Feasibility Comparison of Reanalysis Data from NCEP-Ⅰ and NCEP-Ⅱ in the Himalayas     

XIE Aihong  REN Jiawen  QIN Xiang  KANG Shichang 《山地科学学报》2009,6(1):56-65

Mt. Everest is often referred to as the earth＇s ＇third＇ pole. As such it is relatively inaccessible and little is known about its meteorology. In 2005, an automatic weather station was operated at North Col （28°1′ 0.95＂ N, 86°57′ 48.4＂ E, 6523 m a.s.l.） of Mt. Everest. Based on the observational data, this paper compares the reanalysis data from NCEP/NCAR （hereafter NCEP-Ⅰ） and NCEP-DOE AMIP-Ⅱ （NCEP- Ⅱ）, in order to understand which reanalysis data are more suitable for the high Himalayas with Mr. Everest region. When comparing with those from the other levels, pressure interpolated from 500 hPa level is closer to the observation and can capture more synoptic-scale variability, which may be due to the very complex topography around Mt. Everest and the intricately complicated orographic land-atmosphereocean interactions. The interpolation from both NCEP-Ⅰ and NCEP-Ⅱ daily minimum temperature and daily mean pressure can capture most synopticscale variability （r〉0.82, n=83, p〈0.001）. However, there is difference between NCEP-Ⅰ and NCEP-Ⅱ reanalysis data because of different model parameterization. Comparing with the observation, the magnitude of variability was underestimated by 34.1%, 28.5 % and 27.1% for NCEP-Ⅰ temperature and pressure, and NCEP-Ⅱ pressure, respectively, while overestimated by 44.5 % for NCEP-Ⅱ temperature. For weather events interpolated from the reanalyzed data, NCEP-Ⅰ and NCEP-Ⅱ show the same features that weather events interpolated from pressure appear at the same day as those from the observation, and some events occur one day ahead, while most weather events and NCEP-Ⅱ temperature interpolated from NCEP-Ⅰ happen one day ahead of those from the observation, which is much important for the study on meteorology and climate changes in the region, and is very valuable from the view of improving the safety of climbers who attempt to climb Mt. Everest.  相似文献   

藏南查拉普岩金矿床特征、发现及时代约束   总被引：6，自引：0，他引：6  

郑有业  多吉  马国桃  陈静  代芳华 《地球科学》2007,32(2):185-193

查拉普岩金矿床是藏南著名的北喜马拉雅构造带中新发现的第一个也是最大一个岩金矿床, 是西藏境内迄今为止报道的首个卡林型金矿床.但它的发现只是藏南岩金找矿突破的前奏, 随着勘查研究工作的深入, 北喜马拉雅构造带在岩金或以岩金为主的金锑找矿方面将会取得重大突破.首次系统介绍查拉普岩金矿床成矿环境、成矿特征的同时, 对其成矿时代提出约束, 得出该类型金矿最终成矿作用与藏南大规模拆离系的形成和演化密切相关, 也显示北喜马拉雅与冈底斯斑岩铜矿带在晚新生代成矿方面具有某种成因联系, 为该区进一步的岩金找矿提供了参考和借鉴, 具有重要的理论及现实意义.   相似文献   

A Late Quaternary catastrophic flood in the Lahul Himalayas     

PETER COXON  LEWIS A. OWEN  WISHART A. MITCHELL 《第四纪科学杂志》1996,11(6):495-510

Impressive flood deposits are described resulting from a catastrophic lake outburst in the Upper Chandra valley in the Lahul Himalaya, northern India. Reconstructions of the former glacial lake, Glacial Lake Batal, and the discharges were undertaken using landforms and sediment data. The glacial dam burst released 1.496 km³ of water in 0.72 days, with peak discharges of between 21000 and 27000 m³ s⁻¹ at Batal. Dating by OSL suggests the flood occurred ca. 36.9 ± 8.4 to 43.4 ± 10.3 ka ago. This cataclysmic flood was responsible for major resedimentation and landscape modification within the Chandra valley.  相似文献   

喜马拉雅地区纳木那尼的化学离子特征     

刘勇勤  姚檀栋  田立德  XU Baiqin  WU Guangjian 《地理学报(英文版)》2006,16(4):465-471

A 6-m ice core was recovered in 2004 from the Naimona＇Nyi Glacier, the middle Himalayas. Empirical orthogonal function （EOF） analysis on the major ion reveals that EOF1 represents the variations of majority of ions which may be originated from crustal aerosols. Comparing the calcium concentrations from the Naimona＇Nyi with these from Dasuopu, East Rongbuk and Guliya ice cores, it is observed that calcium, a good indicator of the input of crustal aerosol in snow, concentrates mostly in the Guliya ice core located on the northern Tibetan Plateau, and gradually decreases from west to east in the Himalayas.  相似文献   

珠峰北坡绒布河谷地面风场变化的比较研究     

周立波  邹捍  马舒坡  李鹏  吴瑞欢 《高原气象》2007,26(6):1191-1198

利用2007年6月强化观测实验期间获得的大气观测资料和同时期的NCEP/NCAR大尺度再分析资料,结合2006年同期的分析结果,进一步研究了珠峰北坡绒布河谷地区的地面风场状况及其对南亚夏季风的响应,并与2006年的结果进行了比较.结果表明,2007年6月绒布河谷地区的风场也存在强弱变化,其逐日变化也与南亚夏季风指数有一定关系:在绒布河谷弱风期间,南亚夏季风强盛,在孟加拉湾和阿拉伯海地区形成的强烈涡旋可以把暖湿气流向西北方向输送,从而在河谷地区形成温度和湿度高值;在局地强风期间,南亚夏季风季风指数变化较大,此时绒布河谷地区的风场变化对季风的响应很小,可能主要为大气热力驱动.比较2006年和2007年的观测结果表明,南亚夏季风可以通过改变局地辐射和热力状况的改变而影响珠峰北坡绒布河谷地区地面环流的变化,但其影响程度随季风的强弱可能有所不同.  相似文献   

南亚夏季风对珠穆朗玛峰北坡地面风场的影响   总被引：5，自引：5，他引：0  

周立波  邹捍  马舒坡  李鹏  吴瑞欢 《高原气象》2007,26(6):1173-1186

喜马拉雅山区毗邻南亚季风区,其陡峭的地形和复杂的地表状态在强烈太阳辐射条件下形成了特殊的局地环流系统.为了正确理解该环流系统与南亚天气气候过程的可能关联,本文利用HEST2006珠穆朗玛峰绒布河谷强化实验期间获得的2006年5～6月的地面观测资料和实时的大气环流资料,对该地区地面风场与南亚夏季风的关系进行了研究.研究表明,南亚夏季风间歇期,喜马拉雅山区以晴空天气为主,太阳辐射强烈,绒布河谷地区地面盛行沿河谷方向的偏南下行气流;南亚夏季风强盛期,喜马拉雅山区多为云雨天气,太阳辐射减弱,地面风场强度明显减弱.结果表明,喜马拉雅山地区山谷内部的地面环流系统几乎不受其高层大气环流的影响,而与太阳辐射通量及南亚夏季风指数关系密切.因此,我们认为南亚夏季风对喜马拉雅山区地面环流的影响,主要是通过改变该地区的大气热力和辐射状况完成的.  相似文献   

Traditional agrodiversity management: A case study of central himalayan village ecosystem     

Abhishek CHANDRA  P.Pardha SARADHI  R.K.MAIKHURI  K.G.SAXENA  K.S.RAO 《山地科学学报》2011,8(1):62-74

Environmental, biological, socio-cultural and economic status variation existing in the Central Himalaya have led to the evolution of diverse and unique traditional agroecosystems, crop species and livestock, which facilitate the traditional mountain farming societies to sustain themselves. Indigenous agroecosystems are highly site specific and differ from place to place, as they have evolved along divergent lines. For maintenance of traditional agrodiversity management the farmers of the Central Himalaya have evolved various types of crop rotations in consonance with the varied environmental conditions and agronomic requirements. In irrigated flat lands two crops are harvested in a year with negligible fallow period but in rainfed conditions if a cropping sequence is presumed to be starting after winter fallow phase then four major cropping seasons can be identified namely first kharif season (first crop season), first rabi season (second crop season), second kharif season (third crop season) and second rabi season (fourth crop season). Highest crop diversity is present in kharif season in comparison to rabi season. Traditionally the fields are left fallow after harvest of the second kharif season crop. Important characteristics of agrodiversity management are the use of bullocks for draught power, human energy as labour, crop residues as animal feed and animal waste mixed with forest litter as organic input to restore soil fertility levels. Women provide most of the human labour except for ploughing and threshing grain. The present study deals with assessment of traditional agrodiversity management such as (i) crop diversity, (ii) realized yield under the traditional practices and (iii) assess the differences of realized yields under sole and mixed cropping systems. It indicated that crop rotation is an important feature of the Central Himalayan village ecosystem which helps to continue the diversity of species grown, as are the distribution of crops in the growing period and the management of soil fertility. The cropping diversity existing and the sequences practiced by the traditional farmers seems to have achieved high degree of specialization and thus even when the yield/biomass variations are about 60%, the farmers continue to practice these sequences as they need to maintain diversity and synergistic relationships of crops in addition to manage the food and labour requirements for crop husbandry. Crop yields are generally higher in irrigated systems than rainfed systems and in sole cropping as compared with mixed cropping. However, gross biological and economic yields are higher in mixed cropping than sole cropping systems.  相似文献   

A primitive cladid crinoid from the Jiacun Group,Tibet (Darriwilian,Middle Ordovician)     

Stephen K. Donovan  David A. T. Harper  Zhan Renbin  Lars Stemmerik  Liu Jianbo  Svend Stouge 《Geological Journal》2012,47(6):653-660

A collection of numerous crinoid pluricolumnals from the uppermost Darriwilian (Middle Ordovician) of Tibet were derived from one biological species of crinoid. The specimens were collected from well‐lithified, bioclastic shelf limestones of the upper part of the Lower Chiatsun Group, Pygodus serra Biozone; coeval rocks of similar lithology outcrop at the summit of Everest. A new crinoid morphospecies, Segmentocolumnus (col.) hanshessi, is tentatively considered a ‘stem‐group cladid’, perhaps a dendrocrinid. The proxistele is broad and pentagonal in section with a broad, pentagonal axial canal; the mesistele of similar gross morphology is more slender with a regularly heteromorphic column and a similarly wide axial canal; the dististele is a terminal dendritic radice with a pentastellate axial canal. In the mesistele, the meric sutures correspond to the centres of the sides of the column, but in the dististele they occur in the angles. This range of morphologies would have led to their inclusion in at least two morphogenera if they had not been closely associated; as they belong to a single biological species, they have been ‘lumped’ together herein. This is a rare contribution to our knowledge of the early crinoids from a region outside Europe and North America. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Soil depth estimation through soil-landscape modelling using regression kriging in a Himalayan terrain     

Shraban Sarkar  Archana K. Roy  Tapas R. Martha 《International journal of geographical information science》2013,27(12):2436-2454

Soil formation depends upon several factors such as parent material, soil biota, topography and climate. It is difficult to use conventional soil survey methods for mapping the depth of soil in complex mountainous terrains. In this context, the present study aimed to estimate the soil depth for a large area (330.35 km²) using different geo-environmental factors through a soil-landscape regression kriging (RK) model in the Darjeeling Himalayas. RK with seven predictor variables such as elevation, slope, aspect, general curvature, topographic wetness index, distance from the streams and land use, was used to estimate the soil depth. While topographic parameters were derived from an 8-m resolution digital elevation model, the ortho-rectified Cartosat-1 satellite image was used to prepare the land use map. Soil depth measured at 148 sites within the study area was used to calibrate and validate the RK model. The result showed that the RK model with the seven predictors could explain 67% spatial variability of soil depth with a prediction variance between 0.23 and 0.42 m at the test site. In the regression analysis, land use (0.133) and slope (–0.016) were identified as significant determinants of soil depth. The prediction map showed higher soil depth in south-facing slopes and near valleys in comparison to other areas. Mean, mean absolute and root mean-square errors were used to access the reliability of the prediction, which indicated a goodness-of-fit of the RK model.  相似文献   

High-resolution spatial assessment of population vulnerability to climate change in Nepal     

《Applied geography (Sevenoaks, England)》2017

Current, spatially explicit, and high-resolution assessments of population vulnerability to climate change and variability in developing countries can be difficult to create due to lack of data or financial and technical capacity constraints. We propose a comparative, multiple-approach framework to assess the spatial variation of population vulnerability to climatic changes using several high-resolution variables related to climate, topography, and socioeconomic conditions with an objective to detect the spatial variability of climate vulnerability in Nepal. Nepal is one of the most vulnerable countries to the effects of climate change due to frequent climatic hazards and poor socio-economic capacity. We used a climate vulnerability index (CVI) approach to derive climate vulnerability maps at the one-kilometer resolution and test an additive and a principal components-based composite method of data aggregation. In this work, we attempt to answer three questions. 1) How do different methods of assessment inform the spatial variation of the climate vulnerability in Nepal? 2) How do different variables interact to shape climate vulnerability in Nepal? 3) What proportions of the population in Nepal are vulnerable to climatic disasters and why? Our analysis uncovered significant spatial variations in population vulnerability to climate change across Nepal, with the highest vulnerability being experienced by the High Mountain region followed by the regions in the lower elevations. We find that although the lack of adaptive capacity is the biggest cause of population vulnerability to climate change in Nepal, a resilient community is shaped by both biophysical and socioeconomic characteristics. By performing an iterative sensitivity analysis of our thirteen variables both at the aggregate level (nationally) as well as at the more disaggregated (physiographic region) level, we contribute to identifying important, multi-scalar driving factors for vulnerability that can be employed as leverage points for lowering vulnerability at different scales. After performing analyses at multiple regions, we conclude that region-specific variable selection is needed for more detailed assessments and in order to prioritize adaptation strategies at scales that go beyond the hierarchy of administrative divisions.  相似文献