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1.
基于CMIP5模式鄱阳湖流域未来参考作物蒸散量预估 总被引：3，自引：0，他引：3
预测未来气候情境下鄱阳湖流域参考作物蒸散量(Reference crop Evapotranspiration,ET0)的时空分布可为流域水资源的优化管理,为科学应对气候变化对农业生产的影响提供基础数据支撑.利用鄱阳湖流域14个气象站点1961-2014年逐日气象数据,采用Penman-Monteith公式计算出历史ET0;基于同期美国环境中心(NCEP)再分析数据及2006-2100年CMIP5中CNRM-CM5模式在RCP4. 5和RCP8. 5情景下的预测数据,经统计降尺度模型(statistical downscaling model,SDSM)模拟和偏差校正,预测流域未来ET0;通过Mann-Kendall检验、普通克里金插值和空间自相关法分析了流域1961-2100年ET0的时空演变特征.结果表明:NCEP再分析资料与流域ET0建立的逐步回归降尺度模型模拟效果较好,CNRMCM5模式降尺度模拟结果经偏差校正后,精度明显提高,适宜流域未来ET0的预估.鄱阳湖流域在基准期1961-2010年ET0整体上呈减小趋势,空间分布上呈南北高、中间低的特点,表现出明显的空间差异性.RCP4.5、RCP8.5情景下未来3个时期鄱阳湖流域ET0较基准期均呈不同程度的增加趋势,其空间分布整体表现为东高西低、局地略有突出;无论是在基准期或是未来情景下的3个时期,ET0均具有较强的空间自相关性.在RCP8.5情景下,鄱阳湖1961-2100年干旱指数呈现出较为明显的上升趋势,流域的干旱状况随时间加剧,2011-2100年间流域绝大部分地区由湿润区转为半湿润区,干旱指数自南向北递减,赣江流域将是鄱阳湖流域未来干旱风险的重点防范区. 相似文献
2.
针对四川盆地东部的2006年特大干旱, 分析MODIS遥感观测资料对旱情的响应, 以探求区域干旱遥感监测的可操作性方案. 首先, 依据地面气象和水文观测初步估算了旱情的发展过程和空间分布范围, 利用MODIS产品计算了2001~2006年夏季每8天的地表水分遥感指数; 然后, 构造并计算了地表水分距平遥感指数, 用之检验了四川盆地东部特大干旱的遥感响应; 最后, 基于地表水分距平遥感指数分析了不同植被覆盖类型对干旱的敏感性. 研究结果表明: 该距平指数对水分盈缺敏感, 优于基于绝对含水量的遥感监测方法, 准确提取了四川盆地东部2006年特大干旱的时空格局, 重建了旱情的发展和消退历程, 同相关旱情统计比较吻合. 同干旱的地面监测比较, 该方法不仅考虑了局地需水持水特性, 而且克服了观测站点的空间代表性局限, 能快速提供区域旱情的详细空间分布, 因此为区域干旱的日常监测提供了一个具可操作性的实用方案. 相似文献
3.
鄱阳湖流域干旱气候特征研究 总被引：2，自引：1，他引：1
本文利用鄱阳湖流域127个站点1960-2007年逐日降水和温度资料,选用Z指数对鄱阳湖流域的气象干旱进行分析,并将干旱分为偏旱、大旱和特旱三个等级.研究结果表明鄱阳湖流域干旱基本呈现出南少北多、南强北弱的空间分布形式.鄱阳湖流域7-12月发生的干旱以偏旱为主,大旱和特旱主要出现在1-6月.线性趋势变化分析表明,2000年以来干旱范围和干旱强度均呈现出增加的趋势,其中,2003、2004和2007年的干旱较为严重.2003年大部分月份偏旱范围广、强度大,全年大旱和特旱出现的范围均较小,但3-4月和6-7月的大旱和特旱强度较大;2004年大部分月份偏旱范围和强度均相对较小,但在3月和6月出现范围较大且强度较强的大旱和特旱;2007年干旱分布更为极端,仅在7、10和11月出现范围较广或强度较大的偏旱,而在5月集中出现面积超过80%的大旱和特旱. 相似文献
4.
利用Thornthwaite的干湿分类函数,对近100年中国干旱和半干旱区界限的10年际变动特征进行了分析.结果发现：近50年,在东北中部和华北北部,干旱和半干旱边界呈波动式东移,有明显向东扩展的趋势;在华北南部和陕西南部,半干旱边界也呈波动式南扩,其中陕西南部半干旱边界向南扩展的范围最大.近100年,10年际的干旱和半干旱边界也呈波动式摆动且存在向东和向南扩展的趋势,但在华北南部与东北中部两个地区以20世纪20年代前后干旱和半干旱的范围最大、最强.干旱和半干旱分界线的位置变化与区域升温和降水减少密切相关. 相似文献
5.
以面积达270km2的广州城区为研究区,利用高密度分布的近12 000个钻孔,综合各行业规范对软土的定义,判别出广州城区的软土层,并详细分析其空间分布特征,结果为:研究区内近80%的面积其下伏地层有软土分布,软土层在广州城区埋藏较浅,其顶板埋深约6.0m以浅,并呈现中部浅、南北两侧深的特点;另外,软土层在广州城区沉积厚度差异较大,厚度不足1.5~13.5m者皆有分布,其中厚度大于3.0m的地区占了研究区面积的32%,同时软土的厚度分布呈现出研究区南部、西部的厚度大,中部、北部的厚度小,河流岸边的厚度大,远离河流的厚度小的特点,并且呈现出两个沉积中心。结合上述结果,初步预测出研究区内近1/3的面积在强烈地震时可能产生软土震陷,软土震陷区主要集中在研究区的西部和南部。 相似文献
6.
花粉记录的青藏高原中部中全新世以来植被与环境 总被引：2，自引：0，他引：2
唐领余 沈才明 李春海 彭金兰 刘惠 Kam-Biu Liu Carrie Morrill Jonathan T.Overpeck Jonathan E.Cole 杨保 《中国科学D辑》2009,39(5):615-625
青藏高原中部的草甸/草原混合生态群落, 对气候变化非常敏感. 孢粉记录显示草原发育时期, 莎草减少, 区域气候是相对干旱的, 在时间上对应季风相对弱的时期. 依据唐古拉山垭口湖、阿洪错和错那3个淡水湖泊钻孔孢粉分析, 定量重建的温度和降水指标, 探讨该地区8200 cal a BP以来的植被与气候变化. 8200~6500 cal a BP, 尤其是8200~7200 cal a BP, 植被以草甸/草原混合生态群落为主, 显示强季风控制着青藏高原中部; 6000~4900, 4400~3900以及2800~2400 cal a BP时期区域植被以草原植被为主, 应是3次百年尺度的干旱事件; 4900~4400 cal a BP期间植被类型由草原向草甸转变; 6500~5400和 3000~1600 cal a BP出现两次大的变干事件; 数值摸拟估计, 高原中部接近于现今的环境, 最早可能出现在6500 cal a BP, 自3000 cal a BP以后高原中部季风性降水和湿度逐渐减少至现今水平, 可能在700~300 cal a BP出现一次小冰期变冷事件. 相似文献
7.
极端干旱事件中洞庭湖水面变化过程及成因 总被引：2，自引：0，他引：2
干旱是洞庭湖区长期以来面临的严重自然灾害之一,给周边人们的生产生活造成了极大的影响.针对2006和2011年洞庭湖区发生的极端干旱事件,借助遥感影像大范围、时空连续的优势,结合湖区水文气象等观测资料,从时空两方面阐释了洞庭湖在典型干旱年份水域分布及变化过程,进一步从温度、降水、径流以及蓄水量等方面对比分析不同干旱事件发生、发展过程的一致性和差异性.研究结果表明:2006年干旱大致从7月开始,至12月结束.水面淹没范围由湖心向周边扩展,到7月达到最大值,8月提前进入枯水期,减小范围主要集中在东洞庭湖外围和南洞庭湖的北边.2006年干旱属于由入湖径流减少主导的水文干旱事件;2011年的干旱则从4月开始,至11月结束,在9月以后干旱继续加重.水面淹没范围在6月急剧增大且一直到8月都维持在较高的水平,涨水期水面由中心向四周淹没,退水期水面变化范围与涨水期相反.2011年干旱是由流域降水减少引起的水文和气象干旱事件.研究结果揭示了洞庭湖区干旱成因的多样性和复杂性,对于制定科学合理的干旱灾害防范措施,减缓区域的生态环境问题等具有一定的指导和借鉴意义. 相似文献
8.
基于时间序列MODIS影像的鄱阳湖丰水期悬浮泥沙浓度反演及变化 总被引：2，自引：0，他引：2
悬浮泥沙浓度是描述水质的重要参数之一,获得其在空间和时间上的分布信息对于理解、管理和保护湖泊生态系统是必要的.此研究旨在建立基于中分辨率成像光谱仪(MODIS)影像的鄱阳湖悬浮泥沙浓度反演模型,并利用建立的模型反演2000-2007年鄱阳湖丰水期的悬浮泥沙浓度,分析其在时间和空间上的变化特征并对引起这些变化的原因进行讨论.研究结果揭示:MODIS Terra影像红波段与悬浮泥沙浓度具有显著的相关性(R2=0.92,s.e.=12.02mg/L,F=154.30,P<0.001),可以用于鄱阳湖丰水期悬浮泥沙浓度的反演;自2000-2007年间,鄱阳湖悬浮泥沙浓度呈明显的时间和空间分布特征,在南部水体悬浮泥沙浓度无明显变化,在北部呈增加趋势,而中部水体泥沙浓度波动较大;鄱阳湖北部的采砂活动是导致此区域悬浮泥沙浓度增加的主要原因,其与长江江水倒灌鄱阳湖共同作用引起鄱阳湖中部泥沙浓度的波动,抚河、信江和饶河输沙量的非显著变化也导致南部鄱阳湖水体悬浮泥沙浓度的非显著变化. 相似文献
9.
本研究收集了中国东北地区2008—2016年九年时间内207个固定地震台站和127个NECESSArray流动地震台站的波形资料,利用SKS波分裂的最小切向能量网格搜索方法获得了243个台站的有效分裂结果.研究结果显示,尽管研究区各向异性快波方向基本以NW-SE向为主,但无论是在快波方向上还是快慢波时间延迟上不同构造单元内部与不同构造单元之间均存在着较大差别.大兴安岭造山带北部的各向异性快波方向自北向南由NNE-SSW向转变为NNW-SSE向,在中部以NW-SE向为主,而南部自北而南由NE-SW向逐渐转变为近E-W向;松辽盆地的各向异性快波方向在北部自西向东主要表现为由NNW-SSE向逐渐转变为NW-SE向,在中部自西向东由NE-SW向转变为近E-W向,而在南部既有NE-SW向又有NW-SE向;佳木斯地块各向异性方向由西部的NW-SE转变为东部的NNW-SSE,同时快慢波时间延迟逐渐变大;长白山造山带北部自北向南由NW-SE向逐渐转变为近E-W向,中部各向异性快波方向为NNW-SSE向,且快慢波时间延迟较大,而南部以NW-SE向为主;燕山造山带的各向异性快波方向主要沿E-W向分布,基本平行于燕山造山带的走向.这些结果说明,尽管复杂的各向异性快波方向与局部岩石圈拆沉和热物质上涌有关,但更重要是与"大地幔楔"中物质水平流等动力过程密切相关,也有待将来结合更多地震资料如面波不同深度的特征各向异性进行分析.在阿巴嘎火山群、哈拉哈火山群、长白山火山、龙岗火山和镜泊湖火山区及五大连池火山区等特殊构造区的周边地区,各向异性快波方向围绕这些构造区随方位均发生明显变化,暗示了火山区下方热物质上涌可能影响了"大地幔楔"中的软流圈物质水平流方向. 相似文献
10.
根据波茨坦地磁场模型(POMME6.2),研究喜马拉雅东构造结周围地区地壳磁异常的空间分布、磁异常随高度的衰减特征.利用二维小波变换方法对地表磁异常进行分解,分析小波细节组合和逼近信号的异常特点.讨论磁异常与地质构造的联系.结果表明,研究区内地壳磁异常分布相当不均匀.喜马拉雅—东构造结—龙门山—大巴山地区分布着较强的负磁异常;四川盆地为正磁异常,其他地区磁异常较弱.东构造结对周围地区磁异常有重要影响,它及其周围地区的地壳磁异常都是在负磁或弱磁异常背景上,叠加着中短波长的正负磁异常.这些中小尺度磁异常由中、上层地壳磁性物质产生,走向与地质构造基本一致.沿金沙江、红河断裂带分布着清晰的弱磁异常带.龙门山断裂带、丽江—小金河断裂带和红河断裂带是磁异常强弱过渡带.青蒇高原中部东西向的磁异常,在东构造结弧顶地区呈弧形分布.青藏高原中部和滇中地块带状、团状磁异常具有相同的衰减规律. 相似文献
11.
Moisture budget variations in the Yangtze River Basin, China, and possible associations with large-scale circulation 总被引：3，自引：2，他引：1
Zengxin Zhang Hui Tao Qiang Zhang Jinchi Zhang Nicola Forher Georg Hörmann 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(5):579-589
We analyzed seasonal and annual variations of the whole layer atmospheric moisture budget and precipitation during 1961–2005
and their associations with large-scale circulation in the Yangtze River basin, China. The results indicated increasing moisture
budget in summer and winter, but decreasing moisture budget in spring and autumn. Positive correlations between moisture budget
and precipitation illustrate tremendous impacts the moisture budget has on the precipitation changes across the Yangtze River
basin. In terms of seasonal variations, significant correlations were observed between precipitation and moisture budget in
spring and autumn in the upper Yangtze River basin. Besides, we also analyzed changes of geopotential height. The positive
trends of the geopotential height (850 hPa) were observed in the East Asia and the negative trends in the middle and west
Pacific Ocean, indicating increasing geopotential height from south to north in east Asia which largely limited the moisture
propagation to north China. While decreasing meridional geopotential height from west to east along the Yangtze River basin
caused more moisture propagation from the west to the east parts of the study region, which may benefit more precipitation
in the middle and lower Yangtze River basin. 相似文献
12.
基于GPS多期复测资料, 利用最小二乘配置方法计算川滇地区应变参数, 分析该区域应变率场分布及其变化特征并探讨其分布与强震关系。 研究结果表明: ① 各时段应变率场空间分布的明显变化应属于大于GPS资料误差的真实地壳构造形变信息; ② 最大剪应变率及第一、 第二剪应变率的结果反映了走滑断裂对区域变形的显著控制; ③ 主应变率, 东西、 南北向应变率场动态结果反映的汶川地震孕震的空间尺度较大; ④ 在本区大致反映北东向与北西向剪切变形的第一剪应变率、 东西向应变率、 南北向应变率及最大剪应变率与6级以上地震对应较好。 相似文献
13.
淮河流域焦岗湖水质参数时空变化及影响因素 总被引：3，自引：1，他引：2
焦岗湖是淮河左岸一个天然湖泊,集防洪、灌溉、养殖、旅游等多种功能于一体.利用焦岗湖4个季节水质监测数据,运用Kriging方法,分析焦岗湖水质参数的时空变化及影响因素.结果表明:由于受水文季节变化过程及人类活动等综合影响,焦岗湖水质参数在时间及空间上均存在一定差异.从时间变化来看,夏季透明度较低、秋季较高;溶解氧浓度在春、冬季显著高于夏、秋季;总氮、总磷浓度与高锰酸盐指数均表现为夏季最高、秋季最低.从空间变化来看,4个季节的透明度空间差异较为显著;溶解氧浓度在春、冬季空间分布较为均匀,夏季呈现中心高周围低的变化趋势,秋季则表现为西高东低;总磷浓度春季分布较为均匀,夏、秋及冬季则呈西高东低之势;高锰酸盐指数在春、秋季节呈现东高西低之势,夏季高浓度主要集中在湖区北部,冬季浓度变化不大. 相似文献
14.
Elsa E. Moreira João T. Mexia Luís S. Pereira 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(1):183-193
In the present study, an ANOVA-like inference technique is used aiming at to assess if Alentejo, southern Portugal, could be considered a homogeneous region for drought management purposes. First, Alentejo was divided into four sub-regions according to latitude (north and south), and longitude (west and east). Inside each sub-region, 10 weather stations were considered. The time series of the Standardized Precipitation Index (SPI) were obtained for these stations using precipitation data for the period 1932–1999 (67 years). Contingency tables for the transitions between SPI drought classes were obtained for these time series. Loglinear models were fitted to these contingency tables to estimate the probabilities for drought class transitions. An ANOVA-like inference was applied considering the four sub-regions like treatments of a two way layout with two factors, latitude and longitude, each one with two levels, north and south, and west and east respectively. The weather stations of each sub-region were treated as replicates. Significant differences between west and east were found, that allowed to consider that Alentejo could be composed by two sub-regions. 相似文献
15.
Heilongjiang Province is a major grain production base in China, and its agricultural development plays an important role in China’s social economy. Drought and flood events are the primary disasters in Heilongjiang Province and have considerable impacts on agriculture. In this study, relatively complete monthly precipitation data from 26 meteorological stations in Heilongjiang Province during the period of 1958–2013 were analyzed using the standardized precipitation index (SPI) combined with principal component analysis, Mann–Kendall trend analysis and Morlet wavelet analysis to determine the spatial and temporal distributions of drought and flood events in this province. The results were as follows: (1) the whole of Heilongjiang exhibited an aridity trend. In northern Heilongjiang, spring and summer experienced a wetting trend, and autumn and winter experienced an aridity trend. (2) The SPI3 exhibited 8- and 16-year periodic variation characteristics in spring, 10- and 22-year periodic variation characteristics in summer, and 10- and 32-year periodic variation characteristics in autumn. In addition to the 10-year periodic variation characteristics in winter, other periodic variation characteristics were observed. (3) The increasing trend in the percentage of stations affected by flood was more obvious than that affected by drought. Therefore, Heilongjiang Province is more vulnerable to flooding. (4) The influence of drought and flood disasters in Heilongjiang Province showed a growth trend, but the flood effect was more remarkable. (5) The agricultural area affected by drought and flood disasters in Heilongjiang Province showed an increasing trend. Although there was a greater increase in flood disaster area, the main types of disasters were drought-dominated. 相似文献
16.
利用宁夏区域台网记录的2009年1月至2014年9月的近场小震波形资料, 使用剪切波分裂系统分析方法SAM方法, 对位于青藏高原东北缘的鄂尔多斯块体西侧进行了地壳各向异性研究, 共得到7个台站记录到的19条有效数据。 研究发现, 受复杂的局部构造、 应力场及断裂分布的影响, 研究区地壳各向异性在空间分布上呈现出分区性特点。 受区域构造应力场的控制, 台站的快剪切波偏振方向与区域构造应力的主压应力方向基本一致。 在构造上, 大致以中部的三关口—牛首山NNW向断裂为界, 可以分为南北两部分。 本研究显示, 以快剪切波偏振方向空间分布特征为划分依据, 大致以37°N为界划分南北部, 北部区域的快剪切波偏振方向为近N-S向, 与按构造划分的青藏高原东北缘—鄂尔多斯块体西侧北部区域主压应力场一致; 南部区域的快剪切波偏振方向为近E-W向, 同样与按构造划分的区域主压应力场一致。 相似文献
17.
FOCAL MECHANISM SOLUTION AND TECTONIC STRESS FIELD CHARACTERISTICS OF THE MIDDLE TIANSHAN MOUNTAINS,XINJIANG 
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下载免费PDF全文 ZHANG Zhi-bin ZHAO Xiao-cheng REN Lin 《地震地质》1979,42(3):595-611
The middle part of the Tianshan Mountains in Xinjiang is located in the north-central part of the Tianshan orogenic belt, between the rigid Tarim Basin and Junggar Basin. It is one of the regions with frequent deformation and strong earthquake activities. In this paper, 492 MS>2.5 earthquake events recorded by Xinjiang seismograph network from 2009 to 2018 were collected. The MS3.5 earthquake was taken as the boundary, the focal mechanism solutions of the earthquake events in this region were calculated by CAP method and FOCEMEC method respectively. At the same time the focal mechanism solutions of GCMT recorded historical earthquake events in this region were also collected. According to the global stress map classification standard, the moderate-strong earthquakes in the region are mainly dominated by thrust with a certain slip component, which are distributed near the combined belts of the Tarim Basin, Junggar Basin, Turpan Basin and Yili Basin with Tianshan Mountains. The thrust component decreases from south to north, while the strike-slip component increases. The spatial distribution characteristics of the tectonic stress field in the middle section of the Tianshan Mountains in Xinjiang are obtained by using the damped regional-scale stress field inversion method. The maximum principal compressive stress in axis the study area rotated in a fan shape from west to east, the NW direction in the western section gradually shifted to NE direction, its elevation angle is nearly horizontal, in the state of near horizontal compression. The minimum principal compressive stress axis is nearly EW, and the elevation angle is nearly vertical. Influenced by large fault zones such as Kashi River, Bolhinur, Nalati, Fukang, the southern margin of the Junggar and the north Beiluntai, the local regional stress field presents complex diversity. Under the influence of the northward extrusion of Pamir and Tarim blocks, the whole Tianshan is shortened by compression, but its shortening rate decreases from south to north and from west to east, the stress shape factor increases gradually from west to east, the intermediate principal compressive stress axis exhibits a change in compression to extension. There are some differences in the characteristics of tectonic stress field between the north and south of Tianshan Mountains. The regional maximum principal compressive stress axis is 15° north by east on the south side, while it is nearly NS on the north side. The deformation of the Tianshan Mountains and the two basins on both sides is obviously larger than that in the inside of the mountain. Changes in the crustal shortening rate caused by the rotation of the rigid Tarim block and Junggar block to the relatively soft Tianshan block, as well as the uplifts of Borokonu and Bogda Mountains, the comprehensive influence of the material westward expansion constitute the stress field distribution characteristics of the north and south sides of the middle section of Tianshan Mountains. The recent two MS6.6 earthquakes in the region caused the regional stress field to rotate counterclockwise. The post-earthquake stress field and the main source focal mechanism solution tend to be consistent. The seismic activity in the study area is week in the south and strong in the north. The focal depth is about 20km. Most strike-slip earthquakes occur near the junction belt of the Tianshan and Junggar Basin. 相似文献
18.
利用青海省东部农业区12个气象站的降水资料，分析了该区降水气候倾向率和近期春季、年降水变化趋势，对春季大气、土壤干旱趋势进行了探讨，并提出了相应的减灾对策。 相似文献
19.
Spatial and temporal changes of summer monsoon on the Loess Plateau of Central China during the last 130 ka inferred from Rb/Sr ratios 总被引：2，自引：0，他引：2
The present climate of the Loess Plateau is dominantly controlled by East Asian monsoon. The well-preserved loess-paleosol sequence on the Loess Plateau is commonly interpreted as a product of intensive interactions between the winter and summer paleomons… 相似文献
20.
ABSTRACT This paper presents an analysis of trends in six drought variables at 566 stations across India over the period 1901–2002. Six drought variables were computed using standardized precipitation index (SPI). The Mann-Kendall (MK) trend test and Sen’s slope estimator were used for trend analysis of drought variables. Discrete wavelet transform (DWT) was used to identify the dominant periodic components in trends, whereas the significance of periodic components was examined using continuous wavelet transform (CWT) based global wavelet spectrum (GWS). Our results show an increasing trend in droughts in eastern, northeastern and extreme southern regions, and a decreasing trend in the northern and southern regions of the country. The periodic component influencing the trend was 2–4 years in south, 4–8 years in west, east and northeast, 8–64 years in central parts and 32–128 years in the north; however, most of the periodic components were not statistically significant. 相似文献