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干旱是一种周期性的气候异常,主要受气候自然变率驱动,具有发展缓慢、持续时间长、影响范围广等特征。然而,气候变化使得干旱不仅有增加趋势,其特征也在发生变化。例如,发展迅速的干旱,也称骤旱,近年来频繁发生。此外,人类活动通过改变陆地水循环,直接或间接地影响干旱过程。在全球变化背景下,干旱机制研究由海-陆-气相互作用影响气象干旱的气候动力学研究扩展到包含干旱传递过程机理认识、考虑区域尺度人类活动影响,面向农业、水利、生态等行业的农业干旱和水文干旱研究,为认识干旱可预报性、发展预测方法带来了新的挑战。本文将针对多尺度干旱过程及预测,讨论相关的研究进展及未来发展方向。 相似文献
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干旱是全球普遍存在的对人类影响最为严重的一种自然灾害。近百年气候显著变暖和社会快速发展,加剧了干旱的影响程度,增强了干旱灾害的风险,给全球农业、水资源、生态环境安全以及社会可持续发展造成巨大威胁。提高干旱监测和早期预警技术是应对、管理干旱以及减轻干旱脆弱性的基础。本文介绍了近年来美国在干旱监测、预测业务及研究方面取得的新进展,回顾了美国在区域和全球尺度下干旱监测及数值模式预报系统的发展,重点概述了干旱科学研究与技术进步,并结合2016年美国政府部门的抗旱任务书,讨论了干旱监测和预测面临的机遇与挑战,为我国干旱监测与预测发展提供新视角。 相似文献
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基于1971—2015年汉中11个县区地面气象观测站逐日降水观测资料,以降水距平百分率为干旱划分标准,采用干旱频率、干旱站次比和干旱强度三个指标,分析了汉中地区年尺度和季尺度干旱时空变化特征。结果表明:汉中地区年尺度干旱频率东南部低,西北部高,并从东南部向西北部递增;季节尺度来看,各季干旱频率分布差异明显。年尺度干旱强度从1996年开始有较弱增强趋势,而干旱站次比有明显降低趋势,汉中地区干旱朝着小区域性中旱发展;季尺度干旱特征为春季和夏季干旱站次比有增加趋势,秋季和冬季有减少趋势,春季和夏季干旱范围逐渐扩大,秋季和冬季干旱范围逐渐减少;春季、夏季和秋季干旱强度基本为轻旱,冬季多为中旱,有时能达到重旱。 相似文献
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中国干旱事件成因和变化规律的研究进展与展望 总被引：6，自引：0，他引：6
干旱是世界上危害最广泛、最严重的自然灾害之一。中国地处典型季风气候区,干旱灾害的影响尤为突出。国际上对干旱问题已经进行了大量研究,逐渐由对干旱的定性和表象的认识发展到对干旱客观特征的定量认识和形成机理的深入揭示。自新中国成立以来,中国从以往仅对一些重大干旱事件的零散认识逐步发展到与国际干旱研究的完全接轨,干旱研究取得了长足进展。但是,目前对干旱研究取得的科学进展缺乏客观全面的整体认识,对干旱研究的发展方向尚未能充分洞察。为此,基于国际干旱研究现状,系统回顾了新中国成立以来中国干旱研究的历程,总结了中国干旱研究的重要进展,划分出了干旱事件的现象特征和时空分布、干旱形成机理及变化规律、干旱灾害风险和骤发性干旱研究兴起等中国干旱研究的4个主要发展过程。并从干旱事件特征、干旱时空分布、干旱变化规律、干旱成因、干旱影响机制、干旱风险形成过程以及干旱对气候变暖的响应、骤发性干旱的特殊性等方面归纳凝练了中国干旱研究的主要成果。同时,结合干旱研究的国际前沿、热点问题和发展趋势,科学分析了中国干旱研究的不足和问题,提出了中国未来干旱研究需要在加强典型干旱频发区综合性干旱科学试验研究的基础上,对干旱形成的多因子协同影响、陆-气作用对干旱形成发展的作用、骤发性干旱的判别及监测预测、各类干旱之间转换规律及其非一致性特征、关键影响期对农业干旱发展的作用、干旱对气候变暖响应的复杂性、干旱灾害风险的科学评估等重点科学问题上取得突破。 相似文献
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利用塔城地区9个国家气象观测站1961—2021年逐月降水资料,基于标准化降水量指数(SPI)运用最小二乘法和Mann-Kendall检验等方法分析塔城地区干旱时空分布特征。结果表明：(1)年尺度上,塔城地区干旱发生频率为30.37%,轻旱发生最多,中旱次之；2/3站点SPI呈显著增大趋势,年站次比和干旱强度呈显著减小趋势,干旱程度有所减轻,在1987年之后塔城干旱程度整体偏轻。(2)季节尺度上,夏、秋、冬季在1980年代中期发生干旱减轻的突变,且秋季和冬季分别在2002年和1997年达到显著。(3)在影响范围方面,各季以局域性和全域性干旱为主,全域性干旱发生频率介于20～30%之间；在干旱强度方面,各季轻度干旱发生频率最高,中度以上干旱发生频率介于33～38%之间。(4)近60a塔城地区季节性干旱呈现影响范围缩小,强度减弱的变化趋势,尤其是冬季干旱站次比和干旱强度分别以-7.79%.(10a)-1和-0.11.(10a)-1的倾向率显著减小,干旱减轻趋势在四季中最为显著。 相似文献
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基于CMIP5中的5个全球气候模式统计降尺度的降水、最高和最低气温等数据,利用标准降水蒸发指数（SPEI）和强度-面积-持续时间（IAD）方法识别全球升温1.5℃与2.0℃情景下中亚地区干旱事件,结合30 m分辨率土地利用数据,探讨中亚干旱事件的演变及耕地暴露度变化。结果表明：相比基准期（1986—2005年),中亚地区的降水和潜在蒸发量均有所增加;全球升温1.5℃与2.0℃情景下,中亚地区的干旱事件频次、强度和面积均将增加,其中重旱和极旱事件的频次和影响面积大幅上升,而中旱事件的频次和影响面积持续下降;1986—2005年中亚地区年均干旱耕地暴露度约11.5万km2,全球升温1.5℃和2.0℃情景下,干旱耕地暴露度将分别上升到17.9万km2和28.6万km2,且暴露在极旱下的耕地面积增加最明显。全球升温1.5℃与2.0℃情景下,增加的干旱事件将会严重威胁当地农业生产和粮食安全,中亚地区需对干旱事件采取长期的减缓与适应措施。 相似文献
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探讨精细尺度上的干旱评估指标对于开展冬小麦干旱动态评估具有重要意义。在河南省选择灌耕比相对较小的代表站点,利用1971-2008年10月上旬至次年6月上旬逐日气象资料、冬小麦产量资料,计算了基于全生育期及旬尺度的缺水指数,提取了产量变化率序列,结果发现,冬小麦全生育期及旬缺水指数与产量变化率呈极显著相关。根据二者的回归方程及农业上划分干旱的标准,确定了河南省冬小麦干旱评估指标：全生育期缺水指数－1.5～1为轻旱,－3.1～－1.5为中旱,－4.6～－3.1为重旱,小于－4.6为严重干旱;旬尺度上,缺水指数0.8～1为轻旱,－0.7～0.8为中旱,－2.3～－0.7为重旱,小于－2.3为严重干旱。 相似文献
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本文以吉林省的干旱灾害为研究对象,在分析干旱灾害气候背景和经济环境的基础上,从干旱灾害发生的成灾环境、灾害发生的可能性、以及承灾体的易损性三个方面选取了环境、灾害频率、人口、社会经济等评价因子建立了干旱灾害风险性评估数学模型,通过等级划分后得到农田受旱、人畜饮水困难、牧草受旱等重旱、中旱、轻旱风险区划图,为吉林省农业生产、保险理赔、防灾减灾管理、城乡规划等提供科学依据。 相似文献
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基于2003—2021年江门市6个国家气象观测站和17个区域自动气象站逐月降水和气温资料，应用标准降水蒸发指数(SPEI)分析该区域干旱时空特征。研究结果表明：(1)近19年来，江门市干旱整体有不明显的湿润趋势，年发生频率为31.6%,平均站次比为38.4%,平均强度值为0.7,发生干旱时，以全域性轻旱为主。空间分布上，干旱发生的频率较高，但强度较低且以轻旱为主。全市存在一致变旱或变涝的特征，易出现全域性的干旱或洪涝。(2)江门市除了夏季有微弱的干旱趋势外，其他季节都呈湿润趋势，冬季最为明显。各个季节干旱发生的频率都较高，发生干旱时覆盖的范围也较大，且多数为全域性或区域性干旱。各个季节的干旱强度也比较接近，都以轻旱为主。年尺度SPEI在江门地区的适用性表现优秀，能准确识别出5个干旱过程，但季节尺度SPEI适用性表现一般，仅识别出3个干旱过程。 相似文献
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Flash drought is a rapidly intensifying drought with abnormally high temperature, which has greatly threatened crop yields and water supply, and aroused wide public concern in a warming climate. However, the preferable hydrometeorological conditions for flash drought and its association with conventional drought at longer time scales remain unclear. Here, we investigate two types of flash drought over China: one is high-temperature driven (Type I), while the other is water-deficit driven (Type II). Results show that the frequencies of the two types of flash drought averaged over China during the growing season are comparable. Type I flash drought tends to occur over southern China, where moisture supply is sufficient, while Type II is more likely to occur over semi-arid regions such as northern China. Both types of flash drought increase significantly (p0.01) during 1979-2010, with a doubled rise in Type I as compared with Type II. Composite analysis shows that high temperature quickly increases evapotranspiration (ET) and reduces soil moisture from two pentads before the onset of Type I flash drought. In contrast, there are larger soil moisture deficits two pentads before the onset of Type II flash drought, leading to a decrease in ET and increase in temperature. For flash drought associated with seasonal drought, there is a greater likelihood of occurrence during the onset and recovery phases of seasonal drought, suggesting perfect conditions for flash drought during transition periods. This study provides a basis for the early warning of flash drought by connecting multiscale drought phenomena. 相似文献
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The anthropogenic acceleration and intensification of flash drought over the southeastern coastal region of China will continue into the future 
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下载免费PDF全文 The frequent and rapid onset of flash drought poses a serious threat to agriculture and ecosystems. Detecting human influences on flash droughts and estimating their future risks under climate change have attracted great attention. Focusing on a record-breaking flash drought event in the southeastern coastal region of China in summer 2020, the authors found that the suppression of convective precipitation and high temperature caused by the persistent high geopotential height anomalies and land–atmosphere dry coupling were important reasons for the rapid onset and strong intensity of the flash drought. Event attribution analysis with the latest CMIP6 data showed that anthropogenic climate change has not only increased the likelihood of an onset speed and intensity like those of the 2020 flash drought event, by about 93% ± 20% and 18% ± 15%, respectively, but also increased the chance of their simultaneous occurrence, by about 86% ± 38%, according to their joint probability distribution. Under a business-as-usual future scenario (SSP2-4.5), the likelihood of such an onset speed, intensity, and their simultaneous occurrence will further increase, by 85% ± 33%, 49% ± 8%, and 81% ± 48%, respectively, as compared with current climate conditions. This study highlights the importance of anthropogenic climate change for accelerating and intensifying flash drought in the southeastern coastal region of China.摘要快速爆发的骤旱对农业生产, 生态环境等造成严重威胁, 亟须量化当前及未来气候变化对骤旱爆发过程的影响. 2020年夏季, 在持续高压异常和陆气干耦合的控制下, 我国东南沿海地区出现高温少雨天气并引发极端骤旱事件. 基于第六次国际耦合模式比较计划 (CMIP6) 数据开展归因分析, 本文发现相比天然情景, 温室气体排放等人为因子导致的气候变化不仅使类似2020年骤旱爆发速度和强度的发生概率分别增加93%和18%, 还使其联合概率增加86%. 在目前排放水平下, 此类骤旱爆发速度和强度发生概率及其联合概率在21世纪末将提高85%, 49%, 和81%, 极大增加了干旱适应的挑战. 相似文献
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以长期降雨-径流观测资料为基础,建立小流域水文单位线以有效描述山洪响应特征,并探究变化环境下的山洪响应特征是否发生改变。单位线在山洪预报中应用广泛,但在气象领域受关注较少。以两个美国小流域（USGS站点02137727-卡托巴河、01572025-斯瓦塔拉河）为研究对象,探讨考虑不同前期降水和致洪降水条件下单位线提取和优化方法,以及前期降水对流域单位线的影响。结果表明不同前期影响雨量下的平均单位线对降水-径流模拟总体效果较好,两个流域1985年以来共16个降雨径流事件模拟的平均纳什模型效率系数分别为0.846和0.940,平均峰值相对误差分别为9.40%和7.47%。前期影响雨量越大,则单位线峰值越高,峰现时间提前。同时考虑前期降水和致洪降水组合的单位线,能更好反映雨洪事件中山洪响应特征,模拟效果进一步提高,对提高山洪概率预报很有意义。通过分析卡托巴河流域33 a单位线的年际变化,发现降水增多和强降水频率增加导致流域山洪响应特征发生明显变化,单位线峰值呈现增加趋势,涨洪历时呈减少趋势,未来山洪灾害风险变大。 相似文献
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Statistically different precursory air–sea signals between a super and a regular El Ni no group are investigated, using observed SST and rainfall data, and oceanic and atmospheric reanalysis data. The El Ni no events during 1958–2008 are first separated into two groups: a super El Ni no group(S-group) and a regular El Ni no group(R-group). Composite analysis shows that a significantly larger SST anomaly(SSTA) tendency appears in S-group than in R-group during the onset phase[April–May(0)], when the positive SSTA is very small. A mixed-layer heat budget analysis indicates that the tendency difference arises primarily from the difference in zonal advective feedback and the associated zonal current anomaly(u).This is attributed to the difference in the thermocline depth anomaly(D) over the off-equatorial western Pacific prior to the onset phase, as revealed by three ocean assimilation products. Such a difference in D is caused by the difference in the wind stress curl anomaly in situ, which is mainly regulated by the anomalous SST and precipitation over the Maritime Continent and equatorial Pacific. 相似文献
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The day-to-day monitoring of the 2011 severe drought in China 总被引：1，自引：0，他引：1
Er Lu Wenyue Cai Zhihong Jiang Qiang Zhang Cunjie Zhang R. Wayne Higgins Michael S. Halpert 《Climate Dynamics》2014,43(1-2):1-9
Dry/wet condition has a large interannual variability. Decision-makers need to know the onset, duration, and intensity of drought, and require droughts be monitored at a daily to weekly scale. However, previous tools cannot monitor drought well at this short timescale. The Palmer Drought Severity Index has been found dissatisfactory in monitoring because of its complexity and numerous limitations. The Standardized Precipitation Index (SPI) always asks for a timescale, and precipitation is averaged over the period of the scale. Because of this, the SPI cannot be used for short scales, e.g., several days, and what it tells is the overall drought situation of the period. The weighted average of precipitation (WAP) developed by Lu (Geophys Res Lett 36:L12707, 2009) overcomes the deficiency of the SPI; it does not require a timescale, and can provide the drought (and flood) extent of each day. Therefore, the WAP can monitor drought at scales from daily to weekly, monthly, and any longer scale, and is really “flexible and versatile for all timescales”. In this study, the standardized WAP (SWAP) is used to monitor the 2011 drought over China. Drought swept the country during the year from north to south and from east to west. In spring, a once-in-a-fifty-year drought occurred over the Yangtze River basin and the southern region, causing serious shortage of drinking water for people and livestock, as well as tremendous losses in agriculture and the shipping industry. Results show that the SWAP, with its monthly mean plots, can well reproduce the seasonal shift of the 2011 drought across the country. The animation of daily plots demonstrates that the SWAP would have been able to monitor the day-to-day variation of the spring drought around the Yangtze River basin. It can provide the details of the drought, such as when the drought emerged over the region, how long it maintained there (though drought area may move back and forth with extension and contraction of the area), and when the drought relieved over the basin. 相似文献
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基于气候系统内在层次性的气象干旱指数研究 总被引：3，自引：1，他引：2
气候系统除了具有非线性/非平稳性,还有层次性,许多大小不一的时空尺度构成了多层次结构,不同层次的气候系统具有不同的可预报性和稳定性。对于一种气象干旱指数而言,主要考虑从某一时段(尺度)内降水、温度、土壤湿度等要素测量值来建立干旱指数。本文首先从气候系统的非线性/非平稳性和内在层次性出发,针对中国不同地区的区域气候及其变化特征,使用信息熵方法从降水观测资料中提取出区域降水的两个(均态和变化)本征尺度,提出一种基于区域气候系统层次性内在特征的气象干旱指数MSPI。以2011年长江中下游春季严重气象干旱的发生、发展、持续、缓解情况为例,对MSPI的干旱监测能力进行检验。发现MSPI对不同程度的干旱都有较好的表征能力,并且对于干旱过程也有较好的识别能力。从各方面综合考虑,MSPI是一种可以较好满足逐日气象干旱监测、检测需求的气象干旱指数。在实际应用中,气象干旱指数MSPI可以作为其他不同时间尺度上的各种干旱指数的有益补充。 相似文献
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An extended ocean-atmosphere coupled characteristic system including thermodynamic physical processes in ocean mixed layer is formulated in order to describe SST explicitly and remove possible limitation of ocean-atmos-phere coupling assumption in hydrodynamic ENSO models. It is revealed that there is a kind of abrupt nonlinear characteristic behaviour, which relates to rapid onset and intermittency of El Nino events, on the second order slow time scale due to the nonlinear interaction between a linear unstable low-frequency primary eigen component of ocean-atmosphere coupled Kelvin wave and its higher order harmonic components under a strong ocean-atmos-phere coupling background. And, on the other hand, there is a kind of finite amplitude nonlinear characteristic behaviour on the second order slow time scale due to the nonlinear interaction between the linear unstable primary eigen component and its higher order harmonic components under a weak ocean-atmosphere coupling background in this model system. 相似文献
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A. Henderson-Sellers 《Climatic change》1980,2(3):275-281
Natural changes in surface (and particularly land surface) albedo are described in terms of their impact upon climate. Emphasis is placed upon the importance of the regional or synoptic scale view of albedo change and upon a methodology of monitoring such variations using current satellite surveillance. A case study of the United Kingdom during the 1976 drought reveals the large scale changes in reflectivity that can occur during extreme events. It is possible that such surface changes could have caused positive feedback in the atmospheric circulation thus prolonging the drought conditions. 相似文献