Atmospheric monitoring with a spectrographic imager
A compact airborne spectrographic imager (CASI) mounted on top of an attitude stabilizing platform inside a Cessna 207T was used to monitor changes in and around a lake near Berlin for 4 months in 1993-1994. The radiance was recorded at three different altitudes in the wavelength range 0.4-0.9 mu m. The observed radiances were found to be different from 1 month to another due to the variability of phytoplankton and suspended solids in the lake. The observed radiance was similar when measured at three different altitudes during the same month, whereas the effect of altitude was seen when comparing the radiances from month to month. The radiances in the month of May 1994 have been found to 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 concentration around an altitude of 1500-2000 m in the atmosphere as compared with LOWTRAN modelling.