WFM 6311: Climate Change Risk Management

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WFM 6311 Climate Change Risk Management
Lecture-9 Handson Exercise using SDSM to
downscaling Temperature of a selected station of
Bangladesh

• Akm Saiful Islam

Institute of Water and Flood Management
(IWFM) Bangladesh University of Engineering and
Technology (BUET)
March, 2013
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Lecture Topic

• Download and Installation of SDSM
• Download of GCM data
• Preparation of Station data
• Consistency of station data
• Calibration and validation of model
• Future scenario generations

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Getting Started
First Register yourself
http//co-public.lboro.ac.uk/cocwd/SDSM/
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Installing the software

• After login click on the software of the menu
  bar or go to

https//co-public.lboro.ac.uk/cocwd/SDSM/software.
html

• Download SDSM 4.2.9 and the manual

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Statistical Downscaling Input

• Go to

http//cccsn.ca/?pagesdsm

• Click on the Statistical Downscaling Input on
  the left panel.
• Then click on HadCM3 Predictors

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Statistical Downscaling Input
Which box to choose?
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• (25x 25y)

(90, 25)
(90, 22.5)
(25x 26y)
Dhaka BMD station (90.38 , 23.78) Box ??
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Statistical Downscaling Input

• H3A2a_1961-2099 (Hadley Centre Climate Model 3
  Emissions Scenario A2 - pessimistic)
• h3a2mslpas.dat
• h3a2p5_fas.dat
• H3B2a_1961-2099 (B2 - optimistic)
• h3b2mslpas.dat
• h3b2p5_fas.dat etc
• NCEP_1961-2001
• ncepmslpas.dat
• ncepp5_uas.dat etc (26 files)

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Statistical Downscaling Input

• Depending on the location of the station data,
  choose the right box numbers and click on the
  Get data. For example, for Dhaka station choose
  25X25Y.
• Downloading of the zip file will start.

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source variable grid box .
Datnceprhumee.dat ??????h3b2p8_zsw.dat ??????h2
ggp_thas.dat ??????
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Station Data Preparation(1961 -2000)
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• Select Settings
• Check Calendar (366)
• Uncheck Allow -ve values
• Event threshold 0(temp)
• 1 (rainfall)
• Data 1/1/1961 12/31/2000
• Save the settingc

• For Easy selection
• Select the source directory of your station data
• Select the folder that has your predictand /data

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• Click on advance of settings
• Option None for temperature
• Others for rainfall (i.e., fourth root)
• Save the settings

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• Click Quality Control
• Then Select file
• Open the input station data
• Click on the Check file

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• If OK appears, quality check is complete.
• Manually use the judgment by checking the
  maximum difference of the temperature

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Data Transformation Change of predictors
(optional)
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Screen Variables
ATTENTION Select the NCEP_1961-2000 folder of
appropriate Box
ATTENTION Temp Unconditional Rainfall
Conditional

• Select station data as the predictand file (i.e
  Tmax_dat)
• Select your data period (61-00) and analysis
  period (i.e. Annual)
• Check your process condition (i.e. conditional)
• Amend the significance level (i.e. 0.05 for 5
  significant value).
• SELECT APPROPIATE COMBINATION OF PREDICTOR
  VARIABLES (lt12)
• PRESS

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• Choose those combination of variables where
  partial correlation (r) is high but with P value
  0
• Go back and PRESS

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Example Dhaka Station
Analysis Results
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Example Dhaka Station
Scatter Plot Station data Vs 1 Predictor
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Dhaka Station (CALIBRATE MODEL)
Select those chosen combination
1961-1980 for Tmax_61-80.PAR
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Dhaka Station (Calibration Results)
Standard Error 2 (Average)
Explained Variance 23.65 (Average)
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Weather Generator (to Validate create output
file from 1981-2000)
NCEP Files
1/1/1981 for Tmax_NCEP_81-00 From Tmax_61-80.PAR
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Summary Statistics

• Go to Summary statistics and press
• Select suitable statistics (maximum up to 8),
  and go back

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Summary Statistics
Click
1981-2000
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Compare Results

• Check the results (i.e. mean Vs mean)
• If unsatisfactory, choose another combination of
  screen variables and repeat the above procedures.
  Validation is an iterative process
• If satisfactory, Go to

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Create calibrated file

• Create Tmax_61-00.PAR with same screen variables
  combination (validated)
• Use the data period 1961 2000
• Calculate the Explained Variance

Explained Variance 26.04
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Create Present Climatic data (NCEP_1961-1990)
Tmax_61-00.PAR
NCEP Files
Tmax_NCEP_1961-2000.out
1/1/1961

• Calibrate Model
• 61-00.PAR-gt NCEP_61-00.OUT
• Summary Statistics
• NCEP_61-00.OUT-gtNCEP61-00.TXT

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Creating Model Data
Tmax_61-00.PAR
H3A2_1961-2000

• Change the settings calendar to 360 (GCM)
• Create H3 A2 or H3 B2 model data (.out) through
  Scenario Generation
• for the year 1961-2000

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Creating Model data (present Future)
Choose Modelled
INPUT FILE Tmax_H3A2_1961-2000.out
Analysis period will depend on the desired
(present or future) data time
Summary statistics
Choose Statistics options

• Create text files (Tmax_H3A2_1961-2000.txt,
  Tmax_H3A2_2011-2040.txt etc.)

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Sample Delta Stats Results
Choose Modelled
INPUT FILE H3A2_1961-2000.out
Analysis period 1961-2099
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Sample Delta Stats Results Cont
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Sample Generated output data
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Sample Frequency Analysis
Tmax.dat as the observed data
H3A2_1961-2000.out as the modelled data
Ensemble Mean (Q-Q plot) Ensemble Member 1 (FA)