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1.
The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies. Their use is important for arid areas where the precipitation events are limited, and below-cloud evaporation is strong. This study presents the spatial and temporal characteristics of water vapor isotopologue across the Tianshan Mountains in arid central Asia using the NASA Aura Tropospheric Emission Spectrometer (TES). The near-surface water vapor stable isotopes are enriched in summer and depleted in winter, consistent with the seasonality of precipitation isotopes. From the surface to 200 hPa, the isotope values in water vapor show a decreasing trend as the atmospheric pressure decreases and elevation rises. The vapor isotope values in the lower atmosphere in the southern basin of the Tianshan Mountains are usually higher than that in the northern basin, and the seasonal difference in vapor isotopes is slightly more significant in the southern basin. In addition, bottom vapor isotopologue in summer shows a depletion trend from west to east, consistent with the rainout effect of the westerly moisture path in central Asia. The isotopic signature provided by the TES is helpful to understand the moisture transport and below-cloud processes influencing stable water isotopes in meteoric water.  相似文献   

2.
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   

3.
We present a unique new set of high spatial resolution precipitation data from a storage gauge network, for the sparsely observed northern Sonoran desert in south-west Arizona. We examine the nature and causes of the highly complex seasonal and spatial variability in the data, using fine-scale maps developed via spatial modeling and interpolation. These high-resolution maps had explained variances approaching 1·00, and precipitation errors of about 1% in winter and about 10% in summer. Seasonal precipitation ranges from near zero to almost 15 in across the area, and shows high interannual variability. Localized convectional processes lead to summer anomalies that are more spatially complex than in winter when broad-scale synoptic and frontal processes cause precipitation. In general, summer and winter precipitation variability are tied to meridional-zonal shifts and east–west movement of the respective anticyclone or trough pattern over the region. Statistical links between major weather stations in the region and precipitation across the area are spatially inconsistent, especially in the west.  相似文献   

4.
Past water-balance changes in Tibetan lakes are generally attributed to changes in the strength of the summer monsoon. However, the water balance of a lake reflects many different water fluxes, which are controlled by many climatic and hydrologic processes. In this research, weather data and evaporation models are used to determine the climatic cause of a recent water-balance change in Ahung Co, a lake in central Tibet. Between 1995 and 2001, lake level rose at least 20 cm and the lake began to overflow. Results indicate that an increase in summer monsoon precipitation over the lake and drainage basin is responsible for the rise in lake level. Stronger monsoon conditions between 1995 and 2001 also led to decreased lake evaporation and basin evapotranspiration due to increased clouds and humidity. This contributed to the rise in lake level, but to a much smaller extent than the increase in monsoon precipitation. Lake evaporation during the spring and fall was also reduced between 1995 and 2001 due to longer lasting ice cover. Variations in ice cover play a small role in the overall water balance of Ahung Co, however, because the lake area is small compared to the drainage basin area. If these results hold true for the past, water-balance fluctuations inferred from the geochemistry of sediments from Ahung Co provide a record of variations in monsoon precipitation during the Holocene.  相似文献   

5.
伊犁河流域降水和气温的若干特征   总被引：13，自引：0，他引：13  
本文详细分析了天山山区伊犁河流中低山区降水和气温的变化规律。结果表明，夏季中低山带的降水和气温与其对应高度的关系较好，且梯度值较大；不同年份降水量越大，降水梯度值亦越大，在此基础上结合邻近地区高山区观测资料，获取了伊犁河流域高山区的降水和气温。  相似文献   

6.
应用三维数据的时间小波变换方法, 分析研究了夏季风作用下的纵向岭谷区夏季降水量 在年际变化上的时空特征和规律。结论为: 夏季风作用下的云南纵向岭谷区夏季降水量在年际变 化上的特征时间尺度分别约为2 年、7 年和16 年; 2 年、7 年和16 年特征时间尺度的较大振幅能 量活动区分别与纵向岭谷区的山脉走向一致或正交; 与2 年特征时间尺度相对应的较大振幅能 量活动中心纬度的夏季降水量表现出了明显的东西向波动的时间演变特征, 而与7 年和16 年特 征时间尺度相对应的较大振幅能量活动中心纬度的夏季降水量则分别表现出了一种向西和向东 移动的时间演变趋势; 与2 年特征时间尺度相对应的较大振幅能量活动中心经度的夏季降水量 也表现出了明显的南北向波动的时间演变特征, 而与7 年和16 年特征时间尺度相对应的较大振 幅能量活动中心经度的夏季降水量则分别表现出了一种明显向北和向南移动的时间演变趋势。  相似文献   

7.
柴达木盆地气温、降水突变与周期特征分析   总被引：5，自引：0，他引：5  
利用柴达木盆地6个站1954—2003年逐月气温、降水量资料,分析其近50年来气温、降水突变和周期特征。结果表明,盆地年气温与夏、秋、冬季气温增加趋势超过0.01显著性水平临界值,春季气温增加和年较差减小趋势达到0.05显著性水平。降水序列中,只有年降水与夏季降水增加达到0.10显著性水平。盆地各气温序列均有突变发生,年气温在20世纪80年代前期发生极显著暖突变,秋、冬季气温突变较春、夏季显著,冬季气温突变时间较其他季节偏早,在各气温序列中年较差突变时间最早。年降水在1976年发生突变,四季降水中只有春、夏季有突变。周期分析显示,盆地年气温变化的主周期按强弱依次为12 a、7 a和3 a,年降水主周期则依次为9 a和4 a。  相似文献   

8.
Acid rain has been recognized as a serious environmental problem in China since the 1980s, but little is known about the effects of the climatic change in regional precipitation on the temporal and spatial variability of severe acid rain. We present the effects of the re-gional precipitation trend change on the area and intensity of severe acid rain in southern China, and the spatio-temporal distribution characteristics of SO2 and NO2 concentrations are analyzed on the basis of SO2 and NO2 column concentration data. The results are as follows. (1) The emission levels of SO2 and NO2 have reached or passed the precipitation scavenging capacity in parts of southern China owing to the emission totals of SO2 and NO2 increasing from 1993 to 2004. (2) Notable changes in the proportion of cities subject to severe acid rain occurred mainly in the south of the middle-lower reaches of the Yangtze River during 1993-2004. With an abrupt change in 1999, the severe acid rain regions were mainly located in central and western China during 1993-1999 and moved obviously eastward to the south of the lower-middle reaches of the Yangtze River with the proportion of cities subject to se-vere acid rain increasing significantly from 2000 to 2004. (3) The spatial distribution and variation in the seasonal precipitation change rate of more than 10 mm/10a are similar to those of severe acid rain in southern China. An abrupt change in 1999 is seen for winter and summer precipitation, the same as for the proportion of cities subject to severe acid rain in southern China. The significant increase in summer storm precipitation from 1991 to 1999 mitigated the annual precipitation acidity in the south of the Yangtze River and reduced the area of severe acid rainfall. On the other hand, the decrease in storm rainfall in summer ex-panded the area of severe acid rainfall in the south of the Yangtze River in 2000-2006. Therefore, the change in seasonal precipitation is an important factor in the severe acid rain regions moving eastward and expanding in southern China.  相似文献   

9.
Acid rain has been recognized as a serious environmental problem in China since the 1980s,but little is known about the effects of the climatic change in regional precipitation on the temporal and spatial variability of severe acid rain.We present the effects of the regional precipitation trend change on the area and intensity of severe acid rain in southern China,and the spatio-temporal distribution characteristics of SO2 and NO2 concentrations are analyzed on the basis of SO2 and NO2 column concentration data.The results are as follows.(1) The emission levels of SO2 and NO2 have reached or passed the precipitation scavenging capacity in parts of southern China owing to the emission totals of SO2 and NO2 increasing from 1993 to 2004.(2) Notable changes in the proportion of cities subject to severe acid rain occurred mainly in the south of the middle-lower reaches of the Yangtze River during 1993-2004.With an abrupt change in 1999,the severe acid rain regions were mainly located in central and western China during 1993-1999 and moved obviously eastward to the south of the lower-middle reaches of the Yangtze River with the proportion of cities subject to severe acid rain increasing significantly from 2000 to 2004.(3) The spatial distribution and variation in the seasonal precipitation change rate of more than 10 mm/10a are similar to those of severe acid rain in southern China.An abrupt change in 1999 is seen for winter and summer precipitation,the same as for the proportion of cities subject to severe acid rain in southern China.The significant increase in summer storm precipitation from 1991 to 1999 mitigated the annual precipitation acidity in the south of the Yangtze River and reduced the area of severe acid rainfall.On the other hand,the decrease in storm rainfall in summer expanded the area of severe acid rainfall in the south of the Yangtze River in 2000-2006.Therefore,the change in seasonal precipitation is an important factor in the severe acid rain regions moving eastward and expanding in southern China.  相似文献   

10.
The late Palaeozoic to Triassic sedimentary record of the central Argentinean offshore was analysed through the integration of data from exploratory wells and 2D seismic lines. Our interpretations were combined with existing ones in Argentina, Uruguay, Brazil and South Africa for their analysis in the late Palaeozoic south‐western Gondwana context. The mapped upper Palaeozoic‐Lower Triassic stratigraphic record offshore Argentina bears a thickness of +7000 m south of the Colorado basin and encompasses the time span between Pennsylvanian and Lower Triassic; this means that it triples that of the Sierras de la Ventana of Argentina and involves a far larger time span. On the basis of seismic stratigraphic interpretations in localities near the coast, we interpret that a strong denudation process removed a great portion of the stratigraphic record in the Sierras de la Ventana, the surrounding plains and the Tandilia system of Buenos Aires. The seismic stratigraphic configuration of the late Palaeozoic succession shows continuous and parallel reflections in a wide sediment wedge extending for more than 1000 km between the Gondwanides orogen core to the south and offshore Uruguay to the north. Two salient aspects of this sedimentary wedge are that no flexural depocentre was observed at the Ventania fold belt front, and that deformation in the orogenic front is post‐Lower Triassic. The original westwards extent of the basin is interpreted to have encompassed the whole of Buenos Aires province in continuity with the Chacoparaná basin; to the east continuity and a straightforward correlation with the Karoo basin was interpreted. The name of Hespérides Basin is proposed herein to refer to a Pennsylvanian to Lower Triassic basin mainly controlled by dynamic subsidence that encompasses and exceeds the area of the Sauce Grande and Colorado basins and the Claromecó fore‐deep in Argentina. The Hespérides basin is interpreted to have been in lateral continuity with the Kalahari, Karoo and Chacoparaná basins of Africa and South America forming a +3 000 000 sq. km depocentre.  相似文献   

11.
四川盆地降水变化的区域差异   总被引：3，自引：0，他引：3  
利用四川盆地实测气象资料、NCEP/NCAR再分析资料以及NCDC全球气温距平资料,分析了四川盆地降水变化的区域差异。结果表明:盆地降水空间异常分布主要呈东西振荡特征,近46 a来,盆西降水显著减少,盆东降水总体变化趋势不明显。青藏高原夏季风指数、西太平洋副热带高压北界和脊线指数与盆地夏季降水的相关场表现为盆西和盆东反号分布,表明高原夏季风和西太副高可能是盆地降水东西振荡分布的重要原因。通过与全球气温变化的回归分析发现,盆地降水变化趋势的区域差异,特别是盆西地区的暖干化可能是对全球变暖的区域响应。  相似文献   

12.
Regional-scale middle- and upper-tropospheric troughing over the southwestern United States represents a departure from the modal circulation pattern for western North America. Once developed, southwestern troughs often are associated with positive vorticity advection aloft, surface cyclone formation, and moisture advection over areas of the western Great Plains and Intermountain West. These trough systems may play an important role in the precipitation climatology of the western and central United States. However, very little work has focused on the temporal climatology, developmental characteristics, or climatic impacts of southwestern troughs. This study provides a detailed climatology of southwestern troughing that focuses on: (1) the temporal frequency of these events; (2) the teleconnective circulation changes that are associated with their development; and (3) the importance of these systems in the precipitation climatology of the western and central United States.

The temporal climatology of southwestern troughs reveals that most of these systems occur during spring and autumn, with somewhat fewer events in winter and very few events in summer. An examination of 500-mb geopotential height and 24-hr height change composites during trough development shows that much of the wave-train activity that accompanies trough onset is limited to the North Pacific and North American regions. These changes are characterized by the amplification and eastward movement of a ridge/trough couplet over the eastern Pacific, which is preceded by synoptic-scale transient wave activity over the western and central Pacific. While southwestern troughs occur less than 30% of the time, southwestern trough-derived precipitation comprises over 60% of the monthly totals for some sites.  相似文献   

13.
1951-2002年长江流域降水特征   总被引：2，自引：0，他引：2  
The monthly, seasonal, and annual precipitation trends in the Yangtze river catchment have been detected through analysis of 51 meteorological stations‘ data between 1950-2002 provided by National Meteorological Administration. Results reveal that: 1) Summer precipitation in the Yangtze river catchment shows significant increasing tendency. The Poyanghu lake basin, Dongtinghu lake basin and Taihu lake basin in the middle and lower reaches are the places showing significant positive trends. Summer precipitation in the middle and lower reaches experienced an abrupt change in the year 1992; 2) The monthly precipitation in months just adjoining to summer shows decreasing tendency in the Yangtze river catchment. The upper and middle reaches in Jialingjiang river basin and Hanshui river basin are the places showing significant negative trends; 3) Extreme precipitation events show an increasing tendency in most places, especially in the middle and lower reaches of the Yangtze river catchment.  相似文献   

14.
The monthly, seasonal, and annual precipitation trends in the Yangtze river catchment have been detected through analysis of 51 meteorological stations' data between 1950-2002 provided by National Meteorological Administration. Results reveal that: 1) Summer precipitation in the Yangtze river catchment shows significant increasing tendency. The Poyanghu lake basin, Dongtinghu lake basin and Taihu lake basin in the middle and lower reaches are the places showing significant positive trends. Summer precipitation in the middle and lower reaches experienced an abrupt change in the year 1992; 2) The monthly precipitation in months just adjoining to summer shows decreasing tendency in the Yangtze river catchment. The upper and middle reaches in Jialingjiang river basin and Hanshui river basin are the places showing significant negative trends; 3) Extreme precipitation events show an increasing tendency in most places, especially in the middle and lower reaches of the Yangtze river catchment.  相似文献   

15.
Monthly mean temperatures and monthly precipitation totals at six stations from theCappadocian sub‐region in the continental Central Anatolia region of Turkey were analysed in order to detect the response of the variability in the Cappadocian climate to the variability of the North Sea ‐ Caspian Pattern Index (NCPI). Most of this region is classified as semi‐arid according to various climate classifications. Time series of the NCPI for the period 1958–1998, enabled each month from October toApril to be classified as belonging to the negative phase NCP(?), positive phase NCP(+) or neutral conditions. Monthly temperature and precipitation series for each station were analysed separately for both phases. Temperatures during NCP(?) were found to be considerably higher than during NCP(+). These results confirm previous results regarding the role of the NCP in controlling the temperature regime in that region. No significant differences were found in precipitation totals between the two phases, but major differences were identified in their spatial structure.  相似文献   

16.
利用逐月降水数据和NCEP/NCAR再分析数据,分析了洞庭湖流域春、夏、秋季57年来旱涝异常的年际变化以及典型旱涝异常年份的全球海温分布形势,并利用降尺度和趋势分析方法探究气象因子对ENSO和关键区海温的响应,以加强对流域旱涝前期影响因素的认识。结果表明：1）流域在春、秋季旱涝变化趋势不明显,在夏季较明显地变湿。2）前期冬、夏季ENSO事件分别对流域春、秋季旱涝产生显著影响,而与夏季呈不显著的统计特征。3）在消除前期ENSO信号后,阿留申群岛附近海域（S3）、澳大利亚东部海域（S4）海温和印度洋偶极子（Indian Ocean Dipole, IOD）现象仍分别为春、夏、秋季与流域旱涝有密切联系的海温因素。4）S3区SST对流域春季旱涝的影响通过西风带环流实现,S4区SST偏高似乎是东亚夏季风强度偏弱的表现,成熟的IOD现象为流域秋季旱涝的主导因子。  相似文献   

17.
黄河中上游流域夏季异常降水的变化特征及环流分析   总被引：2，自引：0，他引：2  
王楠  李栋梁  张杰 《干旱区地理》2012,35(5):754-763
 从中国气象局信息中心提供的全国地面台站逐日观测资料中选取黄河中上游流域66 个台站资料,结合NCEP/NCAR再分析资料,运用小波分析等统计方法,对黄河中上游流域夏季降水异常的变化特征、周期分布及影响降水的因子进行分析,研究结果表明：（1）流域旱涝年夏季降水空间分布上差异显著,易涝区位于河套平原,易旱区位于黄土高原东北部;（2）1960-2008年,流域夏季降水量线性趋势变化不明显,但年际间波动较大,多雨年少雨年相间出现,近50 a中降水整体呈现平稳—少雨—多雨—平稳—多雨—少雨的过程;（3）黄河中上游流域降水变化周期复杂多样,总体以2 a周期振荡为主,异常少雨年多表现为9 a周期振荡,异常多雨年多表现为15 a周期振荡,且流域主周期的空间分布可能与地形地貌、海拔高度及流域分布等地理因素有关;（4）丰、枯雨年环流形式差异显著,影响流域降水的环流系统有季风,西太平洋副高,温带气旋及贝加尔湖低压。  相似文献   

18.
石羊河流域1961-2005年蒸发皿蒸发量变化趋势及原因初探   总被引：4，自引：0，他引：4  
 利用1961—2005年石羊河流域上、中、下游当地气象站的逐月20 cm口径蒸发皿蒸发量、平均气温、平均相对湿度、降水量、平均风速、日照时数、最高气温和最低气温资料,研究了近45 a石羊河流域蒸发皿蒸发量变化趋势及原因。结果表明,45 a来,石羊河流域及上、下游年蒸发皿蒸发量呈上升趋势,中游年蒸发皿蒸发量呈下降趋势,上游上升趋势最明显。四季中,春、秋、冬季蒸发皿蒸发量呈上升趋势,上升最明显的是冬季,其次为秋季,春季变化不明显,夏季蒸发皿蒸发量变化呈下降趋势。石羊河流域在不同时段不同区域年蒸发皿蒸发量都存在明显的6～7 a周期和1～2 a的短周期,并都发生了突变。相关系数法分析表明,影响石羊河流域及中、下游年蒸发皿蒸发量变化的主要影响因子是相对湿度和降水,上游的主要影响因子是相对湿度和气温。四季中,春季的主要影响因子是相对湿度和降水;夏季影响石羊河流域及上、中蒸发皿蒸发量变化的主要因子是相对湿度和气温,下游的主要影响因子是相对湿度和降水;秋季影响石羊河流域及中、下游蒸发皿蒸发量变化的主要影响因子是相对湿度和气温日较差,上游其主要影响因子是相对湿度和降水;冬季的主要影响因子是气温和相对湿度。影响年以及春、夏、秋最显著的因子是相对湿度,冬季最显著的影响因子是气温。  相似文献   

19.
We investigated the precipitation characteristics for the summer period of 2013 on the basis of analyzing the daily precipitation amounts according to observational data from the Russian and Chinese meteostations on the territory of the Amur river basin. An analysis is made of the synchronism in the fluctuations of long-term series of precipitation amounts for two summer months (July and August) by using a modified algorithm for a classification of the fields of hydrometeorological characteristics, such as cluster analysis. The study revealed a poor correlation of precipitation amounts in different parts of the basin. We analyzed the interannual fluctuations in absolute maxima of the consecutive precipitation amounts for different periods of time (from 1 to 30 days). It is shown that precipitation over the summer period of 2013 that caused a disastrous flood in the lower reaches of the Amur were extreme primarily as regards the territory encompassed and the flood duration, which was due to a combination of synoptic processes of a different genesis. It was found that the precipitation amounts for periods shorter than 19 days in 2013 were not extreme in terms of intensity. A comparison was made with the year 1984 when there also occurred a flood on the Amur but not as violent. Parameters of the probability curves for 2013 and 1984 are presented for long-term series of maximum precipitation amounts for the summation period of 7 and 30 days. It is concluded that for calculating the maximum possible precipitation amounts which are necessary for assessing the maximum possible floods, it is appropriate to consider synoptic situations with long-lasting precipitation rather than separate short-lasting storm rains.  相似文献   

20.
塔里木河流域TRMM降水数据精度评估   总被引：1，自引：1，他引：0  
沈彬  李新功 《干旱区地理》2015,38(4):703-712
利用塔里木河流域24个气象站降水数据,分析了2000-2013年TRMM多卫星降水数据(TRMM 3B43 v7)在塔里木河流域的适用性。检验结果表明:全年来看,TRMM数据对研究区所有站点的年均降水量拟合较好(R2=0.8846),流域内24个站点平均年降水量相对偏差为19.02%,其中60%的站点表现为TRMM年降水量高于地面实测年降水量;月降水方面,除个别站点(于田、且末、乌恰)较差外,大部分站点的拟合度都较好;就季节而言:春季拟合效果最好,夏、秋季的TRMM数据存在低估问题,而冬季则偏高估;流域降水量由东南向西北递增,并在西北部边缘地区增加较显著,形成一个相对丰水带;而向沙漠腹地方向延伸的降水量则呈减少趋势。同时流域最大降水区域在一年中变化存在一定的规律。  相似文献   

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