Using nctoolbox to access and plot a slice of Hycom Reanalysis

hycom_salinity_nctoolbox

%  This uses the Matlab NCToolbox to access HYCOM data and plot a salinity field
%
%  NCToolbox is available from https://github.com/nctoolbox/nctoolbox
%  HYCOM is available from https://hycom.org/
%
% Dig down from HYCOM to find a DODS Data URL
%
%  This is setup to look for the 2012 GOFS 3.0 Reanalysis
%
% Google for Hycom opendap
%  https://hycom.org/dataserver/
% Choose GOFS 3.0 Reanalysis from the sidebar:
%  https://hycom.org/dataserver/gofs-3pt0/reanalysis
% Choose the 1995-08-01 → 2012-12-31 dataset:
%  https://hycom.org/data/glbu0pt08/expt-19pt1
% choose "Access Data Here" button: to get the list of years
%  http://tds.hycom.org/thredds/GLBu0.08/expt_19.1.html
% choose the 2012 dataset to get the TDS page showing different format
%  http://tds.hycom.org/thredds/GLBu0.08/expt_19.1.html?dataset=GLBu0.08-expt_19.1-2012
% Choose the OpenDAP UI:
%  http://tds.hycom.org/thredds/dodsC/GLBu0.08/expt_19.1/2012.html
% Copy the "Data URL"
%  http://tds.hycom.org/thredds/dodsC/GLBu0.08/expt_19.1/2012
%
uri = 'http://tds.hycom.org/thredds/dodsC/GLBu0.08/expt_19.1/2012'

nc = ncgeodataset(uri)            % get a ncgeodataset handle
nc.variables                      % list the variables
sv = nc{'salinity'};              % get a ncgeovariable handle
sv.attributes

svg = sv.grid_interop(:,:,:,:)    % get the time,z,lon,lat grid info


datestr(sv.timeextent(),29)       % find out it ranges from 2012-01-01 to 2012-12-31

% do some plotting like https://github.com/nctoolbox/nctoolbox/blob/master/demos/geodemo_3.m

[toi,junk] =near(svg.time,datenum(2012,06,01))  % find the index nearest a particular date 
doi = 1;



pcolorjw(svg.lon,svg.lat,double(sv.data(toi,doi,:,:)));  % plot 

title({sprintf('Hycom %s @ %.0fm',...
  sv.attribute('long_name'),svg.z(doi));...
  uri;datestr(svg.time(toi))},'interpreter','none');


% add colorbar with units
hcb = colorbar;
title(hcb,sv.attribute('units'));

print('hycom_salinity_nctoolbox','-dpng')

The above Matlab code produces this figure of HYCOM surface salinity for 2012-06-01.

The code uses the NCToolbox (https://github.com/nctoolbox/nctoolbox) within Matlab on the OpenDAP data available from https://hycom.org/data/glbu0pt08/expt-19pt1 .

Nice! Thanks for sharing @drf5n!

Thanks for sharing.