Climate Change Modeling: An overview

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Climate Change Modeling An overview
Climate Change Training for Water Professionals

• A.K.M. Saiful Islam

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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
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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 0.03 - 0.04.
• Water vapor 0 to 2

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Components of Climate System
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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.

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Green house effect
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Green house effect
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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, )

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Increasing trends of CO2
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Human induced changes of green house gases
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Sector wise Green house gas emission
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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

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Global temperature and Greenhouse gases
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Temperature variation past 1,000 years
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Increase of Temperature past 140 year
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Trends of increase of Temperature
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Surface Air temperature (1960-1990)
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Antarctic Ozone hole

• The Antarctic ozone hole forms in the southern
  hemispheres 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.

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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
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Cracks in Ice bars
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Sea Level Rise (1980-2000)
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Climate Models

• Climate models are computer-based simulations
  that use mathematical formulas to re-create the
  chemical and physical processes that drive
  Earths 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.

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Hardware Behind the Climate Model

• Geophysical Fluid Dynamics Laboratory

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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.

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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.
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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 1995.
  The SRES Scenarios were also used for the Fourth
  Assessment Report (AR4) in 2007.

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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.

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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.

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GCM output described in the 2007 IPCC Fourth
Assessment Report (SRES scenarios), multilayer
mean
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GCM

• BCC-CM1
• AgencyBeijing Climate Center, National Climate
  Center, China Meteorological Administration,
  No.46, S.Road, Zhongguancun Str., Beijing 100081,
  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

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GCM

• CONS-ECHO-G
• 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

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GCM

• MRI-CGCM2_3_2
• 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

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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.

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Predicted Changes of Temperature
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Temperature increase versus SRES
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Predicted Sea Level Rise
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Sea level rise versus SRES
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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 500300
  km

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RCM - more realistically simulation
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RCM can simulate cyclones and hurricanes
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Steps of assessing impact of climate change
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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 (1960-1990) and A1B
  (1949-2100) scenarios over the Bangladesh region.

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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.

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Predicting Rainfall
Output of PRECIS model using SRES A2 scenario
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Predicting Maximum Temperature
Output of PRECIS model using SRES A2 scenario
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Predicting Minimum Temperature
Output of PRECIS model using SRES A2 scenario
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Thank you