The following animation helps to explain the dynamics of subglacial water exchange and what it looks like from space. Starting from an artist's concept of the Antarctic surface we move down to a cross section of the ice sheet with lakes hidden deep beneath. As pressure is exerted on one lake, the water in it is forced to an adjacent lake. This water movement results in elevation changes at the surface over both lakes, detectable by NASA satellites. The camera then moves to a 'top-down' view of a system of these hidden lakes and streams before dissolving into observed satellite data.
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 18.104.22.168.0