气候模式对长江流域气温和降水的模拟性能评估及未来情景预估

利用政府间气候变化专门委员会第四次评估报告的22个新一代全球气候模式基准期(1961～1990年)模拟结果,从时空尺度分别讨论了与观测过程的差异,评估了模式对长江流域气温和降水的模拟性能。结果表明22个气候模式对长江流域具有一定的模拟能力,地面气温的模拟值都偏低,部分降水的模拟值局部偏高。不同的气候模式的模拟能力差异显著,大部分模式对长江流域的模拟精度有待进一步改进,只有少数几个模式（降水有6个模式,气温有5个模式）的年变化趋势与实况基本一致。综合比较,UKMO_HadCM3和NCAR_PCM两个模式基本能再现长江流域降水和气温的年变化特征。长江流域降水和气温未来情景预估表明各个模式和情景结果虽然存在差异,但对未来90年气候变化的模拟趋势基本一致,将持续增温、降水出现区域性增加,并着重讨论了UKMO_HadCM3模式在2020s（2010～2039年）、2050s（2040～2069年）和2080s（2070～2099年）3个时段的降水和气温时空变化特征,研究结果表明3个时段气温和降水在不同情景下都是逐渐增加的,A2情景下未来降水增幅最显著,B1情景增幅最小。     

汉江流域未来降水径流预测分析研究

本文应用统计降尺度法将全球气候模式和VIC分布式水文模型进行耦合,研究未来A2气候情景下汉江流域降水径流变化情况.首先应用基于光滑支持向量机的统计降尺度法在全球气候模式CGCM2和HadCM3的A2气候情景下,分别预测未来汉江流域日降水、气温过程,然后将预测降水过程作为VIC模型的输入,模拟预测未来汉江流域径流过程.研究结果表明,在CGCM2气候模式下,2020s(2011～2040年)时期汉江流域径流小于基准年,2050s(2041～2070年)时期与基准年基本相当,2080s(2071～2100年)时期大于基准年;在HadCM3气候模式下,2020s时期汉江流域径流小于基准年,2050s和2080s时期均比基准年增加;降水、气温预测结果与径流基本一致.     

宁夏近53年冬季气温变化趋势及对农业的影响

根据宁夏20个地面气象观测站1961年来冬季(12月至次年2月)逐日气温资料,采用线性趋势分析、Mann-Kendall检验等方法,分析了宁夏全区、引黄灌区、中部干旱带和南部山区冬季平均、最高、最低气温年际、年代际变化趋势及突变特征;对比分析了21世纪以来冬季最冷月平均气温、0℃负积温变化的新特点及对农业的影响。结果表明:1宁夏全区及各地冬季平均气温2000年以前上升趋势显著,其中引黄灌区冬季增暖最明显,中部干旱带次之,南部山区增暖幅度最小,1985年为宁夏大部分地区冬季平均气温升高的突变点。21世纪以来宁夏大部分地区冬季平均气温上升趋势趋缓,中部干旱带甚至出现下降。2宁夏各地冬季平均最低气温的上升幅度明显高于冬季平均气温和冬季平均最高气温,说明宁夏各地冬季气温升高的原因主要是冬季最低气温升高;进入21世纪以来,冬季平均最高气温变化幅度较冬季平均气温剧烈,大部分地区出现下降;冬季平均最低气温除中部干旱带2002年后略微下降之外,大部分地区持续上升。3冬季最冷月平均气温升高,0℃负积温绝对值大幅降低,有利于越冬作物种植区北界北移,种植面积扩大,遭遇冻害的风险降低,也易使农作物病虫害增加。     

基于CMIP6多模式的和田河流域未来气候变化预估

气候系统模式是对历史和未来气候模拟最广泛有效的工具,但存在一定的不足和局限性,使其无法直接用以预估未来气候变化。本文采用基于分位数映射的日偏差校正(DBC)、多模式集合(MME)平均和基于皮尔逊r相关系数的加权集合(r-MME)平均方法,以1971—2000年为基准期,评估6种气候模式在和田河流域的适用性;运用r-MME方法对未来SSP1-2.6、SSP2-4.5和SSP5-8.5情景下各模式的偏差校正结果进行集合,分析未来近期(2021—2050年)、远期(2061—2090年)日最高、最低气温以及降水的时空演变特征。结果表明：基于DBC的r-MME融合方法能够综合考虑各模式的优势,可大幅提高气候模式模拟的精度,年均最高气温、最低气温和降水量与实测序列的相关系数分别达到0.918、0.821和0.878;3种情景下的气温和降水均呈现增加趋势,其中低强迫SSP1-2.6情景下的增幅最小,远期年最高气温、最低气温和降水的平均增量分别为2.830、2.523℃和46.412 mm,高强迫SSP5-8.5情景下的增幅最大,远期年最高气温、最低气温和降水的平均增量为5.697、6.452℃和9...     

基于RCP情景的黄河流域未来气候变化趋势

根据国家气候中心提供的7个气候模式的情景资料和黄河流域108个站点的实测气候要素资料,评估了不同气候模式对黄河流域历史(基准期1961~1990年)气候要素的模拟能力,在此基础上,采用较为适合黄河流域的气候模式资料,分析了不同RCP排放情景下黄河流域未来的气候变化趋势。结果表明,MPI-ESM模式能够较好地模拟黄河流域气温降水的历史变化。黄河流域未来气温将持续升高,线性升率约为0.28~0.45℃/10a,未来降水变化具有较大的不确定性,与基准期相比,未来黄河流域降水与基准期基本持平或偏少。气温降水变化的季节分配和空间分布差异明显,2、8、9月份升温幅度较大,5月份升温幅度较小;2、5、12月份降水普遍增多,6~8月份降水减少;黄河源头及宁夏内蒙河段升温幅度较大;黄河源头降水以增多或减少幅度较小为主,中游下段及下游地区降水以减少为主。     

区域气候模式水平分辨率对黄淮海流域当代气候模拟的影响

区域气候模式是进行流域尺度气候变化研究的重要工具,其中水平分辨率对流域模拟结果的影响亟待评估。本文使用区域气候模式RegCM4,在ERA-Interim再分析资料驱动下,进行2种水平分辨率（50 km和25 km）1990-2010年东亚区域的长时间连续积分模拟。通过与观测资料的对比,评估RegCM4对黄淮海流域的模拟性能,同时分析水平分辨率对模拟结果的影响。结果表明:① 2组模拟均可以较好地再现黄淮海流域冬季、夏季平均气温和降水的空间分布,以及气温和降水的年循环变化;对极端气候事件指数的分布模拟效果也较好,且对与气温有关的极端气候事件指数模拟效果优于与降水有关的极端气候事件指数。②与观测相比,也存在一定的偏差,如模拟的冬季气温存在冷偏差,夏季气温存在暖偏差,冬季、夏季降水在大部分地区偏多等。③ 2组模拟对比来看,对冬季、夏季平均气温的量级和空间分布,25 km模拟与观测更加接近;对冬季、夏季平均降水,50 km模拟与观测的空间相关系数分别为0.86和0.44,较25 km模拟有较大提高;对极端事件,2组模拟差别不大。模拟结果可为后续此版本模式在黄淮海流域气候变化研究中的应用提供参考。     

环青海湖地区气候变化特征及其季风环流因素

基于青海湖流域及其周边地区11个气象站点1959—2015年逐月气温和降水数据,采用Mann-Kendall趋势分析、突变分析、Morlet连续小波变换、Pearson相关分析和R/S分析等方法,分析了平均气温、平均最高气温、平均最低气温和降水的年、季变化特征及其季风环流影响因素,并探讨了该区域未来气候变化的总体趋势。研究结果表明:(1)环青海湖地区气温和降水总体上呈现出显著增加的趋势,秋季和冬季的平均气温、平均最高气温和平均最低气温上升速率以及夏季和冬季降水增加速率最为明显。(2)气温和降水均存在较为明显的突变现象,气温突变时间普遍在1986年左右,而降水突变时间在2002年左右;研究区气温普遍存在2~3年的短周期,8~10年和30~32年的中长周期变化,而降水则存在着3~4年、6~7年的短周期和30~32年的长周期变化。(3)东亚夏季风指数对研究区秋季气温和夏季降水具有较大的影响,而印度夏季风主要影响了研究区春季气温和降水;北极涛动指数(AO)对研究区秋季和冬季气温的上升影响最大,对春季、夏季和冬季降水的影响也明显高于其他指数;北大西洋涛动指数(NAO)和厄尔尼诺—南方涛动(ENSO)对研究区气温影响较小,NAO主要影响夏季和冬季降水,而ENSO主要影响秋季降水。(4)研究区年均气温和年降水的Hurst指数均大于0.5,说明研究区气温和降水在未来一段时间内仍以上升趋势为主。     

CMIP5多模式集合对南亚印度河流域气候变化的模拟与预估

利用印度河流域CRU、APHRODITE和CMIP5多模式逐月气温、降水格点数据集, 评估了CMIP5模式集合对印度河流域气候变化的模拟能力; 对多模式集合数据进行了偏差订正, 并对流域2046-2065年和2081-2100年气候变化进行了预估. 结果表明: 气候模式对流域年平均气温时间变化和空间分布特征有着较强的模拟能力, 时间空间相关系数均达到了0.01的显著性水平, 尤其对夏季气温的模拟要优于其他季节; 模式对降水的季节性波动也有着较好的模拟能力. 偏差订正后的预估结果表明, RCP2.6、4.5、8.5情景下, 相对于基准期(1986-2005年), 21世纪中期(2046-2065年)和末期(2081-2100年)整个流域年平均气温都有一定上升, 且流域上游增幅较大; 除RCP4.5情景下21世纪中期流域有弱减少趋势外, 年降水量都将有一定增长. 未来夏季持续升温将引起源区冰川的进一步消融, 春季降水对于中高海拔地区水资源的贡献将减弱; 流域北部高海拔区域冬季降水的增加有助冰川累积和上游水资源的增加, 东部高海拔区域冬季降水的减少会减少上游水资源. 两时期夏季降水都有一定的增长, 洪涝的发生风险加大; 流域暖事件和强降水事件也将可能增多.     

乌鞘岭是甘肃气候转型变化的分界线吗?

基于甘肃省及周边地区46个气象站点的气温和降水年值、月值数据,对数据进行均一化检验和订正后,采用气候倾向率法、Mann-Kendall 非参数检验法对甘肃近50a气候变化时空特征进行了分析。结果表明：甘肃省平均气温、平均最低气温、平均最高气温、极端最高气温、极端最低气温均升温明显,其中以最低气温升温最为显著。气温的季节变化空间差异较大,空间上四季最低气温和极端最低气温升温最显著,春、冬季平均最低气温升温最显著;夏、秋季极端最低气温升温最为显著。降水变化的区域差异大,降水气候倾向率最小值达-22.2mm·（10a）^-1,最大值14.1 mm·（10a）^-1,乌鞘岭以东表现为减少趋势,以西增加。河西地区气温突变时间为1986年,早于河东气温突变时间（1993年）。甘肃气候变化时空差异明显,乌鞘岭是近50a甘肃气候转型分异的一条重要分界线。     

基于气候模式筛选的碧流河水库流域未来期径流预估研究

为评估IPCC第四次评估报告中的15个全球气候模式对碧流河水库流域气温和降水的模拟效果,通过LARS-WG降尺度方法,选取了HADCM3等3种气候模式,分析其在A2、A1B和B1三种排放情景下未来期(2011~2040年)碧流河水库流域气温和降水的变化,进而结合ABCD月尺度水文模型,预估未来气候变化下碧流河水库流域的径流变化特征,为流域水资源规划和管理提供依据。结果表明:CNCM3、HADCM3和IPCM4三个模式对碧流河水库流域模拟效果较好;与基准期相比,未来期多年平均降水变幅为-6.4%~3.7%,多年平均温度升高0.8℃~1.2℃,实际蒸发增幅为2.4%~4.4%;多年平均年径流量变化范围为4.8~6.2(108m3),三种排放情景下各模式平均径流量均呈减少趋势,较基准期减幅为-4.7%~-27.1%,未来水资源利用将会面临更大挑战。     

新疆21世纪气候变化的高分辨率模拟

使用一个25 km高水平分辨率区域气候模式(RegCM3),嵌套MIROC3.2_hires全球气候模式结果,进行了IPCC SRES A1B情景下,东亚区域21世纪气候变化的模拟,针对新疆地区进行了分析.首先对模式模拟的当代（1981-2000年）气候进行检验,结果表明:模式对年平均气温、降水的空间分布和数值均具有较...     

Impact of global warming on cyclonic disturbances over south Asian region

A state-of-the-art regional climate modelling system, known as PRECIS (Providing REgional Climates for Impacts Studies) developed by the Hadley Centre for Climate Prediction and Research, UK is applied over the Indian domain to investigate the impact of global warming on the cyclonic disturbances such as depressions and storms. The PRECIS simulations at 50 × 50 km horizontal resolution are made for two time slices, present (1961–1990) and the future (2071–2100), for two socioeconomic scenarios A2 and B2. The model simulations under the scenarios of increasing greenhouse gas concentrations and sulphate aerosols are analysed to study the likely changes in the frequency, intensity and the tracks of cyclonic disturbances forming over north Indian Ocean (Bay of Bengal and Arabian Sea) and the Indian landmass during monsoon season. The model overestimates the frequency of cyclonic disturbances over the Indian subcontinent in baseline simulations (1961–1990). The change is evaluated towards the end of present century (2071–2100) with respect to the baseline climate. The present study indicates that the storm tracks simulated by the model are southwards as compared to the observed tracks during the monsoon season, especially for the two main monsoon months, viz., July and August. The analysis suggests that the frequency of cyclonic disturbances forming over north Indian Ocean is likely to reduce by 9% towards the end of the present century in response to the global warming. However, the intensity of cyclonic disturbances is likely to increase by about 11% compared to the present.     

About the observed and future changes in temperature extremes over India

An attempt is made in the present study to analyse observed and model simulated temperature extremes over Indian region. Daily maximum and minimum temperature data at 121 well-distributed stations for the period 1970–2003 have been used to study the observed changes in objectively defined values of temperature extremes. In addition, an assessment of future scenarios of temperature extremes associated with increase in the concentration of atmospheric greenhouse gases is done using simulations of a state-of-the-art regional climate modelling system known as PRECIS (Providing Regional Climate for Impact Studies) performed to generate the climate for the present (1961–1990) and future projections for the period 2071–2100. Observational analysis done with 121 stations suggests the widespread warming through increase in intensity and frequency of hot events and also with decrease in frequency of cold events. More than 75% stations show decreasing trend in number of cold events and about 70% stations show increasing trend in hot events. Percentage of stations towards the warming through intensity indices of highest maximum temperature, lowest minimum temperature is 78 and 71% stations, respectively. Remaining stations show opposite trends, however, most of them are statistically insignificant. Observational analysis for India as a whole also shows similar results. Composite anomalies for monthly temperature extremes over two equal parts of the data period show increase (decrease) in the frequency of hot (cold) events for all months. In general, PRECIS simulations under both A2 and B2 scenarios indicate increase (decrease) in hot (cold) extremes towards the end of twenty-first century. Both show similar patterns, but the B2 scenario shows slightly lower magnitudes of the projected changes. Temperatures are likely to increase in entire calendar year, but the changes in winter season are expected to be prominent. Diurnal temperature range is expected to decrease in winter (JF) and pre-monsoon (MAM) months.     

Impact assessment of projected climate change on the hydrological regime in the SE Alps, Upper Soča River basin, Slovenia

According to climate change projections, the Alps will be one of the most affected regions in Europe. A basis for adaptation measures to climate changes is the quantification of the impact. This study investigates the impact of projected climate change on the hydrological cycle in the Upper So?a River basin. It is based on the use of climate model data as input for hydrological modelling. The climatic input data used were generated by a global climate model (IPCC A1B emission scenario) and downscaled for local use. Hydrological modelling was performed using the distributed hydrological model MIKE SHE. The simulated impact was quantified by comparing results of the hydrological modelling for the control period (1971–2000) and different scenario periods (2011–2040, 2041–2070, 2071–2100). The climate projections show an increase in the average temperature (+0.9, +2.3, +3.8°C) and negligible changes in average precipitation amounts in the scenario periods. More distinctive are changes in the temporal pattern of mean monthly values (up to +5.2°C and ±45% for precipitation), which result in warmer and wetter winters and hotter and drier summers in the scenario periods. The projected rise in temperature is reflected in the increased actual evapotranspiration, the reduction of snow amount and summer groundwater recharge. Changes of monthly and period average discharges follow the trends of the meteorological variables. Changes in precipitation patterns have a major influence on the projected hydrological cycle and are the most important source of uncertainty. Estimated extreme flows indicated increased hazards related to floods, especially in the near-future scenario period, while in the far future scenario period, distinctive drought conditions are projected.     

青藏高原气候变化的若干事实及其年际振荡的成因探讨

利用1961-2012年青藏高原88个气象台站逐月气温、降水以及温室气体等气候系统监测资料和CMIP5输出的未来气候变化情景数据,分析了近52年来青藏高原气候变化暖湿化的若干事实,揭示了其年际振荡与温室气体、高原加热场、高原季风、AO等气候系统因子的关系,预测了未来20~40年青藏高原可能的气候变化趋势。研究表明：近52年来青藏高原在总体保持气候变暖的趋势下自2006年以来出现了某些增暖趋于缓和的迹象,较全球变化滞后了8年左右;降水量的增加在青藏高原具有明显的普遍性和显著性,气候变湿较变暖具有一定的滞后性,降水量变化的5年短周期日趋不显著,而12年、25年较长周期逐渐明显且仍呈增多趋势。由于温室气体、气溶胶持续增加、高原夏季风趋强、ENSO事件和太阳辐射减少,青藏高原气候持续增暖但有所缓和;春季高原加热场增强、高原夏季风爆发提前且保持强劲,使得高原春、夏季和年降水量增加,而秋、冬季AO相对稳定少动,东亚大槽强度无明显变化,高原冬季风变化不甚显著,导致了高原秋、冬季降水量无明显变化。未来20~40年青藏高原仍有可能继续保持气温升高、降水增加趋势。     

1880年以来的全球升温趋势探究

由于导致全球温度异常的因素的多样性,使得至21世纪末全球温度是否将持续上升存在较大的不确定性.文章基于新兴的非数值算法的遗传算法,对1880～2009年全球温度异常数据,做了驱动因子挖掘,将全球温度异常分解为人类活动的碳排放造成的温度波动和全球气候系统自然振动的温度波动两部分.研究发现,当前全球气候系统存在持续变暖的趋...     

Impact of climate change on rainfed rice and options for adaptation in the lower Mekong Basin

We assessed the potential impact of climate change on the yield of rainfed rice in the lower Mekong Basin and evaluated some adaptation options, using a crop growth simulation model. Future climate projections are based on IPCC SRES A2 and B2 scenarios as simulated by ECHAM4 global climate model downscaled for the Mekong Basin using the PRECIS system. We divided the basin into 14 agro-climatic zones and selected a sub-catchment within each zone for the model and assessed the impact for the period of 2010–2030 and 2030–2050. In general, the results suggest that yield of rainfed rice may increase significantly in the upper part of the basin in Laos and Thailand and may decrease in the lower part of the basin in Cambodia and Vietnam. The increase is higher during 2030–2050 compared to the period of 2010–2030 for A2 scenario. For B2 scenario, yield increase is higher during 2010–2030. The impact is mainly due to the change in rainfall and CO₂ concentration in the atmosphere. We have tested widely used adaptation options such as changing planting date, supplementary irrigation, and reduction in fertility stress and found that negative impact on yield can be offset and net increase in yield can be achieved.     

亚洲高山区全新世中期气候及其影响下的冰川模拟

本文利用一个1 km分辨率冰盖模式和11个PMIP4全球气候模式,研究了全新世中期亚洲高山区气候和冰川的变化特征。多模式集合平均结果显示,(1)全新世中期亚洲高山区年平均温度较工业革命前期降低了约0.7 ℃,夏季气温升高约0.7 ℃,冬季气温降低约1.8 ℃,全新世中期年平均降水略微增加(0.5%),但夏季和冬季降水分别增加和减少了约16%;(2)全新世中期亚洲高山区冰川较工业革命前期整体显著退缩,面积减少了约13%,体积减小了约8%。在区域尺度上,全新世中期亚洲高山区北部冰川的面积(体积)减少了约58%(47%),西部冰川的面积(体积)减少了约26%(25%),而南部冰川的面积(体积)增加了约20%(39%);(3)全新世中期夏季升温主导亚洲高山区北部和西部冰川的退缩,而降水增多是亚洲高山区南部冰川扩张的首要控制因子。本研究有助于加深理解全新世中期亚洲高山区冰川的变化格局和驱动因子。     

近40a来江河源区生态环境变化的气候特征分析

利用月气象资料,对过去40a江河源气候变化特征进行分析,并与全球、全国、青藏高原进行了比较.结果表明:江河源区气温具有增暖趋势,近40a两地年平均气温分别增加约0.8℃和0.7℃,为高原异常变暖区.黄河源区变暖的主要特征是最低气温变暖,日照时数增加;最低、最高气温的显著变暖,以及较黄河源区增加更长的日照时数是长江源区变暖的主要特征.长江源区冬季变暖的作用不是主要的,春季、夏季和秋季的变暖作用比冬季还要大;黄河源区的变暖也并不主要是冬季变暖造成的,秋季变暖的作用与其相当,其它季节的变暖作用也不能忽视.近40a来江河源区降水量略有增加,主要体现在20世纪80年代中后期以来春季与冬季降水量的明显增加,夏季降水量虽然总体上没有明显变化,且局地夏季降水量呈持续减少趋势.与全球、全国以及高原区对比显示,江河源区对全球气候变暖的响应最敏感,变暖首先从长江源和整个高原发端,之后15a.黄河源和全国才进入显著温暖期.黄河源与长江源北部降水量的增加表明,气候变暖有利于高原增加降水量.     

Quantifying 21st-century France climate change and related uncertainties

We tackle here the question of past and future climate change at sub-regional or country scale with the example of France. We assess France climate evolution during the 20th and 21st century as simulated by an exhaustive range of global climate simulations. We first show that the large observed warming of the last 30 years can be simulated only if anthropogenic forcings are taken into account. We also suggest that human influence could have made a substantial contribution to the observed 20th century multi-decadal temperature fluctuations. We then show that France averaged annual mean temperature at the end of the 21st century is projected to be on the order of 4.5 K warmer than in the early 20th century under the radiative concentration pathways 8.5 (RCP8.5) scenario. Summer changes are greater than their winter counterpart (6 K versus 3.7 K). Near-future (2020–2049) changes are on the order of 2.1 K (with 2.6 K in summer and 1.8 K in winter). Model projections also suggest a substantial summer precipitation decrease (−0.6 mm/day), in particular over southern France, and a moderate winter increase, (0.3 mm/day), mostly over the northernmost part of France. Uncertainties about the amplitude of these precipitation changes remain large. We then quantify the various sources of uncertainty and study how their ranking varies with time. We also propose a physically-based metric approach to reduce model uncertainty and illustrate it with the case of summer temperature changes. Finally, timing and amplitude of France climate change in case of a global average 2-K warming are investigated. Aggressive mitigation pathways (such as RCP2.6) are absolutely required to avoid crossing or barely exceeding the 2-K global threshold. However, France climate change requiring adaptation measures is still to be expected even if we achieve to remain below the 2-K global target.