Column optical depth retrieval using surface reflectivity from GLAS

Surface reflectivity data from the satellite lidar Geoscience Laser Altimeter System (GLAS) have provided a new means to retrieve total column optical depth at 1064 nm. When the detailed surface wave-form over ocean is available using the altimetry channel, a comparison can be made to model results predicting ocean reflectivity as a function of sea state when no particulate atmospheric loading is present (pristine atmosphere). The resultant optical depth calculations are then compared to 1) results from an integration of the GLAS 1064 atmospheric signal, 2) AERONET island sites, and 3) Cloud Physics Lidar (CPL) under-flights. Example case studies and results from the GLAS Laser 2A period (September - November 2003) are documented.