IPCC Climate Change Data: NIES99 B2a Model: 2050 Wind Speed
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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. Like B1, the B2 world is one of increased concern for
environmental and social sustainability, but the character of
this world differs substantially. Education and welfare
programs are widely pursued leading to reductions in mortality
and, to a lesser extent, fertility. The population reaches about
10 billion people by 2100, consistent with both the United
Nations and IIASA median projections. Income per capita grows at
an intermediary rate to reach about US$12,000 by 2050. By 2100
the global economy might expand to reach some US$250 trillion.
International income differences decrease, although not as
rapidly as in scenarios of higher global convergence (A1, B1).
Local inequity is reduced considerably through the development
of stronger community support networks. Generally high
educational levels promote both development and environmental
protection. Indeed, environmental protection is one of the few
remaining truly international priorities. However, strategies to
address global environmental challenges are less successful than
in B1, as governments have difficulty designing and implementing
agreements that combine environmental protection with mutual
economic benefits. The B2 storyline presents a particularly
favorable climate for community initiative and social
innovation, especially in view of high educational levels.
Technological frontiers are pushed less than in A1 and B1 and
innovations are also regionally more heterogeneous. Globally,
investment in R and D continues its current declining trend, and
mechanisms for international diffusion of technology and
know-how remain weaker than in scenarios A1 and B1 (but higher
than in scenario A2). Some regions with rapid economic
development and limited natural resources place particular
emphasis on technology development and bilateral co-operation.
Technical change is therefore uneven. The energy intensity of
GDP declines at about one percent per year, in line with the
average historical experience of the last two centuries.
Land-use management becomes better integrated at the local level
in the B2 world. Urban and transport infrastructure is a
particular focus of community innovation, contributing to a low
level of car dependence and less urban sprawl. An emphasis on
food self-reliance contributes to a shift in dietary patterns
towards local products, with reduced meat consumption in
countries with high population densities. Energy systems differ
from region to region, depending on the availability of natural
resources. The need to use energy and other resources more
efficiently spurs the development of less carbon-intensive
technology in some regions. Environment policy cooperation at
the regional level leads to success in the management of some
transboundary environmental problems, such as acidification due
to SO2, especially to sustain regional self-reliance in
agricultural production. Regional cooperation also results in
lower emissions of NOx and VOCs, reducing the incidence of
elevated tropospheric ozone levels. Although globally the energy
system remains predominantly hydrocarbon-based to 2100, there is
a gradual transition away from the current share of fossil
resources in world energy supply, with a corresponding reduction
in carbon intensity.
创建时间:
2015-01-06



