青藏高原积雪的分布特征及其对地面反照率的影响   总被引：7，自引：3，他引：7  

韦志刚  吕世华 《高原气象》1995,14(1):67-73

通过对１９８３年７月至１９９０年６月青藏高原主体５８个格点积雪资料进行ＥＯＦ分析发现，青藏高原主体积雪分布以西部兴都库什山脉。天山山脉以及南部喜马拉雅山脉为主；高原中部唐古拉山脉、北部昆仑山脉和东部巴颜喀拉山脉的积雪相对较少，青藏高原西部、南部的积雪变化与中部、北部和东部的积雪变化趋势存在反位相关系。另外，本文还对积雪对高原地面反照率的影响作了简单分析。  相似文献   

云南省40年降水的基本特征   总被引：5，自引：0，他引：5  

缪启龙  肖伟 《气象科学》1995,15(3):293-299

根据云南省１９５１－１９９０年１８个站的降水资料，用正交函数展开，由方差贡献最大的前三个特征向量场分析了云南省降水距平均的典型分布，指出云南省全省范围内的降水距平同号较少发生，而是较多的发一降水距平异号。进而分析了四十年降水的年际变化特征，并分析了青藏高原积雪对云南降水的影响。  相似文献   

新疆积雪对气候变暖的响应   总被引：38，自引：1，他引：38  

李培基 《气象学报》2001,59(4):491-501

积雪对全球变暖的响应是当前正在争论的问题。文中通过地面气象台站和 SMMR微波卫星遥感两种积雪资料所建立的两个独立的积雪序列的一致性 ,证明前者在表现新疆积雪长期变化能力方面具有可靠性。阐明了积雪年际变化特征及其与冬季气温和降水量年际波动的关系 ,检验了积雪长期变化趋势。研究表明 ,虽然近 5 0 a来新疆冬季变暖十分显著 ,尤其 2 0世纪 90年代为最温暖的时期 ,但是积雪并未出现持续减少的现象 ;积雪长期变化表现为显著的年际波动过程叠加在长期缓慢的增加趋势之上。积雪年际波动是冬季降水量和气温两者年际波动共同作用的结果 ;冬季气温和降雪量变化受不同的欧亚环流振荡所控制 ;积雪增加趋势与降雪量趋势相一致 ,这可能是由于全球变暖导致海洋蒸发量增加 ,以及在寒冷干燥气候下积雪对降雪量变化更为敏感的缘故。  相似文献   

陆面过程模式研究简评   总被引：11，自引：2，他引：11  

史学丽 《应用气象学报》2001,12(1):102-112

主要总结了陆面过程模式的发展状况, 对一些国际间合作进行的计划、试验成果以及我国在这方面的研究情况加以介绍和评述, 最后给出陆面模拟研究中存在的难点、问题及可能的解决途径.  相似文献   

Natural hazards in British Columbia: an interdisciplinary and inter-institutional challenge     

O. Slaymaker 《International Journal of Earth Sciences》1999,88(2):317-324

 Although British Columbia experiences many natural hazards, there is as yet no unified policy to promote natural hazard management in the province. The problem is not in the quantity and quality of geoscience assessment of natural hazards, but instead, it is suggested, in the isolation of that work from broader risk perspectives and in the lack of clarity of division of responsibilities between various levels of government. The example of recent changes in perception of the terrain stability problem illustrates how natural hazard problems are driven by social and political priorities rather than by geoscience priorities. Received: 22 November 1998 / Accepted: 22 November 1998  相似文献   

Mapping runoff generating areas using AGNPS-VSA model     

Kishor Panjabi  Pradeep Goel  Prasad Daggupati  Narayan Kumar Shrestha  Rituraj Shukla 《水文科学杂志》2020,65(13):2224-2232

ABSTRACT

In humid regions, surface runoff is often generated by saturation-excess runoff mechanisms from relatively small variable source areas (VSAs). However, the majority of the current hydrologic models are based on infiltration-excess mechanisms. In this study, the AGricultural Non-Point Source Pollution (AGNPS) model was used to integrate the VSA concept using topographic wetness index (TWI). Both the original and AGNPS-VSA models were evaluated for a small agricultural field in Ontario, Canada. The results indicate that the AGNPS-VSA model performed better than original model. The AGNPS-VSA model predicted that only the saturated portion of the field with higher TWI values produced runoff, whereas the original AGNPS model showed uniform hydrologic response from the entire field. The results of this study are important for accurately mapping the locations of VSAs. This new model could be a powerful tool in identifying critical source areas for applying targeted best management practices to minimize pollutant loads to receiving waters.  相似文献   

高原季风强弱对南亚高压活动的影响   总被引：17，自引：10，他引：7  

马振锋 《高原气象》2003,22(2):143-146

分析了高原季风强弱对夏季南亚高压活动和三峡库区旱涝的影响,揭示了如高原夏季风偏强(弱),育藏高原上空及其以东地区100hPa南亚高压也偏强(弱),位置偏北偏东(偏南偏西)。高原季风强年,南亚高压脊线6月北跳比多年平均早1候,8月南撤晚1～2侯;高原季风弱年。脊线北跳晚1～2候,南撤早1候。同时显示了高原夏季风强年,5～6月三峡库区降水随着南亚高压脊线北移而增多,7～8月三峡库区降水减少;高原夏季风弱年,主汛期前期库区降水少,后期降水略有增多。  相似文献   

Space-time soil wetness variations monitoring by a multi-temporal microwave satellite records analysis     

T. Lacava  E.V. Di Leo  V. Tramutoli 《Physics and Chemistry of the Earth》2006,31(18):1274-1283

In the last few years, remote sensing observations have become a useful tool for providing hydrological information, including the quantification of the main physical characteristics of the catchment, such as topography and land use, and of its variables, like soil moisture or snow cover. Moreover, satellite data have also been largely used in the framework of hydro-meteorological risk mitigation.Recently, an innovative Soil Wetness Variation Index (SWVI) has been proposed, using data acquired by the microwave radiometer AMSU (Advanced Microwave Sounding Unit) which flies aboard NOAA (National Oceanic and Atmospheric Administration) satellites.SWVI is based on a general approach for multi-temporal satellite data analysis (RAT - Robust AVHRR Techniques). This approach exploits the analysis of long-term multi-temporal satellite records in order to obtain a former characterization of the measured signal, in term of expected value and natural variability, providing a further identification of signal anomalies by an automatic, unsupervised change-detection step. Such an approach has already demonstrated, in several studies carried out on extreme flooding events which occurred in Europe in the past few years, its capability in reducing spurious effects generated by natural/observational noise. In this paper, the proposed approach is applied to the analysis of the flooding event which occurred in Europe (primarily in NW Spain) in June 2000. Results obtained, in terms of reliability as well as efficiency in space-time monitoring of soil wetness variation, are presented. Future prospects, in terms of exportability of the methodology on the new dedicated satellite missions, like ESA-SMOS and NASA-HYDROS, are also discussed.  相似文献   

“地气图”方法用于省级旱涝预测的实践     

郭维栋  赵红岩  李栋梁  郭英香 《干旱气象》1998,(4)

简要介绍用“地气图”方法进行降水预测的基本思路,总结此方法的预报实践,指出省级尺度旱涝预测需要解决的几个关键问题,强调除加密观测外,上游地热涡增强的能量频散作用是下游地热涡发展的重要原因  相似文献   

Spatial and seasonal variation of major ions in Himalayan snow and ice: A source consideration   总被引：2，自引：0，他引：2  

Ya-ping Liu  Zhi-xing Geng  Shu-gui Hou   《Journal of Asian Earth Sciences》2010,37(2):195-205

The spatial and temporal variation of major ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, , , and Cl⁻) in Himalayan snow and ice is investigated by using two snow pits from the East Rongbuk glacier (28°01′N, 86°58′E, 6500 m a.s.l.), one snow pit from the Nangpai Gosum glacier (28°03′N, 86°39′E, 5700 m a.s.l.), one snow pit from the Gyabrag glacier (28°11′N, 86°38′E, 6303 m a.s.l.), and three ice cores from the Sentik (35°59′N, 75°58′E, 4908 m a.s.l.), Dasuopu (28°33′N, 85°44′E, 7000 m a.s.l.), and East Rongbuk (27°59′N, 86°55′E, 6450 m a.s.l.) glaciers, respectively. In general, the major ions show a significant seasonal variation, with high concentrations during the non-monsoon (pre-monsoon and post-monsoon) season and relatively low concentrations during the monsoon season. Monsoon precipitation with high local/regional dust loading related to summer circulation is possibly responsible for the high concentrations occurring sporadically during the monsoon season. The crest of the Himalayas is an effective barrier to the spatial distribution of Na⁺, Cl⁻ and concentrations, but not to the major ions associated with dust influx (e.g. Ca²⁺ and Mg²⁺). Atmospheric backward trajectories from the HYSPLIT_4 model used in identifying chemical species sourcing suggest that the major ions in the Himalayan snow and ice come mainly from the Thar Desert located in the North India, as well as West Asia, or even the distant Sahara Desert in the North Africa during the winter and spring seasons. This is different from the conventionally assumed arid and semi-arid regions of the central Asia. Factors, such as different vapor sources due to atmospheric circulation patterns and geographical features (e.g. altitude, topography), may contribute to the differences in major ionic concentrations between the western and eastern Himalayas.  相似文献