Reply to comment on "Retrieval of aerosol properties over the ocean using multispectral and multiangle photopolarimetric measurements from the Research Scanning Polarimeter"

In a recent paper [Chowdhary et al., 2001; hereafter CCM&T], we showed that the inclusion of polarimetric information provides superior results in the retrieval of aerosol properties to those obtained using only the intensity. Having previously shown detailed theoretical analyses of the superiority of well calibrated polarimetric remote sensing to intensity only remote sensing of aerosols [Mishchenko and Travis 1997a, b], the purpose of CCM&T was to demonstrate that such analyses carry over to actual measurements. The excellent agreement between upward looking sunphotometer measurements of spectral optical depth and those inferred from the Research Scanning Polarimeter (RSP) measurements (Fig. 2 of CCM&T) provides a first demonstration of the validity of the previous theoretical analyses in a natural setting. In their commentary [this issue] Martonchik, Kahn, Diner and West (hereafter MKD&W) discuss the complementarity of polarimetric remote sensing and the type of measurements made by MISR. We would concur with MKD&W that it is "essential to validate retrieved spectral refractive indices and particle size distributions" that are possible with polarimetric measurements, just as it is essential to evaluate and validate the true capabilities of MISR. We look forward to such evaluation and analysis of RSP measurements in future co-ordinated field campaigns. In the following we discuss why we believe the set of measurements and the analysis presented in CCM&T provides a fair, although not perfect, representation of the capabilities of MISR and discuss the other issues raised by MKD&W.