IPCC Climate Change Data: NIES99 A1f Model: 2050 Radiation

The model used here is a coupled ocean-atmosphere model that consists of the CCSR/NIES atmospheric GCM, the CCSR ocean GCM, a thermodynamic sea-ice model, and a river routing model (Abe-Ouchi et al., 1996). The spatial resolution is T21 spectral truncation (roughly 5.6 degrees latitude/longitude) and 20 vertical levels for the atmospheric part, and roughly 2.8 degrees horizontal grid and 17 vertical levels for the oceanic part. Flux adjustment for atmosphere-ocean heat and water exchange is applied to prevent a drift of the modelled climate. The atmospheric model adopts a radiation scheme based on the k-distribution, two-stream discrete ordinate method (DOM) (Nakajima and Tanaka, 1986). This scheme can deal with absorption, emission and scattering by gases, clouds and aerosol particles in a consistent manner. In the calculation of sulphate aerosol optical properties, the volumetric mode radius of the sulphate particle in dry environment is assumed to be 0.2 micron. The hygroscopic growth of the sulphate is considered by an empirical fit of d'Almeida et al. (1991). The vertical distribution of the sulphate aerosol is assumed to be constant in the lowest 2 km of the atmosphere. The concentrations of greenhouse gases are represented by equivalent-CO2. Three integrations are made for 200 model years (1890-2090). In the control experiment (CTL), the globally uniform concentration of greenhouse gases is kept constant at 345 ppmv CO2-equivalent and the concentration of sulphate is set to zero. In the experiment GG, the concentration of greenhouse gases is gradually increased, while that of sulphate is set to zero. In the experiments GS, the increase in anthropogenic sulphate as well as that in greenhouse gases is given and the aerosol scattering (the direct effect of aerosol) is explicitly represented in the way described above. The indirect effect of aerosol is not included in any experiment. The scenario of atmospheric concentrations of greenhouse gases and sulphate aerosols is given in accordance with Mitchell and Johns (1997). The increase in greenhouse gases is based on the historical record from 1890 to 1990 and is increased by 1 percent / yr (compound) after 1990. For sulphate aerosols, geographical distributions of sulphate loading for 1986 and 2050, which are estimated by a sulphur cycle model (Langer and Rodhe, 1991), are used as basic patterns. Based on global and annual mean sulphur emission rates, the 1986 pattern is scaled for years before 1990; the 2050 pattern is scaled for years after 2050; and the pattern is interpolated from the two basic ones for intermediate years to give the time series of the distribution. The sulphur emission rate in the future is based on the IPCC IS92a scenario. The sulphate concentration is offset in our run so that it starts from zero at 1890. The seasonal variation of sulphate concentration is ignored. Discussion on the results of the experiments will be found in Emori et al. (1999). Climate sensitivity of the CCSR/NIES model derived by equilibrium runs is estimated to be 3.5 degrees Celsius. Global-Mean Temperature, Precipitation and CO2 Changes (w.r.t. 1961-90) for the CCSR/NIES model. From the IPCC website: The A1 Family storyline is a case of rapid and successful economic development, in which regional averages of income per capita converge - current distinctions between poor and rich countries eventually dissolve. In this scenario family, demographic and economic trends are closely linked, as affluence is correlated with long life and small families (low mortality and low fertility). Global population grows to some nine billion by 2050 and declines to about seven billion by 2100. Average age increases, with the needs of retired people met mainly through their accumulated savings in private pension systems. The global economy expands at an average annual rate of about three percent to 2100. This is approximately the same as average global growth since 1850, although the conditions that lead to a global economic in productivity and per capita incomes are unparalleled in history. Income per capita reaches about US$21,000 by 2050. While the high average level of income per capita contributes to a great improvement in the overall health and social conditions of the majority of people, this world is not without its problems. In particular, many communities could face some of the problems of social exclusion encountered by the wealthiest countries in the 20th century and in many places income growth could come with increased pressure on the global commons. Energy and mineral resources are abundant in this scenario family because of rapid technical progress, which both reduce the resources need to produce a given level of output and increases the economically recoverable reserves. Final energy intensity (energy use per unit of GDP) decreases at an average annual rate of 1.3 percent. With the rapid increase in income, dietary patterns shift initially significantly towards increased consumption of meat and dairy products, but may decrease subsequently with increasing emphasis on health of an aging society. High incomes also translate into high car ownership, sprawling suburbanization and dense transport networks, nationally and internationally. Land prices increase faster than income per capita. These factors along with high wages result in a considerable intensification of agriculture. Three scenario groups are considered in A1 scenario family reflecting the uncertainty in development of energy sources and conversion technologies in this rapidly changing world. Near-term investment decisions may introduce long-term irreversibilities into the market, with lock-in to one technological configuration or another. The A1B scenario group is based on a balanced mix of energy sources and has an intermediate level of CO2 emissions, but depending on the energy sources developed, emissions in the variants cover a very wide range. In the fossil-fuel intensive scenario group A1FI, emissions approach those of the A2 scenarios; conversely in scenario group A1T with low labor productivity or of rapid progress in "post-fossil" energy technologies, emissions are intermediate between those of B1 and B2. These scenario variants have been introduced into the A1 storyline because of its "high growth with high tech" nature, where differences in alternative technology developments translate into large differences in future GHG emission levels Ecological resilience is assumed to be high in this storyline. Environmental amenities are viewed in a utilitarian way, based on their influence on the formal economy. The concept of environmental quality might change in thisstoryline from"conservation" of nature to active "management" - and marketing - of natural and environmental services. Data are available for the following periods: 1961-1990, 2010-2039; 2040-2069; and 2090-2099 Mean monthly and change fields.本研究采用的模型为耦合海气模式（coupled ocean-atmosphere model），由CCSR/NIES大气环流模式（GCM）、CCSR海洋环流模式、热力学海冰模式以及河道汇流模式组成（Abe-Ouchi等，1996）。该模式的空间分辨率设置如下：大气部分采用T21谱截断，分辨率约为5.6度经纬度，包含20个垂直层；海洋部分采用约2.8度的水平网格，包含17个垂直层。为抑制模拟气候的漂移，本研究对海气间的热量与水汽交换实施了通量调整。 大气模式采用基于k分布的辐射方案，即二流离散纵标法（DOM）（Nakajima与Tanaka，1986），该方案可统一处理气体、云系与气溶胶（aerosol）粒子的吸收、发射及散射过程。在硫酸盐气溶胶（sulphate aerosol）光学特性的计算中，假设干燥环境下硫酸盐粒子的体积众数半径为0.2微米；硫酸盐的吸湿增长特性采用d'Almeida等（1991）提出的经验拟合公式进行表征。研究假设硫酸盐气溶胶在大气低层2千米范围内的垂直分布保持恒定，温室气体（greenhouse gases）浓度以等效二氧化碳（CO₂）当量表示。 本研究共开展3组积分试验，积分时长为200个模式年（1890-2090年）： 1. 对照试验（CTL）：全球均匀分布的温室气体浓度固定为345ppmv二氧化碳当量，硫酸盐浓度设为0； 2. GG试验：温室气体浓度逐步升高，硫酸盐浓度保持为0； 3. GS试验：人为源硫酸盐（anthropogenic sulphate）与温室气体浓度均随时间变化，气溶胶散射（气溶胶直接效应）采用前文所述方式显式表征。 所有试验均未考虑气溶胶间接效应。温室气体与硫酸盐气溶胶的大气浓度情景依据Mitchell与Johns（1997）的研究设定：温室气体浓度变化以1890-1990年的历史观测数据为基础，1990年后以每年1%的复合增长率递增。对于硫酸盐气溶胶，以硫循环模式（Langer与Rodhe，1991）估算得到的1986年与2050年硫酸盐负荷的空间分布作为基准形态；基于全球年均硫排放量，1990年前的年份采用1986年基准形态缩放，2050年后的年份采用2050年基准形态缩放，中间年份通过两个基准形态插值得到对应空间分布的时间序列。未来硫排放量的设定依据IPCC IS92a情景，本试验中硫酸盐浓度从1890年的0开始逐年调整，且未考虑其季节变化。相关试验结果的详细讨论可参见Emori等（1999）的研究。通过平衡态积分得到的CCSR/NIES模式的气候敏感性约为3.5摄氏度，对应数据集包含CCSR/NIES模式的全球平均温度、降水与二氧化碳变化（相对于1961-1990年基准期）。 以下内容源自IPCC官网：A1情景族假设经济发展快速且成效显著，区域人均收入水平趋同，最终消除当前贫富国家间的发展差距。该情景族中，人口与经济发展趋势紧密关联：富裕程度与人均寿命延长、家庭规模缩小（低死亡率与低生育率）直接相关。全球总人口将在2050年达到约90亿，2100年回落至约70亿；人口平均年龄持续上升，退休人群的养老需求主要通过个人养老金账户的累积储蓄得到满足。 到2100年，全球经济将以约3%的年均增长率扩张，这与1850年以来的全球平均经济增速大致相当，但推动全球生产率与人均收入增长的历史条件前所未有。到2050年，人均收入将达到约21000美元。尽管较高的人均收入水平可大幅改善多数人群的健康与社会福祉，但该情景下仍存在诸多问题：诸多社区可能面临20世纪发达国家曾遭遇的社会排斥问题，而多数地区的收入增长也将伴随全球公共资源承受的更大压力。 该情景族中，由于技术进步迅速，能源与矿产资源供给充足：技术进步既降低了单位产出的资源消耗，也提升了经济可开采储量。最终能源强度（单位GDP能耗）将以年均1.3%的速率下降。随着收入快速增长，居民饮食结构最初会显著向肉类与乳制品消费倾斜，但随着老龄化社会对健康关注度提升，这类消费可能随后出现回落。高收入水平也将带来私家车保有量提升、郊区蔓延式扩张以及国内国际密集的交通网络建设；土地价格的上涨速度将快于人均收入增速，上述因素与高薪资水平共同推动农业生产强度大幅提升。 A1情景族包含3个情景组，以反映快速变革的全球能源与转换技术发展路径的不确定性：短期投资决策可能会对市场造成长期不可逆影响，最终锁定某一类技术路线。A1B情景组以能源来源均衡混合为基础，二氧化碳排放量处于中等水平，但根据所采用的具体能源技术，不同变体的排放量差异极大。在化石燃料密集型情景组A1FI中，排放量接近A2情景；而在劳动生产率较低或‘后化石’能源技术快速进步的A1T情景组中，排放量介于B1与B2情景之间。 由于A1情景族具有‘高增长、高技术’的特征，不同技术发展路径会导致未来温室气体排放量产生巨大差异，因此设置了上述情景变体。该情景族假设生态系统韧性较高，环境福祉将以功利主义视角进行评估，即基于其对正规经济的影响。该情景下的环境质量理念可能会从‘保护自然’转变为对自然与环境服务的主动‘管理’乃至‘市场化运营’。 以下时段可获取对应数据：1961-1990年、2010-2039年、2040-2069年以及2090-2099年的月平均场与变化场数据。