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1.
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   

2.
利用SWAT模型和IPCC第五次评估报告中全球气候模式BCC-CSM 1.1数据,对未来气候变化RCP 2.6、RCP 4.5、RCP 8.5共3种典型排放情景对洪湖流域水资源的影响进行了模拟研究。结果表明:SWAT模型对洪湖流域供水资源模拟的适用性较好,洪湖流域在未来RCP 2.6、RCP 4.5、RCP 8.5排放情景下的温度增幅分别为1.4℃、1.9℃和2.4℃,降水变率分别为-3.20%、7.60%和7.90%。SWAT模型模拟结果表明,未来3种情景下随着温度上升洪湖流域实际蒸散发量均略增加,径流受降水影响显著且变化不同,RCP 4.5和RCP 8.5情景下地表径流及地下径流均增加,RCP 8.5情景比RCP4.5情景下地表径流增加多;且各种重现期的洪峰流量和洪水发生频次均增加,RCP 2.6情景下地表径流和地下径流减少。3种情景下径流变异系数较基准期均略增大,说明洪湖流域发生干旱和洪涝的可能性增大,水资源可控性和利用率降低。  相似文献   

3.
基于5个全球气候系统模式结果驱动的高分辨率区域气候模式(RegCM4)模拟输出,系统评估了RegCM4模式对中国西南地区极端降水变化的模拟性能,并科学预估了中国西南地区极端降水的未来演变特征。结果表明,RegCM4模式能合理再现西南地区极端降水变化特征,但模拟的四川中部的湿偏差较大而四川盆地干偏差较大;进行偏差校正后,模拟性能有所提升,对西南地区极端降水模拟偏差有所减小。相较于当代气候(1986—2005年),就区域平均而言在21世纪(2021—2098年),有效降水总量(Prcptot)、强降水日数(R10 mm)、日最大降水量(Rx1day)和极端降水量(R95p)都明显增加;在RCP4.5和RCP8.5情景下,Rx1day和R95p在西南大部分地区增多,到21世纪末RCP4.5情景下增加幅度分别为16.0%和12.6%;Prcptot和R10 mm未来变化存在一定的区域差异,但Prcptot和R10 mm变化在空间上较为相似,在云南南部和四川盆地地区呈现减少趋势,其余地区增加明显;且RCP8.5高排放情景的变化幅度明显大于RCP4.5情景。  相似文献   

4.
利用CMIP5全球模式数据集和RegCM4.0区域气候模式进行连续积分获得的模拟数据,对西南区域未来在RCP2.6,RCP4.5和RCP8.5几种温室气体排放情景下年平均降雨、四季降水,极端降雨事件的特征及其相对历史基准期的变化进行预估。结果表明,不同RCP情景下西南区域降水都将呈持续上升趋势,3种情景下西南区域降水在2020—2050年变化特征差别较小,2050年后差别较大,RCP2.6情景下降水变化幅度最小,CMIP5和RegCM4.0模式模拟的西南区域降水变化的地理分布特征基本一致,降水的高值区都位于青藏高原东南部,横断山脉和四川中部,差异在于RegCM4.0模拟的西藏西部的降雨量级更小,而青藏高原东南部、四川中部和贵州的降雨高值区量级更大。未来近期2020—2060年和远期2061—2099年RCP4.5情景下暴雨天数显著减少的区域主要在西藏东南部(0.5~1 d),未来远期2061—2099年RCP4.5情景云南南部和贵州东部区域暴雨天数显著性增加,而RCP8.5情景下上述区域暴雨天数显著性减少。  相似文献   

5.
利用耦合模式比较计划第5阶段(CMIP5)17个全球气候模式的模拟结果和SSPs社会经济预估数据对RCP4.5和RCP8.5排放情景下中国地区21世纪暴雨洪涝灾害风险的可能变化进行分析。结果表明:21世纪末,极端强降水事件将增加,且极端降水的强度和频率也将增强;暴雨洪涝风险可能随时间呈增加趋势,RCP8.5高排放情景下100 a重现期的洪涝风险更为明显;21世纪RCP4.5和RCP8.5情景下10 a和100 a重现期GDP物理暴露度都将增加;RCP4.5情景下,POP物理暴露度随时间的推移呈先增长后减小趋势,RCP8.5情景下则持续增长。区域分布来看,未来暴雨洪涝风险较高的地区集中在中国中东部及沿海地区,相对于1961—2005年基准期,低风险区面积将缩小,中高以上风险区(Ⅳ和Ⅴ级)面积不断扩大,尤其是高风险区(Ⅴ级)面积扩大更加明显。21世纪,10 a重现期暴雨洪涝灾害中高以上风险区域(Ⅳ和Ⅴ级)面积在RCP4.5情景下随时间多呈先增加后减小的趋势,在RCP8.5情景下不断增大;100 a重现期中高以上风险区域面积在2个排放情景下都呈不断增加趋势。  相似文献   

6.
基于最新的第六次国际耦合模式比较计划(CMIP6)14个耦合模式的数值模拟结果,预估研究了中等强迫情景(SSP2-4.5)和高强迫情景(SSP5-8.5)两种共享社会经济路径下21世纪中后期中亚极端降水事件的时空分布特征及其与区域气候增暖之间的关系。结果显示,大多数CMIP6模式基本能够模拟出历史观测降水气候态(1979~2018年)的空间分布特征,但在中亚西南及东南部偏干,北部及中南部偏湿。与历史基准期(1981~2010年)相比,21世纪末期(2071~2100年)中亚强降水强度在SSP2-4.5和SSP5-8.5情景下分别增加0.54 mm/10 a和2.4 mm/10 a,而强降水发生频率则分别增加了5%~27%和6%~210%,尤其是中南部高海拔山区增加的幅度更大。预估结果的信噪比显示,天山以北的中亚东北部区域的极端降水强度及其发生频率的预估结果具有更高的可信度。气候变暖对未来中亚极端降水事件的发生频次具有明显的调控作用,在SSP2-4.5和SSP5-8.5情景下,当气温每升高1 K时,极端强降水事件的发生频次在分别增加约7 d和9 d,而最大连续无降水日数则分别增加约3 d...  相似文献   

7.
利用政府间气候变化专门委员会第5次评估报告(IPCC AR5)耦合模式相互比较计划第5阶段(CMIP5)中所包含的8个模式资料,对长江中下游强降水的气候特征在21世纪的变化进行预估,并与此前基于第3阶段(CMIP3)的7个模式的预估结果进行了对比。所用资料既包括模式对20世纪的历史模拟,也包括它们在未来高、中、低三种排放情景(即RCP8.5、RCP4.5、RCP2.6三种代表性浓度路径)下的预估试验资料。结果表明:1)不同模式的预估结果有较好的一致性。相对于20世纪最后20 a(1980—1999年),21世纪不仅强降水事件频次、强降水事件的平均强度增加,且年际变率也有所增强。就增加幅度而言,西部强度较小,东部强度较大。2)就不同排放情景相互比较而言,在低排放情景和高排放情景(RCP2.6和RCP8.5)下,降水强度和频次的增长均比在中等排放情景(RCP4.5)下大。3)与之前CMIP3的结果相比,尽管二者均预估未来降水强度和频次增长,但二者增加幅度的空间分布并不一致。在CMIP5中,表现为自西向东幅度递增的特点,而在CMIP3中则中部地区增幅最大。  相似文献   

8.
基于CMIP5逐日最低气温的模拟和预估数据,对中国区域性低温事件进行了研究。通过对中国区域性低温事件的历史模拟显示,模式集合的结果低估了中国区域性低温事件的变化趋势,但能够反映出与观测结果相同的减弱趋势,且比单个模式的结果更稳定,其空间分布与观测结果相似度也较高。在此基础上,采用模式集合方案对不同排放情景下(RCP2.6, RCP4.5, RCP8.5)的中国区域性低温事件进行了预估。结果显示,在RCP2.6排放情景下,中国区域性低温事件的减弱趋势较为缓和;在RCP4.5排放情景下,中国区域性低温事件呈现出显著的减弱趋势;在RCP8.5排放情景下,中国区域性低温事件的减弱趋势更明显。温室气体的排放可能主要影响中国区域性低温事件的强度和发生频次,对其空间分布影响较小。  相似文献   

9.
依据政府间气候变化委员会(IPCC)第五次评估报告(AR5)未来不同排放情景(RCPs)下的多模式(CMIP5)气温和降水预估结果,构建基于气温和降水的未来径流量预估模型,并以宜昌站为例分析了不同模式不同排放情景下未来80年(2020~2099年)长江上游年径流量的变化趋势。多模式集合平均预估结果表明:在99%的置信水平下,未来80年长江上游年径流量在RCP2.6排放情景下呈不显著增加趋势,在RCP4.5排放情景下呈不显著减小趋势,而在RCP8.5排放情景下则呈显著减小趋势;在RCP2.6、RCP4.5和RCP8.5排放情景下未来80年长江上游年径流量预估均值相对于1961~2000年分别减少6.42%、10.99%和13.25%;同时,未来80年长江上游年径流量变化具有一定的年代际特征,在RCP2.6和RCP4.5排放情景下21世纪初期偏多、中期偏少而后期变化并不明显,在RCP8.5排放情景下则是21世纪中期以前偏多而中期以后明显偏少。本研究方法可为未来气候变化情景预估分析提供技术参考,本研究成果可供气候变化背景下长江上游乃至长江流域水资源开发利用及对策分析提供决策依据。   相似文献   

10.
针对珠江流域,分析了在全球气候模式(BCC_CSM1.1)驱动下,区域气候模式RegCM4进行的中国区域气候变化模拟中,珠江流域在RCP4.5和RCP8.5温室气体排放情景下,未来2010—2099年的气候变化。结果表明,RegCM4对珠江流域气候特征具有很强的模拟能力。未来RCPS情景下珠江流域气温将持续增大。与参照时段(1980—1999年)相比,RCP4.5和RCP8.5情景下的年平均温度在2020s分别增加0.7 ℃和0.8 ℃,2050s分别增加1.0 ℃和1.6 ℃,2080s分别增加1.6 ℃和2.9 ℃。而未来年降水并未表现出显著的变化趋势,但不同情景、不同地区预估的降水呈现不同的变化趋势。RCP4.5情景下,流域降水2020s将减少4.3%,2050s和2080s将分别增加0.7%和0.1%;RCP8.5情景下,未来不同时段流域降水均呈减少趋势,2020s、2050s和2080s分别减少1.7%、2.9%和0.2%,表明降水预估具有更大的不确定性。两种排放情景下未来降水在东南沿海增加、西北部减少,变化率为±8%。此外,两种排放情景下未来珠江流域的日平均温度统计特征发生改变,揭示未来高温事件可能增加,同时,大雨级别以上的降水发生频率增加,可能导致洪涝事件增加。   相似文献   

11.
利用国家气候中心完成的RegCM4区域气候模式在RCP4.5和RCP8.5两种排放路径下的气候变化动力降尺度试验结果,在检验模式对基准期(1986—2005年)气温和降水模拟能力基础上,进行华北区域21世纪气候变化预估分析。结果表明:RegCM4对华北区域基准期气温和降水的模拟能力较好。未来21世纪,两种情景下华北区域气温、降水、持续干期(consecutive dry days, CDD)和强降水量(R95p)变化逐渐增大,但变化幅度在高排放的RCP8.5情景下更为显著,其中近期(2021—2035年)、中期(2046—2065年)、远期(2080—2098年)RCP8.5情景下年平均气温分别升高1.77、3.44、5.82℃,年平均降水分别增加8.1%、14%、19.3%,CDD分别减少3、3、12 d, R95p分别增加30.8%、41.9%、69.8%。空间上,未来21世纪华北区域内年、冬季、夏季平均气温将一致升高,夏季升温幅度最大;年、冬季、夏季平均降水整体以增加为主,冬季降水增加幅度最大;CDD以减少为主,但近期和中期在山西和京津冀有所增加,而R95p以增加为主,表明21世纪华北区域干旱事件逐渐减少、极端降水事件不断增加。  相似文献   

12.
“一带一路”区域未来气候变化预估   总被引:1,自引:0,他引:1       下载免费PDF全文
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   

13.
This study analyzes projected changes in seasonal extreme precipitation intensity and dry spell length in the investigation area (Côte d’Ivoire) under RCP4.5 and RCP8.5 forcing scenarios. To this end, a multi-model ensemble of fourteen CORDEX-Africa regional climate model simulations is used during the three stages of the West African Monsoon (WAM) season (April–June (AMJ), July–September (JAS), and October–December (OND)). The results indicate that Côte d’Ivoire is subject to a robust increase of cumulative intensity of precipitation associated with an amplification of extreme precipitation events during the WAM. In particular during JAS, a substantial increase in extreme precipitation reaching up to 50–60% compared to the reference mean value prevails in the western and coastal areas in the far future and under the RCP8.5 scenario. In addition, AMJ season is dominated by an increase in dry spell length of about 12% and 17% in the near future and 20% and 30% in the far future in the entire country under RCP4.5 and RCP8.5 scenarios, respectively, albeit considerable uncertainties. OND considered as the post-monsoon season is mostly characterized by a robust decrease in dry spell length more marked in the southwest in the RCP8.5 scenario during the far future. These results suggest that agricultural production and particularly cocoa plantations in the southwestern regions could be at the risk of flooding events and that water stress remains a threat for cocoa, coffee, and other cash crop plantations in the eastern regions.  相似文献   

14.
Extreme precipitation response to increasing temperature includes not only changes of frequency and intensity, but also changes of extreme precipitation interval (EPIV) and the precipitation during the neighboring daily extreme precipitations interval (EPIP). These changes have not been fully evaluated yet in observations or climate model simulations although they are very useful to understand variations of extreme precipitation. We used daily precipitation data from 669 meteorological stations during the past five decades across China and projections of 19 general circulation models from CMIP5 under the RCP4.5 and RCP8.5 scenarios to investigate variations of EPIV and EPIP. We found the national average annual EPIV increased across China during the last five decades, while annual EPIP significantly decreased. The decreases mainly occurred in southwest China, east China, and southeast China. At national and regional scales, the average annual EPIV and EPIP showed greater decreases under the RCP8.5 scenario than those under the RCP4.5 scenario from 2006 to 2100. Annual EPIP showed a stronger correlation with extreme precipitation intensity than EPIV. The national average annual EPIP had a significant positive correlation with the Western Pacific Subtropical High Area Index. The abnormal geopotential heights over western Mongolia and the western Pacific at 500 hpa as well as the abnormal SSTs in Japan Sea and the western of Pacific in rainy seasons would result in abnormal annual EPIVs and EPIPs in China. This study may provide references for flooding prediction, water resources management, and disaster prevention and mitigation.  相似文献   

15.

This study assesses the hydroclimatic response to global warming over East Asia from multi-model ensemble regional projections. Four different regional climate models (RCMs), namely, WRF, HadGEM3-RA, RegCM4, and GRIMs, are used for dynamical downscaling of the Hadley Centre Global Environmental Model version 2–Atmosphere and Ocean (HadGEM2-AO) global projections forced by the representative concentration pathway (RCP4.5 and RCP8.5) scenarios. Annual mean precipitation, hydroclimatic intensity index (HY-INT), and wet and dry extreme indices are analyzed to identify the robust behavior of hydroclimatic change in response to enhanced emission scenarios using high-resolution (12.5 km) and long-term (1981–2100) daily precipitation. Ensemble projections exhibit increased hydroclimatic intensity across the entire domain and under both the RCP scenarios. However, a geographical pattern with predominantly intensified HY-INT does not fully emerge in the mean precipitation change because HY-INT is tied to the changes in the precipitation characteristics rather than to those in the precipitation amount. All projections show an enhancement of high intensity precipitation and a reduction of weak intensity precipitation, which lead to a possible shift in hydroclimatic regime prone to an increase of both wet and dry extremes. In general, projections forced by the RCP8.5 scenario tend to produce a much stronger response than do those by the RCP4.5 scenario. However, the temperature increase under the RCP4.5 scenario is sufficiently large to induce significant changes in hydroclimatic intensity, despite the relatively uncertain change in mean precipitation. Likewise, the forced responses of HY-INT and the two extreme indices are more robust than that of mean precipitation, in terms of the statistical significance and model agreement.

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16.
This paper reports a comprehensive study on the observed and projected spatiotemporal changes in mean and extreme climate over the arid region of northwestern China, based on gridded observation data and CMIP5 simulations under the RCP4.5 and RCP8.5 scenarios. The observational results reveal an increase in annual mean temperature since 1961, largely attributable to the increase in minimum temperature. The annual mean precipitation also exhibits a significant increasing tendency. The precipitation amount in the most recent decade was greater than in any preceding decade since 1961. Seasonally,the greatest increase in temperature and precipitation appears in winter and in summer, respectively. Widespread significant changes in temperature-related extremes are consistent with warming, with decreases in cold extremes and increases in warm extremes. The warming of the coldest night is greater than that of the warmest day, and changes in cold and warm nights are more evident than for cold and warm days. Extreme precipitation and wet days exhibit an increasing trend, and the maximum number of consecutive dry days shows a tendency toward shorter duration. Multi-model ensemble mean projections indicate an overall continual increase in temperature and precipitation during the 21 st century. Decreases in cold extremes, increases in warm extremes, intensification of extreme precipitation, increases in wet days, and decreases in consecutive dry days, are expected under both emissions scenarios, with larger changes corresponding to stronger radiative forcing.  相似文献   

17.
采用应用于跨行业影响模式比较计划(ISIMIP)的5个CMIP5全球气候模式模拟的历史和未来RCP排放情景下的逐日降水数据,在评估模式对汉江流域1961—2005年极端降水变化特征模拟能力的基础上,进一步计算了RCP2.6、RCP4.5和RCP8.5排放情景下汉江流域未来2016—2060年极端降水总量(R95p)、极端降水贡献率(PEP)、连续5 d最大降水(RX5d)和降水强度(SDII),结果表明:RCP4.5情景下的极端降水指数上升最明显,R95p和RX5d分别较基准期增加12.5%和8.2%,PEP增加3.2个百分点,SDII微弱上升。在不同排放情景下,PEP均有一定的增幅,以流域西北和东南部增幅较大;R95p在流域绝大部分区域表现出一定的增加,且流域东南部和北部是增幅高值区;RX5d在RCP2.6和RCP4.5情景下整体表现为增加的特征,但在RCP8.5情景下整体表现为减少的特征。对极端降水预估的不确定性中,SDII的不确定性最小,RX5d的不确定性最大;不确定性大值区主要位于流域东部、东南部和西北部部分区域。  相似文献   

18.
This study assesses future climate change over East Asia using the Global/Regional Integrated Model system—Regional Model Program (RMP). The RMP is forced by two types of future climate scenarios produced by the Hadley Center Global Environmental Model version 2 (HG2); the representative concentration pathways (RCP) 4.5 and 8.5 scenarios for the intergovernmental panel on climate change fifth assessment report (AR5). Analyses for the current (1980–2005) climate are performed to evaluate the RMP’s ability to reproduce precipitation and temperature. Two different future (2006–2050) simulations are compared with the current climatology to investigate the climatic change over East Asia centered in Korea. The RMP satisfactorily reproduces the observed seasonal mean and variation of precipitation and temperature. The spatial distribution of the simulated large-scale features and precipitation by the RMP is generally less reflective of current climatic conditions than that is given by the HG2, but their inter-annual variations in East Asia are better captured by the RMP. Furthermore, the RMP shows higher reproducibility of climate extremes including excessive heat wave and precipitation events over South Korea. In the future, strong warming is distinctly coupled with intensified monsoonal precipitation over East Asia. In particular, extreme weather conditions are increased and intensified over South Korea as follows: (1) The frequency of heat wave events with temperature greater than 30 °C is projected to increase by 131 and 111 % in the RCP 8.5 and 4.5 downscaling, relative to the current climate. (2) The RCP 8.5 downscaling shows the frequency and variability of heavy rainfall to increase by 24 and 31.5 %, respectively, while the statistics given by the RCP 4.5 downscaling are similar to those of the current climate.  相似文献   

19.
Future changes in the 50-yr return level for temperature and precipitation extremes over mainland China are investigated based on a CMIP5 multi-model ensemble for RCP2.6, RCP4.5 and RCP8.5 scenarios. The following indices are analyzed:TXx and TNn(the annual maximum and minimum of daily maximum and minimum surface temperature), RX5 day(the annual maximum consecutive 5-day precipitation) and CDD(maximum annual number of consecutive dry days). After first validating the model performance, future changes in the 50-yr return values and return periods for these indices are investigated along with the inter-model spread. Multi-model median changes show an increase in the 50-yr return values of TXx and a decrease for TNn, more specifically, by the end of the 21 st century under RCP8.5, the present day 50-yr return period of warm events is reduced to 1.2 yr, while extreme cold events over the country are projected to essentially disappear.A general increase in RX5 day 50-yr return values is found in the future. By the end of the 21 st century under RCP8.5, events of the present RX5 day 50-yr return period are projected to reduce to 10 yr over most of China. Changes in CDD-50 show a dipole pattern over China, with a decrease in the values and longer return periods in the north, and vice versa in the south. Our study also highlights the need for further improvements in the representation of extreme events in climate models to assess the future risks and engineering design related to large-scale infrastructure in China.  相似文献   

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