Animation compares the effects of La Niña and El Niño on the formation of Atlantic Hurricanes. El Niño tends to suppress the formation of hurricanes by steering the subtropical jet stream into the hurricanes' path and shearing off the tops of the storms before they develop into full intensity. During La Niña, the jet stream moves north, and hurricanes tend to more easily evolve without interference.
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 22.214.171.124.0