Transcript Update on NCAR Graphics and the NCAR Command Language

Building Analysis and
Visualization Infrastructure for
the Geosciences
Mary Haley
Computing in Atmospheric Sciences 2001
Annecy, France
Tuesday, 30 October 2001
NCAR Command Language
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Introduction to NCL
Brief history of NCL
CCSM-NCL collaboration
Other projects
Future directions
Scientific Computing Division
National Center for Atmospheric Research
Introduction to NCL
• A scripting language designed for the
analysis and visualization of data
• Powerful in 3 areas:
– File input and output
– Data processing
– Graphics
• Based on netCDF model
• Runs on many UNIX systems (Compaq, IBM,
PC/Linux, PC/Windows, SGI, Sun)
• Free to the public
Scientific Computing Division
National Center for Atmospheric Research
Brief history of NCL
NCAR Graphics
Design and development
First version released
CCSM-NCL collaboration
First “climate-enhanced”
version released
Second “C.E.” version
released
NCL free to public
1960s – 1990s
June 1991
August 1995
January 1997
August 1998
May 1999
November 2000
Scientific Computing Division
National Center for Atmospheric Research
CCSM-NCL collaboration
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What is the CCSM?
Requirements for CCSM post-processor
NCL’s role
Support for CCSM-NCL users
Contributions and examples from
climate community
• If I say “CSM”, I mean “CCSM”. 
Scientific Computing Division
National Center for Atmospheric Research
What is the CCSM?
• A fully-coupled, global climate model
that provides state-of-the-art computer
simulations of the earth’s past,
present, and future climate states.
Scientific Computing Division
National Center for Atmospheric Research
Requirements for the CCSM
post-processor
• Read/write certain portable data formats
(netCDF, HDF, HDF-EOS)
• Read GRIB
• Built-in climate analysis functions
• Interface w/user Fortran/C codes and
external libraries (i.e. IMSL)
• Generate different types of graphics in
publication-quality formats
Scientific Computing Division
National Center for Atmospheric Research
NCL’s role:
file input and output
BEFORE
• Read/write netCDF,
HDF, ASCII, binary
• Read GRIB
• Functions for
querying input files
AFTER
• Read GRIB files
containing ECMWF
complex coefficients
• Read CCM history
tape files
• Read multiple files
with one statement
Scientific Computing Division
National Center for Atmospheric Research
NCL’s role:
data processing
BEFORE
AFTER
• Over 100 routines
• Standard math
calculations
• Handle missing data
• Access Fortran & C
routines
• Over 400 routines
• Spherical harmonics
• Scalar and vector
regridding
• 1, 2, 3D interpolations
• Script to simplify
Fortran/C routine access
Scientific Computing Division
National Center for Atmospheric Research
NCL’s role:
data processing (cont’d)
• Sea level pressure computation
• Spectral/cross-spectral analysis
• Geopotential height computation for
CCM hybrid coordinates
• Empirical orthogonal functions, singular
value decomposition
• Other non-CCSM specific functions
Scientific Computing Division
National Center for Atmospheric Research
NCL’s role:
graphics
BEFORE
• Objected-oriented
interface
• Contours, XY plots,
vectors, streamlines,
maps
• Flexibility via
hundreds of
resources
AFTER
• Suite of plotting
templates
• Highly-stylized
• Takes advantage of
meta data
Scientific Computing Division
National Center for Atmospheric Research
Scientific Computing Division
National Center for Atmospheric Research
Support for CCSM-NCL users
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Documentation
CCSM Support Network web site
Consulting
NCL workshops
ncl-talk email list
Scientific Computing Division
National Center for Atmospheric Research
Contributions from users
• Over 100 functions
– zonal averages
– climatologies
– interannual variability
– specialized plotting scripts
– wave number spectra
– diagnostics package
Scientific Computing Division
National Center for Atmospheric Research
Real world examples
• Matthew Huber, Danish Center for Earth System
Science
• Joel Norris, Scripps Institute of Oceanography
• Adam Phillips, Dennis Shea, Mark Stevens, CGD
• Bjorn Stevens, UCLA
• Greg Thompson, Research Applications Program
Scientific Computing Division
National Center for Atmospheric Research
MH2
MH4
JN1
JN2
AP1
AP2
DS1
MS1
DS2
DS3
DS4
AMWG diagnostics package
• Written completely in NCL
• Produces over 475 postscript plots and
tables in a variety of formats from CCSM
monthly netCDF files
• Used to compare two CCSM model
simulations or a model simulation to
observational and reanalysis data
Scientific Computing Division
National Center for Atmospheric Research
MS3
MS4
MS5
BS2
BS3
BS4
GT1
Other current projects
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Weather Research and Forecast Model
Community Data Portal
High resolution maps
Other ports
Scientific Computing Division
National Center for Atmospheric Research
WRF Model
• Next-generation mesoscale forecast model
• NCL’s role
– multi-model comparison
– real-time weather forecasting plots
– horizontal and vertical cross sections
– skew-T plots
– convert WRF data to vis5D data
Scientific Computing Division
National Center for Atmospheric Research
Community Data Portal
• Data Server Pilot Projects
– Live Access Server (LAS)
– Distributed Oceanographic Data System –
(DODS)
– NCL acts as middleware
– DSS Reanalysis II is one such project
– Other data portals in the works (Regional
Climate Data Access System, Vegetation
and Ecosystem modeling/analysis)
Scientific Computing Division
National Center for Atmospheric Research
Future directions
• Mesoscale Model (MM5) - terrain-following
sigma-coordinate model designed to simulate or
predict mesoscale and regional-scale
atmospheric circulation (Penn State, NCAR)
• Earth System Grid - virtual collaborative
environment that links distributed centers,
users, models, and data. Sponsored by DOE
Office of Science, involves 5 laboratories and
one university
Scientific Computing Division
National Center for Atmospheric Research
RANGS/GSHHS Coastline Database
• GSHHS (Global Self-consistent Hierarchical
High-Resolution Coastlines), created by Paul
Wessel and Walter Smith.
• RANGS (Regionally Accessible Nested Global
Shorelines), created by Rainer Feistel.
– Expressed to 0.000001 degrees of lat/lon (about 0.1
meters).
– Actual accuracy is more like 500 meters.
– Points in database are about 300 meters apart.
Scientific Computing Division
National Center for Atmospheric Research
Future directions (cont’d)
• New functionality in NCL
– Curvilinear coordinates
– HDF 5
– More robust 3D capability
- Vis5D, a visualization system for large 5D gridded data sets such as those
produced by numerical weather models
– Other ports (Mac OSX)
Scientific Computing Division
National Center for Atmospheric Research
URLS
• NCL Home Page
http://ngwww.ucar.edu/ncl/
• CCSM Support Network
http://www.cgd.ucar.edu/csm/support/
• Me ([email protected])
Scientific Computing Division
National Center for Atmospheric Research
National Center for Atmospheric Research
Boulder, Colorado
United States