共查询到19条相似文献，搜索用时 453 毫秒
1.
利用东亚区域联合降尺度计划(CORDEX-EA) 15个区域模式的模拟结果,集合预估了高排放情景RCP8.5下东亚陆地区域平均和极端降水的未来时空变化,并量化未来预估的不确定性.结果 表明:区域模式基本上能够再现东亚及各个区域平均和极端降水的多年平均分布.未来多模式集合预估的平均和极端强降水在东亚各区域多表现为增加,连续无降水日数(CDD)表现为南增北减,且变幅多随时间增大.到21世纪末期,冬季和年平均降水的增幅大值都位于中国西部(WC),冬季降水的变化在WC、蒙古(MG)、中国东北(NE)和中国华北及西北地区东部(NC)的确定性都较高,年降水的变化仅在WC和MG确定性较高.夏季降水增幅大值位于朝鲜半岛和日本(KJ),且仅在这一区域确定性较高.最大5日降水量(Rx5day)和大雨日数(R20)以增加为主且变化的空间分布较为均匀,除去中国江南及华南(SC)和KJ的R20变化,其余区域两个变量的变化确定性都较高.CDD的增幅和减幅大值分别位于SC和MG,其变化在MG、NE和SC确定性较高. 相似文献
2.
中国日极端降水和趋势 总被引：1，自引：0，他引：1
《中国科学:地球科学》2017,(12)
利用中国2000多站50年以上的日降水资料,提取各站6个极端降水指数,即历年最大值(top-1)、历年10个最大值(top-10)累积量、历年总降水量、历年夏季top-1、历年夏季top-10累积量、历年夏季总降水量,分别形成各站各极端降水指数时间序列.统计了历年全国及6个子区域整个研究资料时段内出现top-1和top-10值的总站次,分别形成历年全国及6个子区域极端降水总站次时间序列.各极端降水指数时间序列的趋势分析表明,中国各站top-1和top-10累积量时间序列趋势分布存在较为一致的3个明显趋势区域,即中国东南正趋势区、西北正趋势区和华北负趋势区,但各时间序列的趋势分布区域特征和趋势幅度增减程度不尽相同;正负趋势明显地区的大多数站点趋势增(减)幅度比(趋势幅度与平均值的比值)达10~30%,部分站点达30%以上.top-1和top-10降水全国年总站次时间序列表明了一致的线性增加趋势,平均每十年分别增加2.4站和15站,但年际差别较大;极端降水年总站次表现为三段极端降水多发期,分别出现在20世纪60年代初、90年代中后期和21世纪初,6个区域极端降水年总站次趋势特征与全国年总站次不尽相同,极端降水全国年总站次出现较多的年份在区域上表现不一样.与降水有关的环流形势要素的时间序列趋势分析表明,华北及上游蒙古高原地区呈现明显的位势高度增加趋势,而低层从中国南部沿海地区到华北地区呈现一条南风风速减弱的趋势带和华北地区水汽含量减少的趋势区,这些趋势特征有利于华北地区极端降水的减少.经验回归水平分析表明,50年一遇重现水平从南部沿海的400~600mm减少到西北地区的50mm以下,相比20年一遇重现水平提升率平均达6.8%,但比降水最大值可小一倍以上. 相似文献
3.
应用CN05观测资料,以及参与国际耦合模式比较计划第5阶段(CMIP5)中的26个模式,评估了新一代全球气候模式对东北三省气候变化模拟能力并选出4个较优模式,发现经过筛选得出的较优模式集合平均模拟结果的可靠性得到进一步加强,尤其体现在对气温的模拟上.在此基础上着重分析了多模式集合在不同典型浓度路径(RCPs)下对未来气候变化特征的预估.结果表明:21世纪的未来阶段,东北三省将处于显著增温的状态,且RCP8.5情景下的增温速率(0.53℃/10a)明显高于RCP4.5情景下的速率(0.22℃/10a);空间上,北部地区将成为增温幅度最大、增温速率最高的区域.未来降水将会相对增加,但波动较大,21世纪末期RCP4.5和RCP8.5情景下的降水增加幅度分别为11.24%和15.95%;空间上,辽宁省西部地区将成为降水增加最为显著的区域.根据水分盈亏量,21世纪未来阶段,RCP4.5情景下的东北三省绝大多数地区未来将相对变湿,尤其到了中后期;RCP8.5情景下则是中西部地区将相对变干,其余地区则会相对变湿. 相似文献
4.
《中国科学:地球科学》2021,(10)
2020年夏季我国经历了一场非同寻常的梅雨季,其持续时间长、暴雨日数多,为近几十年罕见.梅雨期间从日尺度到月尺度的降水均显著偏多,特别是持续性强降水(如连续四周最大累积降水量, Rx28day),较气候平均态偏多94%,打破了自1961年以来的历史记录.探讨人为强迫对此次梅雨期极端降水的影响及其物理过程,有助于理解和预估极端气候的风险变化.利用第六次耦合模式比较计划(CMIP6)检测归因模式比较计划(DAMIP),从事件归因角度,研究指出,人为强迫使得2020年夏季长江中下游流域持续性强降水(Rx28day)事件的发生概率减小了46%(22～62%).其中,温室气体有利于增加类似极端事件的发生概率(44%),这由增温引起的可降水量增加导致;而人为气溶胶则减少了其发生概率(73%),这与地表降温引起的可降水量减少、东亚夏季风环流减弱有关.未来随着温室气体的排放增加和人为气溶胶的减排,类似持续性强降水事件的发生概率将持续增加.在不同的共享社会经济路径(SSP)下,未来温室排放的情景越高,这类极端降水事件的发生风险越高.在低排放情景SSP1-2.6、中等排放情景SSP2-4.5和高排放情景SSP5-8.5下,到21世纪末,其发生概率分别约为当前气候下的4.6、13.6和27.7倍.因此,采取切实有效的温室气体减排措施,将有利于减缓极端降水事件的发生风险. 相似文献
5.
采用高水平分辨率区域气候模式进行区域未来气候变化预估,对理解全球增暖对区域气候的潜在影响和科学评估区域气候变化有很好的参考价值.这里对国家气候中心使用25 km高水平分辨率区域气候模式RegCM3单向嵌套全球模式MIROC3.2_hires在观测温室气体(1951—2000)和IPCC A1B温室气体排放情景下(2001—2100)进行的共计150年长时间模拟结果,进行华北地区未来气温、降水和极端气候事件变化的分析.模式检验结果表明:模式对当代(1981—2000)气温以及和气温有关的极端气候事件(霜冻日数、生长季长度)的空间分布和数值模拟较好;对降水及和降水有关的极端气候事件(强降水日期、降水强度、五日最大降水量)能够模拟出它们各自的主要空间分布特征,但在模拟数值上存在偏大、偏强的误差.和全球模式驱动场相比,区域模式模拟的气温、降水和极端气候事件有明显的改进.2010—2100年华北地区随时间区域平均气温升高幅度逐渐增大,随之霜冻日数逐渐减少,生长季长度逐渐增多;同时随温室效应的不断加剧,未来降水呈增加的趋势,强降水日期和五日最大降水量逐渐增多、降水强度逐渐增大.从空间分布看,21世纪末期(2081—2100)气温、降水以及有关的极端气候事件变化比21世纪中期(2041—2060)更加明显. 相似文献
6.
利用百分位法提取出江淮流域1979~2016年间50个区域性年极端降水事件,分为长江、江淮和倾斜梅雨暴雨、台风Ⅰ型和Ⅱ型暴雨5类.各类降水事件位涡正异常轨迹显示,降水系统沿500h Pa副高外侧引导气流不断东传,并在江淮地区中重复出现是其共性特征.各类降水事件的传播路径在江淮南部地区汇集, 50个区域性年极端降水事件中有21个集中出现在江淮南部的秦淮河流域,平均雨量超过100mm,其中14个区域性极端降水事件致灾,致洪暴雨中5个为长江梅雨暴雨、6个为江淮梅雨暴雨、2个为台风暴雨、1个为倾斜梅雨暴雨.城市发展、河网水系改变与区域极端降水事件叠加使得江淮南部地区临严重洪涝风险.以致洪暴雨为致灾条件,利用Flood Area水动力模型模拟RCP6.0(RCP8.5)气候变化情景下南京地区土地利用改变带来的洪涝风险,结果显示位于洪涝高风险区的城镇面积将从2010年的3.86km~2(3.86km~2)增加到2100年的9.00km~2(13.51km~2),集中在地势低洼的禄口机场、江宁东山和溧水区,政府决策部门在进行城市发展规划时应当重视可能的洪涝风险. 相似文献
7.
鄱阳湖区域极端降水异常的特征及成因 总被引：3，自引：1，他引：2
鄱阳湖区域4-7月极端降水总量存在显著的2-4年周期变化,且鄱阳湖4-7月极端降水总量的变率存在比较显著的增加趋势.1998年6月鄱阳湖地区极端降水总量异常偏多,而2001年6月异常偏少,仅为1998年的13.5%左右.通过分析大气环流场、水汽输送等方面的差异,发现1998年6月500hPa高度场上乌拉尔山高脊和鄂霍次... 相似文献
8.
利用WRF模式探讨了两种近地层参数化方案(MM5方案和Eta方案)对2013年5月31日海南岛一次海风降水过程模拟的影响.结果表明,改变近地层方案可对当地的海风环流及相应的降水特征产生明显影响,两个试验最重要的差别主要体现在模拟的海风及降水的强度差异上,与MM5试验相比,Eta试验的低层海风及辐合程度更强,相应的降水也更强,表现为岛屿总格点降水量、大于10mm的降水区域、最大格点降水三个量化指标均比较大.通过分析两种方案在不同降水阶段的地表通量及近地层变量场,发现Eta试验模拟的降水前环境场更有利于对流的启动,随着午后热力湍流的不断增强,将MM5方案替换为Eta方案可使近地层感热通量、潜热通量分别增加约3.57%、5.65%,动量通量减小约10.79%,感热、潜热的增加使Eta试验中近地层大气的加热加湿作用更加明显,相应的低层大气不稳定度更高,再配合海风锋前较强的辐合上升运动,局地不稳定能量的释放变的更加容易,因此降水强度更大. 相似文献
9.
本文提供了一个描述西藏地区年、季降水量空间分布的估算模型.利用卫星遥测数字化地形高程资料和西藏地区仅有的27个常规气象站的多年平均降水整编资料,根据地形坡向站点分为三类.再采用多元逐步回归方法,建立西藏地区的年、季降水量和经度、纬度、海拔高度、坡度、坡向、遮蔽度等6个地理、地形因子之间的关系模型,估算西藏地区降水量的空间分布.结果表明,此方法建立的关于西藏地区降水量与诸因子之间方程的相关性显著,平均绝对误差、相对误差分别为093mm和116%,对估算模型进行F检验,均通过置信度为095的相关检验,回归效果较显著.分析表明估算降水能够定量、定性地再现西藏地区的实际降水分布. 相似文献
10.
利用三峡库区35个台站1961-2010年汛期(5-9月)的逐日降水量资料,首先定义不同台站的极端降水量阈值,统计各站近50 a逐年汛期极端降水事件的发生频次,进而分析其时空变化特征.结果表明:三峡库区汛期极端降水事件发生频次的最主要空间模态是主体一致性,同时存在东西和南北相反变化的差异.三峡库区汛期极端降水事件发生频次具有较大的空间差异,可分为具有不同变化特点的5个主要异常区.滑动t检验表明,三峡库区西南部区代表站巴南的极端降水事件在1974年后发生了一次由偏多转为偏少的突变,北部区代表站北碚在1981年后和1993年后分别发生了由偏少转为偏多和由偏多到偏少的突变,中部区代表站武隆在1984年后发生了一次由偏多转为偏少的突变.结合最大熵谱和功率谱分析表明,近50 a来各分区汛期极端降水事件发生频次的周期振荡不太一致,三峡库区东北部区代表站宜昌、北部区代表站北碚和中部区代表站武隆分别存在5、2.4和8.3 a的显著周期. 相似文献
11.
On the basis of daily precipitation records at 76 meteorological stations in the arid region, northwest of China, the spatial and temporal distribution of mean precipitation and extremes were analysed during 1960–2010. The Mann–Kendall trend test and linear least square method were utilized to detect monotonic trends and magnitudes in annual and seasonal mean precipitation and extremes. The results obtained indicate that both the mean precipitation and the extremes have increased except in consecutive dry days, which showed the opposite trend. The changes in amplitude of both mean precipitation and extremes show seasonal variability. On an annual basis, the number of rain days (R0.1) has significantly increased. Meanwhile, the precipitation intensity as reflected by simple daily intensity index (SDII), number of heavy precipitation days (R10), very wet days (R95p), max 1‐day precipitation amount (RX1day) and max 5‐day precipitation amount (RX5day) has also significantly increased. This suggests that the precipitation increase in the arid region is due to the increase in both precipitation frequency and intensity. Trends in extremes are very highly correlated with mean trends of precipitation. The spatial correlation between trends in extremes and trends in the mean is stronger for winter (DJF) than for annual and other seasons. The regional annual and seasonal precipitation and extremes are observed the step jump in mean in the late 1980s. Overall, the results of this study are good indicators of local climate change, which will definitely enhance human mitigation to natural hazards caused by precipitation extremes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
12.
Projections of changes in climate are important in assessing the potential impacts of climate change on natural and social systems. However, current knowledge on assembling different GCMs to estimate future climate change over the Pear River basin is still limited so far. This study examined the capability of BMA and arithmetic mean (AM) method in assembling precipitation and temperature from CMIP5 under RCP2.6, RCP4.5 and RCP8.5 scenarios over the Pearl River basin. Results show that the BMA outperforms the traditional AM method. Precipitation tends to increase over the basin under RCP2.6 and RCP4.5 scenarios, whereas decrease under RCP8.5. The most remarkable increase of precipitation is found in the northern region under RCP2.6 scenario. The linear trend of the monthly mean near-surface air temperature increases with the growing CO2 concentration. The warming trends in four seasons are distinct. The warming rate is prominent in summer and spring than that in other season, meanwhile it is larger in western region than in other parts of the basin. The findings can provide beneficial reference to water resources and agriculture management strategies, as well as the adaptation and mitigation strategies for floods and droughts under the context of global climate change. 相似文献
13.
Five General Circulation Model(GCM) climate projections under the RCP8.5 emission scenario were used to drive the Variable Infiltration Capacity(VIC) hydrologic model to investigate the impacts of climate change on hydrologic cycle over continental China in the 21 st century. The bias-corrected climatic variables were generated for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change(IPCC AR5) by the Inter-Sectoral Impact Model Intercomparison Project(ISIMIP). Results showed much larger fractional changes of annual mean Evapotranspiration(ET) per unit warming than the corresponding fractional changes of Precipitation(P) per unit warming across the country, especially for South China, which led to a notable decrease of surface water variability(P-E). Specifically, negative trends for annual mean runoff up to -0.33%/ year and soil moisture trends varying between -0.02% to -0.13%/year were found for most river basins across China. Coincidentally, interannual variability for both runoff and soil moisture exhibited significant positive trends for almost all river basins across China, implying an increase in extremes relative to the mean conditions. Noticeably, the largest positive trends for runoff variability and soil moisture variability, which were up to 0.41%/year and 0.90%/year, both occurred in Southwest China. In addition to the regional contrast, intra-seasonal variation was also large for the runoff mean and runoff variability changes, but small for the soil moisture mean and variability changes. Our results suggest that future climate change could further exacerbate existing water-related risks(e.g., floods and droughts) across China as indicated by the marked decrease of surface water amounts combined with a steady increase of interannual variability throughout the 21 st century. This study highlights the regional contrast and intra-seasonal variations for the projected hydrologic changes and could provide a multi-scale guidance for assessing effective adaptation strategies for China on a river basin, regional, or as a whole. 相似文献
14.
利用中国740站45年降水资料按5种分辨率分气候区计算了降水年际和年代际变率. 降水年际和年代际变率对空间尺度的敏感性分析表明，中国各气候区降水年际变率对空间尺度的敏感性都随空间尺度的增加而逐渐减小，且存在明显的季节变化，而年代际变率对空间尺度的敏感性却随空间尺度的增加而增大，但不存在季节变化；由于中国各气候区降水的特殊性，各气候区降水年际和年代际变率对空间尺度的敏感程度存在不可忽视的差异.在年际和年代际尺度上，西南地区降水变率对空间尺度都是最敏感的，因而该区域降水年际和年代际变率信号的检测最困难.而华南地区在年际尺度上比较敏感，年代际尺度却不敏感，但华南地区在年际和年代际尺度上区域内降水分布的非均匀程度对空间尺度的敏感性都最大. 相似文献
15.
Richard P. Allan Chunlei Liu Matthias Zahn David A. Lavers Evgenios Koukouvagias Alejandro Bodas-Salcedo 《Surveys in Geophysics》2014,35(3):533-552
Robust and physically understandable responses of the global atmospheric water cycle to a warming climate are presented. By considering interannual responses to changes in surface temperature (T), observations and AMIP5 simulations agree on an increase in column integrated water vapor at the rate 7 %/K (in line with the Clausius–Clapeyron equation) and of precipitation at the rate 2–3 %/K (in line with energetic constraints). Using simple and complex climate models, we demonstrate that radiative forcing by greenhouse gases is currently suppressing global precipitation (P) at ～?0.15 %/decade. Along with natural variability, this can explain why observed trends in global P over the period 1988?2008 are close to zero. Regional responses in the global water cycle are strongly constrained by changes in moisture fluxes. Model simulations show an increased moisture flux into the tropical wet region at 900 hPa and an enhanced outflow (of smaller magnitude) at around 600 hPa with warming. Moisture transport explains an increase in P in the wet tropical regions and small or negative changes in the dry regions of the subtropics in CMIP5 simulations of a warming climate. For AMIP5 simulations and satellite observations, the heaviest 5-day rainfall totals increase in intensity at ～15 %/K over the ocean with reductions at all percentiles over land. The climate change response in CMIP5 simulations shows consistent increases in P over ocean and land for the highest intensities, close to the Clausius?Clapeyron scaling of 7 %/K, while P declines for the lowest percentiles, indicating that interannual variability over land may not be a good proxy for climate change. The local changes in precipitation and its extremes are highly dependent upon small shifts in the large-scale atmospheric circulation and regional feedbacks. 相似文献
16.
ABSTRACTThis review article discusses the climate, water resources and historical droughts of Africa, drought indices, vulnerability, impact of global warming and land use for drought-prone regions in West, southern and the Greater Horn of Africa, which have suffered recurrent severe droughts in the past. Recent studies detected warming and drying trends in Africa since the mid 20th century. Based on the Fourth Assessment Report of the Intergovernmental Panel on Climate Change and the Coupled Model Intercomparison Project Phase 5 (CMIP5), both northern and southern Africa are projected to experience drying, such as decreasing precipitation, runoff and soil moisture in the 21st century and could become more vulnerable to the impact of droughts. The daily maximum temperature is projected to increase by up to 8°C (RCP8.5 of CMIP5), precipitation indices such as total wet day precipitation (PRCPTOT) and heavy precipitation days (R10 mm) could decrease, while warm spell duration (WSDI) and consecutive dry days (CDD) could increase. Uncertainties of the above long-term projections, teleconnections to climate anomalies such as ENSO and the Madden-Julian Oscillation, which could also affect the water resources of Africa, and capacity building in terms of physical infrastructure and non-structural solutions are also discussed. Given that traditional climate and hydrological data observed in Africa are generally limited, satellite data should also be exploited to fill the data gap for Africa in the future.
Editor D. Koutsoyiannis; Associate editor N. Ilich 相似文献
17.
为高分辨率气候模式检验等的需要,基于2400余个中国地面气象台站的观测资料,通过插值建立了一套0.25°×0.25°经纬度分辨率的格点化数据集(CN05.1).CN05.1包括日平均和最高、最低气温,以及降水4个变量.插值通过常用的"距平逼近"方法实现,首先将计算得到的气候平均场使用薄板样条方法进行插值,随后使用"角距权重法"对距平场进行插值,然后将两者叠加,得到最终的数据集.将CN05.1与CN05、EA05和APHRO三种日气温和降水资料(四种资料的分析时段统一为1961-2005年)进行对比,分析了它们对气候平均态和极端事件描述上的不同,结果表明几者总体来说在中国东部观测台站密集的地方差别较小,而在台站稀疏的西部差别较大,相差最大的是青藏高原北部至昆仑山西段等地形起伏较大而很少或没有观测台站的地方,反映了格点化数据在这些地区的不确定性,在使用中应予以注意. 相似文献
18.
Based on observations and historical simulations from the fifth phase of the Coupled Model Intercomparison Project(CMIP5) archive, the contributions of human activities(including greenhouse gases(GHGs), anthropogenic aerosols(AAs), and land use(LU)) and external natural forcings(Nat) to climate changes in China over the past 50 years were quantified. Both anthropogenic and external natural forcings account for 95%–99% of the observed temperature change from 1951–1975 to 1981–2005. In particular, the temperature changes induced by GHGs are approximately 2–3 times stronger than the observed changes, and AAs impose a significant cooling effect. The total external forcings can explain 65%–78% of the observed precipitation changes over the past 50 years, in which AAs and GHGs are the primary external forcings leading to the precipitation changes; in particular, AAs dominate the main spatial features of precipitation changes in eastern China. Human activities also dominate the long-term non-linear trends in observed temperature during the past several decades, and, in particular, GHGs, the primary warming contributor, have produced significant warming since the 1960 s. Compared to the long-term non-linear trends in observed precipitation, GHGs have largely caused the wetting changes in the arid-semiarid region since the 1970 s, whereas AAs have led to the drying changes in the humid-semihumid region; both LU and Nat can impose certain impacts on the long-term non-linear trends in precipitation. Using the optimal fingerprinting detection approach, the effects of human activities on the temperature changes can be detected and attributed in China, and the effect of GHGs can be clearly detected from the observations in humid-semihumid areas. However, the anthropogenic effects cannot be detected in the observed precipitation changes, which may be due to the uncertainties in the model simulations and to other issues. Although some results in this paper still need improvement due to uncertainties in the coupled models, this study is expected to provide the background and scientific basis for climate changes to conduct vulnerability and risk assessments of the ecological systems and water resources in the arid-semiarid region of China. 相似文献
19.
Based on daily precipitation data of more than 2000 Chinese stations and more than 50 yr, we constructed time series of extreme precipitation based on six different indices for each station: annual and summer maximum(top-1) precipitation,accumulated amount of 10 precipitation maxima(annual, summer; top-10), and total annual and summer precipitation.Furthermore, we constructed the time series of the total number of stations based on the total number of stations with top-1 and top-10 annual extreme precipitation for the whole data period, the whole country, and six subregions, respectively. Analysis of these time series indicate three regions with distinct trends of extreme precipitation:(1) a positive trend region in Southeast China,(2) a positive trend region in Northwest China, and(3) a negative trend region in North China. Increasing(decreasing)ratios of 10–30% or even 30% were observed in these three regions. The national total number of stations with top-1 and top-10 precipitation extremes increased respectively by 2.4 and 15 stations per decade on average but with great inter-annual variations.There have been three periods with highly frequent precipitation extremes since 1960:(1) early 1960 s,(2) middle and late 1990 s,and(3) early 21 st century. There are significant regional differences in trends of regional total number of stations with top-1 and top-10 precipitation. The most significant increase was observed over Northwest China. During the same period, there are significant changes in the atmospheric variables that favor the decrease of extreme precipitation over North China: an increase in the geopotential height over North China and its upstream regions, a decrease in the low-level meridional wind from South China coast to North China, and the corresponding low moisture content in North China. The extreme precipitation values with a50-year empirical return period are 400–600 mm at the South China coastal regions and gradually decrease to less than 50 mm in Northwest China. The mean increase rate in comparison with 20-year empirical return levels is 6.8%. The historical maximum precipitation is more than twice the 50-year return levels. 相似文献