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1.
近60年西安市极端气温事件变化特征分析   总被引:4,自引:0,他引:4  
分析西安市近60年极端温度事件的变化特征以及极端温度指数与气温的关系。选取1951—2010年西安市逐日平均气温、日最高气温以及日最低气温资料,采用世界气象组织(WMO)公布的极端温度指数,利用Mann-Kendall(M-K)方法进行极端气温事件分析。认为近60年来,西安年平均气温、年平均最低气温、年平均最高气温呈上升趋势,20世纪90年代增温尤为明显;3种气温的变化趋势除夏季平均最高气温呈下降趋势外,各季节均为上升趋势;年平均气温与极端气温指数之间存在明显的相关性;暖夜日数和暖昼日数呈上升趋势,而霜冻日数、冷夜指数和冷昼日数呈下降趋势,冷夜指数减小、暖夜指数增大的幅度远大于冷昼日数减少的幅度,夜间气温的上升对增暖的贡献更大;极端气温指数的变化存在明显的年际变化特征,并伴有突变发生,西安市气温升高主要发生在20世纪90年代初期。  相似文献   

2.
利用1961~2005年南宁市最高、最低和平均温度资料,分析近50a来南宁市的气温变化特征,通过气候变暖前后灾害性天气气候事件的对比,分析南宁市灾害性天气气候事件的变化规律。结果表明,1961~2005年南宁市年平均气温增温趋势明显,温度变率为0.3C/10a,各季节平均气温均呈上升趋势,秋季增温最明显,冬季次之,夏季位居第三,春季增温最小。年平均最高气温呈较弱的增暖,变率为0.13C/10a,而年平均最低气温的增暖趋势比年平均最高气温明显,为0.36C/10a。年平均日校差的变化则呈递减的趋势,变率为-0.23C/10a。在全球气候增暖和城市化快速发展的过程中,南宁市的灾害性天气气候事件发生了明显的变化:极端强降水有增加趋势,高温天气明显增多,持续高温天气加剧,雷暴和大风日数明显减少,春季低温阴雨天气减少。南宁市灾害性天气气候事件变化的原因可能与全球气候变暖有关,城市化可能是造成南宁市灾害性天气气候事件变化的主要原因。  相似文献   

3.
利用昌宁国家一般气象站1961~2010年的观测资料,采用数理统计、趋势拟合等方法,分析了昌宁近50 a气温、降水的变化特征.结果表明:近50 a昌宁年平均气温、年平均最高气温、年平均最低气温、四季平均气温均呈上升趋势,20世纪90年代中期以后气温增温非常明显,气候变暖主要来自秋、冬气温增高的贡献;降水量呈缓慢下降趋势,夏、冬下降趋势最为明显.过去50 a昌宁县气候存在凉湿—凉干—暖湿—暖干的变化过程.  相似文献   

4.
新余市51年气温变化特征分析   总被引:1,自引:0,他引:1  
根据新余观测站1959~2009年的气温资料,从年平均气温、夏季、冬季平均气温和年平均最高气温、年平均最低气温趋势变化角度对新余51年的气温变化作了全面分析。分析表明:新余市51年来年平均气温、年平均最高气温、年平均最低气温都呈上升趋势,90年代中期之后增温尤其明显。夏季、冬季气温趋势变化中,夏季变暖趋势不明显,冬季变暖趋势显著。  相似文献   

5.
选用湖北省77个代表站1960-2003年逐日气温观测资料,分析了湖北省气温的年、季节变化规律及其地域分布特征.结果表明:湖北省近44年气温呈上升趋势,至2003年气温上升了0.5℃,增温速率约为0.12℃/10a,和近50年来的全球平均增温速率相当.20世纪90年代升温最剧烈.春季、秋季和冬季气温均呈上升趋势,冬季增温最明显,而夏季气温却呈下降趋势.夏季平均日最高气温也呈下降趋势,冬季平均日最低气温上升趋势显著.气温变化不同的地区差异较大,西部地区变化趋势不明显,有微弱的下降趋势,而中东部地区则有较明显的升温趋势.  相似文献   

6.
利用1961~2006年喀什气候观象台月最高气温、最低气温、平均气温、风沙日数资料,研究其长期变化趋势和年际变化,得出:气温具有增暖趋势,90年代增暖最强,特别是最低气温增暖明显;而最高气温呈下降趋势,风沙和大风日数都呈下降趋势。  相似文献   

7.
根据果洛州气象台1970~2006年定时、逐日、月、年气温资料,统计分析了该地区年内各月及年际气温变化特征。研究表明:果洛地区年内最高气温出现在7月或8月初,最低气温出现在1月或2月初。年平均气温呈明显的上升趋势,气温变化存在明显的季节性差异,冬季变暖趋势最明显,致使气温年较差逐渐减小。进入21世纪后夜间气温升温幅度大于白天气温升温幅度,气温日较差显著减小。  相似文献   

8.
本文就临汾市近48年来(1954年—2001年)的气温、降水进行了认真、细致的诊断分析.结果表明:气温呈非连续性的增暖趋势,线性变化率:年平均气温为0.25.(10a)-1,年平均最高气温线性变化率为0.1℃.(10a)-1,年平均最低气温线性变化率为0.45℃.(10a)-1.从变化规律分析,60年代较50年代有所增暖,60年代至80年代中期变化不明显.而从1989年以后,呈连续性增暖趋势.到1999年出现了1954年以来的最暖年,年平均气温14.1℃,究其变化原因,可能与90年代频繁发生的厄尔尼诺及城市热岛效应有关.降水变化存在着明显的年代际变化规律,平均每6年—8年为一周期,降水量从50年代至90年代呈连续性的递减趋势,线性变化率为-21.9mm(10a)-1,90年代较50年代降水量减少了83.4mm.  相似文献   

9.
1961-2010年新疆极端气温时空演变特征研究   总被引:1,自引:0,他引:1  
根据1961-2010年新疆50个气象测站逐日均温、日最高温、日最低温资料,选取国际上常用的22个极端气温指数,运用多种统计方法全面、系统地分析新疆地区极端气温事件时空变化特征。研究结果表明:1全疆日均温、年均温1996年后均呈显著上升变化,冬季、夏季最低温上升趋势明显,且变暖幅度冬季大于夏季;2除GTmax、GTavg、DTR及极值指数(TXx、TNx、TXn、TNn)未表现显著变化外,20世纪90年代末期后,冷指数呈下降趋势,暖指数呈上升趋势,总体上,变暖幅度冷指数大于暖指数、低温指数大于高温指数、夜指数大于昼指数,且变暖幅度盆地大于山区;3极端冷指数转折主要发生在80年代中后期,而极端暖指数的趋势变化主要在90年代末期发生转折,无论从平均气温序列的变化,还是极端气温事件的发生来看,新疆变暖趋势明显;4生长季节极端气温指数GTavg、GTmax均表征为上升趋势,日均温上升会导致热浪日数HWDI强度增加以及生长季节长度GSL延长,且新疆生长季节长度变化规律表现为:南疆北疆东疆,盆地山区。  相似文献   

10.
利用1961~2006年喀什气象站月平均最高气温、平均最低气温以及平均气温资料,研究其长期变化趋势和年际变化,得出平均气温具有增暖趋势,90年代增暖最强,特别是最低气温增暖明显;而最高气温呈下降趋势.  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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