SPECTROSCOPIC STUDY OF TWILIGHT INTENSITY IN THE RED REGION OVER AHMEDABAD (23-DEGREES-N) AFTER THE MT-PINATUBO ERUPTION

The behaviour of stratospheric aerosols formed after the eruption of M t. Pinatubo has been studied by a simple and inexpensive ground based technique. The technique involves measurements of the scattered sky ra diation intensity during twilight in the near IR region. Several inter esting results have been obtained. Sometimes a single aerosol layer, a nd sometimes multiple aerosol layers, have been seen. The bottom heigh t of the single layer has been found to vary from about 18 km to 25 km . The thickness of this layer also changes from about 6 km to 12 km. T he magnitude of the aerosol feature became a maximum towards the end o f December 1991 and at the beginning of January 1992, and decreased th ereafter. (C) 1997 Elsevier Science Ltd.