Spatial Synoptic Classification system
Based upon the Bergeron air mass classification scheme is the Spatial Synoptic Classification system, or SSC. There are six categories within the SSC scheme: Dry Polar, Dry Moderate, Dry Tropical, Moist Polar, Moist Moderate, and Moist Tropical.
The SSC was originally created in the 1950s to improve weather forecasting, and by the 1970s was a widely accepted classification system for climatologists. The initial iteration of the SSC had a major limitation: it could only classify weather types during summer and winter season.