Field experiments with aircraft sampling and lidar systems are needed to evaluate the vertical structure of the aerosol layers. The satellite data can give only partial information on the vertical distribution. The use of the water vapor band at 1.375 um or the use of oxygen absorption bands can distinguish between tropospheric and stratospheric aerosols. The only information on absorption given today by satellite data is from the absorption difference in TOMS UV channels. There is a need to develop operational methods for estimation of the aerosol absorption from satellites and from ground-based measurements.
Some experimental methods are available.
They were followed by a paper on laboratory measurements of aerosols and a discussion headed by B. Herman of the remote sensing techniques. Over the oceans, the dark and more predictable water surface reflectance allows the determination of additional aerosol parameters. Information on the aerosol model or the particle size can be obtained from most systems, and refractive index from polarization measurements. Many of the problems mentioned in regard to remote sensing over the land were discussed in the context of measurements over the ocean. The assumptions used in the inversion of the satellite data are used differently by the algorithm developers.