The files are 2 byte shorts.  the grid size are as follows:
northern hemisphere = 304 X 448
southern hemisphere = 316 X 332


bootstrp.d	contains bootstrap ice concentration values WITH land mask all ready defined
			bs_01024_n.f13
			1    2   3  4
		2 layers.  total year, multi year

nst.d		contains nasa team ice concentration values WITH land mask all ready defined
			nst_01024_n.f13
		3 layers.  total year, first year, multi year


cv.d		contains cal-val ice concentration values WITH land mask all ready defined
			cv_01024_n.f13
		3 layers.  total year, first year, multi year

thin.d	contains nic hybrid team ice concentration values WITH land mask all ready defined
			nh_01024_n.f13
		4 layers.  total year, first year, thin, multi year


where - 	1 = algorithm	bs = bootstrap
					nst = nasa team
					cv = cal-val
					nh = nic hybrid

            2 = yyjjj		yy  = year, 2 digit
					jjj = julian, 3 digit

		3 = hemisphere	n = north
					s = south

		4 = satellite	f13 = f13

layers are defined as x*y bytes.  
	ex: bootstrap has 2 layers.  
		the 1st layer is 1 to x*y bytes.  
		the 2nd layer would be (x*y)+1 to x*y*2

if you have any questions, contact mchase@natice.noaa.gov.