Categorization of cold period weather types in Greece on the basis of the photointerpretation of NOAA/AVHRR imagery

The Advanced Very High Resolution Radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration (NOAA) satellites may be used to detect and monitor prevailing synoptic weather systems and to describe the state of the atmosphere with very good spatial and temporal resolution. In this study, the synoptic weather types which are responsible for severe cold and rainy weather conditions in Greece during the cold period of the year were examined with the use of NOAA/AVHRR satellite images in conjunction with weather charts. An attempt was made to develop a classification scheme for these synoptic weather types on the basis of their tracks and cloud patterns inferred by satellite images. Forty-two visible and thermal infrared AVHRR images were interpreted with emphasis on the analysis of cloud patterns formed in synoptic weather systems in order to relate cloud features in every image to physical processes. Synoptic maps (12:00 UTC) from the European Centre for Medium-Range Weather Forecasts (ECMWF) were used as auxiliary data. The final product was a categorization of the cloud features formed by each of the four prevailing weather types in the area of Greece for the winter rainy period (three Depressional Weather Types and one Mixed Weather Type).