1. Climate Change Modeling: An overview
Climate Change Training for Water Professionals
Climate Change Modeling: An overview
A.K.M. Saiful Islam

2. Presentation outline Overview of climatic system Green house effect
Global warming
Ice melt and rise of sea level
Climate model and predictions
General Climate Model - GCM
Regional Climate Model – RCM
Climate modeling at BUET
3D models

3. Climate Systems
• The complicated system consisting of various components, including the dynamics and composition of the atmosphere, the ocean, the ice and snow cover, the land surface and its features, the many mutual interactions between them, and the large variety of physical, chemical and biological processes taking place in and among these components.
• Climate refers to the state of the climate system as a whole, including a statistical description of its variations.
Atmosphere
78% nitrogen, 21% oxygen, and 1% other gases.
Carbon dioxide accounts for just %.
Water vapor 0 to 2%

4. Components of Climate System

5. Green house gases CO2 and some other minor gases
Absorb some of the thermal radiation leaving the surface of the earth.
Emit radiation from much higher and colder levels out to space.
These radiatively active gases are known as greenhouse gases.
They act as a partial blanket for the thermal radiation from the surface which enables it to be substantially warmer than it would otherwise be, analogous to the effect of a greenhouse.

6. Green house effect

7. Green house effect

8. Human induced climate variation
Perturbations of the atmospheric composition – the enhanced greenhouse effect
Effect of aerosols:
direct effect (scattering of incoming solar radiation)
indirect effect (affecting the radiative properties of clouds)
Land-use change (agriculture, deforestation, reforestation, afforestation, urbanisation, traffic, …)

9. Increasing trends of CO2

10. Human induced changes of green house gases

11. Sector wise Green house gas emission

12. Country wise emission of CO2
Per capita emissions of CO2 is less than 0.2 ton annually in Bangladesh, compared to 1.6 tons in the developing countries

13. Global temperature and Greenhouse gases

14. Temperature variation past 1,000 years

15. Increase of Temperature past 140 year

16. Trends of increase of Temperature

17. Surface Air temperature (1960-1990)

18. Antarctic Ozone hole
The Antarctic ozone hole forms in the southern hemisphere’s spring (Sept.-Nov) following the bitterly cold and dark Antarctic winter when stratospheric ice clouds promote production of chemically active chlorine and bromine.
This, in turn, leads to ozone destruction when sunlight returns in the Antarctic spring.
The serious thinning of the stratospheric ozone layer is caused by anthropogenic emissions of ozone depleting substances, such as chlorofluorocarbons (CFC) and halons. The atmospheric concentrations of these compounds have increased during the last several decades as a consequence of human activity.

20. Ice melting
Images from gathered from the Defense Meteorological Satellite Program of NASA show the minimum Arctic sea ice concentration 1979 (left) and 2003 (right).
1979
2003

21. Cracks in Ice bars

22. Sea Level Rise ( )

23. Climate Models
Climate models are computer-based simulations that use mathematical formulas to re-create the chemical and physical processes that drive Earth’s climate. 
To “run” a model, scientists divide the planet into a 3-dimensional grid, apply the basic equations, and evaluate the results.
Atmospheric models calculate winds, heat transfer, radiation, relative humidity, and surface hydrology within each grid and evaluate interactions with neighboring points.
Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice.

25. Hardware Behind the Climate Model
Geophysical Fluid Dynamics Laboratory

26. General Circulation Model (GCM)
General Circulation Models (GCMs) are a class of computer-driven models for weather forecasting, understanding climate and projecting climate change, where they are commonly called Global Climate Models.
Three dimensional GCM's discretise the equations for fluid motion and energy transfer and integrate these forward in time. They also contain parametrisations for processes - such as convection - that occur on scales too small to be resolved directly.
Atmospheric GCMs (AGCMs) model the atmosphere and impose sea surface temperatures.
Coupled atmosphere-ocean GCMs (AOGCMs, e.g. HadCM3, EdGCM, GFDL CM2.X, ARPEGE-Climate) combine the two models.

27. GCM typical horizontal resolution of between 250 and 600 km, 10 to 20 vertical
layers in the atmosphere and sometimes as many as 30 layers in the oceans.

28. Special Report on Emissions Scenarios (SRES)
The Special Report on Emissions Scenarios (SRES) was a report prepared by the Intergovernmental Panel on Climate Change (IPCC) for the Third Assessment Report (TAR) in 2001, on future emission scenarios to be used for driving global circulation models to develop climate change scenarios.
It was used to replace the IS92 scenarios used for the IPCC Second Assessment Report of The SRES Scenarios were also used for the Fourth Assessment Report (AR4) in 2007.

29. SERS Emission Scenarios
A1 - a future world of very rapid economic growth, global population that peaks in mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies. Three sub groups: fossil intensive (A1FI), non-fossil energy sources (A1T), or a balance across all sources (A1B).
A2 - A very heterogeneous world. The underlying theme is that of strengthening regional cultural identities, with an emphasis on family values and local traditions, high population growth, and less concern for rapid economic development.
B1 - a convergent world with the same global population, that peaks in mid-century and declines thereafter, as in the A1 storyline.
B2 - a world in which the emphasis is on local solutions to economic, social and environmental sustainability.

30. Non SRES Scenarios Non-SRES Scenario: PICTL
Experiments run with constant pre-industrial levels of greenhouse gasses.
Non-SRES Scenario: 20C3M
Experiments run with greenhouse gasses increasing as observed through the 20th century.
Non-SRES Scenario: COMMIT
An idealised scenario in which the atmospheric burdens of long-lived greenhouse gasses are held fixed at AD2000 levels.
Non-SRES Scenario: 1PTO2X (1% to double)
Experiments run with greenhouse gasses increasing from pre-industrial levels at a rate of 1% per year until the concentration has doubled and held constant thereafter.
Non-SRES Scenario: 1PTO4X (1% to quadruple)
Experiments run with greenhouse gasses increasing from pre-industrial levels at a rate of 1% per year until the concentration has quadrupled and held constant thereafter.

31. GCM output described in the 2007 IPCC Fourth Assessment Report (SRES scenarios), multilayer mean
Models
Scenarios
Variables
BCC:CM1 BCCR:BCM2 CCCMA:CGCM3_1-T47 CCCMA:CGCM3_1-T63 CNRM:CM3 CONS:ECHO-G CSIRO:MK3 GFDL:CM2 GFDL:CM2_1 INM:CM3 IPSL:CM4 LASG:FGOALS-G1_0 MPIM:ECHAM5 MRI:CGCM2_3_2 NASA:GISS-AOM NASA:GISS-EH NASA:GISS-ER NCAR:CCSM3 NCAR:PCM NIES:MIROC3_2-HI NIES:MIROC3_2-MED UKMO:HADCM3 UKMO:HADGEM1
1PTO2X 1PTO4X 20C3M COMMIT PICTL SRA1B SRA2 SRB1
specific humidity precipitation flux air pressure at sea level net upward shortwave flux in air air temperature air temperature daily max air temperature daily min eastward wind northward wind

32. GCM BCC-CM1 BCCR CGCM3 CNRM-CM3
AgencyBeijing Climate Center, National Climate Center, China Meteorological Administration, No.46, S.Road, Zhongguancun Str., Beijing , China
BCCR
Bjerknes Centre for Climate Research (BCCR), Univ. of Bergen, Norway
CGCM3
Canadian Centre for Climate Modelling and Analysis (CCCma)
CNRM-CM3
Centre National de Recherches Meteorologiques, Meteo France, France

33. GCM CONS-ECHO-G CSIRO, Australia INMCM3.0 GFDL NASA-GISS-AOM
Meteorological Institute of the University of Bonn (Germany), Institute of KMA (Korea), and Model and Data Group.
CSIRO, Australia
INMCM3.0
Institute of Numerical Mathematics, Russian Academy of Science, Russia.
GFDL
Geophysical Fluid Dynamics Laboratory, NOAA
NASA-GISS-AOM
NASA Goddard Institute for Space Studies (NASA/GISS), USA

34. GCM MRI-CGCM2_3_2 NCAR-PCM Model NIES-MIROC3_2-MED UKMO-HADCM3
Meteorological Research Institute, Japan Meteorological Agency, Japan
NCAR-PCM
National Center for Atmospheric Research (NCAR), NSF (a primary sponsor), DOE (a primary sponsor), NASA, and NOAA
Model NIES-MIROC3_2-MED
CCSR/NIES/FRCGC, Japan
UKMO-HADCM3
Hadley Centre for Climate Prediction and Research, Met Office, United Kingdom

35. Prediction of Global Warming
Figure shows the distribution of warming during the late 21st century predicted by the HadCM3 climate model. The average warming predicted by this model is 3.0 °C.

36. Predicted Changes of Temperature

37. Temperature increase versus SRES

38. Predicted Sea Level Rise

39. Sea level rise versus SRES

40. Regional Climate modeling
An RCM is a tool to add small-scale detailed information of future climate change to the large-scale projections of a GCM. RCMs are full climate models and as such are physically based and represent most or all of the processes, interactions and feedbacks between the climate system components that are represented in GCMs.
They take coarse resolution information from a GCM and then develop temporally and spatially fine-scale information consistent with this using their higher resolution representation of the climate system.
The typical resolution of an RCM is about 50 km in the horizontal and GCMs are typically 500~300 km

41. RCM - more realistically simulation

42. RCM can simulate cyclones and hurricanes

43. Steps of assessing impact of climate change

44. Climate change modeling in Bangladesh
PRECIS regional climate modeling is now running in Climate change study cell at IWFM,BUET.
It takes more than 2 months to completely run an experiment of 30 years.
Currently running baseline ( ) and A1B ( ) scenarios over the Bangladesh region.

45. Bangladesh region for PRECIS
Grids: 88 x 88
Predict up to 3 hourly
Needs more than 100 GB free space.
Intel Pentium take one day to simulate 6 month.
Uses LBC data from GCM (e.g. HadCM3)
Data available for A2, B2, A1B scenarios.

46. Predicting Rainfall
[Output of PRECIS model using SRES A2 scenario]

47. Predicting Maximum Temperature
[Output of PRECIS model using SRES A2 scenario]

48. Predicting Minimum Temperature
[Output of PRECIS model using SRES A2 scenario]

49. Thank you