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1.
1961-2015年青藏高原降水量变化综合分析 总被引：2，自引：0，他引：2
降水量及其季节分配与降水形式变化一直是全球气候变化研究的热点之一。使用青藏高原72个气象站点1961-2015年的逐日降水量资料,基于趋势、波动特征和极端事件相结合的新视角,全面剖析了该地区近55年降水量的趋势、波动与极端事件变化。结果表明：（1）时间上,近55年青藏高原年降水量、年最大日降水量和一年中日降水量≥ 10 mm的天数分别以6.59 mm·（10a）-1、0.33 mm·（10a）-1和0.26 d·（10a）-1的速率显著增加,增幅分别达到36.2 mm、1.8 mm和1.4 d。（2）空间上,过去55年青藏高原绝大部分地区年降水量增加,不稳定性增强。但波动变化存在较大的地区差异,广大的中西部地区年降水量波动缓慢增强,而高原东部地区自北向南波动快速增强区与快速减弱区相间分布,极端降水强度与频数亦有类似的变化格局。（3）趋势、波动与极端变化三者组合预示,青藏高原东部的祁连山地区、柴达木盆地东部、青海湖流域与长江源区极端降水事件将明显增加,高原中西部地区发生强降水的可能性亦增加,而高原东南缘地区干旱事件将增多。 相似文献
2.
BRIJESH KUMAR KANHU CHARAN PATRA VENKAT LAKSHMI 《Journal of Earth System Science》2016,125(5):919-934
Satellite precipitation products offer an opportunity to evaluate extreme events (flood and drought) for areas where rainfall data are not available or rain gauge stations are sparse. In this study, daily precipitation amount and frequency of TRMM 3B42V.7 and CMORPH products have been validated against daily rain gauge precipitation for the monsoon months (June–September or JJAS) from 2005–2010 in the trans-boundary Gandak River basin. The analysis shows that the both TRMM and CMORPH can detect rain and no-rain events, but they fail to capture the intensity of rainfall. 相似文献
3.
Mohammadreza Kavianpour Mohammadreza Seyedabadi Saber Moazami 《Environmental Earth Sciences》2018,77(22):769
Drought as a natural disaster impresses people living. The main tool in better management of such phenomena is to explain its characteristics, using drought indices. The indices use precipitation, temperature, streamflow, and other hydrological variables to explain such events. In this study, standardized precipitation index (SPI) and stream-flow drought index (SDI) were used to develop a new combined drought index (CDI) based on copula functions. The proposed index function was evaluated in Khuzestan, Yazd and Golestan provinces of Iran from 1982 to 2012. These areas introduce different climate conditions. The index was analyzed temporally and spatially. In the temporal analysis, CDI was calculated separately for each station and the finest index was chosen by Kolmogorov–Smirnov and Chi-squared tests. In the spatial analysis, CDI was computed for two main scenarios and twenty sub-scenarios for the whole area of Golestan Province. The optimum index was chosen based on comparison with initial SPI and SDI. The results showed that CDI is more meticulous than both singular SPI and SDI, as it can trace a drought onset earlier and drought duration more accurate than the two individual indices and obviously display extreme states. 相似文献
4.
为了科学评估变化环境下城市地区降水结构变化和深入认识特大型城市降水极值演变特征,以北京市为例,采用《北京市暴雨图集》中6种历时（10 min、30 min、1 h、6 h、24 h和72 h）的年最大暴雨统计数据和北京地区45个雨量站点1960-2012年汛期（6-9月）逐日降水观测资料,分别选择年最大值法和百分位阈值法,基于暴雨图集中的6种历时暴雨的统计特征值和两种百分位阈值下（95%和99%）的3种极端降水指标（发生次数、降水量和降水贡献率）分析北京地区降水极值的时空变化特征。研究结果表明:① 北京地区降水极值的空间分布受地形特征和城市化发展等因素影响而呈现出从东向西递减的趋势,且形成了局部区域高值中心;② 近50年来北京地区极端降水发生频次、极端降水量和极端降水的贡献率均表现出显著的下降趋势,在95%（99%）阈值条件下极端降水发生次数、极端降水量和极端降水贡献率的下降速率分别为0.13次/10 a（0.04次/10 a）、11.59 mm/10a（5.28 mm/a）和2%/10 a（1%/10 a）;③ 两个阶段（1960-1985年和1986-2012年）的城区与近郊的极端降水指标差异表现不同,1960-1985年在极端降水频次方面郊区占优,而极端降水量和贡献率则是城区较高,1986-2012年3个指标均表现为城区较高。 相似文献
5.
1961-2010年西北干旱区极端降水指数的时空变化分析 总被引：3，自引：0，他引：3
结合绝对阈值和百分位法定义极端降水事件的优点,提出了一种更灵敏的检测极端降水事件的方法. 该方法不仅能检测出常用降水指数无法检测到的降水量稀少地区尤其干旱区的极端降水事件,同时也能过滤掉其检测到的降水量丰富地区的虚假极端降水事件. 此方法首次被应用于统计1961年1月至2010年2月西北干旱区72个气象站点的年和季节的极端降水指数（大降水和强降水指数）,并分析了极端降水指数的时间变化趋势及其空间分布特征. 结果表明：西北干旱区春（3-5月）、秋（9-11月）、冬（12月至次年2月）三季极端降水指数无显著（P>0.05）变化趋势,夏季（6-8月）大降水的频率和降水量以及大降水降水量占总降水量的比重都显著增加;新疆地区极端降水指数为增加趋势的区域基本都分布在海拔较高（约海拔1 000 m以上）的地区;西北干旱区东部极端降水指数变化趋势的空间分布有明显的季节差异,表现为夏、秋季大部分地区为增加趋势,冬、春季大部分地区为减小趋势. 相似文献
6.
Rainfall is one of the pivotal climatic variables, which influence spatio-temporal patterns of water availability. In this study, we have attempted to understand the interannual long-term trend analysis of the daily rainfall events of ≥?2.5 mm and rainfall events of extreme threshold, over the Western Ghats and coastal region of Karnataka. High spatial resolution (0.25°?×?0.25°) daily gridded rainfall data set of Indian Meteorological Department was used for this study. Thirty-eight grid points in the study area was selected to analyze the daily precipitation for 113 years (1901–2013). Grid points were divided into two zones: low land (exposed to the sea and low elevated area/coastal region) and high land (interior from the sea and high elevated area/Western Ghats). The indices were selected from the list of climate change indices recommended by ETCCDI and are based on annual rainfall total (RR), yearly 1-day maximum rainfall, consecutive wet days (≥?2.5 mm), Simple Daily Intensity Index (SDII), annual frequency of very heavy rainfall (≥?100 mm), frequency of very heavy rainfall (≥?65–100 mm), moderate rainfall (≥?2.5–65 mm), frequency of medium rainfall (≥?40–65 mm), and frequency of low rainfall (≥?20–40 mm). Mann-Kendall test was applied to the nine rainfall indices, and Theil-Sen estimator perceived the nature and the magnitude of slope in rainfall indices. The results show contrasting trends in the extreme rainfall indices in low land and high land regions. The changes in daily rainfall events in the low land region primarily indicate statistically significant positive trends in the annual total rainfall, yearly 1-day maximum rainfall, SDII, frequency of very heavy rainfall, and heavy rainfall as well as medium rainfall events. Furthermore, the overall annual rainfall strongly correlated with all the rainfall indices in both regions, especially with indices that represent heavy rainfall events which is responsible for the total increase of rainfall. 相似文献
7.
广东省近50年极端降水事件的时空特征及成因分析 总被引：3，自引：1，他引：2
利用广东省境内25个测站1961~2010年逐日降水资料,综合运用Mann-Kendall检验、正交分解函数和Morlet小波分析等方法,剖析了广东省极端降水的空间结构分布与时间变化特征,并从水汽辐合的角度解释了极端降水的时空特征。结果表明:全省极端降水事件的总量、频次、强度空间分布差异较大,从北到南,极端降水总量和强度增加,频次减少;全省大部分区域极端降水总量和频次都有增加的趋势;广东省极端降水受大尺度天气系统的影响,存在全区一致的多雨或少雨,但也存在东西、四周、中心以及南北的差异;极端降水空间异常可分为4个气候区(异常型),即粤东北区,粤西区,粤中部区以及粤东沿海区,各降水异常区存在20a左右的长周期、10a左右较长周期的和3~4a的短周期振荡;广东省极端降水与极端水汽辐合对应关系较好,区域内水汽辐合的改变可能是影响广东省极端降水变化的重要气候因子。 相似文献
8.
Spatial contribution of one-day precipitations variability to rainy days and rainfall amounts in Iran 总被引：2，自引：0，他引：2
H. Nazaripour M. R. Mansouri Daneshvar 《International Journal of Environmental Science and Technology》2014,11(6):1751-1758
Rainfalls with short persistency are the tangible characteristics of arid and semiarid regions such as Iran. Iran is an arid and semiarid region with dramatic tempo-spatial changes of rainfall. In this regard, the short persistency of rainfall is approximately observed from 1 to 7 days in whole parts, while the greater ones are only separated in eastern parts of Iran. According to the results, the rainfall persistency is ranged from 1 to 45 days, but the maximum amount and rainy days are generated by rainfalls with short persistency. So, the rainfall events with long persistency are considered as an extreme event with extreme variability. One-day precipitations generate the maximum rainy days and rainfall amounts, especially in eastern parts of Iran. Decrease in the one-day precipitations contribution to eastern parts may indicate to decrease in regional precipitation. However, decrease in contribution in western parts may indicate to increased amounts of rainfall at other persistency rates. Our results revealed that the contribution of the one-day precipitation to general rainfall has reductive trends in almost 17.5 % of the whole Iran. The most integrated and significant reductive trend of one-day precipitation contribution to rainfall spreads northeastern and eastern parts of Iran. However, in the western parts of Iran, decreasing one-day precipitation contribution to rainy days affects to increase in the diurnal rainfall. The mentioned variability can be considered as the climate change signals in respect of one-day precipitation. 相似文献
9.
从趋势性、滞后性及相关性三方面,对2002—2013年间GRACE重力卫星反演的长江上游与中游陆地水储量与模型模拟土壤含水量、实测降水和实测径流数据进行了对比分析,并从干旱强度及发展时间两方面评估了标准化陆地水储量指数SWSI、标准化降水指数SPI、标准化径流指数SRI和标准化土壤含水量指数SSMI对区域性干旱的表征能力.结果表明:长江上游地区陆地水储量与降水、径流和土壤水蓄量均无显著变化,而中游地区陆地水储量则与水库蓄量同样具有显著性增加,反映人类活动对中游地区陆地水储量变化有很大影响;各指标指示的各等级干旱月份数量基本相当,但各指标反映的特旱具体月份有较大差别,基于GRACE数据构建的SWSI指标对特大干旱的指示性不好;对比各指标对上游与中游地区干旱事件发展时间,体现出水文干旱、农业干旱对气象干旱存在一定的迟滞关系. 相似文献
10.
使用1951-2004年中国738个测站逐日降水资料,采用百分位的方法定义极端降水事件的阈值,分析了不同持续时间的极端降水事件的时空分布及变化趋势特征。结果表明,极端降水事件多发于35°N以南,特别是在长江中下游和江南地区以及高原东南部,且在这些地区极端降水事件持续时间也较长。季节分布上,主要出现在夏季,以低持续性事件为主。在中国东部地区,持续时间越长的极端降水其强度往往越强。趋势分析表明,全国持续1d极端事件的相对频数具有上升趋势而平均强度具有下降趋势,其空间上均表现为全国大部分上升、华北和西南等地下降的趋势。持续2d以上极端事件在长江中下游流域、江南地区和高原东部等地区有显著增多和增强的趋势,而在华北和西南地区有减少和减弱趋势,但全国平均的趋势不显著。 相似文献
11.
利用西藏珠穆朗玛峰地区5个气象站点1971-2012年逐日降水量资料,采用滑动平均、线性回归、Mann-Kendall非参数检验和Morlet小波分析等方法,分析了珠穆朗玛峰地区极端降水事件的时空变化特征. 结果表明：1971-2012年42 a来,珠穆朗玛峰地区大部分极端降水指数呈现出自东向西逐渐增大的空间分布格局, 连续干旱日数、连续湿日和降水强度表现为增加趋势,其他极端降水指数趋于减少. 其中,强降水量、极强降水量和年降水总量减幅较大,分别为-5.74 mm·（10a）-1、-1.20 mm·（10a）-1和-5.32 mm·（10a）-1,在喜马拉雅山南坡的聂拉木站表现的最为明显. 大部分极端降水指数在21世纪最初的10 a减幅最大,在30 a际尺度上也表现为减少趋势. 除连续干旱日数外,极端降水与年降水总量关系密切. 各项极端降水指数都存在3～4 a显著周期,也存在10 a、12 a和15 a的周期. 在时间转折上,各项极端降水指数均未发生气候突变. 相似文献
12.
It has been often accepted that rising troposphere temperatures will lead to higher precipitation intensities. This argument is based on the Clausius?CClapeyron (C?CC) relation, which indicates an increase in atmospheric moisture storage capacity of approximately 7?% K?1. However, recent studies carried out in mid-latitude regions indicate that changes in precipitation intensity as a function of temperature do not necessarily follow the C?CC relation. This study aimed to evaluate the correlation between precipitation extremes and temperature in tropical regions, using measured data obtained at low latitude ranges over Brazil. The results indicate that, at daily timescale, the C?CC relation alone is unlikely to explain the relation between precipitation extremes and temperatures in tropical regions. Additional aspects, such as moisture availability and the duration of precipitation events, should be further analyzed to allow a comprehensive understanding of the relationship between temperature and precipitation intensity. Moreover, we show that in tropical regions, higher temperatures may reduce the magnitude of extreme precipitation events at daily timescales, independent of the season of the year. 相似文献
13.
He Jun Yang Xiao-Hua Li Jian-Qiang Jin Ju-Liang Wei Yi-Ming Chen Xiao-Juan 《Natural Hazards》2014,75(2):199-217
Meteorological droughts can affect large areas and may have serious environmental, social and economic impacts. These impacts depend on the severity, duration, and spatial extent of the precipitation deficit and the socioeconomic vulnerability of the affected regions. This paper examines the spatiotemporal variation of meteorological droughts in the Haihe River basin. Meteorological droughts events were diagnosed using daily meteorological data from 44 stations by calculating a comprehensive drought index (CI) for the period 1961–2011. Based on the daily CI values of each station over the past 50 years, the drought processes at each station were confirmed, and the severity, duration and frequency of each meteorological drought event were computed and analyzed. The results suggest the following conclusions: (1) the use of the CI index can effectively trace the development of drought and can also identify the duration and severity of each drought event; (2) the average drought duration was 57–85 days in each region of the Haihe River basin, and the region with the highest average values of drought duration and drought severity was Bohai Bay; (3) drought occurred more than 48 times over the study period, which is more than 0.95 times per year over the 50 years studied. The average frequencies of non-drought days, severe drought days and extreme drought days over the study period were 51.2, 3.2 and 0.4 %, respectively. Severe drought events mainly occurred in the south branch of the Hai River, and extreme drought events mainly occurred in the Shandong Peninsula and Bohai Bay; (4) the annual precipitation and potential evapotranspiration of the Haihe River basin show decreasing trends over the past 50 years. The frequency of severe drought and extreme drought events has increased in the past 20 years than during the period 1961–1990. The results of this study may serve as a reference point for decision regarding basin water resources management, ecological recovery and drought hazard vulnerability analysis.
相似文献14.
Spatiotemporal variation of meteorological droughts based on the daily comprehensive drought index in the Haihe River basin,China 总被引：4，自引：0，他引：4
Jun He Xiao-Hua Yang Jian-Qiang Li Ju-Liang Jin Yi-Ming Wei Xiao-Juan Chen 《Natural Hazards》2015,75(2):199-217
Meteorological droughts can affect large areas and may have serious environmental, social and economic impacts. These impacts depend on the severity, duration, and spatial extent of the precipitation deficit and the socioeconomic vulnerability of the affected regions. This paper examines the spatiotemporal variation of meteorological droughts in the Haihe River basin. Meteorological droughts events were diagnosed using daily meteorological data from 44 stations by calculating a comprehensive drought index (CI) for the period 1961–2011. Based on the daily CI values of each station over the past 50 years, the drought processes at each station were confirmed, and the severity, duration and frequency of each meteorological drought event were computed and analyzed. The results suggest the following conclusions: (1) the use of the CI index can effectively trace the development of drought and can also identify the duration and severity of each drought event; (2) the average drought duration was 57–85 days in each region of the Haihe River basin, and the region with the highest average values of drought duration and drought severity was Bohai Bay; (3) drought occurred more than 48 times over the study period, which is more than 0.95 times per year over the 50 years studied. The average frequencies of non-drought days, severe drought days and extreme drought days over the study period were 51.2, 3.2 and 0.4 %, respectively. Severe drought events mainly occurred in the south branch of the Hai River, and extreme drought events mainly occurred in the Shandong Peninsula and Bohai Bay; (4) the annual precipitation and potential evapotranspiration of the Haihe River basin show decreasing trends over the past 50 years. The frequency of severe drought and extreme drought events has increased in the past 20 years than during the period 1961–1990. The results of this study may serve as a reference point for decision regarding basin water resources management, ecological recovery and drought hazard vulnerability analysis. 相似文献
15.
基于线性倾向估计、小波分析、Mann-Kendall检验及空间插值等方法,对1962—2013年28个均匀分布在青海省内的气象站点数据近50 a(1962—2013年)极端降水事件的时空特征进行了分析。结果表明,在长期趋势上青海省极端降水事件呈上升趋势,其强度与频数变化分别具有28 a和15 a±的主周期,并且少数站点在20世纪90年代发生突变;青海省内的极端降水事件在空间上存在明显差异,整体呈自西向东逐渐增强的特征,极端降水事件在南部地区发生频率总体高于北部地区,东南部发生极端降水的频率最高;近50 a青海省内大部分地区极端降水事件的强度与频数均呈上升趋势,其中东北部地区极端降水事件的强度上升趋势较为明显,仅有东南端与西北端呈现下降趋势,极端降水事件频数的上升趋势由东南端及西北端分别向中部加强。 相似文献
16.
基于塔里木河流域39个气象站1961—2010年逐日观测数据和NCEP/NCAR再分析数据,采用标准化降水蒸散指数（Standardized Precipitation Evapotranspiration Index,SPEI）,分析了该流域近50年来干湿时空变化特征及典型干湿月份和突变前后的大气环流特征。对SPEI序列进行的趋势检验和突变分析表明,近50年来,塔里木河流域显著变湿并在1986年发生显著突变,SPEI上升趋势显著的站点较多的月份主要集中在暖季（5~10月）。对突变前后不同等级干湿事件频率变化的统计结果表明,突变后,极端干旱事件发生频率略有增加,但轻度和中度干旱事件发生频率有所减少,而不同等级的湿事件发生频率则一致地表现为增加。对典型干湿月份和突变前后对应的北半球500hPa位势高度场和风场变化的合成分析表明,暖季典型干湿月份环流系统配置存在明显差异,增加的水汽和弱不稳定大气层结构是该区域1986年后暖季变湿的原因之一。 相似文献
17.
利用历史文献记录重建了公元1000—2000年中国北方地区极端干旱事件序列,在此基础上分析极端干旱事件的发生特征与规律。研究得出以下结论:(1)极端干旱事件在公元1000—2000年中存在200年左右的周期波动。在15世纪中期、17世纪初期和18世纪末期存在3次极端干旱事件高发期。(2)极端干旱事件的变动与中国东部地区干湿变化相一致,在偏干的时期极端干旱事件发生次数上升,在偏湿时则下降。(3)在中世纪暖期和现代暖期,温度愈高,极端干旱事件偏多;而在小冰期,则温度偏低的时期极端干旱事件多发。(4)西风带影响下的非季风区,干湿变化与极端干旱事件的关系与华北季风区相反,这可能与所谓的“丝绸之路遥相关”和NAO(NorthAtlanticOscillation,北大西洋涛动)的影响有关。 相似文献
18.
为改进、完善对中国现代降水长期变化规律的理解,利用2 300个国家级气象站网观测资料,更新分析了全国1956—2013年基本降水指标的趋势变化特征。主要结果:① 全国平均年和季节降水量、降水量距平百分率未表现出显著趋势变化,但秋、冬季降水量距平百分率分别表现出较明显的下降和上升;② 年和夏季降水减少主要发生在东北中南部、华北、华中和西南地区,而东南沿海、长江下游、青藏高原和西北等地区年降水增加较明显;③ 降水趋势变化的空间结构相对稳定,北方降水减少范围有由黄土高原、华北平原向东北和西南扩散趋向,东北北部和长江中下游的降水增加范围变小,总体看东部降水减少和增加的区域均在萎缩,“南涝北旱”现象趋向缓解;④ 全国年平均暴雨量、日数呈现出较显著的增加,但暴雨强度没有明显变化,暴雨量和日数增加主要发生在珠江和东南诸河流域,而海河和西南诸河流域暴雨量、日数和强度呈较明显减少趋势;⑤ 东部季风区1日、连续3日和连续5日最大降水量均有一定程度增加,1日最大降水量增加最明显,连续5日最大降水量增加最弱,极端强降水事件持续时间呈现出短历时性倾向。 相似文献
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近30年雷州半岛季节性气象干旱时空特征 总被引：1，自引：0，他引：1
为进一步分析日尺度有效干旱指数(Effective Drought Index,EDI)的适应性,基于雷州半岛1984~2013年逐日降水资料进行验证,对比EDI和月尺度标准化降水指数(Standardized Precipitation Index,SPI)的干旱识别效果,进而结合线性趋势、M-K趋势检验和空间插值方法 ,分析雷州半岛季节性气象干旱时空特征。结果表明:(1)日尺度EDI和6个月时间尺度SPI(SPI-6)适用于雷州半岛的干旱监测,但EDI对严重干旱和突发干旱的识别比SPI-6更准确;(2)1984~2013年,雷州半岛秋冬季干旱频率和干旱站次比均呈减少趋势,但春夏季干旱频率和干旱站次比略有增加趋势;(3)春旱频率从南向北递增,重旱高频地区位于西北部,而夏季重旱高频区位于西部沿海;秋旱南部重于北部,高频中心在雷中西部沿海和曾家周边;冬季重旱以西部沿海、雷州市和徐闻县交界处频率最高。 相似文献
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利用1960-2010年江淮流域34个地面气象观测站的逐日降水、日平均气温、相对湿度等实测资料, 分别计算了江淮流域的Z指数、降水距平百分率、相对湿润指数、标准化降水指数以及CI指数, 经与江淮流域干旱记录对比分析, 结果表明: 月尺度的Z指数在5种干旱指数中应用效果最好, 符合率达70%以上;在时间域上, 月尺度的Z指数仅在春季吻合率稍差, 其余月份均在70%以上;月尺度的SPI指数在冬季吻合率较差, 其余月份同Z指数总体相当;MI指数效果最差;日尺度的CI指数应用效果存在时空差异, 在河南最好, 在山东最差, 夏季效果最好, 春季、冬季最差. 相似文献