IPCC Climate Change Data: NIES99 A1f Model: 2050 Minimum Temperature

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.

本研究所采用的模式为耦合海气模式（coupled ocean-atmosphere model），由CCSR/NIES大气环流模式（General Circulation Model, GCM）、CCSR海洋环流模式（General Circulation Model, GCM）、热力学海冰模式以及河道汇流模式组成（Abe-Ouchi等，1996）。大气部分的空间分辨率采用T21谱截断（约5.6度经纬度），设20个垂直层；海洋部分采用约2.8度的水平网格，设17个垂直层。为抑制模拟气候的漂移，对海气间的热量与水汽交换进行通量调整。

该大气模式采用基于k分布的双流离散纵标法（two-stream discrete ordinate method, DOM）辐射方案（Nakajima与Tanaka，1986），该方案可统一处理气体、云系与气溶胶粒子的吸收、发射与散射过程。在硫酸盐气溶胶光学特性的计算中，假设干燥环境下硫酸盐粒子的体积众数半径为0.2微米；参考d'Almeida等（1991）的经验拟合公式，考虑硫酸盐的吸湿增长特性。同时假设硫酸盐气溶胶在大气低层2 km范围内的垂直分布保持恒定。温室气体浓度以二氧化碳当量（equivalent-CO2）表征。

本研究共开展3组积分试验，时长为200个模式年（1890-2090年）。其中对照试验（CTL）中，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；GG试验中，温室气体浓度逐步升高，硫酸盐浓度保持为0；GS试验中，同时考虑人为硫酸盐与温室气体的浓度增长，并按照前述方式显式表征气溶胶散射（气溶胶直接效应）。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参考Mitchell与Johns（1997）的研究设定：温室气体浓度的增长以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Langer与Rodhe（1991）通过硫循环模型（sulphur cycle model）估算得到的1986年与2050年硫酸盐载荷的空间分布作为基准分布；基于全球年均硫排放速率，对1990年前的年份采用1986年基准分布进行缩放，2050年后的年份采用2050年基准分布进行缩放，中间年份则通过两个基准分布插值得到对应年份的分布时序。未来硫排放速率参考政府间气候变化专门委员会（Intergovernmental Panel on Climate Change, IPCC）的IS92a情景设定。本试验中硫酸盐浓度经偏移处理，使得1890年时浓度为0，且未考虑硫酸盐浓度的季节变化。

相关试验结果的讨论详见Emori等（1999）的研究。通过平衡态模拟得到的CCSR/NIES模式气候敏感度约为3.5摄氏度。本数据集包含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）。

以下内容来自IPCC官网：
A1情景族假设经济发展快速且成效显著，区域人均收入均值逐步趋同，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绑定：富裕程度与预期寿命延长、家庭规模缩小（低死亡率与低生育率）直接相关。全球人口将在2050年增至约90亿，2100年回落至约70亿；人口平均年龄逐步升高，退休人群的养老需求主要通过私人养老金体系中的累积储蓄得到满足。

至2100年，全球经济将以年均约3%的速率扩张，尽管推动全球生产率与人均收入增长的条件在历史上尚无先例，但该增速与1850年以来的全球平均经济增速基本持平。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：具体而言，诸多社区可能面临20世纪富裕国家曾遭遇的社会排斥问题；同时在多数地区，收入增长将伴随全球公共资源的使用压力加剧。

该情景族中，由于技术快速进步，能源与矿产资源供给充足：一方面降低了既定产出所需的资源投入，另一方面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，饮食结构最初会显著向肉类与乳制品消费倾斜，但随后由于老龄化社会对健康的关注度提升，肉类与乳制品消费可能出现回落。高收入水平也会带来私家车保有量攀升、郊区无序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超过人均收入增速，上述因素与高薪资共同推动农业生产强度大幅提升。

A1情景族下设3个情景组，以反映快速变革的全球能源结构与转化技术发展路径的不确定性。短期投资决策可能会给市场带来长期不可逆的影响，使得市场锁定于某一类技术路径。A1B情景组以能源结构均衡混合为基础，二氧化碳排放水平处于中等区间；但根据所采用的能源技术路径不同，该情景组下各变体的排放量跨度极大。在化石燃料密集型情景组A1FI中，排放量接近A2情景组的水平；而在以低劳动生产率或后化石能源技术（post-fossil energy technologies）快速进步为特征的A1T情景组中，排放量介于B1与B2情景组之间。

鉴于A1情景族高增长与高技术（high growth with high tech）的特性，不同技术发展路径的差异会导致未来温室气体排放水平出现显著分化，因此设置了上述情景变体；该情景族假设生态系统恢复力处于较高水平。该情景族以功利主义视角看待环境福祉，仅关注其对正规经济的影响；在此情景下，环境质量的概念可能从自然保护（conservation）转变为对自然与环境服务的主动管理（management）乃至市场化运营。

本数据集覆盖以下时段：1961-1990年、2010-2039年、2040-2069年以及2090-2099年，包含月平均场与变化场。