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本文利用卫星遥感资料以及常规气象资料驱动基于地表净辐射、植被指数、平均气温和日温差的蒸散模型来估测日实际蒸散量,并与栾城站涡动相关法测量的实际蒸散作对比验证。定性分析了实际蒸散与各相关影响因子的时空变化规律;通过蒸散干旱指数（EDI）分析华北地区的干旱分布特点,并分别与PDSI指数和降水距平百分率作对比。结果表明：ET模型估测的蒸散值与实测值的相关性很好,其模拟精度对于大面积干旱监测的空间尺度上是可用的;EDI距平指数表征干旱分布的空间分辨率较高,且对旱情的指示和干旱程度的判定比较可靠。 相似文献
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利用1951～2011年中国台站观测的逐日降水、温度和美国NCEP/NCAR再分析月平均资料, 本文分析2010年秋、冬季(11月至次年2月)发生在华北地区持续性干旱的大气环流和海温异常特征, 并讨论了北极涛动(AO)和La Ni?a事件对此次干旱事件的影响。分析表明, 2010年发生在华北秋、冬季节的持续性干旱是叠加在降水减少气候趋势之上的一次极端干旱事件, 但本次极端干旱事件主要成因是受到同期较强的AO负位相和La Ni?a事件共同的影响。统计发现:AO的负位相有利于乌拉尔山阻塞高压维持和发展, 而贝加尔湖上空出现负位势高度异常, 导致东亚中高纬度经向环流加强和冷空气向南侵袭。AO负位相可导致贝加尔湖上空气压场偏低并影响冷空气的路径和强度, 进而间接地导致华北地区的干冷气候, 而同期La Ni?a的海温异常分布导致西北太平洋副热带高压偏弱偏南, 抑制了西太平洋水汽向华北地区输送, 从而直接导致该地区的干旱。由于2010年AO负指数和La Ni?a事件较历史干旱年份表现出较强和长时间持续性, 从而导致了锋面位置位于华北以南和华北本次的持续性干旱事件。 相似文献
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利用淮河流域河南、安徽、山东、江苏4省170个站1961—2010年逐日气温、降水以及土壤墒情和干旱灾情资料,从干旱年际变化、季节演变、空间分布、典型干旱过程诊断、不合理跳跃点以及与土壤墒情、干旱灾情相关性等方面,对比分析降水距平百分率 (Pa)、Z指数、标准化降水指数 (SPI)、相对湿润度指数 (MI)、综合气象干旱指数 (CI) 和改进的CI (CINew) 在淮河流域的适用性。结果表明:各干旱指数对淮河流域的典型旱年均有较好的诊断能力;在干旱季节演变及空间分布的诊断方面,Pa,MI,CI和CINew与实际较为吻合,而Z指数和SPI诊断效果较差;在典型干旱过程诊断以及不合理跳跃次数方面,CI和CINew更能刻画出干旱发生发展机制,而Pa,Z指数,SPI,MI效果较差;与土壤墒情和历史干旱灾情相关性方面,CI和CINew比Pa,Z指数,SPI,MI具有更好的相关性。即对于淮河流域的干旱监测诊断,CI和CINew要优于Pa,Z指数,SPI及MI,具有更好的适用性。 相似文献
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干旱与可持续发展及抗旱减灾技术研究 总被引：17，自引：4，他引：17
讨论了干旱与可持续发展的关系，介绍了20世纪90年代以来全国受旱、成灾状况以及干旱气候资源。分析表明，在干旱严重发生地区，采用改善生态环境、优化农业结构、提高水资源利用率、大力开发空中水资源等措施是目前较为有效的抗旱减灾技术。 相似文献
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安徽省MODIS干旱监测技术研究 总被引：4，自引：0，他引：4
为了更有效地监测安徽省农业干旱,以安徽省半湿润区、过渡区为研究对象,利用MODIS资料,在对比分析了基于植被供水指数和温度植被干旱指数两种干旱监测方法基础上,结合已业务应用的农业干旱指标累积湿润指数,开展安徽省分时段的晴空遥感干旱监测研究,建立并确定了部分时段半湿润区、过渡区的MODIS植被供水指数和温度植被干旱等级标准,同时结合当地台站监测土壤墒情对干旱监测进行检验。结果表明,作物生长季节VSWI、TVDI与累积湿润指数存在相关性,两种方法建立指标和模型可以用来分时段进行区域干旱监测,得出了初夏旱TVDI更适合于研究区域的干旱监测。 相似文献
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华南旱、涝年前汛期水汽输送特征的对比分析 总被引：16，自引：5，他引：11
利用卫星遥感反演的降水资料及中国740个测站逐日降水资料,根据定义的旱涝指数,划分了1957—2002年期间的华南旱涝年份。利用NCEP/NCAR逐日再分析资料,分别讨论华南前汛期4~6月、4月及6月的水汽输送的气候特征。在此基础上,进一步研究了4~6月、4月及6月水汽输送及其源地在华南前汛期涝年和旱年的不同特征。结果表明:影响华南的水汽输送环流在南海夏季风建立前后具有明显不同的气候特征,华南前汛期(4~6月)降水应分为南海夏季风爆发前4月份至夏季风爆发与南海夏季风爆发至6月两个时段。来源于西太平洋的水汽输送变化和来自中国北方的水汽输送变化对华南降水异常有重要作用,而阿拉伯海—孟加拉湾地区的水汽输送变化对华南的降水异常影响不大。 相似文献
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Characteristics of the Regional Meteorological Drought Events in Southwest China During 1960–2010 
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下载免费PDF全文 LI Yunjie REN Fumin LI Yiping WANG Pengling YAN Hongming 《Acta Meteorologica Sinica》2014,28(3):381-392
An objective identification technique for regional extreme events(OITREE) and the daily compositedrought index(CI) at 101 stations in Southwest China(including Sichuan, Yunnan, Guizhou, and Chongqing)are used to detect regional meteorological drought events between 1960 and 2010. Values of the parameters of the OITREE method are determined. A total of 87 drought events are identified, including 9 extreme events. The 2009–2010 drought is the most serious in Southwest China during the past 50 years. The regional meteorological drought events during 1960–2010 generally last for 10–80 days, with the longest being 231days. Droughts are more common from November to next April, and less common in the remaining months.Droughts occur more often and with greater intensity in Yunnan and southern Sichuan than in other parts of Southwest China. Strong(extreme and severe) regional meteorological drought events can be divided into five types. The southern type has occurred most frequently, and Yunnan is the area most frequently stricken by extreme and severe drought events. The regional meteorological drought events in Southwest China have increased in both frequency and intensity over the study period, and the main reason appears to be a significant decrease in precipitation over this region, but a simultaneous increase in temperature also contributes. 相似文献
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内蒙古地区干旱风险评估 总被引：1，自引：0，他引：1
分析了形成旱灾风险的有关因素,表明旱灾风险不仅与缺雨程度及持续时间有关,而且还有明显的季节性差异。用单位评价期内的降水距平百分率反映缺雨程度,用作物和生态系统不同季节的缺雨敏感度反映干旱影响的季节性差异,并以干旱持续期内单位时段旱灾风险的累加反映其累积效应,从而建立起旱灾风险的识别指数。应用旱灾风险指数对60年来内蒙古的旱灾风险进行了初步评估。给出了各级旱灾发生的概率,并统计出及各级旱灾对应的后果。对影响范围大、跨经两个以上作物生长年份、最大旱灾风险指数双倍于特旱的极端干旱在内蒙古的发生情况进行了分析。结果表明,20世纪80年代中期以来,内蒙古的极端干旱过程在逐渐东扩,内蒙古东部地区的旱灾出现了增多增强的趋势。 相似文献
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In the spring of 2021, southwestern China (SWC) experienced extreme drought, accompanied by the highest seasonal-mean temperature record since 1961. This drought event occurred in the decaying phase of a La Ni?a event with negative geopotential height anomalies over the Philippine Sea, which is distinct from the historical perspective. Historically, spring drought over SWC is often linked to El Ni?o and strong western North Pacific subtropical high. Here, we show that the extreme drought in the spring of 2021 may be mainly driven by the atmospheric internal variability and amplified by the warming trend. Specifically, the evaporation increase due to the high temperature accounts for about 30% of drought severity, with the contributions of its linear trend portion being nearly 20% and the interannual variability portion being about 10%. Since the sea surface temperature forcing from the tropical central and eastern Pacific played a minor role in the occurrence of drought, it is a challenge for a climate model to capture the 2021 SWC drought beyond one-month lead times. 相似文献
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五种干旱指标在安徽省应用研究 总被引：9，自引：2，他引：7
运用安徽省78个代表站1961-2008年逐日气温和降水资料,采用累积频率法对五种干旱指标的阈值进行修正,用修正后干旱指标来分析安徽省干旱的年际变化、季节演变及空间分布等特征.结果表明:五种干旱指标按照干旱过程计算得到历年总干旱日数的演变趋势基本一致,干旱日数较多的年份与安徽省历史典型大旱年记录非常吻合;Z指数和SPI指数无明显季节变化趋势,而Pa,MI和CI三种指标季节变化趋势明显且基本一致,安徽省秋旱最多,夏旱次之,冬、春旱相对较少;Z指数和SPI指数尤明显的空间分布特征,Pa,MI和三种指标的空间分布基本一致,呈现纬向空间分布,干旱频率自北向南递减;对于安徽干旱监测业务来说,五种干旱指标中CI指数为最优. 相似文献
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2009/2010年云贵地区（YGR）和2013年夏季中南地区（CSC）发生了近几十年以来最严重的干旱事件。文中对比了两次干旱事件的发展速度,基于水分收支原理,诊断影响干旱发展的物理过程。结果显示,CSC干旱发展前,温度升高,蒸散发增加,土壤湿度减少,高温和降水减少对干旱有触发作用;而YGR的降水减少使干旱开始发展。CSC干旱事件发展迅速,YGR干旱事件发展缓慢,同时前者干旱的维持和恢复时间也短于后者,这些差异与蒸散发过程强弱有关。CSC干旱事件发展阶段,蒸散发过程强,平均为4.7 mm/d,8 d时间,土壤湿度从45%减少到20%,促使干旱快速形成（典型骤发干旱）。YGR干旱发展阶段,蒸散发过程弱,平均为1.7 mm/d,土壤湿度从45%减少到20%历时2个多月（传统干旱）。蒸散发的强弱主要与区域大气柱的水汽净辐散有关。CSC干旱发展阶段,其大气柱水汽净辐散达每天3.1 kg/m2,增强了陆气水分交换,使蒸散发远大于降水,土壤湿度快速下降,加快干旱发展速度。YGR的区域大气柱水汽净辐散为每天1.1 kg/m2,只有CSC的1/3,使干旱发展缓慢。两个干旱事件的大气柱水汽净辐散主要发生在经向方向,即由区域北界相对较强的经向水汽输送引起。 相似文献
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The Response of Anomalous Vertically Integrated Moisture Flux Patterns Related to Drought and Flood in Southern China to Sea Surface Temperature Anomaly 下载免费PDF全文
下载免费PDF全文 With the extreme drought (flood) event in southern China from July to August in 2022 (1999) as the research object, based on the comprehensive diagnosis and composite analysis on the anomalous drought and flood years from July to August in 1961-2022, it is found that there are significant differences in the characteristics of the vertically integrated moisture flux (VIMF) anomaly circulation pattern and the VIMF convergence (VIMFC) anomaly in southern China in drought and flood years, and the VIMFC, a physical quantity, can be regarded as an indicative physical factor for the "strong signal" of drought and flood in southern China. Specifically, in drought years, the VIMF anomaly in southern China is an anticyclonic circulation pattern and the divergence characteristics of the VIMFC are prominent, while those are opposite in flood years. Based on the SST anomaly in the typical draught year of 2022 in southern China and the SST deviation distribution characteristics of abnormal draught and flood years from 1961 to 2022, five SST high impact areas (i.e., the North Pacific Ocean, Northwest Pacific Ocean, Southwest Pacific Ocean, Indian Ocean, and East Pacific Ocean) are selected via the correlation analysis of VIMFC and the global SST in the preceding months (May and June) and in the study period (July and August) in 1961-2022, and their contributions to drought and flood in southern China are quantified. Our study reveals not only the persistent anomalous variation of SST in the Pacific and the Indian Ocean but also its impact on the pattern of moisture transport. Furthermore, it can be discovered from the positive and negative phase fitting of SST that the SST composite flow field in high impact areas can exhibit two types of anomalous moisture transport structures that are opposite to each other, namely an anticyclonic (cyclonic) circulation pattern anomaly in southern China and the coastal areas of east China. These two types of opposite anomalous moisture transport structures can not only drive the formation of drought (flood) in southern China but also exert its influence on the persistent development of the extreme weather. 相似文献
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The Limiting Effect of Deep Soil Water on Evapotranspiration of a Subtropical Coniferous Plantation Subjected to Seasonal Drought简 总被引：4，自引：0，他引：4
Seasonal drought is a common occurrence in humid climates.The year 2003 was the driest year during the period 1985-2011 in southeastern China.The objective of this study was to elucidate the impact of the exceptional drought in 2003,compared with eddy flux measurements during 2004-11,on the dynamics of evapotranspiration （ET） and related factors,as well as their underlying mechanisms,in a subtropical coniferous plantation in southeastern China.It was found that daily ET decreased from 5.34 to 1.84 mm during the intensive drought period and recovered to 4.80 mm during the subsquent recovering drought period.Path analysis indicated that ET was mainly determined by canopy conductance and deep soil water content （50 cm） during the intensive drought and recovering drought periods,respectively.The canopy conductance offset the positive effect of air vapor pressure deficit on ET when suffering drought stress,while the canopy conductance enhanced the positive effect of air temperature on ET during the late growing season.Because the fine roots of this plantation are mainly distributed in shallow soil,and the soil water in the upper 40 cm did not satisfy the demand for ET,stomatal closure and defoliation were evident as physiological responses to drought stress. 相似文献
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利用土壤相对湿度数据和县级春玉米单产数据,在气象干旱指数SWAP（standardized weighted average of precipitation）的基础上,研究我国东北地区春玉米受干旱影响的界限指标,结果表明:SWAP在春玉米播种-出苗期低于-0.9,出苗-拔节期低于-1.0,拔节-抽穗期低于-1.2,抽穗-乳熟期低于-0.7时,土壤相对湿度偏低,即气象干旱一般为中旱时,不利于春玉米生长。以此构建春玉米干旱指数,对比我国东北地区春玉米干旱指数与省级农作物干旱受灾面积的关系,发现两者相关关系显著,尤其在典型干旱年份,两者对应关系更好,说明构建的东北地区春玉米干旱指数能够较好地反映干旱对春玉米的实际影响。利用东北地区县级春玉米单产数据对春玉米干旱指数进行等级划分,划分结果可为东北地区春玉米防旱减灾和安全生产提供参考。 相似文献
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Based on the Multi-Scale Standardized Precipitation Index (MSPI), extreme severe drought events in China during 1961-2010 were identified, and the seasonal, annual, and interdecadal variations of the clustering extreme drought events were investigated by using the spatial point process theory. It is found that severe droughts present a trend of gradual increase as a result of the significant increase and clustering tendency of severe droughts in autumn. The periodicity analysis of the clustering extreme droughts in different seasons suggests that there is a remarkable interdecadal change in the occurrence of clustering extreme droughts in winter. Meanwhile, it is revealed that the clustering extreme drought events exhibit greatly different annual mean spatial distributions during 1961-2010, with scattered and concentrated clustering zones alternating on the decadal timescale. Furthermore, it is found that the decadal-mean spatial distributions of extreme drought events in summer are correlated out of phase with those of the rainy bands over China in the past 50 years, and a good decadal persistence exists between the autumn and winter extreme droughts, implying a salient feature of consecutive autumn-winter droughts in this 50-yr period. Compared with other regions of China, Southwest China bears the most prominent characteristic of clustering extreme droughts. 相似文献