Dean as seen by the naked eye
Polarized light shows clouds in their true light
To find out, Parasol trains its “third eye” on the hurricane to see how light is polarized by the different particles reflecting it. By comparing these polarization measurements with data from the MODIS satellite-borne instrument, we obtain an image that shows precisely the state of water at the top of Dean’s clouds. Although the hurricane is over the Tropics, most of the water is ice (in blue). Why? To answer that question, we need a map of “apparent pressure” at the cloud tops.