The enclosed directories contain processed QuikSCAT 
images of derived ice concentration, ice edge, and 
ice drift as derived from near-real-time (NRT)
enhanced resolution images by Joerg Haarpaintner 
(Joerg.Haarpaintner@itek.norut.no>  The image projection
is a standard SIR regions known as NHe (Northern
Hemisphere), which is similar to Arc, but covers a
larger area.  

A SIR file format image containing the NHe land mask 
(which also contains the map projection information for
the NHe region in the file header) is qus-NHe.sir.lmask.gz

This data covers most of 2003 and 2004, plus the first portion
of 2005.


Documentation

This file and the files it references are the ONLY docuementation
for these products.

A paper describing these products was presnted at IGARSS'06
and can be downloaded in PDF form from PID235348.pdf  
Individual product notes for each product follow.


Ice Drift

Drift images are stored as jpeg (.jpg) images in the drift/72h or
drift/48h subdirectories.


Ice Edge

Edge product files are stored as png (.png) images in the edge 
subdirectory.

The algorithm for computing the Ice Edge is described in:

J. Haarpainter, R.T. Tonboe, D.G. Long and M. L. VanWoert, "Automatic
Detection and Validity of the Sea Ice Edge: An Application of Enhanced
Resolution QuikScat/SeaWinds Data," IEEE Transactions on Geoscience
and Remote Sensing, Vol. 42, No. 7, pp. 1433-1443, 2004.


Ice Concentration

Concentration product files are stored as png (.png) images in the 
icon subdirectory.

The ice concentration method has not been published yet. The 
validation is also quite superficial: the method consists in 
comparing sigma0(hh), the std and the APR (Active Polarisation 
Ratio) with NASA Team SSMI ice concentration, which gives me 
an exponential regression lines for each parameter, i.e. an ice
concentration for each value of each parameter.  I separate 
the ice cover into 3 areas MYI, FYI and MIZ by
 ?HH(FYI) < -13dB < ?HH(MYI)
 MIZ: ice border of 20 pixels (~125 km)

Then for each area, I combine the different ice concentration 
results of each parameter into one final ice concentration:
MYI:	IC = max(IC(APR), IC(STD))
FYI:	IC = (max(IC(HH), IC(STD)) + IC(APR)) / 2
MIZ:	IC = (IC(HH) + IC(STD) + IC(APR)) / 3

So the method is very empirical and has NOT been validated.

The ice concentration data is averaged by 3x3 pixel (
6.675 km grid, 1560x1560 pixels) and it is rotated by 45
degrees (Greenwich is the vertical).  This is somewhat
different that the standard SIR convention.
Also, the concentration is then again averaged over 3x3 pixels
(20.025 km) (to be more correspondent to SSM/I concentration, but it
is still on the 6.675 km grid.

Lat/lon images (images with the lattitude or longitude in the image)
are contained in lat_1560.ima.gz and lon_1560.ima.gz