of Canaima National Park, Venezuela. The institutional culture of the environmental management agency EDELCA is in part premised on narratives of history and indigeneity coupled with a desire for an imagined, forested landscape. Because of the social constructions shaping this institutional culture, the agency maintains an approach to fire management that emphasizes fire suppression. However, an ecological field study suggests that fire suppression is leading to increased fuel loads, especially in ecologically significant boundaries between grasslands and forest. Although these boundary zones are the focus of indigenous practices of prescribed burning, they fall in-between the state management categories of forest and ecotone. As a result, these interstitial spaces become theaters for performances of domination and resistance, leading to contradictory and inconsistent approaches to fire management that place gallery forests at risk.  相似文献   

Forest–savanna–morichal dynamics in relation to fire and human occupation in the southern Gran Sabana (SE Venezuela) during the last millennia     

Encarni Montoya  Valentí Rull  Nathan D. Stansell  Mark B. Abbott  Sandra Nogué  Broxton W. Bird  Wilmer A. Díaz 《Quaternary Research》2011,76(3):335-344

The southern Gran Sabana (SE Venezuela) holds a particular type of neotropical savanna characterized by the local occurrence of morichales (Mauritia palm swamps), in a climate apparently more suitable for rain forests. We present a paleoecological analysis of the last millennia of Lake Chonita (4°39′N–61°0′W, 884 m elevation), based on biological and physico-chemical proxies. Savannas dominated the region during the last millennia, but a significant vegetation replacement occurred in recent times. The site was covered by a treeless savanna with nearby rainforests from 3640 to 2180 cal yr BP. Water levels were higher than today until about 2800 cal yr BP. Forests retreated since about 2180 cal yr BP onwards, likely influenced by a higher fire incidence that facilitated a dramatic expansion of morichales. The simultaneous appearance of charcoal particles and Mauritia pollen around 2000 cal yr BP supports the potential pyrophilous nature of this palm and the importance of fire for its recent expansion. The whole picture suggests human settlements similar to today – in which fire is an essential element – since around 2000 yr ago. Therefore, present-day southern Gran Sabana landscapes seem to have been the result of the synergy between biogeographical, climatic and anthropogenic factors, mostly fire.  相似文献   

三轴压缩条件下基于CT实时监测的冻结兰州黄土细观损伤变化研究   总被引：4，自引：3，他引：1  

郑剑锋  马巍  赵淑萍  蒲毅彬 《冰川冻土》2011,33(4):839-845

在IMPa围压下,对不同温度条件下的冻结兰州黄土三轴压缩试验过程进行CT动态扫描,获得了由CT数表示的土体损伤量表达式．结果表明：冻结兰州黄土最初在围压作用下,试样沿径向方向被压缩,导致试样轴向伸长;低温冻结试样的弹性变形持续时间长于高温试样,如-2．3℃试样在应变达到0．32％时即开始屈服进入塑性变形,而-7℃试样的...  相似文献   

新厝公路拓宽工程软土路基施工监测分析     

郭锡斌 《福建地质》2011,30(4):352-356

福清新厝公路拓宽海堤段海堤内侧采用分级加载进行路基施工填筑软基加例处理,通过3个断面监测数据分析,最大水平位移日变量为2．28mm／d,最大沉降速率为5．97nm/d,各测点的沉降速率和水平位移均在安全控制范围之内。至监测末期最大总沉降量占淤泥层厚度7％,海堤地基固结度76．3％～85．0％,但尚有10．9～15．8m...  相似文献   

古火灾历史重建的研究进展     

占长林  曹军骥  韩永明  安芷生 《地球科学进展》2011,26(12):1248-1259

火是地球系统的重要组成部分,与气候、植被、生物地球化学循环和人类活动密切相关。火对全球气候和生态系统的影响已成为目前全球变化研究的一个热点。火灾发生后会在周围的环境中留下许多燃烧产物,如黑碳、木炭屑、多环芳烃、左旋葡萄糖等,它们广泛存在于海洋、湖泊、河流、土壤和陆地风成沉积物中;还会留下一些火灾痕迹,如树木火疤、土壤磁...  相似文献   

“井水不犯河水”水文地质学含义初步探讨   总被引：1，自引：0，他引：1  

刘元章  武强  刘久荣  林沛  邢立亭  刘守强 《地下水》2011,(6):122-127

利用水化学及同位素水文地质学的方法,对密云水库、潮白河及位于潮白河边的2个地下水分层专门监测井进行取样测试,并结合收集相关资料,从水位、水质及氚、氘、氧-18等同位素方面进行分析研究,对中国古语“井水不犯河水”的水文地质学方面的含义进行了一定的微观层次的分析探讨.得出研究点处潮白河水对50 m外的25 m深的浅井井水有...  相似文献