1961—2009年辽河流域水文气象要素变化特征   总被引：1，自引：0，他引：1  

梁红  孙凤华  隋东 《辽宁气象》2012,(1):59-64

依据1961—2009年辽河流域5个气象观测站点逐日降水和气温观测资料,运用非参数检验方法（Mann-Kendall法）,对辽河流域降水和气温的变化趋势进行了分析。利用2006—2010年夏季共162d降水日的铁岭站日降水量与铁岭水文站径流量资料,探讨了日降水量与径流量之间的相关关系。结果表明：辽河流域年降水量减少趋势明显,降水量偏少年份明显增加,其主要原因为占全年降水量65%的夏季降水以7.4 mm/10 a的气候趋势倾向率递减,呈现出明显的减少趋势;辽河流域的年平均气温是在波动中逐渐上升的,且升温趋势明显,春季呈明显的升温趋势,夏季略有下降,秋季变化不大,冬季是气温上升最明显的季节;日降水量与径流量存在正相关关系,且日降水量与降水第二日的径流量相关显著。  相似文献   

贺兰山至吉兰泰盐湖的水化学特征及演化规律     

魏国孝  朱锡芬  马金珠  许翔  徐涛 《广东气象》2012,31(4)

在对吉兰泰盐湖南部地下水化学组分特征分析的基础上,利用PHREEQC软件对水文地球化学演化规律进行模拟研究。结果表明,从贺兰山西侧山前到吉兰泰盐湖,水化学类型由HCO-3型过渡到Cl-—SO24-型、最后变为Cl-型;Ca2＋、Mg2＋与SO24-相关分析表明发生石膏溶解出的Ca2＋置换了MgCO3中Mg2＋,从而产生了CaCO3沉淀的水岩反应,而白云石、石膏、岩盐、CO2（g）的溶解是常量离子增加的物质来源,同时伴有强烈的蒸发浓缩作用及阳离子交换作用。特别是深层地下水具有较高的mNa/Cl值与较低的mCa/Na值,表明发生强烈的阳离子交换作用,这对认识吉兰泰盐湖地区及干旱区沙漠地区水体发生的水岩相互作用与演化机制具有借鉴作用。  相似文献   

1959-2008年广西西江流域洪涝气候特征   总被引：5，自引：0，他引：5       下载免费PDF全文

何慧  陆虹  欧艺 《气候变化研究进展》2009,5(3):134-138

 利用1959-2008年西江流域气象测站降水资料、西江干流及其支流年最高水位资料,建立逐年洪涝发生站次序列,并分析其时空特征和演变规律。结果表明：西江干流发生洪涝的频率比各支流大,各支流的中下游发生洪涝频率比上游大;西江流域洪涝的发生站次具有较显著的阶段性和突变性特征,主要突变发生在1967年和1993年;近16 a洪涝发生频率显著偏多,流域性大洪涝基本集中在这一时期。了解西江流域洪涝变化的规律,有利于提高洪涝灾害评估和预测水平,为防灾减灾提供科学依据。  相似文献   

登陆孟加拉湾风暴结构个例分析与数值模拟   总被引：1，自引：0，他引：1  

王曼  李华宏  段旭  刘建宇 《气象科技》2009,37(1):12-18

采用NCEP-NCAR再分析资料,分析了2006年4月29日登陆缅甸并造成云南省强降水过程的孟加拉湾风暴结构。并且利用美周新一代中尺度WRF（weather Researchand Forecast）模式对2006年4月28～30日云南强降水过程进行了数值模拟研究。结果表明：孟加拉湾风暴登陆前后结构具有明显变化,从基本对称结构演变为非对称结构,WRF模式较好地模拟出盂加拉湾风暴登陆前后环流场特征和风暴移动路径以及造成云南强降水雨带的分布特征。  相似文献   

集合预报风场扰动的物理结构及演变特征          下载免费PDF全文

张瑜  时洋  周勃旸  马旭林 《大气科学学报》2022,45(2):268-279

初始扰动结构和振幅的合理性直接影响到集合预报的质量和整体性能,合理的初始扰动结构是确保集合预报扰动质量的关键.本文基于欧洲中期天气预报中心数据、我国T639全球集合预报系统以及GRAPES区域集合预报系统的预报场,针对模式初值不确定性,主要研究了风场初始扰动结构及其集合离散度、扰动能量等结构和演变特征,分析了集合预报风...  相似文献   

秦岭勉略缝合带组成与古洋盆演化   总被引：1，自引：7，他引：1       下载免费PDF全文

李亚林李三忠  张国伟 《中国地质》2002,29(2):129-134

秦岭勉略构造带是典型的蛇绿构造混杂岩带,带内组成复杂、变形强烈,其主导构造样式表现为以系列北倾逆冲断层为格架,不同岩片推覆叠置的叠瓦状构造。详细的组成及构造研究表明,缝合带由洋盆形成演化不同阶段、不同性质的陆缘沉积岩系、不同类型蛇绿岩以及洋盆俯冲－碰撞造山过程中以不同方式出露的构造岩块组成,同时区域地层对比表明勉略古洋盆形成过程具有自西而东“剪刀式”打开扩展的性质与特点。  相似文献   

The local far-infrared galaxy colour–luminosity distribution: a reference for BLAST and Herschel/SPIRE submillimetre surveys     

E. L. Chapin  D. H. Hughes  I. Aretxaga 《Monthly notices of the Royal Astronomical Society》2009,393(2):653-662

We measure the local galaxy far-infrared (FIR) 60 to 100 μm colour–luminosity distribution using an all-sky IRAS survey. This distribution is an important reference for the next generation of FIR–submillimetre surveys that have and will conduct deep extragalactic surveys at 250–500 μm. With the peak in dust-obscured star-forming activity leading to present-day giant ellipticals now believed to occur in submillimetre galaxies near   z ∼ 2.5  , these new FIR–submillimetre surveys will directly sample the spectral energy distributions of these distant objects at rest-frame FIR wavelengths similar to those at which local galaxies were observed by IRAS . We have taken care to correct for the temperature bias and the evolution effects in our IRAS 60-μm-selected sample. We verify that our colour–luminosity distribution is consistent with the measurements of the local FIR luminosity function, before applying it to the higher redshift Universe. We compare our colour–luminosity correlation with recent dust–temperature measurements of submillimetre galaxies and find evidence for pure luminosity evolution of the form  (1 + z )³  . This distribution will be useful for the development of evolutionary models for Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and Spectral and Photometric Imaging Receiver (SPIRE) surveys as it provides a statistical distribution of the rest-frame dust temperatures for galaxies as a function of luminosity.  相似文献   

The evolution of the red sequence slope in massive galaxy clusters     

J. P. Stott  K. A. Pimbblet  A. C. Edge  G. P. Smith  J. L. Wardlow 《Monthly notices of the Royal Astronomical Society》2009,394(4):2098-2108

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The role of minor mergers in the recent star formation history of early-type galaxies     

Sugata Kaviraj  Sebastien Peirani  Sadegh Khochfar  Joseph Silk  Scott Kay 《Monthly notices of the Royal Astronomical Society》2009,394(4):1713-1720

We demonstrate that the large scatter in the ultraviolet (UV) colours of intermediate-mass early-type galaxies in the local Universe and the inferred low-level recent star formation (RSF) in these objects can be reproduced by minor mergers in the standard Λ cold dark matter (ΛCDM) cosmology. Numerical simulations of mergers with mass ratios ≤1:4, with reasonable assumptions for the ages, metallicities and dust properties of the merger progenitors, produce good agreement with the observed UV colours of the early-type population, if the infalling satellites are assumed to have (cold) gas fractions ≥20 per cent. Early-types that satisfy  ( NUV − r ) ≲ 3.8  are likely to have experienced mergers with mass ratios between 1:4 and 1:6 within the last ∼1.5 Gyr, while those that satisfy  3.8 < ( NUV − r ) < 5.5  are consistent with either recent mergers with mass ratios ≤1:6 or mergers with higher mass ratios that occurred more than ∼1.5 Gyr in the past. We demonstrate that the early-type colour–magnitude relations and colour distributions, in both the UV and optical spectral ranges, are consistent with the expected frequency of minor merging activity in the standard ΛCDM cosmology at low redshift. We present a strong plausibility argument for minor mergers to be the principal mechanism behind the large UV scatter and associated low-level RSF observed in early-type galaxies in the nearby Universe.  相似文献   

The near-IR luminosity function and bimodal surface brightness distributions of Virgo cluster galaxies     

Michael McDonald †  Stéphane Courteau  R. Brent Tully 《Monthly notices of the Royal Astronomical Society》2009,394(4):2022-2042

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