Validating NPP Ocean Color with Optical Closure using HydroLight-BRDF

HydroLight-BRDF is an extension of the well known application HydroLight created by Dr. Curtis A. Mobley and Sequoia Scientific Inc. This tool is used by Northrop Grumman to create valid models of the ocean using a wide variety of built-in validation data. The product of the application provides a BRDF of the water-leaving radiance which can then be coupled to any atmospheric Radiative Transfer Model to ascertain predicted Top-of-the-atmosphere radiances. Since the BRDF can also be used in conjunction with the surface irradiance, it can be utilized in validating the performance of the retrieval of ocean color from VIIRS on NPP. Using this tool for Optical closure, one can compare results from any two sensors, satellites, airborne and in-situ instruments for validation. This paper describes the processes, benefits and methods used in adapting this simulation tool for product validation.