Daily ice motion vectors are computed from Advanced Very High Resolution Radiometer (AVHRR), Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I), and International Arctic Buoy Programme (IABP) buoy data. Daily gridded fields combine data from all sensors, from November 1978 through December 2006. Grids extend from 48.4° N to 90° N, and from 53.2° S to 90° S. ... Mean gridded fields include yearly, monthly, and weekly means, and a mean for the entire time series. Both daily and mean gridded fields are in 2-byte integer format, reprojected to 25 km Northern and Southern Hemisphere EASE-Grids. Browse images of mean fields are available in Portable Network Graphics (PNG) and Enhanced Postscript (EPS) format. Raw ice motion vectors from each sensor are in tab-delimited ASCII text format. The complete data set is available via FTP. Registration for data is optional, but encouraged; registered users automatically receive email notification of data updates.