The Change of North China Climate in Transient Simulations Using the IPCC SRES A2 and B2 Scenarios with a Coupled Atmosphere-Ocean General Circulation Model

This paper applies the newest emission scenarios of the sulfur and greenhouse gases, namely IPCC SRES A2 and B2 scenarios, to investigate the change of the North China climate with an atmosphere-ocean coupled general circulation model. In the last three decades of the 21st century, the global warming enlarges the land-sea thermal contrast, and hence, causes the East Asian summer (winter) monsoon circulation to he strengthened (weakened). The rainfall seasonality strengthens and the summer precipitation increases significantly in North China. It is suggested that the East Asian rainy area would expand northward to North China in the last three decades of the 21st century. In addition, the North China precipitation would increase significantly in September. In July, August, and September, the interannual variability of the precipitation enlarges evidently over North China, implying a risk of flooding in the future.

Analyses on the climate change responses over China under SRES B2 scenario using PRECIS

The PRECIS,a regional climate model system developed at the UK Met Office Hadley Cen- tre for Climate Prediction and Research,which is nested in one-way mode within the HadAM3P,a higher-resolution version of the atmospheric com- ponent of the Hadley Centre climate model HadCM3,is employed to simulate the baseline (1961—1990) climate for evaluation of model’s capacity of simu- lating present climate and analyze the future climate change responses in the time-slice of 2071—2100 (2080s) under SRES B2 scenario over China relative to baseline average. It is indicated from the com- parison of the simulated baseline climate with in situ observation that PRECIS can simulate the local dis- tribution characteristics of surface air temperature over China quite well; generally speaking,the simu- lation for precipitation in the north of China and in winter is better than in the south of China and in summer,respectively; the simulation of precipitation in summer is sensitive to topography,and the simu- lated precipitation values are lower than observations over southeast coastal areas. It is shown from the analyses on the simulated climate change responses in 2080s under SRES B2 scenario relative to base- line that there would be an obvious surface air tem- perature increase in the north of China relative to that in the south of China,and especially in Northwest China and Northeast China,the amplitude ofsummer mean surface air temperature increments could reach 5℃; there would be an overall increase of the simulated precipitation in 2080s under SRES B2 scenario over most areas of China,while there would be significant precipitation decreases in South China in winter; there would be obvious precipitation decreases in Northeast China and North China in summer with high surface air temperature increase. However,it presents an obvious precipitation in- crease over the middle and lower reaches of the Yangtze River in summer.

PRECIS对SRESA1B情景下的中国区域气候变化预估分析

利用海气耦合大气环流模式Had CM3为PRECIS提供初始场和边界条件,驱动PRECIS模拟产生SRES A1B情景下的区域气候情景数据,分析了中国区域1961—2100年降水、气温的变化。结果表明:在SRES A1B情景下,中国区域未来降水量、气温总体呈现明显上升趋势,气温中日最低气温增幅最大,日最高气温增幅最小;21世纪前半叶(2011—2040年)到中叶(2041—2070年)期间,降水量、气温增加速率达到最高;降水在总体增加趋势中呈现出较多局地特征,21世纪后半叶,105°E以东地区出现多个降水增幅大值区;平均气温在未来各时段各区域均表现出升温的整体特征,新疆和东北地区升温幅度最大。

A Coupled Model Study on the Intensification of the Asian Summer Monsoon in IPCC SRES Scenarios

The Asian summer monsoon is an important part of the climate system. Investigating the response of the Asian summer monsoon to changing concentrations of greenhouse gases and aerosols will be meaningful to understand and predict climate variability and climate change not only in Asia but also globally. In order to diagnose the impacts of future anthropogenic emissions on monsoon climates, a coupled general circulation model of the atmosphere and the ocean has been used at the Max-Planck-Institute for Meteorology. In addition to carbon dioxide, the major well mixed greenhouse gases such as methane, nitrous oxide, several chlorofluorocarbons, and CFC substitute gases are prescribed as a function of time. The sulfur cycle is simulated interactively, and both the direct aerosol effect and the indirect cloud albedo effect are considered. Furthermore, changes in tropospheric ozone have been pre-calculated with a chemical transport model and prescribed as a function of time and space in the climate simulations. Concentrations of greenhouse gases and anthropogenic emissions of sulfur dioxide are prescribed according to observations （1860-1990） and projected into the future （1990-2100） according to the Scenarios A2 and B2 in Special Report on Emissions Scenarios （SRES, Nakcenovic et al., 2000） developed by the Intergovernmental Panel on Climate Change （IPCC）. It is found that the Indian summer monsoon is enhanced in the scenarios in terms of both mean precipitation and interannual variability. An increase in precipitation is simulated for northern China but a decrease for the southern part. Furthermore, the simulated future increase in monsoon variability seems to be linked to enhanced ENSO variability towards the end of the scenario integrations.

PRECIS模式对宁夏气候变化情景的模拟分析

使用英国Hadley气候中心区域气候模式PRECIS,分析了B2温室气体排放情景下,相对于气候基准时段1961～1990年宁夏2071～2100年(2080s)地面气温、降水量等的变化。结果表明:PRECIS模式能够很好地模拟宁夏气温的分布特征,对夏季最高气温的模拟效果好于冬季最低气温;较好地模拟出了宁夏降水南多北少的空间差异特征,且对夏季降水的模拟能力明显强于年均降水和冬季降水。相对于气候基准时段,在B2情景下,2080s宁夏年平均、冬季和夏季平均气温均明显上升,宁夏北部和南部的部分地区气温上升幅度最大,夏季平均气温和最高气温上升幅度大于冬季平均气温和最低气温;未来宁夏年、冬季和夏季平均降水较基准时段均有所增加,但降水随年代际却呈减少趋势,由于气温和降水的气候变率加大,2080s宁夏出现高温、干旱、洪涝等异常天气事件的可能性增大。

Simulation of the future change of East Asian monsoon climate using the IPCC SRES A2 and B2 scenarios

In this paper, we applied the newest emission scenarios of the sulfur and greenhouse gases, i.e. Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 and B2 scenarios, to investigating the change of the East Asian climate in the last three decades of the 21st century with an atmosphere-ocean coupled general circulation model. The global warming enlarges the land-sea thermal contrast and, hence, enhances (reduces) the East Asian summer (winter) monsoon circulation. The precipitation from the Yangtze and Huaihe river valley to North China increases significantly. In particular, the strong rainfall increase over North China implies that the East Asian rainy area would expand northward. In addition, from the southeastern coastal area to North China, the rainfall would increase significantly in September, implying that the rainy period of the East Asian monsoon would be prolonged about one month. In July, August and September, the interannual variability of the precipitation enhances evidently over North China, meaning a risk of flooding in the future.

Prediction of Climate Change in Yangtze-Huaihe Region under the Background of Global Warming

Based on the prediction results of over twenty new climate models provided by Intergovernmental Panel on Climate Change(IPCC) ,the climate change trends in Yangtze-Huaihe region during 2011-2100 were analyzed under the SRES A1B scenario. The results showed that annual mean temperature in Yangtze-Huaihe region would go up gradually under the background of global warming,and temperature increase rose from southeast to northwest,while annual average temperature would increase by 3.3 ℃ in the late 20th century. Meanwhile,annual average precipitation would rise persistently,and precipitation increase would go up with the increase of latitude and the lapse of time,being obviously strengthened after 2041.

Projecting Spatial Patterns of Flood Hazard: Recent Climate and Future Changes over Yangtze River Basin

Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results showed the mean annual rainstorm days over the basin by the near-term, mid-term and long-term would increase from 3.9 days to 4.7, 4.9 and 5.1 days, and the mean annual maximum 3-day precipitation from 122 mm to 143, 146 and 149 mm, respectively. The flood hazard of the basin would become more severe, especially in the middle and lower reaches. Flood hazard grade 5 by the nearterm, mid-term and long-term would extend from 10.99% to 25.46, 28.14 and 29.75%, respectively.

Study on Climate Change Tendency in the Future in Weifang

The air temperature and precipitation in Weifang during 2021 -2050 were simulated by using the regional climate mode PRECIS. The trend of climate change was analyzed by using 5-year moving average and linear trend estimation. The results showed that in the future, the mean, maximum and minimum temperatures in Weifang all would rise, and annual precipitation would increase. In addition, both high temperature days and rainstorm days would increase.

SRES A1B情景下未来宁夏玉米生育期气候资源变化分析

玉米是宁夏的三大粮食作物之一,其种植分布广泛,中部干旱带和南部山区基本属于雨养玉米区,气候条件对当地的玉米生产影响很大。观测到的气候变化已经对当地农业造成不利影响,未来SRES A2和B2情景下宁夏地区的气候变化研究也有一定成果。由于气候变化引发宁夏的气温和降水出现异常,为分析未来中等排放情景下气候变化可能对当地玉米生产造成的影响,本文利用订正后的英国Hadley气候中心区域气候模式PRECIS模拟的情景数据,分析了SRES A1B情景下宁夏未来2020s、2050s和2080s时段相对于气候基准时段(1961—1990年)的玉米生育期(4—9月)平均气温、最高气温、最低气温、≥10℃有效积温和降水的变化,具体方法为先分析气候基准时段宁夏的气候要素分布并与实际状况进行比较,再将未来3个时段的气象要素与气候基准时段求差值(其中降水用距平百分率表示),分析未来玉米生育期的气候变化。结果表明:平均、最高和最低气温以及≥10℃有效积温的模拟值普遍低于实际值,且具有相似的北高南低的空间分布状态,而降水的模拟值在大范围区域内高于实测值,亦呈现出相似的南高北低分布状态,总体来讲模拟值可以较合理地反映出宁夏的实际状况。相对于气候基准时段,未来各气象要素总体表现为增加,且增幅随时间推移而加大;未来最高气温在宁夏南部增加剧烈,平均气温、最低气温和≥10℃有效积温在宁夏北部增加较多,降水则呈现北增南减的分布。在未来3个时段,最高气温和降水分别为增量最大和波动最大的气象要素,出现极端高温天气和发生干旱或洪涝等异常气候事件的可能性增大。总体上看,未来气温升高对宁夏北部灌区的玉米生产有一定促进作用,尤其是≥10℃有效积温的增加可以提供更充足的热量;而南部山区气温增加虽然对玉米生产有利,但是未来降水的减少将会给雨养玉米造成不利影响,应当采取合理的应对措施。

SRESA2情景下中国区域性高温热浪事件变化特征

随着全球变暖,应对高温热浪事件是未来现代化城市面临的难题之一。本文利用全球模式—Had AM3p提供的3组不同边界场和初始场驱动区域气候模式系统PRECIS的输出结果,模拟未来情景下中国区域性高温热浪事件发生频率、强度及持续时间的变化趋势。结果表明:全球PRECIS对基准时段(1961—1990年)的高温热浪事件的发生的频率、强度和持续时间及对应的大气环流特征具有较强的模拟能力。相对于基准时段,未来情景下未来时段(2071—2100年)中国各地区的高温热浪事件的强度增加,发生频率增幅超过100%,且持续时间增加30%以上。此外,观测资料和模拟结果均表明武汉和哈尔滨地区的高温热浪与500 h Pa高度场的正距平密切相关。而未来情景下,武汉和哈尔滨地区500 h Pa高度场的正距平呈增加的趋势,表明这些地区未来可能出现危害更严重的高温热浪事件。

中国未来极端降水事件的变化——基于气候变化预估结果的分析

利用区域气候模式PRECIS单向嵌套Hadley气候中心海-气耦合模式HadCM3高分辨率的大气部分HadAM3P,分别进行了气候基准时段(1961—1990年)和2080 s时段(2071—2100年)中国区域各30年时间长度的模拟试验,以分析PRECIS对当代中国区域极端降水事件的模拟能力和SRES B2情景下2080s时段相对于气候基准时段中国区域极端降水事件的可能变化趋势。气候基准时段模拟结果与观测值的对比分析表明:PRECIS能够较好地模拟出中国区域年平均极端降水事件的空间分布特征,但模式模拟的大雨事件和湿日数高值区范围较观测值偏大,对华南地区暴雨事件和日最大降水事件的模拟结果较观测值偏低。SRES B2情景下,2080s时段年平均大雨事件除东北和华南地区外,全国均呈增多趋势。暴雨事件在西部地区以减少为主,而东部地区主要呈增加趋势。年平均日最大降水事件的分布型与大雨事件基本一致。湿日数除华北、西北和青藏高原部分地区外均呈减少趋势。未来长江流域洪涝灾害事件发生的频率将可能增大。

华南地区未来地面温度和降水变化的情景分析

利用英国Hadley气候预测和研究中心的区域气候模式系统PRECIS,模拟分析基于政府间气候变化专门委员会(IPCC)2000年发布的《排放情景特别报告》(SRES)中设计的B2情景下华南区域2071～2100年的温度和降水量的可能变化,结果显示:2071～2100年均地面温度相对于气候基准时段(1961～1990年)上升约2～4℃;华南区域未来夏季降水量在22°N以北区域较气候基准时段增加,而以南区域减少;冬季降水则表现为华南区域较气候基准时段减少。2071～2100年华南区域的温度气候趋势系数为正值,年均降水气候趋势系数为负值。2071～2100年的高温事件和强降水事件的发生频率均比气候基准时段明显增加。

呼伦贝尔草甸草原地上净初级生产力对气候变化响应的模拟

利用内蒙古呼伦贝尔草原额尔古纳右旗牧业气象试验站1994-2009年牧草生长季逐月实测资料,对CEN-TURY模型进行检验,模拟了呼伦贝尔草甸草原1961-2010年间地上净初级生产力(ANPP)动态,并与26个气象因子进行相关性分析。模型检验结果显示,生长季内逐月地上生物量模拟值与观测值之间的相关系数为R2=0.53,斜率b=0.94,误差平方根值为72.07 g/m2,平均绝对百分比误差为38.02%。检验结果表明,CENTURY模型能够成功地模拟这类草原的季节动态和年际变化。在过去的50年中,呼伦贝尔草甸草原温度增加,降水略增,AN-PP增加。相关分析表明,ANPP与生长季降水量(r=0.372)呈极显著正相关;与年平均最低气温、年平均地面气温、年平均气温、7月降水量呈显著正相关;与年平均风速(r=-0.382)呈极显著负相关;与其他气象因子无显著的相关关系。应用区域气候模式系统PRECIS输出的2021-2050年气候情景数据分析得出,在SRES B2、A2和A1B情景下,未来呼伦贝尔草甸草原平均最高气温和最低气温都将呈显著升高趋势,降水量略增,ANPP虽然在年际间存在波动,但总体呈明显增加态势,分别较基准时段增加了67.14%,69.65%和76.58%,增加速率分别为16.51,17.34和16.42 g/(m2.10 a)。在3种情景下,未来气候变化均会对呼伦贝尔草甸草原群落生产力产生显著的正面影响。

未来气候情景下广西冬季农业气候生产潜力的变化特征

利用区域气候模式(PRECIS),模拟生成A2情景下广西冬季气温和降水气候情景数据,经模型订正后,应用迈阿密模型(Miami Model)和桑斯韦特纪念模型(Thornthwait Montreal Model)估算基于广西冬季平均温度、降水量的作物生产量和平均蒸散量的作物气候生产力,预估未来广西冬季农业气候生产潜力的时空变化特征。结果表明:基于未来广西冬季平均温度估算的作物生产潜力随时间呈增长趋势,具有南高北低的纬向空间分布特征;基于冬季平均降水量估算的作物生产力和蒸散量估算的作物气候生产潜力随时间推移而减少,呈现东多西少的经向空间分布特征。未来广西的冬季热量资源良好,但是受降水限制,基于平均蒸散量估算的广西冬季作物气候生产潜力下降,使得广西冬季农业气候生产潜力下降的趋势明显,表明降水量是广西冬季农业气候生产潜力的决定性驱动因子。

气候变化对中国南方稻区水稻产量影响的模拟和分析

采用了DSSAT作物模式和区域气候模式相连接,模拟分析了A2和B2气候变化情景对中国主要地区灌溉水稻产量的影响。气候变化情景采用了IPCC发布的SRES(Special Report on Emissions Scenarios)系列的最新温室气体排放情景,气候情景值采用区域气候模式PRECIS(Provide Regional Climates for Impact Studies)的模拟值。通过研究站点水稻对A2和B2增温梯度敏感性的分析表明:温度增加,水稻产量呈下降趋势,随着温度增加,产量下降幅度增大。且在同一增温水平下,在南方热带地区的昆明和海口,产量下降幅度大于其他站点。A2和B2的产量相对于基准年(1961~1990年)的变化分别为:气候变化对不同站点的年代际水稻平均产量表现了正面或负面的影响(A2情景下为2.3%^-10.2%,B2情景下为4.0%^-13.6%),在某一些站点,水稻高产年和低产年的概率明显增加,产量分布趋于两极化。

气候变化对中国黄淮海农业区小麦生产影响模拟研究

研究首先利用1980—2000年黄淮海农业区10个站点的农业数据对CER ES-W heat动态机理作物模型进行详细的验证,然后将CERESW-heat模型与两个全球气候模式(G ISS和H adley)结合,同时考虑到CO2对小麦的直接施肥作用,模拟了黄淮海农业区10个站点在IPCC SR ES A 2和B2两个气候情景下雨养和灌溉小麦产量和水分利用的变化趋势。得到如下结论:在不考虑CO2直接肥效的情况下,黄淮海农业区雨养小麦全面减产,空间分布特点是西部减产幅度大,东部减产幅度小;在充分灌溉的情况下,灌溉小麦产量维持了现有水平,但灌溉水量增加。因此,在未来该地区水资源短缺的情况下,如何合理利用有限的水资源将成为黄淮海农业区主要面临的问题。在考虑CO2直接肥效的情况下,雨养和灌溉小麦产量都全面增产,雨养小麦的增产幅度明显偏高,灌溉小麦约增产10%～30%,但CO 2的肥效能否充分实现还需要进一步研究证明。

内蒙古典型草原地上净初级生产力对气候变化响应的模拟

利用内蒙古锡林浩特国家气候观象台1994～2009年牧草生长季逐月实测资料,对CENTURY模型进行检验,模拟内蒙古典型草原1953～2010年间地上净初级生产力(ANPP)动态,并与26个气象因子进行相关性分析。模型检验结果显示,模拟值与观测值之间的相关系数为R2=0.66,斜率b=0.95,误差平方根值为50.51g.m-2,平均绝对百分比误差为44.19%。结果表明:(1)CENTURY模型能比较准确地模拟这类草原的季节动态和年际变化;在过去的58年中,内蒙古典型草原温度增加,降水减少,ANPP下降;ANPP变化趋势与降水量相似。(2)用实际气象观测资料模拟获得的ANPP随气温和降水的变化呈现出明显的变化规律,生长季内地上生物量对降水和温度的季节性分布也非常敏感;相关分析进一步表明,ANPP对生长季内降水量和极端高温非常敏感,而与年极端最低气温、平均地面温度、日照时数、平均风速和最大积雪深度无显著相关关系;过去58年研究区ANPP下降是降水减少、温度升高以及干旱事件频发共同作用的结果。(3)根据预测,在SRES B2情景下,未来50～100年内蒙古典型草原生长季平均最高气温和最低气温都将呈升高趋势,2080s分别升高4.01℃、4.35℃,每10年增加速率分别为0.35℃和0.38℃;降水量略呈增加,2020s、2050s和2080s研究区生长季将分别增加3.17%、5.13%和7.03%,每10年增加速率为0.09mm;ANPP呈下降趋势年际间波动较大,2020s、2050s和2080s研究区将分别下降5.76%、7.52%和11.42%,每10年下降速率为0.76g.m-2。

镶黄旗典型草原地上净初级生产力对气候变化响应的模拟

利用内蒙古锡林郭勒盟镶黄旗1994~2014年牧草生长季逐月观测资料,对CENTURY模型进行了检验,通过检验的CENTURY模型模拟了镶黄旗典型草原1961~2014年地上净初级生产力（ANPP）动态,并分析了气象因子的相关性。结果表明,CENTURY模型的ANPP模拟值具有代表性,模拟值与观测值相关性较好,能够较好地反应镶黄旗典型草原ANPP的季节性和年际性变化;镶黄旗典型草原地上生物量的主要限制因子是降水,其次为年平均最高气温和生长季平均最高气温;未来镶黄旗典型草原气温、降水和ANPP都会有不同程度的增加,其ANPP变化速率为每10年增加0.131g/m2,随温度和降水增加,气温对镶黄旗典型草原ANPP的负效应将会进一步加强。

未来情景下东北地区极端气候事件的模拟分析

为了预测评估全球变暖背景下东北地区所面临的极端气候事件的可能变化趋势,并为粮食生产应对极端气候事件提供参考依据。利用Hadley气候预测与研究中心的区域气候模式系统PRECIS进行中国东北区域气候基准时段（1961—1990年）和SRES A2情景下2071—2100年极端事件变化响应的分析。气候基准时段的模拟结果与观测资料的对比分析表明：PRECIS具有对中国东北地区极端事件的模拟能力,能够模拟出极端事件的空间分布以及随地形变化的细节特征。对SRES A2情景下相对于气候基准时段的极端气候事件的变化响应分析表明：东北地区极端事件发生频率呈明显变化,极端低温事件减少,高温事件增加。夏季日数增加明显,增幅范围为50%~400%。极端温较差也呈增加趋势,大部分地区增幅为0%~5%。生长季长度呈地理特征的变化,东部和西部地区增幅较大。冰冻日数和最大连续霜冻日数都呈减少趋势。