Post-processing WRF-ARW data using NCL 15th Annual WRF User’s Workshop Mary Haley Ÿ CISL / Cindy Bruyère & Abby Jaye Ÿ NESL June 23-27, 2014 The National Center for Atmospheric Research is sponsored by the National Science Foundation. Four main goals 1.  Introduce you to NCL and WRF-NCL 2.  Get you familiar with WRF-NCL scripts •  Opening and examining a WRF output data file •  Reading and querying variables •  Plotting variables 3.  Sneak in tips and information for existing users 4.  Tell you what’s new in V6.2.0 and future plans NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l Topics •  Overview •  NCL language basics •  File input/output •  Data Analysis •  Visualization •  Calling Fortran code from NCL •  Tips, where to get help •  What’s new NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l A scripting language developed at NCAR and tailored for the analysis and visualization of geoscientific data http://www.ncl.ucar.edu/ NCL •  Developed in NCAR/CISL in close collaboration with CGD & MMM staff •  Open source, binaries and source available •  Extensive NCL website, hundreds of examples •  Hands-on workshops •  Well-supported NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l What is NCL? •  A scripting language similar to Matlab, Python, IDL •  Tailored to climate and weather sciences •  Has variable types, “if-then-end if”, “do” loops, arithmetic operators •  F90-like array arithmetic that automatically ignores missing values (where it makes sense) •  Can call your own Fortran 77/90 or C routines 1.  Simple, robust file input/output 2.  Hundreds of data analysis routines 3.  Publication-quality graphics that are highly customizable NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l NCL: File input and output •  Data model based on netCDF model (metadata describes data) •  One function reads all supported data formats: −  NetCDF3, GRIB 1 and 2, HDF4, HDF5, HDF-EOS2, HDF-EOS5, shapefiles, NetCDF4 (groups, compound data, variable length arrays) −  Writes NetCDF3, NetCDF4, and HDF4 •  OPeNDAP-enabled client available •  ASCII, binary (read and write) •  “Never fear a data format” NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l NCL: Data analysis •  Array-based math •  Hundreds of functions -  WRF-ARW specific functions (“wrf_user_getvar” is one) -  Spherical harmonics -  Scalar and vector regridding -  Vertical interpolation -  EOFs •  Many tailored to geosciences •  Most automatically handle missing data •  Can call C and Fortran routines - WRAPIT NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l NCL: Visualization •  High-quality and customizable visualizations •  Contours, XY, vectors, wind barbs, streamlines •  Maps with common map projections •  Handles data on rectilinear, curvilinear, and unstructured grids (MPAS, triangular meshes) •  Specialized scripts for meteograms, skew-T, wind roses, histograms, cross section, panels •  Suite of wrf_xxxx functions: simplifies visualization for WRF-ARW data •  Over 1,400 visualization “options” NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l NCL Training Workshops -  First training workshop in 2000 (72 total, 1120 attendees) -  4-5 local workshops a year -  1-2 annual workshops at U.S. universities -  One annual invited international workshop -  Lectures taught by a scientist and a software engineer -  Includes special lecture on various data formats used in geosciences – lots of students working with WRF! -  Four hands-on labs sessions; students encouraged to bring their own datasets NCL & WRF-NCL WRF User’s Workshop June 23-27, 2014 l l