ATMOSPHERIC MONITORING WITH A SPECTROGRAPHIC IMAGER

A compact airborne spectrographic imager (CASI) mounted on top of an a ttitude stabilizing platform inside a Cessna 207T was used to monitor changes in and around a lake near Berlin for 4 months in 1993-1994. Th e radiance was recorded at three different altitudes in the wavelength range 0 . 4-0 . 9 mu m. The observed radiances were found to be diffe rent from 1 month to another due to the variability of phytoplankton a nd suspended solid's in the lake. The observed radiance was similar wh en measured at three different altitudes during the same month, wherea s the effect of altitude was seen when comparing the radiances from mo nth to month. The radiances in the month of May 1994 have been found t o be anomalous when comparing the radiances measured at the altitudes 1500 and 2000 m in the months of July and September 1993 and February 1994. This anomaly was found to be associated with aerosol concentrati on around an altitude of 1500-2000 m in the atmosphere as compared wit h LOWTRAN modelling.