State of Climate Change and State of Climate Change and Water Modeling in BangladeshWater Modeling in Bangladesh

A.K.M. Saiful IslamAssociate Professor, IWFM

Coordinator, Climate Change Study Cell

Bangladesh University of Engineer and Technology (BUET)

Training Program on Water Security and Climate Change

Presentation Outline

• Overview of the Trend of temperature of Bangladesh and Climate System

• Modeling of Climate Change• General Circulation Model (GCM)• IPCC SRES Scenarios• Climate Change Scenarios• Regional Climate Model (RCM)• Climatic Modeling at BUET• Storm Surge and Salinity modeling due to

SLR

Location of BMD Stations

TemperatureStations (30)

RainfallStations (30)

Trends of Temperature of Bangladesh (1947-2007)

y = 0.0063x + 17.855

29.4

29.6

29.8

30

30.2

30.4

30.6

30.8

31

31.2

31.4

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Trends of Maximum Temperature

y = 0.0137x - 6.0268

20

20.2

20.4

20.6

20.8

21

21.2

21.4

21.6

21.8

22

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Trends of Minimum Temperature

Max. Temp. = 0.63 0C/100 year Min. Temp. = 1.37 0C/100 year

Trends of Discharge

Ganges at Hardinge Bridge

0

15000

30000

45000

60000

75000

90000

1934 1944 1954 1964 1974 1984 1994 2004

Year

Dis

char

ge

(m

3/s

)

Average flood discharge (Jul-Sep)

Annual maximum discharge

Brahmaputra at Bahadurabad

0

20000

40000

60000

80000

100000

120000

1954 1964 1974 1984 1994 2004

Year

Dis

char

ge

(m

3/s

)

Average flood discharge (Jul-Sep)

Annual maximum discharge

Maximum TemperatureMaximum increase: 0.0581 at ShitakundaMinimum increase: -0.026 at Rangpur

Minimum TemperatureMaximum increase: 0.0404 at BograMinimum increase: -0.023 at Tangail

Spatial Distribution of Trends of Temperature (1947-2007)

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.

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 parameterizations 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.

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.

Heart of Climate ModelConservation of momentum

Conservation of mass

Conservation of energy

Complexity of GCM

Hardware Behind the Climate Model

• Geophysical Fluid Dynamics Laboratory

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.

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.

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

BCC:CM1BCCR:BCM2CCCMA:CGCM3_1-T47CCCMA:CGCM3_1-T63CNRM:CM3CONS:ECHO-GCSIRO:MK3GFDL:CM2GFDL:CM2_1INM:CM3IPSL:CM4LASG:FGOALS-G1_0MPIM:ECHAM5MRI:CGCM2_3_2NASA:GISS-AOMNASA:GISS-EHNASA:GISS-ERNCAR:CCSM3NCAR:PCMNIES:MIROC3_2-HINIES:MIROC3_2-MEDUKMO:HADCM3UKMO:HADGEM1

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

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.

Prediction of Temperature increase

Observed Ice melting

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

1979 2003

http://www.worldwithoutwinter.com/melting%20ice%20caps.jpg

Predicted Arctic sea Ice

Arctic Sea Ice in 2040

Arctic Sea Ice in 2000

Results from community climate system models

Prediction of Sea level rise

Regional details of Climate Change

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

Regional Climate change modeling in Bangladesh

• PRECIS regional climate modeling is now running in Climate change study cell at IWFM,BUET.

• Uses LBC data from GCM (e.g. HadCM3).

• LBC data available for baseline, A2, B2, A1B scenarios up to 2100.

• Predictions for every hour. Needs more than 100 GB free space.

Domain used in PRECIS experiment

Topography of Experiment Domain

Zoom over BangladeshSimulation Domain = 88 x 88 Resolution = 0.44 degree

Yearly Average Temperature

Yearly Average Temperature Map

Station PRECIS

Yearly Average Precipitation of Bangladesh

Yearly Average Precipitation Map

Station PRECIS

Predicted Change of Mean Temperature (0C) using A1B

2050 2090

Baseline = 2000

Change of Mean Rainfall (mm/d) using A1B Scenarios

2050 2090

Baseline = 2000

Predicting Maximum Temperature using A2 Scenarios

[Output of PRECIS model using SRES A2 scenario]

Change of Mean Rainfall (mm/d) using A1B Scenarios

2050 2090

Baseline = 2000

Change of mean climatic variables of Bangladesh using A1B Scenarios

Temperate (0C) Rainfall (mm/d)

High-resolution Regional Climate Change Information for Bangladesh to inform Impacts assessments, Vulnerability

indicators and Adaptation policies

Experiment ID Description of the Simulation Time Frame Length( years)

adqcm ERA40:Reanalysis 1957-2001 40erain ERA-Interim: Reanalysis 1989-2009 20ncepb NCEP_R2:Reanalysis 1979-2004 25addfa HadAM3P:Baseline#1 1960-1990 30addfb HadAM3P:Baseline#2 1960-1990 30addfc HadAM3P:Baseline#3 1960-1990 30addja HadAM3P:SRES_A2#1 2070-2100 30addje HadAM3P:SRES_A2#2 2070-2100 30addjf HadAM3P:SRES_A2#3 2070-2100 30addjd HadAM3P:SRES_B2 2070-2100 30aenwh HadCM3Q0:SRES_A1B 1949-2099 150echfa ECHAM4:Baseline 1960-1990 30echja ECHAM4:SRES_A2 2069-2100 30echjd ECHAM4:SRES_B2 2069-2100 30echvc ECHAM5:SRES_A1B 1950-2100 150

Storm Surge Model during SIDR

Source: http://www.oar.noaa.gov/spotlite/2007/spot_cyclone.html

Advanced Circulation (ADCIRC) model to predict storm surge 

Hassan Mashriqui, an assistant extension professor of coastal engineering of Louisiana State University (LSU) Has simulated storm surge model during SIDR

2D Hydrodynamic Modeling for Salt water Intrusion

Five ppt line for different sea level rise in dry season

IWM studied “Impact of Sea level Rise on Coastal Rivers of Bangladesh”

What will happen to Artic Polar Bears ?

Antarctic Penguins are watching…

The Sundarbans ..Mangrove forest?

Thank you