ISIS Topside Sounder ionograms in standard resolution and OS2 binary format

This directory contains ionogram data in OS2 binary format from the ISIS 1 and 2 
topside sounder instruments. The digital ionograms are the result of a data 
restoration project at GSFC (PI: R. Benson). More information about this project 
can be found at the homepage <http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html>. 
The data format description for ISIS-1 is provided at 
<http://spdf.gsfc.nasa.gov/isis/des_av_i1.html> and for ISIS-2 at 
<http://spdf.gsfc.nasa.gov/isis/des_av.html>.

Subdirectories:
/sss_lat_long/isis&/yyyy   
	'sss' is the 3-digit identification code of the ground station (a list 
	   of stations can be found at http://nssdc/space/isis/isis-table1-new.html); 
	'lat' and 'long' are the geodetic latitude and longitude of the ground station.
	'isis&' is either 'isis1' or 'isis2'
	'yyyy' is the 4-digit year
/x_truncated_ionogram_files
    This directory includes ionogram data files that were inadvertently truncated 
    when the data were moved to DIOnAS/nssdcftp.  
 
These data are also available in CDF format for viewing and downloading on CDAWeb at 
<http://cdaweb.gsfc.nasa.gov/>.

A search page (http://spdf.gsfc.nasa.gov/isis/isis_menu4.html) lets users
locate data for specified dates, times, locations and other search criteria. 
Currently only ISIS-2 data are considered.

An interactive IDL/Fortran program for tracing and inverting ionograms (in CDF 
format) to electron density profiles can be downloaded from
http://spdf.sci.gsfc.nasa.gov/pub/data/isis/topside_sounder/software/interactive_tracing_inversion/

NSSDC Contact: <mailto:request@nssdca.gsfc.nasa.gov> or phone 1-301-286-6695

Please acknowledge the NASA Space Physics Data Facility and the instrument's Principal
Investigator for data usage.

Keywords: ionosphere, topside, sounder, ionogram

Data contact: Dieter.Bilitza-1@nasa.gov>
NASA Official: Dr. Robert McGuire <robert.e.mcguire@nasa.gov>