WFM 6311: Climate Change Risk Management

WFM 6311: Climate Risk Management © Dr. Akm Saiful Islam

WFM 6311: Climate Change Risk Management

Akm Saiful Islam

Lecture-9: Handson Exercise using SDSM to downscaling Temperature of a

selected station of Bangladesh

March, 2013

Institute of Water and Flood Management (IWFM)Bangladesh University of Engineering and Technology (BUET)


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


Getting Startedhttp://co-public.lboro.ac.uk/cocwd/SDSM/

First Register yourself


Installing the software

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

WFM 6311: Climate Risk Management © Dr. Akm Saiful IslamStatistical Downscaling Inputhttp://cccsn.ca/?page=sdsm

WFM 6311: Climate Risk Management © Dr. Akm Saiful IslamStatistical Downscaling Input


(25x 25y)

(25x 26y)

(90, 25)

(90, 22.5)

Dhaka BMD station(90.38 , 23.78)

Box # ??


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)

Statistical Downscaling Input


Statistical Downscaling Input

WFM 6311: Climate Risk Management © Dr. Akm Saiful Islam[source] [variable] [grid box] . Datnceprhumee.dat ??????h3b2p8_zsw.dat ??????h2ggp_thas.dat ??????

WFM 6311: Climate Risk Management © Dr. Akm Saiful IslamStation Data Preparation(1961 -2000)


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


Click on advance of settings

Option ‘None’ for temperature

Others for rainfall (i.e., fourth root)

Save the settings


Click Quality Control

Then Select file

Open the input station data

Click on the Check file


If OK appears, quality check is complete.

Manually use the judgment by checking the maximum difference of the temperature


Data TransformationChange of predictors (optional)


Screen Variables

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 (<#12)

PRESS

ATTENTIONTemp Unconditional

Rainfall Conditional

ATTENTIONSelect the NCEP_1961-2000

folder of appropriate Box


Choose those combination of variables where

partial correlation (r) is high but with P value ≈ 0

Go back and PRESS


Example: Dhaka Station

Analysis Results


Scatter Plot

Station data Vs 1 Predictor

Example: Dhaka Station


Dhaka Station (CALIBRATE MODEL)

Select

those

chosen

combination

1961-1980 for

Tmax_61-80.PAR


Standard Error = 2%(Average)

Explained Variance = 23.65%(Average)

Dhaka Station (Calibration Results)


Weather Generator (to Validate create output file from 1981-2000)

1/1/1981 for

Tmax_NCEP_81-00

From

Tmax_61-80.PAR

NCEP Files


Summary Statistics

Go to Summary statistics and pressSelect suitable statistics (maximum up to 8), and go back


Summary Statistics

Click

1981-2000


Compare ResultsCheck 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


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%

Create calibrated file


Create Present Climatic data (NCEP_1961-1990)

NCEP Files

Calibrate Model

61-00.PAR-> NCEP_61-00.OUT

Summary Statistics

NCEP_61-00.OUT->NCEP61-00.TXT

Tmax_61-00.PAR

1/1/1961

Tmax_NCEP_1961-2000.out


Creating Model Data

Change the settings calendar to 360 (GCM)

Create H3 A2 or H3 B2 model data (.out) through Scenario Generation

for the year 1961-2000

H3A2_1961-2000

Tmax_61-00.PAR


Creating Model data (present +Future)

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

‘Summary statistics’ Choose Statistics options

Analysis period will depend

on the desired (present or

future) data time

Choose Modelled

INPUT FILE

Tmax_H3A2_1961-2000.out


Sample: Delta Stats Results

Choose Modelled

INPUT FILE

H3A2_1961-2000.out

Analysis period 1961-2099


Sample: Delta Stats Results……… Cont


Sample: Generated output data


Ensemble Mean (Q-Q plot)

Ensemble Member 1 (FA)

Ensemble Mean (Q-Q plot)

Ensemble Member 1 (FA)

Sample: Frequency AnalysisTmax.dat as the observed dataTmax.dat as the observed data

H3A2_1961-2000.out as the modelled dataH3A2_1961-2000.out as the modelled data

WFM 6311: Climate Change Risk Management

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