Depending on what the user is investigating, the MODIS 250 meter imagery
might be useful. Below is a sample image cropped from an image found at
http://rapidfire.sci.gsfc.nasa.gov/realtime/ . It was collected by
MODIS on the Aqua satellite on April 6, 2004.
http://seawifs.gsfc.nasa.gov/staff/norman/modis/MODIS.DeadSea.6Apr2004.250m.jpgOcean color bands (for MODIS or SeaWiFS) are only available at 1 kilometer
resolution, however. Also, the user would need to perform some sort of regionally
tuned processing because of the issues you mention. It would be inappropriate, for
instance, to rely on the chlorophyll concentrations produced by this project's
globally-tuned algorithms.
Norman