Antarctica Basal Heat Flux

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A NetCDF file containing updated basal heat flux data for Antarctica projected and interpolated onto the standard 5km grid can be downloaded by clicking here. Metadata in the file describes its contents and is also given in the table below. An archive including the python scripts to create: (1) the NetCDF file, (2) the table of metadata, and (3) the figure at the bottom of this page, along with the data files used by these scripts is available by clicking here. More information on the data can be obtained by contacting Michael Purucker (michael.e.purucker -at- nasa.gov). To help us notify you when improved data becomes available, please email Michael Purucker, if you use this data.

Meta-data for Antarctica_heat_flux_5km.nc
GLOBAL ATTRIBUTES  
title   Antarctica basal heat flux
creator_name   Glen Granzow
institution   University of Montana
date_created   October 1, 2012
summary   This data set contains basal heat flux data for Antarctica based on satellite magnetic field measurements. The data has been projected and interpolated onto the standard CISM grid.
mapping  
ellipsoid   WGS84
grid_mapping_name   polar_stereographic
latitude_of_projection_origin   [-90.]
standard_parallel   [ 71.]
straight_vertical_longitude_from_pole   [ 0.]
false_easting   [ 0.]
false_northing   [ 0.]
bheatflx  
long_name   geothermal heat flux - Fox Maule et al
standard_name   upward_geothermal_flux_at_ice_base
units   W / m^2
grid_mapping   mapping
creator_name   Glen Granzow
contributor_name   Michael Purucker
contributor_role   Michael Purucker provided the original data from which this data set was interpolated.
contributor_url   http://core2.gsfc.nasa.gov/research/purucker/heatflux_updates.html
reference_url   http://www.sciencemag.org/content/309/5733/464.abstract?sid=337116ad-a56c-4bea-9636-9b542bc5498d
source   http://core2.gsfc.nasa.gov/research/purucker/heatflux_mf7_foxmaule05.txt
reference   Fox Maule, C., Purucker, M.E., Olsen, N. & Mosegaard, K., 2005. Heat flux in Antarctica revealed from satellite magnetic data, Science, 309, 464-467, doi: 10.1126/science.1106888.
comments   The original data, provided by Mike Purucker, giving the basal heat flux at specific longitudes and latitudes is quite sparse. Projection and interpolation of the data onto the CISM standard grid was accomplished using a python script written by Glen Granzow. This script used pyproj, a python interface to the PROJ.4 library, to generate x,y coordinates in the required stereographic projection then matplotlib.mlab.griddata for interpolation. matplotlib.mlab.griddata implements natural neighbor interpolation which is based on Delaunay triangulation. To interpolate onto grid points outside the convex hull of the original data set, four fictitious points were added to the original data, one outside each corner of the final data grid. The assumed value of heat flux at the fictitious points was the mean of the heat flux at the actual data points. The vast majority of the interpolated data influenced by these fictitious points are in the ocean and thus of little concern.
x1  
long_name   Cartesian x-coordinate
standard_name   projection_x_coordinate
units   meters
y1  
long_name   Cartesian y-coordinate
standard_name   projection_y_coordinate
units   meters
time  
calender   none
long_name   Time
standard_name   time
units   year since 1-1-1 0:0:0

Antarctica heat flux 5km.png

The crosses "+" in the above figure represent the location of the data points which were interpolated to create the Antarctica_heat_flux_5km.nc data file. The four points just outside the four corners of the final grid were not in the original data but were created to allow interpolation outside the convex hull of the original data. The assumed value of heat flux at these "fictitious" points was the mean of the heat flux at the actual data points. The vast majority of the interpolated data influenced by these fictitious points are in the ocean and thus of little concern.