This animation shows the annual minimum sea ice extent and concentration for 25 years, from 1979 to 2005. Average climatology from 1979 to 2004 which is shown as a yellow outline is also included. Three year moving average are shown from 1979-1981 through 2003-2005.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 184.108.40.206.0