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1.
雅鲁藏布江流域降水中δ18O 的时空变化 总被引：5，自引：0，他引：5
通过研究2005年西藏雅鲁藏布江流域拉孜、奴各沙、羊村和奴下4个站点降水中的δ18O变化,揭示了雅鲁藏布江流域降水中稳定同位素的时空变化规律.研究显示,雅鲁藏布江流域降水中δ18O季节变化明显,高值出现在季风降水之前的春季,而低值出现在季风降水季节,其间降水中δ18O具有明显的"降水量效应";从空间上看,降水中的δ18O从下游至上游递减,造成这种分布特征主要是由于"高程效应"以及水汽远距离输送导致其中的18O被贫化的结果.经计算表明,雅鲁藏布江流域降水中δ18O由于"高程效应"造成的递减率为0.34‰/100m,而水平方向上自东向西由于水汽远距离输送造成的递减率为0.7‰/100km.从季风期间大范围的降水过程来看,降水中δ18O的空间变化主要受"降水量效应"制约. 相似文献
2.
This paper reveals the temporal and spatial variations of stable isotope in precipita-tion of the Yarlung Zangbo River Basin based on the variations of δ18O in precipitation at four stations (Lhaze,Nugesha,Yangcun and Nuxia) in 2005. The results show that δ18O of pre-cipitation has distinct seasonal changes in the Yarlung Zangbo River Basin. The higher value of δ18O occurs in spring prior to monsoon precipitation,and the lower value occurs during monsoon precipitation. From the spatial variations,with the altitude-effect and rainout process during moisture transport along the Yarlung Zangbo River Valley,18O of precipitation is gradually depleted. Thus,δ18O of precipitation decreases gradually from the downstream to the upstream,and the lapse rate of δ18O in precipitation is approximately 0.34‰/100m and 0.7‰/100km for the two reasons. During monsoon precipitation,spatial variation of δ18O in precipitation is dominated by the amount effect in the large scale synoptic condition. 相似文献
3.
Temporal and spatial variations of δ^18O in precipitation of the Yarlung Zangbo River Basin 总被引：1，自引：0，他引：1
LIU Zhongfang TIAN Lide YAO Tandong GONG Tongliang YIN Changliang YU Wusheng 《地理学报(英文版)》2007,17(3):317-326
This paper reveals the temporal and spatial variations of stable isotope in precipitation of the Yarlung Zangbo River Basin based on the variations of δ^18O in precipitation at four stations （Lhaze, Nugesha, Yangcun and Nuxia） in 2005. The results show that δ^18O of precipitation has distinct seasonal changes in the Yarlung Zangbo River Basin. The higher value of δ^18O occurs in spring prior to monsoon precipitation, and the lower value occurs during monsoon precipitation. From the spatial variations, with the altitude-effect and rainout process during moisture transport along the Yarlung Zangbo River Valley, δ^18O of precipitation is gradually depleted. Thus, δ^18O of precipitation decreases gradually from the downstream to the upstream, and the lapse rate of δ^18O in precipitation is approximately 0.34‰/100m and 0.7%J‰/100km for the two reasons. During monsoon precipitation, spatial variation of δ^18O in precipitation is dominated by the amount effect in the large scale synoptic condition. 相似文献
4.
Oxygen-18 in different waters in Urumqi River Basin 总被引：1，自引：0，他引：1
The variations of the stable oxygen isotope in different water mediums in Urumqi River Basin, China, are analyzed. The stable oxygen isotope in precipitation has marked temperature effect either under synoptic or seasonal scale at the head of Urumqi River. The linear regression equations of δ18O against temperature are δ18O=0.94T-12.38 and δ18O=1.29T-13.05 under the two time scales, respectively. The relatively large δ18O/temperature slopes show the strong sensitivity of δ18O in precipitation to temperature variation at the head of Urumqi River. According to the analyses on the δ18O in precipitation sampled at three stations with different altitudes along Urumqi River, altitude effect is notable in the drainage basin. The δ18O/altitude gradients have distinct differences: the gradient from Urumqi to Yuejinqiao is merely -0.054‰/hm, but -0.192‰/hm from Yuejinqiao to Daxigou, almost increasing by 2.6 times over the former. No altitude effect is found in surface firn in the east branch of Glacier No.1 at the head of Urumqi River, showing that precipitation in the glacier is from the cloud cluster with the same condensation level. Influenced by strong ablation and evaporation, the δ18O in surface firn increases with increasing altitude sometimes. Survey has found that the δ18O in meltwater at the terminus of Glacier No.1 and in stream water at Total Control have the similar change trend with the former all smaller than the latter, which displays the different runoff recharges, and all mirror the regime of temperature in the same term basically. 相似文献
5.
1961-2015年雅鲁藏布江流域降雨侵蚀力 总被引：2，自引：1，他引：2
降雨是土壤侵蚀的主要动力，也是风水蚀复合区沙漠化的主要驱动力。研究降雨侵蚀力时空变化对雅鲁藏布江流域土壤侵蚀的监测、评估、预报和治理具有重要意义。利用1961-2015年雅鲁藏布江流域8个气象站日降雨量气象资料，采用趋势系数、气候倾向率、MK检验等研究方法对雅鲁藏布江流域降雨侵蚀力时空变化进行分析。结果表明：雅鲁藏布江流域年降雨侵蚀力平均值为758.1 MJ·mm·hm-2·h-1，变差系数Cv值为0.29，趋势系数r值为0.3140。空间分布呈现由东向西逐渐递减的特点，东部可达2 000 MJ·mm·hm-2·h-1以上，最西部仅为200 MJ·mm·hm-2·h-1。雅鲁藏布江流域年降雨侵蚀力总体呈波动上升趋势，其中嘉黎和波密站年降雨侵蚀力上升趋势明显，日喀则、泽当站年降雨侵蚀力呈下降趋势。通过MK检验及滑动T检验得知，流域内年降雨侵蚀力在1982年发生突变，年侵蚀性降雨突变不显著。雅鲁藏布江流域年降雨侵蚀力与侵蚀性降雨相关性显著，侵蚀性降雨的分布也极大地影响降雨侵蚀力。 相似文献
6.
2005 年10-11 月中美联合考察队在各拉丹冬峰北部果曲冰川平坦的粒雪盆 (33o34'37.8"N, 91o10'35.3"E, 5720 m a.s.l.) 钻取了一支冰芯, 通过对该冰芯进行多参数定年, 恢复了青藏高原中部各拉丹冬地区近70 年来降水中δ18O 的变化历史。根据冰芯中季风期和非季风期δ18O 值与临近气象台站气温的正相关性, 重建了该地区70 年来的春季和夏季的气温变化。结果表明, 各拉丹冬冰芯中δ18O 记录的春季和夏季升温趋势非常明显; 根据回归分析, 冰芯中非季风期的δ18O 每增大(或减小) 1‰相当于春季气温升高(或降低) 1.3 oC; 季风 期的δ18O 每增大(或减小) 1‰相当于夏季气温升高(或降低) 0.4 oC; 各拉丹冬冰芯中δ18O 记录恢复的春季和夏季气温与北半球春季和夏季的气温变化具有一致的趋势, 但各拉丹冬地区的增温幅度比北半球要大, 同时春季的增温幅度也高于夏季。 相似文献
7.
近45年雅鲁藏布江流域极端气候事件趋势分析 总被引：23，自引：2，他引：21
利用雅鲁藏布江流域10个气象台站1961-2005年逐日最高气温、最低气温和日降水量资料,分析了该流域气温和降水等气候极端事件的变化趋势.研究表明:近45年以来,雅鲁藏布江流域夜间和白天极端低温日数分别以1.94和0.97天/10年的趋势在显著减少,夜间极端低温日数减少在冬季最明显,白天极端低温日数在秋季减少最明显:夜间极端高温日数和白天极端高温日数分别以3.03和1.26天/10年的速度显著增加,夜间极端高温日数增加在夏季最明显,白天极端高温日数增加在冬季最明显;日较差以0.11℃/10a的速度在显著减少,主要发生在冬季:最大的1天降水总量和逐年连续无降水天数有减少趋势,最大的5天降水总量、中雨天数、逐年平均降水强度和逐年连续降水天数有增加趋势,90年代以来增加趋势明显,与该地区经向风与水汽通量增加有关. 相似文献
8.
雅鲁藏布江径流水文规律及水体同位素组成 总被引：5，自引：1，他引：4
由雅鲁藏布江各站径流量数据和水体的同位素数据,分析了径流的时空分布特点以及大气降水的同位素效应。该区干流流域年平均径流量分布呈从下游到上游逐渐减少的趋势, 且地表径流的年内分配主要集中在夏、秋两季(6-10 月)。流域内大部分雨水和河水样品的同位素组成均落在全球大气降水线δD = 8δ18O +10 的右上方,显示出强烈蒸发的特征。水体同 位素组成区域大陆性效应和高度效应明显,这种分布特征与来自孟加拉湾、怒江方向降水云汽的运移以及青藏高原的地形、气候条件有关。 相似文献
9.
1961～2015年雅鲁藏布江流域风蚀气候侵蚀力变化 总被引：3，自引：1，他引：3
根据雅鲁藏布江流域13个气象站观测资料,利用联合国粮农组织给出的公式计算雅鲁藏布江流域风蚀气候因子指数值,分析雅江风蚀气候侵蚀力基本特征。结果表明,雅江流域风蚀气候因子指数分布范围为4.2~31.9,平均值为14.7。从空间分布来看,风蚀气候因子指数由西向东呈减小趋势,西部可达40,东部加查-米林段降到了5左右。风蚀气候因子指数具有显著的季节变化,春季最大为8.5,冬季次之为5.2,夏季、秋季都很小。雅江流域风蚀气候因子指数年、春季、秋季、冬季下降趋势显著,夏季上升趋势不显著。通过Mann-Kendall（M-K）检验分析可知,风蚀气候因子指数在1987年发生突变。 相似文献
10.
雅鲁藏布江流域NDVI变化与 主要气候因子的关系 总被引：10，自引：3，他引：10
对流域NDVI进行计算的前提下,分析了雅鲁藏布江流域NDVI时空变化特征。时间上,流域NDVI具有很强的季节性。空间上,流域NDVI高值区主要分布于下游与中游的部分地区,而流域中上游与源头NDVI值相对较小。在流域DEM的支持下,把流域站点主要气候因子降水量与平均气温等数据采用Kriging方法插值成与流域NDVI相一致的空间Grid数据。流域NDVI与降水量、平均气温的关系进行F检验与双样本方差分析结果P＝0,表明其相关分析的可信度较高。在0.05的置信水平上对其进行了线性与对数相关分析。结果表明,流域NDVI与降水量的平均线性相关系数达0.8,对数相关系数为0.71;流域NDVI与流域平均气温线性相关系数为0.77,对数相关系数为0.7。 相似文献
11.
WANG Tong WANG Jingsheng DING Yuke LIU Wenjing BAO Xiaoting LI Chao 《资源与生态学报(英文版)》2019,10(4):389-396
Based on vegetation survey data and environmental data of the Yarlung Zangbo River Basin, we conducted a quantitative ecological analysis of the vegetation community composition and the relationship between species and the environment in the study area. The results showed that 44 sampling sites and 68 plant species in the study area can be classified into seven subtypes: Artemisia minor + Stipa purpurea; Artemisia demissa + Stipa purpurea + Artemisia wellbyi; Kobresia pygmaea; Trikeraia hookeri; Sophora moorcroftiana + Cotoneaster multiflorus + Pennisetum centrasiaticum; Artemisia frigida; Potentilla fruticosa + Orinus thoroldii. Detrended correspondence analysis (DCA) indicated that both longitude and altitude play important roles in site and species distribution patterns. In addition, canonical correspondence analysis (CCA) revealed that in the upper and middle reaches of the Yarlung Zangbo River Basin, changes in temperature and precipitation caused by longitude are the main factors controlling the formation and transition of vegetation community types. Moreover, natural vegetation could be divided into three types: desert steppe community (source area), alpine steppe community (middle reaches region), and shrub community (confluence of Yarlung Zangbo River and Nyangqu River). 相似文献
12.
LIU Jianrong SONG Xianfang YUAN Guofu SUN Xiaomi LIU Xin WANG Zhimin WANG Shiqin 《地理学报》2008,18(2):155-165
Summer monsoons (South Asian monsoon, South China Sea monsoon and Sub-tropical monsoon) are prominent features of summertime climate over southern China. Dif-ferent monsoons carry different inflow moisture into China and control the temporal and spa-tial distributions of precipitation. Analyses of meteorological data, particularly wind, tempera-ture and pressure anomalies are traditional methods of characterizing moisture sources and transport patterns. Here, we try to utilize the evidence from stable isotopes signatures to trace summer monsoons over southern China. Based on seven CHNIP (Chinese Network of Iso-topes in Precipitation) observatory stations located in southern China, monthly composite precipitation samples have been collected and analyzed for the composition of δ18O during July, 2005. The results indicated that the spatial distributions of δ18O in precipitation could properly portray the moisture sources together with their transport pathways. Moreover, the amount effect, altitude effect, temperature effect and the correlation between δ18O vs. relative humidity were discussed. 相似文献
13.
论文对比分析了1980—2016年基于站点插值降水数据CMA(China Meteorological Administration)和APHRODITE(Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation)、卫星遥感降水数据PERSIANN-CDR(Precipitation Estimation from Remotely Sensed Information using Artificial Neural Network-Climate Data Record)和GPM(Global Precipitation Measurement)、大气再分析数据GLDAS(Global Land Data Assimilation System)以及区域气候模式输出数据HAR(High Asia Refined analysis)在雅鲁藏布江7个子流域的降水时空描述,利用国家气象站点数据对各套降水数据进行单点验证,并以这6套降水数据驱动VIC(Variable Infiltration Capacity)大尺度陆面水文模型反向评估了各套降水产品在雅鲁藏布江各子流域径流模拟中的应用潜力。结果表明：① PERSIANN-CDR和GLDAS年均降水量最高(770~790 mm),其次是HAR和GPM(650~660 mm),CMA和APHRODITE年均降水量最低(460~500 mm)。除GPM外,其他降水产品在各子流域都能表现季风流域的降水特征,约70%~90%的年降水量集中在6—9月份。② 除PERSIANN-CDR和GLDAS外,其他降水产品皆捕捉到流域降水自东南向西北递减的空间分布特征。其中,HAR数据空间分辨率最高,表现出更详细的流域内部降水空间分布特征。③ 与对应网格内的国家气象站降水数据对比显示,APHRODITE、GPM和HAR降水整体低估(低估10%~30%),且严重低估的站点主要集中在下游(低估40%~120%)。PERSIANN-CDR和GLDAS整体表现为高估上游流域站点降水(高估28%~60%),但低估下游流域站点降水(低估11%~21%)。④ 在流域径流模拟上,当前的6套降水产品在精度或时段上仍无法满足水文模型模拟的需求。⑤ 通过水文模型反向评估,6套降水产品中区域气候模式输出的HAR在流域平均降水量和季节分配上更合理。 相似文献
14.
河宽作为河流形态的基本参数之一,对于理解地表水过程和河流生态系统功能至关重要。雅鲁藏布江是全球具有典型地域特色的高原河流,也是重要的国际河流。雅鲁藏布江地处偏远山区,其地形环境条件恶劣、测量站分布稀疏,严重限制了对雅鲁藏布江河流水文动态变化特征的科学理解。遥感卫星通过提供多时相、长时序观测影像数据,使雅鲁藏布江河宽长期动态变化监测和水文特征分析成为可能。本文基于全球地表水变化数据集（GLAD）,利用水体边界水淹频率阈值分割法重建了2000—2020年雅鲁藏布江逐月完整的水域范围,进而提取和解析雅鲁藏布江干流河宽的时空变化特征。研究结果表明：2000—2020年期间,受年内气温和降水季节性差异等影响,雅鲁藏布江干流河宽呈现出显著的季节性变化特征,中游河段的季节性变幅最大（453.6 m）,下游河段季节性变幅最小（90.3 m）;雅鲁藏布江干流河道受气候和地形的影响,空间分布差异大,河道可观察到的最窄处约30 m（即Landsat卫星影像的最小空间分辨率）,中下游辫状河流有效河宽最大可达6000 m,全程约50%长度的河道宽度小于150 m,仅2.0%的河道宽度大于2000 m;2000—2020年雅鲁藏布江干流河道的年平均河宽呈现先下降、后上升、再下降的变化特征,雅鲁藏布江全程平均河宽与降水、气温之间呈现较显著的正相关关系（通过p<0.01的显著性检验）,相关性系数R值均为0.7。此外,本文利用10 m分辨率Sentinel-2影像数据目视解译提取的河宽信息与本文基于GLAD重建的河宽结果进行对比验证,两者的相对偏差低于2%,表明本文雅鲁藏布江河宽的提取结果总体可信。 相似文献
15.
ZHANG Xiaolong XU Sheng CUI Lifeng ZHANG Maoliang ZHAO Zhiqi LIU Congqiang 《地理学报(英文版)》2022,32(2):333-357
Investigating topographic and climatic controls on erosion at variable spatial and temporal scales is essential to our understanding of the topographic evolution of the orogen.In this work,we quantified millennial-scale erosion rates deduced from cosmogenic 10Be and 26Al concentrations in 15 fluvial sediments from the mainstream and major tributaries of the Yarlung Zangbo River draining the southern Tibetan Plateau (TP).The measured ratios of 26Al/10Be range from 6.33 ± 0.29 to 8.96 ± 0.37,suggesting steady-state erosion processes.The resulted erosion rates vary from 20.60 ± 1.79 to 154.00 ± 13.60 m Myr-1,being spatially low in the upstream areas of the Gyaca knickpoint and high in the downstream areas.By examining the relationships between the erosion rate and topographic or climatic indices,we found that both topography and climate play significant roles in the erosion process for basins in the upstream areas of the Gyaca knickpoint.However,topography dominantly controls the erosion processes in the downstream areas of the Gyaca knickpoint,whereas variations in precipitation have only a second-order control.The marginal Himalayas and the Yarlung Zangbo River Basin (YZRB) yielded significantly higher erosion rates than the central plateau,which indicated that the landscape of the central plateau surface is remarkably stable and is being intensively consumed at its boundaries through river headward erosion.In addition,our 10Be erosion rates are comparable to present-day hydrologic erosion rates in most cases,suggesting either weak human activities or long-term steady-state erosion in this area. 相似文献
16.
The suspected impact of climate warming on precipitation distribution is examined in the Yangtze River Basin. Daily precipitation data for 147 meteorological stations from 1961–2000 and monthly discharge data for three stations in the basin have been analyzed for temporal and spatial trends. The methods used include the Mann–Kendall test and simple regression analysis. The results show (1) a significant positive trend in summer precipitation at many stations especially for June and July, with the summer precipitation maxima in the middle and lower Yangtze River basin in the 1990s; (2) a positive trend in rainstorm frequency that is the main contributor to increased summer precipitation in the basin; and (3) a significant positive trend in flood discharges in the middle and lower basin related to the spatial patterns and temporal trends of both precipitation and individual rainstorms in the last 40 years. The rainstorms have aggravated floods in the middle and lower Yangtze River Basin in recent decades. The observed trends in precipitation and rainstorms are possibly caused by variations of atmospheric circulation (weakened summer monsoon) under climate warming. 相似文献
17.
亚洲降水中δ18O沿不同水汽输送路径的变化 总被引：8，自引：0，他引：8
利用IAEA/WMO全球监测网和青藏高原的监测站,建立了由赤道地区经我国西南水汽通道至长江中下游的南方水汽输送路径、沿西风带自我国西部经华北至日本的北方水汽输送路径以及自南亚穿喜马拉雅山到我国青藏高原的水汽输送路径的取样剖面,比较了三条水汽路径在不同季节降水中啄18O的变化及其与温度、降水量的关系。沿南方水汽路径,低纬度地区取样站降水中平均啄18O的季节差异较小。沿北方水汽路径,郑州以西取样站平均啄18O的季节差均大于郑州以东的取样站。随着经度的增加,降水中平均啄18O的季节差减小。沿高原水汽路径,印度次大陆南部降水中的啄18O相对较高,随着纬度的增加,降水中啄18O逐渐减小。在翻越喜马拉雅山后,由于强烈的洗涤作用,降水中啄18O急剧下降。 相似文献
18.
雅鲁藏布江流域不同源降水数据质量对比研究 总被引：2，自引：0，他引：2
本文以雅鲁藏布江流域为研究区,利用13个气象站点的实测降水量数据在年和月尺度上验证了中国地面降水网格数据、CRU(Climatic Research Unit)降水数据和GLDAS(Global Land Data Assimilation System)降水数据的精度,并分析了不同源数据降水量年际变化特征和概率分布特性之间的差异。结果表明：4种不同来源的降水数据均存在一定程度的差异。年尺度和月尺度上中国地面降水网格数据与实测降水量数值最接近;而CRU降水数据和GLDAS降水数据与实测降水量相差较大,在使用时需谨慎。从空间差异性看,年尺度上CRU降水数据在每个站点与实测降水数据的相关性均高于GLDAS降水数据,说明前者的空间一致性较好,但相对误差却比GLDAS降水数据大。从年内变化趋势看,中国地面降水网格数据能较好地反映流域降水月尺度的变化特征,CRU降水数据则在流域大部分地区的汛期时段都存在明显的高估,而GLDAS数据无法反映月降水变化趋势,年内坦化现象十分显著。从年际变化特征看,中国地面降水网格数据能较好地反映实际降水量的年际变化特征,而GLDAS降水数据和CRU降水数据反映的降水量年际变化特征偏小,其中GLDAS数据的坦化现象更严重,会高估低降水值,低估高降水值。从降水概率分布情况来看,3种来源的降水数据均不能反映站点实测的极端降水事件。 相似文献
19.
雅鲁藏布江流域径流特性变化分析 总被引：8，自引：2，他引：6
本文采用Morlet小波对1956~2000年雅鲁藏布江流域6个站点的径流序列进行了分析,揭示了不同时间尺度下四个季节以及年平均径流量的丰枯交替特性、突变性和周期性,通过小波方差确定各序列存在的主要周期。结果表明:在15年时间尺度上,雅江流域四个季节的径流变化趋势基本一致;发生突变的年份主要在1957、1967、1976、1983、1992年;径流序列第一主周期主要以15年长周期和2年短周期为主,第二主周期以15、6、2~3年的长、中、短周期为主;秋季和冬季径流序列的周期空间分布基本一致,年平均径流序列的周期分布与夏季最为接近;除拉萨河子流域春季在2~3年尺度上处于枯水期外,其他子流域其他时段在任何时间尺度上未来几年里都将处于丰水期。 相似文献