WFM 6311: Climate Change Risk Management Lecture-9: Handson Exercise using SDSM to downscaling Temperature of a selected station of Bangladesh Professor A.K.M. Saiful Islam Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) 10 August, 2016

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 Started First http://co-public.lboro.ac.uk/cocwd/SDSM/ Register yourself http://co-public.lboro.ac.uk/cocwd/SDSM/

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

Statistical Downscaling Input Go to http://cccsn.ca/?page=sdsm Click on the ‘Statistical Downscaling Input’ on the left panel. Then click on HadCM3 Predictors

Statistical Downscaling Input Which box to choose?

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

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)

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.

[source] [variable] [grid box]. Dat nceprhumee. dat. h3b2p8_zsw. dat [source] [variable] [grid box] . Dat nceprhumee.dat ?????? h3b2p8_zsw.dat ?????? h2ggp_thas.dat ??????

Station Data Preparation (1961 -2000)

Uncheck ‘Allow -ve values’ Event threshold = 0(temp) = 1 (rainfall) 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 Transformation Change of predictors (optional)

Screen Variables ATTENTION 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 (<#12) PRESS

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

Example: Dhaka Station Scatter Plot Station data Vs 1 Predictor

Dhaka Station (CALIBRATE MODEL) Select those chosen combination 1961-1980 for Tmax_61-80.PAR

Dhaka Station (Calibration Results) Standard Error = 2% (Average) Explained Variance = 23.65% (Average)

(to Validate create output file from 1981-2000) 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

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

Summary Statistics Click 1981-2000

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

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%

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

Creating Model Data Change the settings calendar to 360 (GCM) 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

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.)

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

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)