中国北方农牧交错带气候变化特征及未来趋势

利用1951—2006年中国台站日平均观测资料对北方农牧带过去56a气候变化特征进行了分析,指出该农牧带年降水量具有明显的年际和年代际变化特征,近10a来呈明显的下降趋势;年平均气温在20世纪90年代前期变化幅度较小,1987年之后持续偏暖,与全球及中国温度变化趋势一致;降水和温度变化具有明显的季节和区域差异。在气候特征分析基础上,利用全球海气耦合模式嵌套区域气候模式在SRES A2排放情景下对未来30a（2001-2030年）的气候变化进行了预估,对照30a模式气候场（1961—1990年）,分析了未来30a北方农牧交错带降水和温度变化的可能趋势,结果表明,未来该区平均地面气温持续升高,升温幅度达0．3℃,温度日较差将明显减小;年降水量呈增加趋势,但增加幅度较小,且降水变化具有明显的季节和地域差异;未来黄河上游地区干旱的威胁仍十分严峻。     

华南地区城市化对区域气候变化的影响

按照人口数将华南地区站点分为大城市站、一般城市站、郊区站,并利用华南地区1960~2011年的站点观测资料分别计算了3类站点年平均、季节平均的气温、高温日数、降水、相对湿度、风速、日照时数距平序列的变化,分析了城市化对华南地区区域气候的影响。结果表明:相较于背景场,大城市的平均气温有更明显的上升趋势;高温日数在3类站点中均有增加的趋势,在城市化的影响下,大城市的高温日数有明显的增加;平均气温日较差在整个华南地区均有下降趋势,特别是在大城市中。在3类站点中,降雨总量均有减少的趋势,且降雨更多的以中雨及以上的形式表现。该地区的相对湿度、风速、日照时数均呈现减少趋势,在城市化影响下,大城市的相对湿度、风速、日照时数均有明显的减少。华南地区处于我国最大的城市群之一——珠江三角洲地区,同时处于气候系统复杂的热带季风区,因此有必要研究城市化对该地区多个气象变量的可能影响。     

气候变化背景下珠江流域极端洪水事件的变化趋势

根据1951-2010年珠江流域23个典型断面流量资料,用P-III型分布曲线拟合洪水系列进行频率计算,分析了珠江流域极端洪水事件的变化趋势。结果表明：1980年以来,珠江流域极端洪水事件发生的频次明显增加,尤其是自1990年以来增加趋势显著;1981-2010年较1951-1980年珠江流域约70%典型断面极端洪水事件呈增加趋势,主要分布在西江、北江、粤西;而近30%的典型断面呈减少趋势,主要分布在东江和桂南。     

近45年吐鲁番地区气候变化趋势

分析了1954-1998年吐鲁番地区各县（市）气温、降水、无霜期、大风日数、酷热日数、寒冷日数、各界限积温、日平均气温≥0℃生长期、气温日较差等气候要素的变化趋势。     

气候和气候变化领域的研究进展

该文回顾了过去几十年来中国气象科学研究院在气候和气候变化研究方面的成果, 主要包括对我国历史气候资料的恢复、重建和整理, 气候区划, 对我国气温和降水的研究, 对青藏高原温度和降水、近地层与边界层地-气过程, 大气热源特征和臭氧变化的研究, 古气候模拟, 对气候变化的预测理论和方法以及气候和气候变化对我国社会、经济的影响等方面的研究。近50年中国气象科学研究院收集大量气候资料并整理出版了《中国近五百年旱涝分布图集》; 对风能等资源进行了气候区划; 明确了近几十年中国地区在20世纪40年代和90年代出现了两个暖期, 20世纪50—60年代出现了相对冷期; 在全球变暖的背景下, 以四川为中心的西南地区自20世纪50年代到80年代一直在变冷; 20世纪80年代以后, 多雨带由华北南移到长江中下游地区; 提出青藏高原近地层与边界层地-气过程的综合物理图像; 发现青藏高原夏季臭氧低值中心; 模拟出青藏高原隆起过程中中国气候变化特征; 揭示出东亚季风环流系统及其成员; 设计了多种预报方法; 还将气候和气候变化研究成果向国家经济转化。     

巴州地区气候变化趋势的几点分析

根据巴州地区4个代表站的41年年温度、1月气温和降水、夏季降水量、初霜日、终霜日、入冬日等气候资料，用5年滑动平均法做其趋势项，分析各气象要素随时间的变化特点，从而增加对巴州地区气候变化的感性认识。     

小兴安岭五营林区近49a气候变化趋势及突变分析

利用1958～2006年五营林区的地面资料,采用气候倾向率、累积距平、信噪比等气候统计方法,研究了近49a五营气候的变化趋势、气候突变和异常年份等。结果表明:五营林区近49a气候明显变暖,雪季升温较雨季快。降水量异常的年份增加,年降水量呈显著减少的趋势,-22.44mm/10a。前后10a降水中心生了明显的时空变化。雨季降水日数、年平均气温分别在1974年、1987年发生了气候突变。     

Prediction Research of Climate Change Trends over North China in the Future 30 Years

A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 （Global Ocean-Atmosphere-Land system coupled model）, developed by the State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP）, Chinese Academy of Sciences （CAS）. In order to validate the model, the modern climate during 1951-2000 was first simulated by the GOALS model with the actual greenhouse gas concentration, and the simulation results were compared with observed data. The simulation results basically reproduce the lower temperature from the 1960s to mid-1970s and the warming from the 1980s for the globe and Northern Hemisphere, and better the important cold （1950 1976） and warm （1977-2000） periods in the past 50 years over North China. The correlation coefficient is 0.34 between simulations and observations （significant at a more than 0.05 confidence level）. The range of winter temperature departures for North China is between those for the eastern and western China＇s Mainland. Meanwhile, the summer precipitation trend turning around the 1980s is also successfully simulated. The climate change trends in the future 30 years were simulated with the CO2 concentration under IPCC SRES-B2 emission scenario. The results show that, in the future 30 years, winter temperature will keep a warming trend in North China and increase by about 2.5~C relative to climate mean （1960-1990）. Meanwhile, summer precipitation will obviously increase in North China and decrease in South China, displaying a south-deficit-north-excessive pattern of precipitation.     

长江流域近40年强降水的变化趋势

利用长江流域109个气象站1960-2001年的逐日降水资料，采用泰森多边形方法计算整个长江流域的面雨量，研究了长江流域面雨量的变化趋势。结果表明：长江流域年面雨量呈增加趋势，但不显著。从长江流域各站暴雨日数和暴雨量趋势变化的空间分布来看，长江流域年、夏季6～8月的暴雨日数和暴雨量表现为较大范围的增加趋势，但通过显著性检验的站并不多，显著增加的中心在江西省。     

中国气候变化的研究

总结了近10余年对中国气候变化的研究,重点对不同时间尺度的气温变化进行了分析.讨论了大暖期千年尺度气候振荡,中世纪暖期、小冰期及现代气候变暖等问题.     

Recent Progress in Studies of Climate Change in China

An overview of basic research on climate change in recent years in China is presented. In the past 100 years in China, average annual mean surface air temperature (SAT) has increased at a rate ranging from 0.03℃ (10 yr)-1 to 0.12℃ (10 yr)-1 . This warming is more evident in northern China and is more significant in winter and spring. In the past 50 years in China, at least 27% of the average annual warming has been caused by urbanization. Overall, no significant trends have been detected in annual and/or summer precipitation in China on a whole for the past 100 years or 50 years. Both increases and decreases in frequencies of major extreme climate events have been observed for the past 50 years. The frequencies of extreme temperature events have generally displayed a consistent pattern of change across the country, while the frequencies of extreme precipitation events have shown only regionally and seasonally significant trends. The frequency of tropical cyclone landfall decreased slightly, but the frequency of sand/dust storms decreased significantly. Proxy records indicate that the annual mean SAT in the past a few decades is the highest in the past 400-500 years in China, but it may not have exceeded the highest level of the Medieval Warm Period (1000-1300 AD). Proxy records also indicate that droughts and floods in eastern China have been characterized by continuously abnormal rainfall periods, with the frequencies of extreme droughts and floods in the 20th century most likely being near the average levels of the past 2000 years. The attribution studies suggest that increasing greenhouse gas (GHG) concentrations in the atmosphere are likely to be a main factor for the observed surface warming nationwide. The Yangtze River and Huaihe River basins underwent a cooling trend in summer over the past 50 years, which might have been caused by increased aerosol concentrations and cloud cover. However, natural climate variability might have been a main driver for the mean and extreme precipitation variations observed over the past century. Climate models generally perform well in simulating the variations of annual mean SAT in China. They have also been used to project future changes in SAT under varied GHG emission scenarios. Large uncertainties have remained in these model-based projections, however, especially for the projected trends of regional precipitation and extreme climate events.     

国际气候变化适应战略与态势分析

在对国际气候变化适应行动进行回顾和展望的基础上,介绍了以《联合国气候变化框架公约》为主的国际气候变化适应政策的发展轨迹和趋势,分析了欧盟主要国家、澳大利亚、美国、加拿大、日本、俄罗斯和印度等国所采取的气候变化适应战略,总结出国际气候变化适应行动选择主要集中在极端气候事件与自然灾害、安全的淡水供应、基础设施建设、粮食安全,以及应对气候变化的协调机制等方面。     

未来气候变化对西南地区地质灾害的可能影响

本研究利用区域气候模式RegCM4提供的RCP8.5(高排放)和RCP4.5(中排放)情景下的逐日平均气温和降水量,计算并分析了西南地区21世纪不同阶段平均气温、平均降水、连续干旱日数(CDD)、> 20mm的降水日数(R20mm)、连续5天最大降水量(Rx5day)和单日降水强度指数(SDII)相对于参照期(1986～2005年)的变化特征,进而定性地给出未来气候变化对西南地区地质灾害的可能影响。结果表明：未来西南地区因平均气温升高、平均降水量变化、持续干旱变化、强降水变化、降水集中程度变化和单日降水强度变化将导致地质灾害发生的可能性增大,但诱因不同、影响区域有差异;另外温室气体浓度越高,平均气温、平均降水以及相关极端指数相对于基准期变幅基本上都越大,相关地质灾害风险增加的可能性也越大。     

Projected Climate Change in the Northwestern Arid Regions of China: An Ensemble of Regional Climate Model Simulations

The projected temperature and precipitationchange under different emissions scenarios using Coupled Model Intercomparison Project Phase 5 models over the northwestern arid regions of China(NWAC) were analyzed using the ensemble of three high-resolution dynamical downscaling simulations: the simulation of the Regional Climate Model version 4.0(Reg CM4) forced by the Beijing Climate Center Climate System Model version 1.1(BCC_CSM1.1); the Hadley Centre Global Environmental Model version 3 regional climate model(Had GEM3-RA) forced by the Atmosphere-Ocean coupled Had GEM version 2(Had GEM2-AO); and the Weather Research and Forecasting(WRF) model forced by the Norwegian community Earth System Model(Nor ESM1-M). Model validation indicated that the multimodel simulations reproduce the spatial and temporal distribution of temperature and precipitation well. The temperature is projected to increase over NWAC under both the 4.5 and 8.5 Representative Concentration Pathways scenarios(RCP4.5 and RCP8.5, respectively) in the middle of the 21 st century, but the warming trend is larger under the RCP8.5 scenario. Precipitation shows a significant increasing trend in spring and winter under both RCP4.5 and RCP8.5; but in summer, precipitation is projected to decrease in the Tarim Basin and Junggar Basin. The regional averaged temperature and precipitation show increasing trends in the future over NWAC; meanwhile, the large variability of the winter mean temperature and precipitation may induce more extreme cold events and intense snowfall events in these regions in the future.     

库尔勒近50a气候特征分析

利用1961—2010年库尔勒气象站年平均气温、年平均气压、年降水量、年平均地面风速、年沙尘日数、年沙尘暴日数及年日照时数等资料,分析了近50 a库尔勒市气候变化基本特征。分析表明:(1)近半个世纪来库尔勒市年平均气温上升速率为0.29℃/10 a,高于0.22℃/10 a的全国平均水平,与全球变暖的大背景相一致;(2)年降水量变化趋势不明显,但年际变率大;(3)年平均地面风速减小速率为0.25 m/s/10 a;(4)年沙尘日数、年沙尘暴日数都呈减少趋势,减少速率分别为14.3 d/10 a和0.77 d/10 a;(5)库尔勒年平均气压前期和后期较低、中期较高,年日照时数年际变化较大;(6)库尔勒的气温、年沙尘日数用Mann-kendall方法检验分别在不同年份发生了的突变。与同期相邻轮台站相比,年平均气温、年平均地面风速、年沙尘日数和年沙尘暴日数变化趋势存在明显不同,这可能和两地不同的城市化速度、绿程度有关。     

Projections of Climate Change over China for the 21st Century

1. IntroductionUnder the background of global warming in the20th century, it was also getting warmer of 0.2-0.7°C/100 yr over China for the last 100 years, espe-cially for the last 50 years (0.6-0.9°C/50 yr) based onthe instrumental observations (Wang and Gong, 2000;Ren et al., 2004; Zhao et al., 2004). In another way, itwas noticed that the concentration of greenhouse gasesand sulfate aerosols in the atmosphere increased by thehuman emissions. Some new evidences indicated thatthe greenho…     

北方农牧交错带中部区域气候变化特征

分析北方农牧交错带中部区域1951-2005年温度、降水的变化特征,结果表明,研究区近55 a的气温和降水具有如下特征：1）增温明显,气温变率为0.4℃/10 a,不同季节增温幅度以冬、春、夏、秋依次递减;2）降水变化可分为3个阶段：20世纪50-60年代降水量呈减少趋势,70-80年代处于较平稳的过渡期,90年代以来降水量又呈现增加趋势。夏季降水与年降水变化趋势类似,秋季与冬季降水波动较小,基本保持平稳。研究区高温、干旱有所加强,暴雨、低温事件减少。     

土地利用变化对我国区域气候影响的数值试验

使用RegCM2区域气候模式单向嵌套澳大利亚CSIRO R21L9全球海-气耦合模式,通过将中国区域植被覆盖由理想状况改变为实际状况的数值试验对比分析,探讨了当代中国土地利用变化对中国区域气候的影响,并对结果进行了统计显著性检验。研究表明,土地利用的变化,会导致我国西北等地区年平均降水减少,导致年平均气温在内陆部分地区升高和在沿海个别地区降低,引起许多地方夏季日平均最高气温升高,而冬季日平均最低气温则在我国东部部分地区降低的同时在西北地区升高,土壤湿度的变化表现为大范围的降低。研究同时表明,相同的土地变化在不同的地理环境下引起的气候要素变化有一定的不一致性。     

我国大陆大尺度气候观测网的理想密度和分布

以我国大陆2416个气象观测站点组成的站网为参考,以观测序列的相关性表示对气候变化信号的监测能力,分析不同地区单位经纬度网格内站点数对信号监测能力的影响,得到特定监测能力要求下所需的站点数,为大尺度气候观测站网的站点设置提供科学依据。对2.5°×2.5°网格来说,当要求子集站网气温序列与标准站网气温序列相关系数超过0.99和0.95时,所需的站点数分别为750和377;当要求子集站网降水量序列与标准站网降水量序列的相关系数超过0.95和0.90时,需要的站点数分别为670和417。对2.5°×3.5°和5.0°×5.0°经纬度网格的分析发现,对站点数量要求较高的区域大部分是地形过渡区,一般来说,降水量观测对站点密度的要求高于气温。     

1961-200年中国各季降水趋势变化

Trends in six indices of precipitation in China for seasons during 1961-2007 were analyzed based on daily observations at 587 stations. The trends were estimated by using Sen＇s method with Mann-Kendall＇s test for quantifying the significance. The geographical patterns of trends in the seasonal indices of extremes were similar to those of total precipitation. For winter, both total and extreme precipitation increased over nearly all of China, except for a small part of northern China. Increasing trends in extreme precipitation also occurred at many stations in southwestern China for spring and the midlower reaches of the Yangtze River and southern China for summer. For autumn, precipitation decreased in eastern China, with an increasing length of maximum dry spell, implying a drying tendency for the post-rainy season. Wetting trends have prevailed in most of western China for all seasons. The well-known ＇flood in the south and drought in the north＇ trend exists in eastern China for summer, while a nearly opposite trend pattern exist for spring.