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。     

Responsibility for Past and Future Global Warming: Uncertainties in Attributing Anthropogenic Climate Change

During the negotiations on the Kyoto Protocol, Brazil proposed a methodology to link the relative contribution of Annex I Parties to emission reductions with the relative contributions of Parties to the global-mean temperature increase. The proposal was not adopted during the negotiations but referred to the Subsidiary Body for Scientific and Technological Advice for consideration of its methodological aspects. In this context we analyze the impact of model uncertainties and methodological choices on the regionally attributed global-mean temperature increase. A climate assessment model has been developed to calculate changes in greenhouse gas concentrations, global-mean temperature and sea-level rise attributable to individual regions. The analysis shows the impact of the different choices in methodological aspects to be as important as the impact of model uncertainties on a region's contribution to present and future global temperature increases. Choices may be the inclusion of the anthropogenic non-CO₂ greenhouse gas emissions and/or theCO₂ emissions associated with land-use changes. When responsibility to global temperature change is attributed to all emitting Parties, the impacts of modeling uncertainties and methodological choices on contributions of individual Parties are considerable. However, if relative contributions are calculated only within the group of Annex I countries, the results are less sensitive to the uncertainty aspects considered here.     

Climate Variability and Change: Past, Present and Future – An Overview

Prior to the 20th century Northern Hemisphere average surface air temperatures have varied in the order of 0.5 ^°C back to AD 1000. Various climate reconstructions indicate that slow cooling took place until the beginning of the 20th century. Subsequently, global-average surface air temperature increased by about 0.6 °C with the 1990s being the warmest decade on record. The pattern of warming has been greatest over mid-latitude northern continents in the latter part of the century. At the same time the frequency of air frosts has decreased over many land areas, and there has been a drying in the tropics and sub-tropics. The late 20th century changes have been attributed to global warming because of increases in atmospheric greenhouse gas concentrations due to human activities. Underneath these trends is that of decadal scale variability in the Pacific basin at least induced by the Interdecadal Pacific Oscillation (IPO), which causes decadal changes in climate averages. On interannnual timescales El Niño/Southern Oscillation (ENSO) causes much variability throughout many tropical and subtropical regions and some mid-latitude areas. The North Atlantic Oscillation (NAO) provides climate perturbations over Europe and northern Africa. During the course of the 21st century global-average surface temperatures are very likely to increase by 2 to 4.5 ^°C as greenhouse gas concentrations in the atmosphere increase. At the same time there will be changes in precipitation, and climate extremes such as hot days, heavy rainfall and drought are expected to increase in many areas. The combination of global warming, superimposed on decadal climate variability (IPO) and interannual fluctuations (ENSO, NAO) are expected lead to a century of increasing climate variability and change that will be unprecedented in the history of human settlement. Although the changes of the past and present have stressed food and fibre production at times, the 21st century changes will be extremely challenging to agriculture and forestry.     

Climate Variability and Change in High Elevation Regions: Past, Present and Future

This special issue of Climatic Change contains a series of researchand review articles, arising from papers that were presented and discussed at a workshop held in Davos, Switzerland on 25–28 June 2001. The workshop was titled `Climate Change at High Elevation Sites: Emerging Impacts', and was convened to reprise an earlier conference on the same subject that was held in Wengen, Switzerland in 1995 (Diaz et al., 1997). The Davos meeting had as its maingoals, a discussion of the following key issues: (1) reviewing recent climatic trends in high elevation regions of the world, (2) assessing the reliability of various biological indicators as indicators of climatic change, and (3)assessing whether physical impacts of climatic change in high elevation areas are becoming evident, and to discuss a range of monitoring strategies needed to observe and to understand the nature of any changes.     

Changing Gradients of Climate Change in Southern Africa during the Past Millennium: Implications for Population Movements

Climates of equatorial East Africa and subtropical Southern Africa have varied inversely over long periods of time. The high-resolution ¹⁸O stalagmite record from Cold Air Cave in the Makapansgat valley in South Africa and a similar resolution lake-level record for Lake Naivasha in Kenya have been in anti-phase for much of the last thousand years. A similar relationship is evident in the twentieth century meteorological record. The changes in rainfall in the two regions on multi-decadal to centennial scales have influenced both settlement patterns and livelihoods of Iron Age agriculturalists. The resulting latitudinal gradient of change may have been a significant factor in promoting southward migration of Sotho-Tswana speaking people from equatorial East Africa during the first few centuries of the last millennium and earlier. This would have occurred at times when environments in the north were deteriorating and those to the south were ameliorating.     

Past and Future Changes in the Climate of Hong Kong

Over the years, the Hong Kong Observatory has carried out scientific studies to evaluate the observed climate trends and project the future climate in Hong Kong. Analysis of the meteorological observations at the observatory's headquarters in Tsim Sha Tsui since 1885 reveals that the temperature rise in Hong Kong during the past 124 years is in accord with the global rising trend. The accelerated rising trend in the mean temperature in last few decades may be attributed to the anthropogenic influences, especially urbanization. A similar increasing trend is also observed for rainfall. Other observations such as increasing cloud amount and decreasing total global solar radiation are all consistent with the global trend. Studies of past occurrences of extreme temperature and rainfall have also been carried out. The results indicate that cold episodes have become rarer while very hot days and heavy rain events are becoming more frequent. The observatory also makes use of the data from the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) and employs statistical downscaling techniques to carry out projections of temperature and precipitation in the 21st century. It is found that the rise in temperature in Hong Kong will be slightly higher than the global mean in the 21st century. The annual rainfall in Hong Kong is also expected to rise by the end of the 21st century, so is its year-to-year variability.     

气候变化及其未来情景

论述了百余年来气候变化的事实及对未来情景的预估。1861年以来,全球平均温度升高了0.6±0.2℃。20世纪90年代是20世纪最暖的10a。近百年来,降水分布也发生了变化,大陆地区尤其是中高纬地区降水增加,非洲等一些地区降水减少。气候模式模拟表明:全球平均地表气温到2100年时将比1990年上升1.4￣5.8℃。21世纪全球平均降水将会增加,但大部分年平均降水增加的区域很可能同时出现大的年际变化。全球平均海平面到2100年时将比1990年上升0.09￣0.88m。北半球雪盖和海冰范围将进一步缩小。未来,若干极端事件发生的频率会增加。     

Recent and Future Climate Change in Northwest China

As a consequence of global warming and an enhanced water cycle, the climate changed in northwest China, most notably in the Xinjiang area in the year 1987. Precipitation, glacial melt water and river runoff and air temperature increased continuously during the last decades, as did also the water level of inland lakes and the frequency of flood disasters. As a result, the vegetation cover is improved, number of days with sand-dust storms reduced. From the end of the 19th century to the 1970s, the climate was warm and dry, and then changed to warm and wet. The effects on northwest China can be classified into three classes by using the relation between precipitation and evaporation increase. If precipitation increases more than evaporation, runoff increases and lake water levels rise. We identify regions with: (1) notable change, (2) slight change and (3) no change. The future climate for doubled CO₂ concentration is simulated in a nested approach with the regional climate model-RegCM2. The annual temperature will increase by 2.7 ^ C and annual precipitation by 25%. The cooling effect of aerosols and natural factors will reduce this increase to 2.0 ^C and 19% of precipitation. As a consequence, annual runoff may increase by more than 10%.     

The Challenges of Modeling Climate Variability and Change in West Africa

This paper overviews observations and examines modeling issues associated with the mean state, climate variability and climate change in West Africa. The Tropical Rain Measuring Mission (TRMM) satellite allows for the first time estimates of Unconditional, Convective and Stratiform rain rates in West Africa. The 1998 estimated TRMM rates are compared to long-term observed rain rates and a merged rain data set (CMAP) during 1998. Further, the TRMM estimates are compared to the simulated rain rates from the Community Climate Model Version 3.6. The TRMM Precipitation Radar rain estimates are generally lower than either the long-term observations or the CMAP rates during 1998. Moreover, the TRMM rain estimates show a significant fraction of the total rain (convective + stratiform) is characterized as stratiform rain (30–40%). The CCM3 simulates primarily convective rain and negligible amounts of non-convective rain for West Africa. Furthermore, the TRMM high-resolution rain patterns strongly imply that rain in West Africa occurs on mesoscales in association with mesoscale convective systems (squall lines, mesoscale convective complexes and non-squall tropical clusters). We demonstrate this by briefly examining two mesoscale convective systems during May 1998 with METEOSAT data. Regional climate models may offer the best solution to understanding climate change in West Africa because of their ability to capture mesoscale systems and better their representation of orographic features. Adequate boundary conditions from Global Climate Models are still necessary for regional climate model simulations to successfully reproduce mean climate conditions and provide understanding with respect to future climate change. Observations in West Africa should be maintained or increased for monitoring climate variability and possibility of climate change in West Africa, proper initialization of numerical weather prediction models and the validation of climate models.     

气候现象及其与未来区域气候变化的联系

<正>与IPCC以前的评估报告相比,第五次评估报告(AR5)增加了单独一章,即第十四章~([1]),比较系统地评估了关于气候现象及其与未来区域气候变化关系方面取得的最新研究进展。这是AR5的亮点之一。区域气候是很多复杂的大气过程共同影响的结果。在全球变暖的背景下,这些过程对大尺度强迫的响应有明显的区域特征,所以区域气候变化存在显著差异。与CMIP3模式比,CMIP5模式对大尺度     

栾川县近40年气候变化分析

利用1961～2000年栾川站气象资料,分析了栾川县气候变化特征,结果表明近40年来栾川气温呈上升趋势,年降水量和平均湿度呈下降趋势,光照呈增加趋势;降水的年变化趋势与气温年变化之间,有气温偏低时期降水偏多、气温偏高时期降水偏少的反相位关系.     

未来气候变化对云南柠檬气候适宜性的影响

气候变化影响柠檬生长、产量和品质,本文利用云南省125个国家气象站1981-2018年,月平均气温、月平均降水量、月日照时数,进行基准年代下云南柠檬气候适宜性分区;采用RCP2.6、RCP4.5、RCP8.5气候情景模式,研究2021-2030年、2031-2040年、2041-2050年云南柠檬气候适宜区的变化,探讨...     

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。     

近40年三工河流域气候变化分析

通过近40年三工河流域不同海拔高度的典型地貌气象资料的统计，对影响流域气候变化的气温、降水、蒸发气象要素进行线性趋势分析，得出中山森林区气候暖湿化相对较弱，平原区气候暖湿化特征显著，近山倾斜平原绿洲区是气候暖湿化最为明显的地域。流域降水与蒸发呈反相关关系，降水增加起到绝对增湿作用，蒸发减小起到相对增湿作用。在此气候趋势变化下，三工河流域和有相似地理环境的天山北坡各流域已显现出降水量增大、洪水发生频率增高、荒漠植被显著增加以及区域农业生产环境改善的暖湿化特征。     

商丘市近44年来蒸发量与气候变化的关系

利用商丘市8个台站1961～2004年蒸发量、日照、风速和气温资料,分析了蒸发量的变化趋势及蒸发量变化与日照、风速、气温变化的关系,结果表明蒸发量的年际变化是波动式减少的;蒸发量的变化与日照存在明显的正相关,与风速存在明显的正相关,相比较而言,日照、风速对蒸发量的影响超过了温度对蒸发量的影响.     

藏北地区气候变化特征及其影响分析

藏北地区地域广阔、地势高,自然条件极为严酷,其环境状况直接影响到我国的江河、气候及生态环境,甚至对全球也有不容忽视的影响。本研究选取藏北地区有长期、连续记录的5个气象站点,分析藏北地区近40年来的气候变化特征,并对其可能影响进行分析。藏北地区近40年来温度上升趋势明显,尤其是最低温度的升温率达0.79℃.(10a-1),高于青藏高原的平均水平;降水的年际波动大,自20世纪90年代以后明显增多。近40年藏北地区的气候有暖湿化趋势,这将有利于该地区的动、植物生长,但是该地区冰川冻土面积大,气温升高会引起冰川退缩和冻土层融化,又将给藏北地区脆弱的生态系统带来不利影响。     

Impacts of Present and Future Climate Change and Climate Variability on Agriculture in the Temperate Regions: North America

The potential impact of climate variability and climate change on agricultural production in the United States and Canada varies generally by latitude. Largest reductions are projected in southern crop areas due to increased temperatures and reduced water availability. A longer growing season and projected increases in CO₂ may enhance crop yields in northern growing areas. Major factors in these scenarios analyzes are increased drought tendencies and more extreme weather events, both of which are detrimental to agriculture. Increasing competition for water between agriculture and non-agricultural users also focuses attention on water management issues. Agriculture also has impact on the greenhouse gas balance. Forests and soils are natural sinks for CO₂. Removal of forests and changes in land use, associated with the conversion from rural to urban domains, alters these natural sinks. Agricultural livestock and rice cultivation are leading contributors to methane emission into the atmosphere. The application of fertilizers is also a significant contributor to nitrous oxide emission into the atmosphere. Thus, efficient management strategies in agriculture can play an important role in managing the sources and sinks of greenhouse gases. Forest and land management can be effective tools in mitigating the greenhouse effect.     

全球气候模式对宁夏区域未来气候变化的情景模拟分析

利用多个全球气候模式(GCM)的情景模拟结果分析只考虑温室气体效应的IS92a GG情景和同时考虑温室气体效应和硫化物气溶胶辐射效应的IS92aGS情景以及SRESA2、B2情景下宁夏区域21世纪地面气温和降水量的可能变化,并进行不确定性分析。气候基准时段(1961~1990年)模拟结果与观测资料的对比分析表明,GCM对宁夏气候具有一定的模拟能力;整体上讲,GCM对地面气温的模拟值偏低,对降水量的模拟值偏高,其中ECHAM4和HadCM3对宁夏基准时段地面气温和降水量的模拟结果与观测比较接近。各GCM模拟值的平均结果显示,4种温室气体排放情景下21世纪宁夏区域气温持续升高,至21世纪末宁夏升温幅度可达4~6℃,与全国平均的增温幅度大致相当;与升温趋势相应的是降水量的增加,但降水变化呈现出很大的波动性,至21世纪末宁夏的降水变化幅度可达10%~40%。各个GCM模拟的宁夏气候变化的总趋势是一致的,但各模式在不同情景下模拟结果的差异很大,存在较大的不确定性。