introduction to hands on training in cordex south asia data analysis module-1 j. sanjay centre for...
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Introduction to Hands On Training in CORDEX South Asia Data Analysis
Module-1
J. Sanjay
Centre for Climate Change Research (CCCR)Indian Institute of Tropical Meteorology (IITM), Pune
(An Autonomous Institute of the Ministry of Earth Sciences, Govt. of India)
Email: sanjay@tropmet.res.in
CORDEX-South Asia Evaluation Runs available for Hands On Analyses & Visualization
Institute
Model Experiment Resolution
Driving Model
Driving Experiment
IITM WRF3.1.1 BMJ Cu Scheme
50 km; Mercator
ERA-Interim Global 0.75o
IITM RegCM3.0 Grell Cu Scheme
50 km; Mercator
ERA-Interim Global 1.5o
IITM LMDZ AGCM
Emanuel Cu Scheme
35 km; Variable
ERA-Interim Nudged with ERA-Interim
IITM LMDZ AGCM
Tiedtke Cu Scheme
35 km; Variable
ERA-Interim Nudged with ERA-Interim
• All RCM outputs regridded on a common region and 0.5o lat./lon. Grid in NetCDF
• Monthly/Daily mean Precipitation for the period 1989-2005
Network Common Data Form•NetCDF is a set of software libraries and self-describing machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data
NetCDF Utilities
•ncdump reads a netCDF dataset and prints a textual representation of the information in the dataset
•ncdump –h file.nc prints the header information in a NetCDF file
Climate Data Operators
•CDO is a collection of command line Operators to manipulate and analyse Climate and NWP model Data (from MPIM https://code.zmaw.de/projects/cdo)
•Supported data formats are GRIB 1/2, netCDF 3/4, SERVICE, EXTRA and IEG. There are more than 600 operators available
•CDO has very small memory requirements and can process files larger than the physical memory
•CDO is open source
•Full documentation available as html or pdf from homepage (https://code.zmaw.de/projects/cdo)
• CDO User’s Guide Version 1.6.1
• CDO Reference Card
Grid Analysis and Display System(from COLA http://www.iges.org/grads)
•GrADS is an interactive desktop tool that is used for easy access, manipulation, and visualization of earth science data
•GrADS has two data models for handling gridded and station data
•GrADS supports many data file formats, including binary (stream or sequential), GRIB (version 1 and 2), NetCDF, HDF (version 4 and 5), and BUFR (for station data)
• GrADS has been implemented worldwide on a variety of commonly used operating systems and is freely distributed over the Internet
•Online documentation has become the new standard for GrADS. Documentation page (http://www.iges.org/grads/gadoc) has
• User's Guide• Tutorial• useful Index for quick reference
Structure of Files
Start Virtual Box Fedora14
Login
User : CORDEXPasswd: cordex123
Home Directory: /home/CORDEX/Desktop/Modules
DATA Directories:
OBS: Observation Data -MonthlyRegCM/LMDZ/ARW: Model Data –Monthly (1989-2005)
OBS/DAILY: Daily Files (1996-2005)
What to do:
CDO & GrADS Scripts
$ cd scripts/CDA1 (Climate Data Analysis Module-1)$cd plot[1-5] (Change to each sub-module directory)
Thanks to Sandip & Sabin
Climate Data Analysis Module: CDA1 (CORDEX South Asia: Climate model outputs) – Mean & VariabilityDay 4: Friday, 30 August 2013 09:00 – 11:00 Hands on training: 1 (Trainers: J. Sanjay, Jayashree Revadekar, Rajiv Chaturvedi, Milind Mujumdar and Vimal Mishra)
Precipitation Analyses and Visualization of:
•Observed Mean spatial patterns during Summer monsoon (JJAS) and Winter (DJF) seasons
•Comparison of RCMs simulated mean spatial patterns during Summer monsoon (JJAS) season
•Area averaged mean monthly annual cycle
•Comparison of RCMs simulated spatial patterns of interannual variability (standard deviation) during Summer monsoon (JJAS) season
•Temporal evolution of area averaged interannual variability (summer monsoon season anomalies normalized with standard deviation)
Scripts provided: Analyses using CDO (Climate Data Operators) and visualization using GrADS (Graphical Analysis and Display System)
Precipitation Observed Mean Spatial patterns during Summer monsoon (JJAS) and Winter (DJF) seasons
File: CDA1/plot1/seasonal-mean.cdo
•Select months
cdo -selmon,6,7,8,9 $DATADIR/OBS/CRU_precip_mon_1989-2005-WA.nc CRU_precip_jjas.nc
•Time average over season
cdo -timmean CRU_precip_jjas.nc CRU_precip_jjas_mean.nc
File: CDA1/plot1/seasonal-mean.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot1/seasonal-mean.sh
•Unix shell script for CDO analysis & GrADS output
Exercise:
•Please bring out the differences in the two seasons
Comparison of RCMs simulated mean precipitation spatial patterns during Summer monsoon (JJAS) season
File: CDA1/plot2/mul-mod-seasonal-mean.cdo
•Select JJAS monthscdo -selmon,6,7,8,9 $DATADIR/OBS/CRU_precip_mon_1989-2005-WA.nc CRU_precip_jjas.nccdo -selmon,6,7,8,9 $DATADIR/LMDZ/LMDZ1_precip_mon_1989-2005-WA.nc LMDZ1_precip_jjas.nc
•Compute JJAS mean & set relative time axis
cdo -r -settaxis,2000-07-15,00:00,1mon -timmean CRU_precip_jjas.nc CRU_precip_jjas-mean.nccdo -r -settaxis,2000-07-15,00:00,1mon -timmean LMDZ1_precip_jjas.nc LMDZ1_precip_jjas-mean.nc
•Compute Ensemble JJAS mean
cdo -ensmean LMDZ1_precip_jjas-mean.nc LMDZ2…..nc RegCM…...nc ARW……..nc ENS_precip_jjas-mean.nc
File: CDA1/plot2/mul-mod-seasonal-mean.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot2/mul-mod-seasonal-mean.sh
•Unix shell script for CDO analysis & GrADS output
Exercise:
•Please bring out the differences in the simulations
Area averaged mean monthly annual cycle of precipitation
File: CDA1/plot3/annual-cycle.cdo
•Compute monthly mean climatologycdo -ymonmean $DATADIR/OBS/CRU_precip_mon_1989-2005-WA.nc CRU_precip_mon_CLIM.nc cdo -ymonmean $DATADIR/LMDZ/LMDZ1_precip_mon_1989-2005-WA.nc LMDZ1_precip_mon_CLIM.nc
•Select regioncdo -sellonlatbox,70,90,10,25 CRU_precip_mon_CLIM.nc CRU_precip_mon_CLIM_IND.nccdo -sellonlatbox,70,90,10,25 LMDZ1_precip_mon_CLIM.nc LMDZ1_precip_mon_CLIM_IND.nc
•Area averagecdo -fldmean CRU_precip_mon_CLIM_IND.nc CRU_precip_mon_CLIM_IND_fldmean.nc cdo -fldmean LMDZ1_precip_mon_CLIM_IND.nc LMDZ1_precip_mon_CLIM_IND_fldmean.nc
•Set relative time axiscdo -r -settaxis,2000-01-15,12:00,1mon CRU_precip_mon_CLIM_IND_fldmean.nc CRU_precip_mon_CLIM_IND_fldmean-n.nc cdo -r -settaxis,2000-01-15,12:00,1mon LMDZ1_precip_mon_CLIM_IND_fldmean.nc LMDZ1_precip_mon_CLIM_IND_fldmean-n.nc
File: CDA1/plot3/annual-cycle.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot3/annual-cycle.sh
•Unix shell script for CDO analysis & GrADS output
Exercise:
•Please bring out the differences in the annual cycle
•Analyse for a region of your choice
Comparison of RCMs simulated spatial patterns of summer monsoon (JJAS) season precipitation interannual variability (standard deviation)
File: CDA1/plot4/mul-mod-seasonal-std.cdo
•Select JJAS months & seasonal mean for each year
cdo -yearmean -selmon,6/9 $DATADIR/OBS/CRU_precip_mon_1989-2005-WA.nc CRU_precip_jjas.nccdo -yearmean -selmon,6/9 $DATADIR/LMDZ/LMDZ1_precip_mon_1989-2005-WA.nc LMDZ1_precip_jjas.nc
•Compute standard deviation of JJAS mean
cdo -timstd CRU_precip_jjas.nc CRU_precip_jjas-timstd.nccdo -timstd LMDZ1_precip_jjas.nc LMDZ1_precip_jjas-timstd.nc
File: CDA1/plot4/mul-mod-seasonal-std.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot4/mul-mod-seasonal-std.sh
•Unix shell script for CDO analysis & GrADS output
Exercise:
•Please bring out the differences in the simulations
Temporal evolution of area averaged of summer monsoon (JJAS) season precipitation interannual variability (seasonal anomalies normalized with standard deviation)
File: CDA1/plot5/IAV.cdo
•Compute JJAS mean for each year
cdo -selmon,6,7,8,9 $DATADIR/CRU_precip_mon_1989-2008-WA.nc CRU_precip_jjas.nccdo -yearmean CRU_precip_jjas.nc CRU_precip_jjas-mean.nc
•Select region and area average
cdo -sellonlatbox,70,90,10,25 CRU_precip_jjas-mean.nc CRU_precip_jjas-mean-IND.nccdo -fldmean CRU_precip_jjas-mean-IND.nc CRU_precip_jjas-mean-IND-fldmean.nc
• Compute area averaged seasonal anomalies
cdo -timmean CRU_precip_jjas-mean-IND-fldmean.nc CRU_precip_jjas-mean-IND-fldmean-timmean.nccdo -sub CRU_precip_jjas-mean-IND-fldmean.nc CRU_precip_jjas-mean-IND-fldmean-timmean.nc CRU_precip_jjas-mean-IND-anom.nc
•Prepare the observed summer monsoon precipitation index
cdo -timstd CRU_precip_jjas-mean-IND-fldmean.nc CRU_precip_jjas-mean-IND-fldmean-std.nccdo -div CRU_precip_jjas-mean-IND-anom.nc CRU_precip_jjas-mean-IND-fldmean-std.nc CRU_precip_jjas-mean-IND-std-fldmean.nccdo -r -settaxis,1989-07-15,00:00,1year CRU_precip_jjas-mean-IND-std-fldmean.nc CRU_precip_jjas-mean-IND-std-fldmean-n.nc
File: CDA1/plot5/IAV.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot5/IAV.sh
•Unix shell script for CDO analysis & GrADS output
Exercise:
•Please indicate the extreme monsoon years
File: CDA1/plot6/mul-mod-seas-mean-bias.cdo
•Compute JJAS long-term mean bias
File: CDA1/plot6/mul-mod-seas-mean-bias.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot6/mul-mod-seas-mean-bias.sh
•Unix shell script for CDO analysis & GrADS output
cdo -sub ../plot2/LMDZ1_precip_jjas-mean.nc ../plot2/CRU_precip_jjas-mean.nc LMDZ1_precip_jjas-bias.nc
Comparison of RCMs simulated Summer monsoon (JJAS) season mean precipitation bias
File: CDA1/plot7/mul-mod-seas-mean-cv.cdo
•Compute JJAS mean CV
File: CDA1/plot7/mul-mod-seas-mean-cv.gs
•GrADS script to plot & prepare output in EPS format
File: CDA1/plot7/mul-mod-seas-mean-cv.sh
•Unix shell script for CDO analysis & GrADS output
Comparison of RCMs simulated and Observed Summer monsoon (JJAS) season mean precipitation Coefficient of Variation (CV = Standard Deviation / Mean)
cdo -mulc,100.0 -div ../plot4/CRU_precip_jjas-timstd.nc ../plot2/CRU_precip_jjas-mean.nc CRU_precip_jjas-cv.nccdo -mulc,100.0 -div ../plot4/LMDZ1_precip_jjas-timstd.nc ../plot2/LMDZ1_precip_jjas-mean.nc LMDZ1_precip_jjas-cv.nc
Thanks for your attention
Email: sanjay@tropmet.res.in
Many Thanks to:
• My Team members• Sabin & Sandip
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