杭州市区春节期间空气质量变化特点   总被引：11，自引：0，他引：11       下载免费PDF全文

洪盛茂 何曦祁国伟  孙鸿良王晓熊  陈超徐鸿 《气象科技》2003,31(6):340-344

分析近3年春节期间的空气质量资料，结果表明，杭州市区环境空气中PM10、SO2、NO2浓度较高，烟花爆竹燃放期间3种污染物出现高峰值，这与烟花爆竹燃放有关，PM25／PM10的比值高于年均值。  相似文献   

斜向坡变形破坏机制的数值模拟研究   总被引：3，自引：0，他引：3  

孔红月  尚岳全 《地质灾害与环境保护》1996,7(1):47-54

本文讨论了斜向坡的旋转式变形和破坏机制，用有限元法计算了此种斜坡中的剩余下滑力的分布方式，并以此来解释在滑动过程中发生一定旋转的原因；论文还运用离散元法，模拟了此种滑坡的滑动过程。  相似文献   

某滑坡区滑带土工程地质特性研究   总被引：5，自引：0，他引：5  

刘耀涛  邓荣贵 《地质灾害与环境保护》1996,7(2):6-11

本文论述了某滑坡滑带土的工程地质特性及其滑坡稳定性的影响，为滑坡的合理整治提供了依据。  相似文献   

滑坡时间预报的费尔哈斯反函数模型法   总被引：7，自引：0，他引：7  

李天斌  陈明东 《地质灾害与环境保护》1996,7(3):13-17

费尔哈斯模型是德国生物学家费尔哈斯１９３７年提出的一种生物增长模型。本文利用这一模型的反函数来拟合和描述边坡变形特征，建立了滑坡时间的预报判据和预报模型。  相似文献   

边坡变形系统失稳控制因素研究   总被引：3，自引：0，他引：3  

王来贵  黄润秋 《地质灾害与环境保护》1997,8(2):26-30

通过对顺层变形几何非线性和连续变形物理非线性边坡模型的讨论，建立了边坡为形系统失稳的条件，找出影响系统稳定性的控制变量，并就控制变量的因素进行探讨，提出了人为调整控制变量，来防止边坡系统失稳措施的设想。  相似文献   

Meteorological Office, Pune-411 005     

U. S. De  Medha Khole  M. M. Dandekar 《Natural Hazards》2004,31(2):487-497

Natural disasters like floods, tornadoes, tropicalcyclones, heat and cold wavewreak havoc and cause tremendous loss ofproperty all over the world. Most ofthe natural disasters are either dueto weather or are triggered due toweather related processes.Extreme weather events claimed thousands oflives and caused damage on vastscale. Recent super cyclone which affectedOrissa in 1999, Bangladesh cyclone of1970 and Hurricane Andrew in 1992 areexamples of some of the more damagingtropical cyclones which affected developingas well as the developed world. Heatand cold waves are also extreme events,which cause enormous losses in terms oflives lost and human discomfort and ailmentsarising out of them. The heat waveof 1995 and 1998 are still fresh in the mindof the Indian public. The estimated lossof human lives due to heat wave in 1998 was morethan 15,000. Economic losses asa result of these disasters and in particular inassociation with tropical cyclones haveincreased enormously over the last three decades.During 1961–1991, total loss oflives from drought alone was 1,333,728 overthe whole world. In terms of economiclosses, there is 8–10 fold increase from thebase figure of 1960. The socio-economicimpact of natural disaster is complex dependingupon the vulnerability of the placeand mitigation strategies that are put in place.Meteorology plays a crucial role in forewarningpeople about the severe/extremeweather systems and a constant endeavour by themeteorological services worldover has gone a long way towards minimizing thelosses caused by natural disasters.The paper summarises the natural disasterstatistics over south Asia and the possibleprediction strategies for combating theirsocio-economic impacts.  相似文献   

Data driven bivariate landslide susceptibility assessment using geographical information systems: a method and application to Asarsuyu catchment, Turkey   总被引：27，自引：0，他引：27  

Mehmet Lütfi Süzen  Vedat Doyuran 《Engineering Geology》2004,71(3-4):303-321

In the last decades, landslide hazard assessment has attracted many researchers' attention. A number of parameters are suggested to be responsible to quantitatively explain the mechanism of landslides; many of these parameters are very important and factual. However, some data types and models are site-specific and could not be applied to different locations. Furthermore, the data stored in continuous parameter maps are divided into a number of classes arbitrarily, depending on the vision of the expert. Basically, this division controls the result of bivariate analysis. Besides, the responsible portion of the parameter map controlling the mechanism is also weighted arbitrarily. Based on these two facts, the class boundaries put a prejudice on the produced susceptibility/hazard maps, which result in dependence on the knowledge of the user rather than being dependent on the data and the fact itself. The aim of this study is to refine the previously defined methods in a more data-dependent trend. To achieve this goal, two new concepts: seed cells and percentile maps are introduced. Seed cells are the zones that are considered to represent the best undisturbed morphological decision rules (conditions before landslide occurs) and would be achieved by adding a buffer zone to the crown and flank areas of the landslide. To quantitatively classify the input parameter maps, the data distributions of seed cells in the parameter maps are divided into a number of classes on the basis of their distribution's percentile break-points upon which the parameter maps are directly dependent on the seed cell distributions, hence to the data itself.  相似文献   

Determination and application of the weights for landslide susceptibility mapping using an artificial neural network   总被引：38，自引：0，他引：38  

Saro Lee  Joo-Hyung Ryu  Joong-Sun Won  Hyuck-Jin Park 《Engineering Geology》2004,71(3-4):289-302

The purpose of this study is the development, application, and assessment of probability and artificial neural network methods for assessing landslide susceptibility in a chosen study area. As the basic analysis tool, a Geographic Information System (GIS) was used for spatial data management and manipulation. Landslide locations and landslide-related factors such as slope, curvature, soil texture, soil drainage, effective thickness, wood type, and wood diameter were used for analyzing landslide susceptibility. A probability method was used for calculating the rating of the relative importance of each factor class to landslide occurrence. For calculating the weight of the relative importance of each factor to landslide occurrence, an artificial neural network method was developed. Using these methods, the landslide susceptibility index (LSI) was calculated using the rating and weight, and a landslide susceptibility map was produced using the index. The results of the landslide susceptibility analysis, with and without weights, were confirmed from comparison with the landslide location data. The comparison result with weighting was better than the results without weighting. The calculated weight and rating can be used to landslide susceptibility mapping.  相似文献   

孟湾槽在百色市异常降雪天气中的作用     

邓海光  唐毓勇 《云南地理环境研究》2004,(Z1)

通过对1983年12月28日、2002年12月26日百色市两次异常降雪天气过程的对比分析,发现冬季孟加拉湾槽的发展东移在其中起到了关键性的作用。由于孟加拉湾槽前暖湿气流强盛,这种强盛的西南暖湿气流在低空冷空气堆(冷锋)上发生强烈的系统性上升运动,从而导致百色市及其邻近地区出现异常的雨雪天气。  相似文献   

Correlation distance of waveforms for closely located events—I. Implication of the heterogeneous structure around the source region of the 1995 Hyogo-Ken Nanbu, Japan, earthquake (M_w= 6.9)     

Hisashi Nakahara 《Geophysical Journal International》2004,157(3):1255-1268

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