The Caspian Sea bottom topography was found to erroneous, set to a constant
-30m, in the September 2001 ETOPO2 dataset.  More accurate definition is
required so global models can better estimate surface flux parameters.

A Caspian Sea dataset containing digitized depth contours from GEBCO charts
was found at http://www.caspianenvironment.org/NewSite/Data-MAP_GIS.htm
and under the GIS Data, http://www.caspianenvironment.org/dim/menu5.htm.

Dr. Peter Sloss and Lisa Taylor, NGDC, converted the digitized contours to a
2'x2' resolution to match ETOPO2 and offset them -29m to account for the
fact the Caspian Sea surface is below mean sea level.  The final data were
blended into ETOPO2 to create the April 2006 dataset.  The file Caspian_color.pdf
illustrates the correction.