Aerosol impacts on scene contrast

Atmospheric aerosols scatter and absorb radiation, which impacts greatly on the amount of solar radiation reaching a surface, thereby changing the amount of radiation available for heating up a target. The presence of aerosols also reduces the amount of target radiation that reaches the sensor, and causes a part of the solar radiation to be scattered into the sensor. In terms of sensor performance this results in reduced detection, identification and recognition ranges (DRI) due to degraded image quality and reduced contrast between target and background. Standard aerosol models available in, e.g. Modtran, assess these effects, but do not properly account for the spatiotemporal variations of the aerosol concentration and composition. This can be especially challenging in the (offshore) coastal zone. Experimental and numerical tools to mitigate the shortcomings of the standard models are now available, in the Angstrom coefficient and aerosol transport models coupled to numerical weather prediction codes (NWP).