OSI and NSIDC show about the same Arctic sea ice extent during the winter, but during summer NSIDC is lower. Click on the image to see it larger.
ftp://osisaf.met.no/prod_test/ice/index/v2p2/nh/osisaf_nh_sie_daily.txt
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v3.0.csv
