11th Conference on Atmospheric Radiation and the 11th Conference on Cloud Physics

Monday, 3 June 2002
Airborne retrievals of aerosol burden and microphysical properties using polarimetric measurements during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment.
Brian Cairns, Columbia University, New York, NY; and J. Chowdhary, M. I. Mishchenko, J. Redemann, P. B. Russell, P. V. Hobbs, W. L. Smith Jr., T. P. Charlock, K. Rutledge, J. V. Martins, L. A. Remer, B. Holben, B. Schmidt, E. E. Russell, J. M. Livingston, and R. Kahn
The Research Scanning Polarimeter was operated onboard a Cessna 210 for six days during the period July 10 to July 17, 2001 at the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment. The main objectives for the RSP participation in this experiment were as follows: to characterize ocean surface BRDF and aerosol optical thickness and microphysics in the Chesapeake Lighthouse area, to evaluate MODIS aerosol and ocean surface retrievals, to test the use of glint and off-glint radiance measurements to estimate the loading of absorbing aerosols, to evaluate photo-polarimetric retrievals of aerosol properties over ocean and land surfaces and to characterize land surface BRDF and aerosol properties in the Dismal Swamp area.

To meet these objectives data were acquired at high (12,000 feet) and low (200, or 500 feet) altitude with a range of relative solar azimuths (0,45,90,135,180) which are designed to provide a characterization of BRDF for small, or inhomogeneous targets and to provide a set of observations with varying scattering geometries which allow the sensitivity of polarimetric aerosol retrievals to viewing geometry to be evaluated. The low altitude measurements were required to meet the desire of the CERES, MODIS and MISR teams for better characterization of surface/ocean BRDF properties. The high altitude measurements were designed to be comparable with the measurements made by satellite instruments for the purpose of retrieving aerosol properties, since the majority of the aerosol burden is below 12,000 feet. The participation of the AATS-14 sunphotometer mounted on the University of Washington CV-580 aircraft ensures that appropriate corrections for aerosols above 12,000 feet can be made in the comparison with satellite instruments.

In this paper we will evaluate the retrievals of aerosol optical depth using RSP data against the more direct estimates of aerosol optical depth made by the AATS-14 instrument and the AERONET sun/sky radiometers at the Chesapeake Lighthouse and Wallops Flight Facility. We will also examine the consistency of the aerosol microphysical model inferred from the RSP measurements with in situ measurements made on the CV-580 and aerosol model inferences from the AERONET sun/sky radiometer measurements. The final part of this paper will examine the use of the sunglint in constraining the single-scattering albedo inferred from remote sensing measurements.

Supplementary URL: