Thermospheric O/N2 ratios for major magnetic storms from IMAGE FUV SI-13 measurements.

These data were generated by Yongliang Zhang (APL/JHU) with support from a NASA's
HDEE grant.
 
This data set provides the O and N2 column density ratio referenced at N2 column density 
of 10^17 cm-2. The O/N2 maps are derived from IMAGE SI-13 [Mende et al., 2000] dayglow 
data. The O/N2 maps are obtained for major magnetic storms (Dst index < -80 nT) between 
2000 and 2005 and when IMAGE SI-13 was taking measurements of emissions from the sunlit 
thermosphere. Consult the BACKGROUND.PDF document for more information, caveats, and 
references to related science articles. 

The data are provided as IDL savesets and include the following parameters:
parmeter   			variable_type    	example
Day of month		String				15
Day of Year			String				186
Geodetic Latitude   Real array[128,128]
Geodetic Longitude	Real array[128,128]
Month				String
O/N2 column ratio	Real array[128,128]
SI-13 image			Real array[128,128]
Universal Time		String				19:01
X					Integer array[100]
Year				String

The directory "aa_pre_generated_plots" contains three types of image files:
(1) The global O/N2 ratio in a cylindrical projection as a GIF image 
(on2_yyyydoy_hhmm.gif); 
(2) The global O/N2 ratio in a polar projection as a PNG image (on2_yyyydoy_hhmm.png);
(3) SI-13 airglow in a polar projection as a PNG image (si13_yyyydoy_hhmm.png). 
The original SI-13 images are provided to help identify the auroral region because 
auroral emissions are not removed and therefore the O/N2 ratio in the auroral oval 
are questionable (see background document).