IPCC Climate Change Data: NIES99 A1t Model: 2080 Maximum 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 A1tI, 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.

本研究采用的模式为耦合海气模式，由CCSR/NIES大气环流模式（General Circulation Model，GCM）、CCSR海洋环流模式（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度经纬度分辨率），垂直方向共20层；海洋部分的水平网格分辨率约为2.8度，垂直方向共17层。为抑制模拟气候的漂移，研究采用了海气间热量与水汽交换的通量调整方案。该大气模式采用基于k分布的辐射方案，即双流离散纵标法（Discrete Ordinate Method，DOM）（Nakajima与Tanaka，1986），可统一处理气体、云和气溶胶粒子的吸收、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；硫酸盐的吸湿性增长采用d'Almeida等（1991）提出的经验拟合方案进行表征。研究假设硫酸盐气溶胶在大气低层2公里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）进行表征。

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）。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，且硫酸盐浓度设为0；GG试验中，温室气体浓度逐步升高，而硫酸盐浓度保持为0；GS试验中，人为源硫酸盐与温室气体浓度均随时间变化，且气溶胶散射（气溶胶直接效应）采用前文所述方式进行显式表征。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参考Mitchell与Johns（1997）的研究设定：温室气体浓度的变化以1890-1990年的历史观测数据为基准，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分布模式；基于全球年平均硫排放速率，1986年的基准分布模式用于1990年前的年份，2050年的基准分布模式用于2050年后的年份；中间年份的分布模式则通过两个基准模式插值得到，从而得到分布的时间序列。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）IS92a情景设定。本试验中硫酸盐浓度进行了偏移校正，使得1890年时的初始浓度为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。通过平衡积分得到的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情景族假设全球经济实现快速且成功的发展，区域人均收入水平趋同——当前穷国与富国之间的差距最终将消失。在该情景族中，人口与经济趋势紧密关联，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）呈正相关。全球人口将在2050年达到约90亿，2100年回落至约70亿；人口平均年龄不断上升，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。

到2100年，全球经济将以约3%的年均增长率扩张，这一增速与1850年以来的全球平均经济增速大致相当，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。到2050年，全球人均收入将达到约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，但该情景下的世界仍存在诸多问题：具体而言，诸多社群可能面临20世纪发达国家曾遭遇的社会排斥问题，而在许多地区，收入增长将伴随全球公共资源承受更大压力。

该情景族中，由于技术快速进步，能源与矿产资源储量十分充裕——技术进步既降低了单位产出所需的资源消耗，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，饮食结构最初会显著向增加肉类与乳制品消费的方向转变，但随着老龄化社会对健康关注度提升，后续肉类与乳制品消费可能出现下降。高收入也将带来私家车保有量提升、郊区无序扩张以及国内国际密集的交通网络；土地价格的上涨速度将快于人均收入增速，上述因素与高薪资共同推动农业生产大幅集约化。

A1情景族包含3个子情景组，以反映快速变化的全球能源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，导致市场锁定于某一种技术路径。其中A1B子情景组以能源来源均衡混合为基础，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，该子情景组内的排放差异跨度极大。在化石燃料密集型子情景组A1tI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子情景组中，排放量处于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水平出现显著差异，因此设置了上述子情景变体；该情景族假设生态系统韧性较高。该情景下，环境福祉的价值以功利主义视角进行评估，即基于其对正规经济的影响；环境质量的概念可能从‘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’。

本数据集可获取以下时段的数据：1961-1990年、2010-2039年、2040-2069年以及2090-2099年的月平均与变化量场数据。