Spectroscopic study of twilight intensity in the red region over Ahmedabad (23 °N) after the Mt. Pinatubo eruption
Abstract The behaviour of stratospheric aerosols formed after the eruption of Mt. Pinatubo has been studied by a simple and inexpensive ground-based technique. The technique involves measurements of the scattered sky radiation intensity during twilight in the near IR region. Several interesting results have been obtained. Sometimes a single aerosol layer, and sometimes multiple aerosol layers, have been seen. The bottom height 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. The magnitude of the aerosol feature became a maximum towards the end of December 1991 and at the beginning of January 1992, and decreased thereafter.
The database developed for the meteorological radar of Spino d'Adda in north Italy is presented as an example of automation in this field. The system has facilities for collection, retrieval, and modeling of radar images of rain as well as their components (individual patterns) and descriptors. The SPINO80-GRM software applies techniques of image analysis to radar rain data in order to identify and characterize the required data items (rain patterns) and then organizes them into a hierarchical, relational database. The component retrieval is based on a free combination of its attributes: some statistical investigations are also possible. >