5. Forcing agents
Greenhouse Gases
(CO2, CH4, N2O, O3, CFCs)
Aerosols
(SO4, Carbon, Nitrate, Dust etc.)
Land use and Land Cover
Solar
Volcano
etc.
Factors that change the climate
(Source: IPCC, 2013 )
Sources/Actors:
People, Industry, Agriculture, Urbanization, Vehicles, Disaster etc.
6. Important 5 components to
understand climate models
1. Solar Radiation
(absorbed by the atmosphere and
sea)
2. Dynamics
(e.g. movement of energy/heat and
mass by winds)
3. Surface processes
(effects of ice, snow, vegetation,
albedo, and moisture interchanges)
(Source: McGuffie and Henderson-Sellers, 2005)
7. Important 5 components to
understand climate models
4. Chemistry
(Chemical composition of
atmosphere and interactions, e.g.
CO2 exchanges between sea, land
and atmosphere)
5. Resolution in both time and
space
(the timestep of the model and
horizontal & vertical scales
resolved)
Note: Model setup & programming
language and platform
(Source: McGuffie and Henderson-Sellers, 2005)
8. Basic 4 types of climate
model
1. Energy balance models (EBMs)
(Surface temperature as a function
of the energy balance on the Earth)
2. One-dimensional radiative-
convective (RC) models
(the temperature profile based on
the modelling of radiative and a
‘convective adjustment’ which
depend on the predetermined lapse
rate )
(Source: McGuffie and Henderson-Sellers, 2005)
9. Basic 4 types of climate
model
3. Dimensionally-constrained models
(Statistical dynamical (SD) models,
which deal with surface processes
and dynamics)
4. Global climate models (GCMs)
(3-dimensional nature of the
atmosphere and ocean is
incorporated)
(Source: McGuffie and Henderson-Sellers, 2005)
10. A GCMs, a type of climate model, is
a mathematical model of the general
circulation of a atmosphere and ocean;
and based on the Navier–Stokes
equations on a rotating sphere with
thermodynamic terms for various
energy sources (radiation, latent heat).
𝜌
𝐷𝑣
𝐷𝑡
= 𝛻𝑝 + 𝜇𝛻2
𝑣 + 𝑓
(Where, “𝜌” is a density; “𝑣” is a flow
speed; “𝑡” is a time; “𝑝” is a pressure;
“𝜇” is a dynamic viscosity; and “𝑓” is a
body forces)
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Spencer, 2009)
11. 1. Conservation of energy
(the first law of thermodynamics)
i.e. Input energy = Increase in internal energy
+ Work done
2. Conservation of momentum
(Newton’s second law of motion)
i.e. Force = Mass × Acceleration
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
Fundamental 4-laws considered in GCMs
12. 3. Conservation of mass
(the continuity equation)
𝜕𝜌
𝜕𝑡
+
𝜕𝜌
𝜕𝑥
𝑢 𝑥 +
𝜕𝜌
𝜕𝑦
𝑢 𝑦+
𝜕𝜌
𝜕𝑧
𝑢 𝑧 = 0
(Where, “𝜌” is a density; “𝑡” is a time; “𝑥, 𝑦, 𝑧”
are the three orthogonal directions; and “𝑢” is
a flow speed)
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
4. Ideal gas law
(an approximation to the equation of state – atmosphere only)
i.e. Pressure × Volume ∞ Absolute temperature × Density
Fundamental 4-laws considered in GCMs
13. There are seven primitive equations for all
models, with the prognostic equations being
energy (temperature), moisture (water), the
wind components (u, v, w), mass (air density,
and pressure).
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
Fundamental 4-laws considered in GCMs
14. Types of GCMs
1. AGCM (Atmospheric GCM)
Atmosphere and impose sea
surface temperature
2. OGCM (Ocean GCM)
Global sea patterns
3. AOGCM (Atmosphere and Ocean
GCM) or CGCM (Coupled GCM)
Coupled atmosphere-ocean models
(e.g. CCSM4, HadCM3, GFDL)
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
15. REGIONAL CLIMATE MODELS (RCMs)
(Source: Feser et al., 2011; Giorgi, 2008)
RCMs are tools used to achieve high-resolution climate data from coarsely
resolved GCMs.
16. Higher detail for mountain ranges
and coastal zones
More detail on differing vegetation
coverage and soil characteristics
A description of smaller-scale
atmospheric processes
To produce model output that is closer to
the real heterogeneity condition
(Physiographic details) of the nature.
REGIONAL CLIMATE MODELS (RCMs)
(Source: Evans, 2012; Feser et al., 2011; Wang et al., 2012)
The added value of the RCMs in comparison with the GCMs
17. Higher detail for mountain ranges
and coastal zones
More detail on differing vegetation
coverage and soil characteristics
A description of smaller-scale
atmospheric processes
To produce model output that is closer to
the real heterogeneity condition
(Physiographic details) of the nature.
REGIONAL CLIMATE MODELS (RCMs)
The added value of the RCMs in comparison with the GCMs
(Source: Evans, 2012; Feser et al., 2011; Wang et al., 2012)
Temperature
Anomaly
18. Development of Climate Model
Mid-1970s
Mid-1980s
First Assessment Report 1990 (FAR)
Second Assessment Report 1995 (SAR)
Third Assessment Report 2001 (TAR)
Fourth Assessment Report 2007 (AR4)
Fifth Assessment Report 2013 (AR5)
INTERGOVERNMENTAL PANEL ON CLIMATE
CHANGE (IPCC)
(Source: IPCC, 2013 )
24. REFERENCES
Evans, J.P., 2012. Regional Climate Modelling: The Future for Climate Change Impacts and Adaptation Research.
Earthzine. http://www.earthzine.org/2012/02/14/regional-climate-modelling-the-future-for-climate-change-impacts-and-
adaptation-research/. Accessed 7 Mar 2014.
Feser, F., B. Rockel, H. von Storch, J. Winterfeldt, and M. Zahn, 2011. Regional Climate Models Add Value to Global
Model Data: A Review and Selected Examples. Bulletin of the American Meteorological Society 92:1181–1192.
Giorgi, F., 2008. Regionalization of Climate Change Information for Impact Assessment and Adaptation. WMO Bulletin
57:86–92
IPCC, 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change S. Solomon, D. Qin, M. Manning, M. Marquis,
K. Averyt, M. M. B. Tignor, and H. L. Miller (Editors). Cambridge University Press, Cambridge, United Kingdom and
New York, NY, USA.
IPCC, 2013. The Physical Science Basis Contribution of Working Group I to the Fifth Assessment Report of the
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Boschung, A. Nauels, Y. Xia, V. Bex, and P. M. Midgley (Editors). Cambridge University Press, Cambridge, United
Kingdom and New York, NY, USA.
Islam, S. U., 2013. Role of Modeling and Simulation in Climate Predictions. Presentation at Climate Science Informal
Seminars. University of Northern British Columbia.
McGuffie, K. and A. Henderson-Sellers, 2005. A Climate Modelling Primer. John Wiley & Sons, Ltd, Chichester, England.
Spencer, R.W., 2009. How Do Climate Models Work? Global Warming. http://www.drroyspencer.com/2009/07/how-do-
climate-models-work/. Accessed 7 Mar 2014.
Wang, T., A. Hamann, D.L. Spittlehouse, and T.Q. Murdock, 2012. ClimateWNA—High-Resolution Spatial Climate Data
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