南疆西部山区一次特大暴雨特征分析     

胡翠珍 《沙漠与绿洲气象(新疆气象)》2002,25(3):9-11

通过对2001年9月22－23日南疆西北部山区特大暴雨的环流背景、物理量场、卫星云图分析，揭示了这场特大暴雨的物理机制和各要素场特征。  相似文献   

1999年杭嘉湖平原一次连续暴雨过程诊断分析   总被引：1，自引：1，他引：1       下载免费PDF全文

郭可义  盛文斌 《应用气象学报》2002,13(6):696-703

用新的曲面拟合法(NMOCSF)对江淮和杭嘉湖平原一次连续暴雨过程作物理诊断，结合天气形势讨论了准静止华北高压的形成及其对江淮和杭嘉湖平原连续暴雨的贡献。指出，当江淮和杭嘉湖平原处在梅雨期时，应特别注意华北高压的强度和位置，一旦构成阻塞形势，就极可能发生大范围、持续性的强降水过程。  相似文献   

An integrated hydrological model for rain‐induced landslide prediction     

P. L. Wilkinson  M. G. Anderson  D. M. Lloyd 《地球表面变化过程与地形》2002,27(12):1285-1297

This paper describes an extension to the Combined Hydrology And Stability Model (CHASM) to fully include the effects of vegetation and slope plan topography on slope stability. The resultant physically based numerical model is designed to be applied to site‐specific slopes in which a detailed assessment of unsaturated and saturated hydrology is required in relation to vegetation, topography and slope stability. Applications are made to the Hawke's Bay region in New Zealand where shallow‐seated instability is strongly associated with spatial and temporal trends in vegetation cover types, and the Mid‐Levels region in Hong Kong, an area subject to a variety of landslide mechanisms, some of which may be subject to strong topographic control. An improved understanding of process mechanism, afforded by the model, is critical for reliable and appropriate design of slope stabilization and remedial measures. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

初论古文化类型演替与传承模式的区域分异——以西拉沐沦河流域和汶泗流域为例   总被引：6，自引：0，他引：6       下载免费PDF全文

崔之久  杨晓燕  夏正楷 《第四纪研究》2002,22(5):434-441

西拉沐沦河流域地处中国地貌大势三大台阶之中台阶与低台阶的过渡区。该区的中度抬升和下切,造成了西拉沐沦河流域考古文化遗址在空间上的垂向迁移;频繁的迁移也导致了考古遗址在堆积形态上主要表现为单一型,体现了不同考古文化之间“间断”的,不稳定的传承方式。位于中国地貌大势之低台阶上的汶泗流域,属自下古生代以来就十分稳定的剥蚀区,这些自然条件造成了汶泗流域遗址在堆积形态上主要表现为叠置型,考古文化在时空上,很少随着时间做空间上的改变,基本上在同一水平空间稳定不动,体现了不同考古文化之间“连续”、稳定的传承方式。两个流域的对比研究说明,不同地域、不同的自然条件,可以造成考古文化演替与传承模式的区域分异  相似文献   

An Agricultural Land Resource Assessment Study Based on GIS—An Example from Guiyang City     

刘建军  李春来  万鹰昕 《中国地球化学学报》2002,21(1):79-88

This paper assesses the agricultural land resources of Guiyang City by means of GIS,on the basis of the pressure-state-response model in which soil heavy metal contamination is selected as a pressure indicatror.he results suggest that most of the agricultural land resources are of good quality,However,there are 17.11km^2 dry land and paddy field,which belong to the region of serious heavy metal contamination and are not fit for planting crops.At the same time,the high quality plowland,which is suitable for cultivation,has decreased nearly by 1/3 due to soil heavy metal contamination.These findings may improve our understanding that it is very important to prevent and cure heavy metal contamination of Guiyang City.  相似文献   

Momentum transport of wave zero during March: A possible predictor for the Indian summer monsoon     

S. M. Bawiskar  V. R. Mujumdar  S. S. Singh 《Journal of Earth System Science》2002,111(2):153-157

Analysis of monthly momentum transport of zonal waves at 850 hPa for the period 1979 to 1993, between ‡S and ‡N for January to April, using zonal (u) and meridional (v) components of wind taken from the ECMWF reanalysis field, shows a positive correlation (.1% level of significance) between the Indian summer monsoon rainfall (June through September) and the momentum transport of wave zero TM(0) over latitudinal belt between 25‡S and 5‡N (LB) during March. Northward (Southward) TM(0) observed in March over LB subsequently leads to a good (drought) monsoon season over India which is found to be true even when the year is marked with the El-Nino event. Similarly a strong westerly zone in the Indian Ocean during March, indicates a good monsoon season for the country, even if the year is marked with El-Nino. The study thus suggests two predictors, TM(0) over LB and the strength of westerly zone in the Indian Ocean during March.  相似文献   

Variabilité isotopique des précipitations sahéliennes à différentes échelles de temps à Niamey (Niger) entre 1992 et 1999 : implication climatiqueIsotopic variability of Sahelian rainfall at different time steps in Niamey (Niger, 1992–1999): climatic implications     

Jean-Denis Taupin  Gaëlle Gaultier  Guillaume Favreau  Christian Leduc  Christelle Marlin 《Comptes Rendus Geoscience》2002,334(1):43-50

The isotopic content of rainfall was measured in Niamey (Niger) over a period of eight years (1992–1999). Seasonal distribution of rainy events depends on the monsoon movement over the region. At the beginning and at the end of the rainy season, low rainfall, high temperatures and low relative humidity favour isotopic enrichment. In the middle of the rainy season, heavy rainfall, low temperatures and relative humidity close to saturation lead to isotopically depleted contents because of the mass effect; moreover, in the case of low rainfall, marked vertical convective development favours high altitude condensation. How far the Intertropical Front moves north, determines the quality of the rainy season and influences the isotopic contents. Thus the isotopic contents of rainfall are good climatic indicators. To cite this article: J.-D. Taupin et al., C. R. Geoscience 334 (2002) 43–50  相似文献   

Vegetation influences on water yields from grassland and shrubland ecosystems in the Chihuahuan Desert     

Mel Neave  Athol D. Abrahams 《地球表面变化过程与地形》2002,27(9):1011-1020

This study examines runoff generated under simulated rainfall on Summerford bajada in the Jornada Basin, New Mexico, USA. Forty‐five simulation experiments were conducted on 1 m² and 2 m² runoff plots on grassland, degraded grassland, shrub and intershrub environments located in grassland and shrubland communities. Average hydrographs generated for each environment show that runoff originates earlier on the vegetated plots than on the unvegetated plots. This early generation of runoff is attributed to soil infiltration rates being overwhelmed by the rapid concentration of water at the base of plants by stemflow. Hydrographs from the degraded grassland and intershrub plots rise continuously throughout the 30 min simulation events indicating that these plots do not achieve equilibrium runoff. This continuously rising form is attributed to the progressive development of raindrop‐induced surface seals. Most grassland and shrub plots level out after the initial early rise indicating equilibrium runoff is achieved. Some shrub plots, however, display a decline in discharge after the early rise. The delayed infiltration of water into macropores beneath shrubs with vegetation in their understories is proposed to explain this declining form. Water yields predicted at the community level indicate that the shrubland sheds 150 per cent more water for a given storm event than the grassland. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

SIMULATION OF HEAVY RAINFALL IN THE SUMMER OF 1998 OVER CHINA WITH REGIONAL CLIMATE MODEL   总被引：11，自引：0，他引：11  

刘一鸣  丁一汇 《Acta Meteorologica Sinica》2002,(3)

The heavy rainfall in the summer of 1998 over China has been simulated with the NCCRegional Climate Model(RegCM_NCC).It was successful for RegCM_NCC to reproduce thelocation and seasonal shift of the seasonal rain belt in the summer of 1998 over China.The rainyseason in the summer of 1998 over China can be divided into 7 episodes,including the pre-summerrainy season in South China.the Meiyu onset over the Yangtze-Huaihe River Basin,shortappearance of North China rain season and the retreat of seasonal rain belt,the second Meiyuseason over the Yangtze River Valley,the rainy period over the Yellow and Huaihe River Valleyand the seasonal retreat of rain belt over North China.The shortcoming of the RegCM_NCC isover-estimation of precipitation amounts.The regions with large latent heat flux,upper soilmoisture and total runoff are located in the rainy area and move with the simulated rain belt duringthe different episodes.On the contrary,the regions with small sensible heat flux are located in thesimulated rainy area and move with the simulated rain belt during the different episodes.  相似文献   

黄河中游降雨特性对泥沙粒径的影响   总被引：6，自引：3，他引：6  

卢金发  刘爱霞 《地理科学》2002,22(5):552-556

以黄河中游36个有泥沙粒径资料的水文测站流域为样本，在不同自然地理类型流域划分的基础上，建立了流域泥沙粒径特片与降雨特性的关系。结果表明，在不同类型流域，流域泥沙的粗细与降雨季节性变率和年际变率之间存在着相当好的线性正相关关系；而与年降雨量和降雨不均匀系数之间呈明显的非线性关系。流域地面物质、植被和地貌发育程序等下垫面环境因素对泥沙粒径特性与降雨特性之间关系起着十分重要的控制作用。不同类型流域曲线的斜率各不相同，在图中所处的位置也不相同。  相似文献