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1.
气候变化背景下蚌埠市暴雨与淮河上游洪水遭遇概率分析 总被引：1，自引：0，他引：1
利用6个全球/区域气候模式和VIC模型,预估了IPCC RCPs情景下2021—2050年淮河干流蚌埠水文站(吴家渡断面)的日流量过程。在此基础上,运用Copula函数构建了蚌埠市暴雨与淮河上游洪水遭遇概率模型,分析了RCP2.6、RCP4.5和RCP8.5情景下不同重现期暴雨和洪水组合遭遇概率的变化趋势。结果表明,2021—2050年多模式预估上游洪水与城市暴雨遭遇的概率较基准期(1971—2000年)有所增大,具有较高的一致性,平均增幅46%~79%。暴雨与洪水遭遇概率的增大,将会增加未来蚌埠市防洪工作的难度。 相似文献
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IPCC《气候变化中的海洋和冰冻圈特别报告》评估了全球和区域海洋的气候变化及其对生态系统和人类社会的影响、风险及应对措施。结果表明,近几十年来,海洋的物理和化学性质发生了明显变化,如升温、酸化、脱氧和营养盐减少等气候致灾因子（事件）的危害（险）性不断加剧（高信度）。这种变化正在影响从上层到底层的海洋生态系统和人类社会的可持续发展,如海洋初级生产力的下降、物种地理分布的变迁、渔业资源潜在渔获量的下降以及食品供应的减少（高信度）。在气候变化与非气候人为干扰因素的综合影响下,随着温室气体排放的增加（从RCP2.6到RCP8.5情景）,到21世纪末,几乎所有类型的海洋和海岸带生态系统将处于高或很高的风险水平（高信度);其中,暖水珊瑚礁生态系统尤其严重,如果全球升温1.5℃和2℃,将分别消失70%~90%和99%以上（很高信度）。然而,当前多种减缓气候变化的海洋应对措施的作用较小,有的可能带来生态危险,而许多降低气候风险的海洋适应措施的作用也很有限,特别是在RCP8.5情景下的作用更小;未来海洋生态系统的风险水平在RCP2.6情景下均低于RCP8.5情景（很高信度)。因此,这凸显了减缓气候变化尤其是减缓和适应气候变化综合治理的重要性。 相似文献
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IPCC《气候变化中的海洋和冰冻圈特别报告》评估了气候变化对全球、区域海平面变化和极端海面（极值水位）升高的贡献,以及海平面上升对低海拔（小鱼10 m）岛屿、沿海地区和社会的影响及相关的风险。评估表明,全球变暖背景下,全球平均海平面上升的证据是确凿的,且明显加速（高信度),极端海面高度升高,主要是由陆地冰川和冰盖融化以及海洋热膨胀引起,且前者的贡献已大于后者（很高信度);与此同时,海洋变暖速率倍增,强热带气旋、风暴潮增多,极值水位重现期缩短;至21世纪末,全球海平面还将上升约0.43 m（温室气体低排放情景,RCP2.6）和0.84 m（高排放情景,RCP8.5）（中等信度）,很多沿海地区当前较少发生的百年一遇的极值水位将变为一年一遇或更频繁,而对于许多沿海低洼地而言,类似事件甚至在21世纪中叶就可能发生（高信度)。评估还表明,持续上升的海平面、趋于频发的极值水位,以及人为地面沉降等因素,增加了沿海社会-生态系统的暴露度和脆弱性;并且,与海平面上升有关的危害（险）性事件,如海岸侵蚀、洪灾、盐碱化和生境退化等将显著增加（高信度)。报告指出,如未采取充分的适应海平面上升的措施,在RCP8.5情景下,沿海大城市、城市环礁群岛、热带农业三角洲地区和北极沿岸社区将处于高或很高的灾害风险中（高信度)。 相似文献
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《气候变化研究进展》2015,(3)
利用CMIP5耦合模式RCP2.6、RCP4.5和RCP8.5情景预估结果,以1890一1900年为基准气候,确定了2℃全球变暖时间、对应时期青藏高原平均气候和极端气候事件变化幅度,多模式集合平均结果表明:RCP2.6、RCP4.5和RCP8.5情景下2℃全球变暖分别发生在2063年、2040年和2036年;对应着2℃全球变暖,三种情景下青藏高原平均气温分别升高2.99℃、3.22℃和3.28℃,均超过全球2℃的升温水平;年降水量亦增加,分别增加8.35%、7.16%和7.63%。受气温升高和降水量增多影响,RCP4.5情景下霜冻日数、冰封日数减少,暖夜日数、暖昼日数增多;RCP4.5情景下中雨日数、强降水量、降水强度均增加,持续干期天数减少。从各地平均气候和极端气候事件变化结果来看,柴达木盆地是青藏高原气候变化的敏感区。 相似文献
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利用RCP4.5和RCP8.5情景下区域气候模式RegCM4.0单向嵌套BCC_CSM1.1全球气候系统模式输出结果中海南岛区域的格点进行站点插值后的预估数据,分析了海南本岛21世纪气候变化情景,结果表明:21世纪海南岛总体呈变暖、变湿趋势.在RCP4.5情景下,年增暖倾向率为1.4℃/100a,在RCP8.5情景下,年增暖倾向率为3.4℃/100a.RCP4.5情景下,增温幅度最大的是冬季;RCP8.5情景下,前期增温幅度最大的是冬季,中期增温幅度最大的是夏季,后期增温幅度最大的在秋季.21世纪年降水距平百分率的变化有明显的阶段性变化.RCP4.5情景下前、后期降水增多不明显,中期增多明显;RCP8.5情景下前、后期的降水增加幅度比中期更明显.21世纪冷季降水可能减少,秋季可能更明显,冬季次之;暖季降水可能增加,夏季可能更明显. 相似文献
6.
IPCC第五次评估报告第一工作组报告的亮点结论 总被引：44，自引：0，他引：44
IPCC第五次评估报告(AR5)第一工作组(WGI)报告的亮点结论,是过去7年全世界气候变化科学研究成果凝练出来的精华。20世纪50年代以来全球气候变暖的一半以上是人类括动造成的。1971年以来人为排放温室气体产生热量的93%进入了海洋,海洋还吸收了大约30%人为排放的CO_2,导致海表水pH值下降了0.1,等等。采用全球耦合模式比较计划第五阶段(CMIP5)的模式,预估未来全球气候变暖仍将持续,21世纪末全球平均地表温度在1986—2005年的基础上将升高0.3~4.8℃。限制气候变化需要大幅度持续减少温室气体排放。如果将1861一1880年以来的人为CO_2累积排放控制在1000 GtC,那么人类有超过66%的可能性把未来升温幅度控制在2℃以内(相对于1861一1880年)。 相似文献
7.
利用耦合模式比较计划第5阶段(CMIP5)提供的18个全球气候模式的模拟结果,预估了3种典型浓度路径(RCP2.6、RCP4.5、RCP8.5)下“一带一路”地区平均气候和极端气候的未来变化趋势。结果表明:在温室气体持续排放情景下,“一带一路”地区年平均气温在未来将会持续上升,升温幅度随温室气体浓度的增加而加大。在高温室气体排放情景(RCP8.5)下,到21世纪末期,平均气温将普遍升高5℃以上,其中北亚地区升幅最大,南亚和东南亚地区升幅最小。对于降水的变化,预估该区域大部分地区的年降水量将增加,其中西亚和北亚增加最为明显,而且在21世纪中期,RCP2.6情景下的增幅要比RCP4.5和RCP8.5情景下的偏大,而在21世纪后期,RCP8.5情景下降水的增幅比RCP2.6和RCP4.5情景下的偏大。未来极端温度也将呈升高的趋势,增温幅度高纬度地区大于低纬度地区、高排放情景大于低排放情景。而且在高纬度区域,极端低温的增暖幅度要大于极端高温的增幅。连续干旱日数在北亚和东亚总体呈现减少趋势,而在其他地区则呈增加趋势。极端强降水在“一带一路”区域总体上将增强,增强最明显的地区位于南亚、东南亚和东亚。 相似文献
8.
针对参加“国际耦合模式比较计划”(CMIP5)的IAP/LASG气候系统模式FGOALS-s2,评估了其对南半球气候平均态的模拟能力,在此基础上,预估了未来不同“典型浓度路径”(RCPs)情景下南半球气候的变化特征.对20世纪历史气候模拟结果的分析表明,模式能够合理再现南半球大气环流气候态分布特征,包括6～8月平均(JJA)南半球双西风急流现象,只是模拟的北支急流偏弱、南支急流偏强.未来气候预估试验中,不同RCPs情景下南半球温度变化以增暖为主要特征,陆地增温大于海洋,只有南大西洋—印度洋海盆存在局部变冷.综合四种不同情景,未来随着温室气体浓度的增加,南半球中纬度高压带将显著加强,绕极低压带将加深.降水呈现出增多的特征,12月到来年2月平均(DJF)强于JJA,海洋强于陆地,只有南印度洋和南太平洋中部局部降水减少.未来不同RCPs情景下,马斯克林高压表现出先减弱后增强的特征,而澳大利亚高压则呈现出先增强后减弱的特征.南极涛动(AAO)的变化表现为:RCP2.6和RCP4.5情景下AAO都表现为先增强后减弱,RCP6.0和RCP8.5情景下都为一致的增强趋势,这主要与四种情景中模拟的未来温度变化结构不同有关.例如在RCP6.0和RCP8.5情景下,南半球高纬高层温度增暖趋势小于中纬地区,使得经向温度梯度增大,中纬度西风加强,60°S以南位势高度减小,最终令AAO增强. 相似文献
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10.
介绍了政府间气候变化专门委员会（IPCC）为第五次评估报告开发的新情景——代表性浓度路径（RCPs）,分析了RCPs情景的内在优势,并描述了4类代表性RCPs（RCP8.5、RCP6、RCP4.5和RCP3-PD）的特征。利用IPCC最新发布的RCPs数据,分析了高端、中端稳定和低端浓度路径下,全球温室气体的排放空间、区域分担和减排成本,并着重探讨了低端路径与全球温度升幅限制在2℃以下目标之间的关系及其给中国带来的主要挑战和应对途径。 相似文献
11.
Climate models project a positive Indian Ocean Dipole(p IOD)–like SST response in the tropical Indian Ocean to global warming. By employing the Community Earth System Model and applying an overriding technique to its ocean component(version 2 of the Parallel Ocean Program), this study investigates the similarities and differences of the formation mechanisms for the changes in the tropical Indian Ocean during the p IOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, wind–thermocline–SST feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases. Some differences are also found, including the fact that the cooling effect of the vertical advection over the eastern tropical Indian Ocean is dominated by the anomalous vertical velocity during the p IOD but by the anomalous upper-ocean stratification under global warming. These findings are further examined through an analysis of the mixed layer heat budget. 相似文献
12.
海洋在气候变暖过程中的重要性通常用海洋热吸收来衡量,热吸收的大小影响全球变暖的幅度。本文利用FGOALS-g2、FGOALS-s2（以下分别缩写为g2、s2）两个耦合模式的CO2浓度以每年1%速率增长（1pctCO2）试验,评估和分析海洋热吸收与气候敏感度的关系。结果表明:进入海洋净热通量（s2模式大于g2模式）会使得s2模式的海洋热吸收总体比g2模式大;更为重要的是,由于s2模式中的海洋热吸收主要集中在上层,使得耦合模式s2中的瞬态气候响应（TCR,或称气候敏感度）比g2大。当CO2浓度加倍时,在两个耦合模式中,海洋热吸收的空间分布呈现显著性的差异,s2模式中上层热吸收明显比深层大,上层热吸收主要位于太平洋和印度洋,而g2模式中上层和深层热吸收差别较小,深层主要位于大西洋和北冰洋。进一步研究表明,海洋热吸收分布特征与两个耦合模式海洋环流变化有关。在g2模式中北大西洋经圈翻转环流（AMOC）强度强且深度大,在CO2浓度加倍时,AMOC减弱小,这样AMOC可将热量带到海洋的深层,增加海洋深层热吸收。而在s2模式中,平均AMOC弱且浅,在CO2浓度加倍时,AMOC减弱明显,热量不易到达深层,主要集中在海洋上层,对气候敏感度影响更快且更强。海洋环流导致热吸收及其空间差异同时影响到气候敏感度的差异。因此,探讨海洋热吸收与气候敏感度之间的关系,利于明确气候敏感度不确定性的来源。 相似文献
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Tropical cyclone heat potential (TCHP) in the ocean can affect tropical cyclone intensity and intensification. In this paper, TCHP change under global warming is presented based on 35 models from CMIP5 (Coupled Model Intercomparison Project, Phase 5). As the upper ocean warms up, the TCHP of the global ocean is projected to increase by 140.6% in the 21st century under the RCP4.5 (+4.5 W m-2 Representative Concentration Pathway) scenario. The increase is particularly significant in the western Pacific, northwestern Indian and western tropical Atlantic oceans. The increase of TCHP results from the ocean temperature warming above the depth of the 26°C isotherm (D26), the deepening of D26, and the horizontal area expansion of SST above 26°C. Their contributions are 69.4%, 22.5% and 8.1%, respectively. Further, a suite of numerical experiments with an Ocean General Circulation Model (OGCM) is conducted to investigate the relative importance of wind stress and buoyancy forcing to the TCHP change under global warming. Results show that sea surface warming is the dominant forcing for the TCHP change, while wind stress and sea surface salinity change are secondary. 相似文献
14.
在工业革命以来全球长期增暖趋势背景下,全球平均表面气温还同时表现出年代际变化特征,二者叠加在一起使得全球平均气温在某些年份增暖相对停滞(如1999～2008年)或者增暖相对较快(如1980～1998年).利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室(LASG)发展的耦合气候模式FGOALS-s2历史气候和典型路径浓度(RCPs)模拟试验结果研究了可能造成全球增暖的年代际停滞及加速现象的原因,特别是海洋环流对全球变暖趋势的调制作用.该模式模拟的全球平均气温与观测类似,即在长期增暖趋势之上,还叠加了显著的年代际变化.对全球平均能量收支分析表明,模拟的气温年代际变化与大气顶净辐射通量无关,意味着年代际表面气温变化可能与能量在气候系统内部的重新分配有关.通过对全球增暖加速和停滞时期大气和海洋环流变化的合成分析及回归分析,发现全球表面气温与大部分海区海表温度(SST)均表现出几乎一致的变化特征.在增暖停滞时期,SST降低,更多热量进入海洋次表层和深层,使其温度增加;而在增暖加速时期,更多热量停留在表层,使得大部分海区SST显著增加,次表层海水和深海相对冷却.进一步分析表明,热带太平洋表层和次表层海温年代际变化主要是由于副热带—热带经圈环流(STC)的年代际变化所致,然后热带太平洋海温异常可以通过风应力和热通量强迫作用引起印度洋、大西洋海温的年代际变化.在此过程中,海洋环流变化起到了重要作用,例如印度尼西亚贯穿流(ITF)年代际异常对南印度洋次表层海温变化起到关键作用,而大西洋经圈翻转环流(AMOC)则能直接影响到北大西洋深层海温变化. 相似文献
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Torben Koenigk Laurent Brodeau Rune Grand Graversen Johannes Karlsson Gunilla Svensson Michael Tjernström Ulrika Willén Klaus Wyser 《Climate Dynamics》2013,40(11-12):2719-2743
The Arctic climate change is analyzed in an ensemble of future projection simulations performed with the global coupled climate model EC-Earth2.3. EC-Earth simulates the twentieth century Arctic climate relatively well but the Arctic is about 2 K too cold and the sea ice thickness and extent are overestimated. In the twenty-first century, the results show a continuation and strengthening of the Arctic trends observed over the recent decades, which leads to a dramatically changed Arctic climate, especially in the high emission scenario RCP8.5. The annually averaged Arctic mean near-surface temperature increases by 12 K in RCP8.5, with largest warming in the Barents Sea region. The warming is most pronounced in winter and autumn and in the lower atmosphere. The Arctic winter temperature inversion is reduced in all scenarios and disappears in RCP8.5. The Arctic becomes ice free in September in all RCP8.5 simulations after a rapid reduction event without recovery around year 2060. Taking into account the overestimation of ice in the twentieth century, our model results indicate a likely ice-free Arctic in September around 2040. Sea ice reductions are most pronounced in the Barents Sea in all RCPs, which lead to the most dramatic changes in this region. Here, surface heat fluxes are strongly enhanced and the cloudiness is substantially decreased. The meridional heat flux into the Arctic is reduced in the atmosphere but increases in the ocean. This oceanic increase is dominated by an enhanced heat flux into the Barents Sea, which strongly contributes to the large sea ice reduction and surface-air warming in this region. Increased precipitation and river runoff lead to more freshwater input into the Arctic Ocean. However, most of the additional freshwater is stored in the Arctic Ocean while the total Arctic freshwater export only slightly increases. 相似文献
16.
Effects of solar radiation modification on the ocean carbon cycle: An earth system modeling study 
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下载免费PDF全文 Solar radiation modification (SRM, also termed as geoengineering) has been proposed as a potential option to counteract anthropogenic warming. The underlying idea of SRM is to reduce the amount of sunlight reaching the atmosphere and surface, thus offsetting some amount of global warming. Here, the authors use an Earth system model to investigate the impact of SRM on the global carbon cycle and ocean biogeochemistry. The authors simulate the temporal evolution of global climate and the carbon cycle from the pre-industrial period to the end of this century under three scenarios: the RCP4.5 CO2 emission pathway, the RCP8.5 CO2 emission pathway, and the RCP8.5 CO2 emission pathway with the implementation of SRM to maintain the global mean surface temperature at the level of RCP4.5. The simulations show that SRM, by altering global climate, also affects the global carbon cycle. Compared to the RCP8.5 simulation without SRM, by the year 2100, SRM reduces atmospheric CO2 by 65 ppm mainly as a result of increased CO2 uptake by the terrestrial biosphere. However, SRM-induced change in atmospheric CO2 and climate has a small effect in mitigating ocean acidification. By the year 2100, relative to RCP8.5, SRM causes a decrease in surface ocean hydrogen ion concentration ([H+]) by 6% and attenuates the seasonal amplitude of [H+] by about 10%. The simulations also show that SRM has a small effect on globally integrated ocean net primary productivity relative to the high-CO2 simulation without SRM. This study contributes to a comprehensive assessment of the effects of SRM on both the physical climate and the global carbon cycle.摘要太阳辐射干预地球工程是应对气候变化的备用应急措施. 其基本思路是通过减少到达大气和地表的太阳辐射, 从一定程度上抵消温室效应引起的全球变暖. 本研究使用地球系统模式模拟理想化太阳辐射干预方法对海洋碳循环的影响. 模拟试验中, 通过直接减少太阳辐射将RCP8.5 CO2排放情景下的全球平均温度降低到RCP4.5情景下的温度. 模拟结果表明, 到2100年, 相对于RCP8.5情景, 减少太阳辐射通过增加陆地碳汇, 使大气CO2浓度降低了65 ppm. 减少太阳辐射对海洋酸化影响很小. 到 2100 年, 相对于RCP8.5情景, 减少太阳辐射使海表平均氢离子浓度减少6%, pH上升0.03, 同时使海表平均氢离子浓度的季节变化振幅衰减约10%. 模拟结果还表明, 减少太阳辐射对全球海洋净初级生产力的影响较小. 本研究有助于深化我们对太阳辐射干预地球工程的气候和碳循环效应的认知和综合评估. 相似文献
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Igor V. Polyakov Vladimir A. Alexeev Uma S. Bhatt Evgenia I. Polyakova Xiangdong Zhang 《Climate Dynamics》2010,34(2-3):439-457
Climate fluctuations in the North Atlantic Ocean have wide-spread implications for Europe, Africa, and the Americas. This study assesses the relative contribution of the long-term trend and variability of North Atlantic warming using EOF analysis of deep-ocean and near-surface observations. Our analysis demonstrates that the recent warming over the North Atlantic is linked to both long-term (including anthropogenic and natural) climate change and multidecadal variability (MDV, ~50–80 years). Our results suggest a general warming trend of 0.031 ± 0.006°C/decade in the upper 2,000 m North Atlantic over the last 80 years of the twentieth century, although during this time there are periods in which short-term trends were strongly amplified by MDV. For example, MDV accounts for ~60% of North Atlantic warming since 1970. The single-sign basin-scale pattern of MDV with prolonged periods of warming (cooling) in the upper ocean layer and opposite tendency in the lower layer is evident from observations. This pattern is associated with a slowdown (enhancement) of the North Atlantic thermohaline overturning circulation during negative (positive) MDV phases. In contrast, the long-term trend exhibits warming in tropical and mid-latitude North Atlantic and a pattern of cooling in regions associated with major northward heat transports, consistent with a slowdown of the North Atlantic circulation as evident from observations and confirmed by selected modeling results. This localized cooling has been masked in recent decades by warming during the positive phase of MDV. Finally, since the North Atlantic Ocean plays a crucial role in establishing and regulating the global thermohaline circulation, the multidecadal fluctuations discussed here should be considered when assessing long-term climate change and variability, both in the North Atlantic and at global scales. 相似文献
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The deep ocean below 2000 m is a large water body with the sparsest data coverage, challenging the closure of the sea-level budget and the estimation of the Earth's energy imbalance. Whether the deep ocean below 2000 m is warming globally has been debated in the recent decade. However, as the regional signals are generally larger than the global average, it is intriguing to investigate the regional temperature changes. Here, we adopt an indirect method that combines altimetry, GRACE, and Argo data to examine the global and regional deep ocean temperature changes below 2000 m. The consistency between high-quality conductivity-temperature-depth (CTD) data from repeated hydrographic sections and our results confirms the validity of the indirect method. We find that the deep oceans are warming in the Middle East Indian Ocean, the subtropical North and Southwest Pacific, and the Northeast Atlantic, but cooling in the Northwest Atlantic and Southern oceans from 2005 to 2015. 相似文献