How Well Do Satellites See Microscopic Plants?
UD marine scientists have been using satellites to monitor El Niño, predict the path of oil spills, and track the weed Phragmites in marshes. Now they are testing how well two new sensors can detect concentrations of microscopic plants in coastal waters. Oceanographer Xiao-Hai Yan and his research team are using Synthetic Aperture Radar (SAR) and the Sea-Viewing Wide-of-Field Sensor (SeaWiFS) to determine how much plant life exists in Delaware and New Jersey waters under different seasons, temperatures, and wind conditions. The sensors “read” the light reflected by the tiny plants’ green pigment, or chlorophyll. The amount of chlorophyll in surface waters is a key indicator of aquatic health. While the satellites can easily detect chlorophyll in the open ocean, where the water is clear, the sensors’ vision clouds near shore. The problem is the high sediment inputs from land. Yan and his team are developing new data processing techniques that may help the sensors sort out what is chloro
