Characterization of snowfall events in the northern Iberian Peninsula and the synoptic classification of heavy episodes (1988–2018)

• Published in: International journal of climatology 2021-01, Vol.41 (1), p.699-713
• Main Authors: Pablo Dávila, Fernando, Rivas Soriano, Luís J., Mora García, Manuel, González‐Zamora, Ángel
• Format: Article
• Language: English
• Subjects: Circulation patterns; Clustering; Dynamic height; Geopotential; Geopotential height; Heavy snowfall; Monthly distribution; northern Iberian Peninsula; Pressure; Principal components analysis; Sea level pressure; Snow; Snowfall; spatio‐temporal variations; Stations; synoptic situations; Temperature; Weather
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.6646

Historic snowfall events in the northern Iberian Peninsula recorded between 1988 and 2018 are presented and analysed. This study makes use of data collected over a course of 31 years from 105 observation stations. These weather reports describe the temporal and spatial characteristics of five Spanish provinces facing the Cantabrian Sea. The average number of snow events observed per year (as recorded by all 105 stations) was 133, where a maximum of 421 snow events was recorded in 2010 and a minimum of 24 events were recorded in 2002. In addition, the monthly distribution of snow events per day had a maximum of 630 events, (February), with a mean monthly value of 170 snow events. Other features like the distribution of snow events depending on the altitude of each province studied and the corresponding spatial patterns are also shown. Furthermore, the circulation patterns responsible for heavy snowfall in the region were also examined. To carry out this study, we considered the daily patterns at 1,200 UTC of the geopotential height at 500 and 850 hPa pressure levels and sea‐level pressure and temperature at 500 and 850 hPa, respectively. The synoptic situations were classified based on a principal component analysis coupled with a K‐means clustering, and four groups associated with heavy snowfall events were subsequently identified. The analysis of the daily synoptic patterns showed that a trough was present over the Iberian Peninsula, or close by, and a low appeared over the Mediterranean Sea or Central Europe. The low‐level flow was from the north (N) or northeast (NE) in ~85% of the cases and the temperature at 850 hPa pressure level was lower than −3°C in ~70% of the cases. Snowfall events in the northern Iberian Peninsula, (five Spanish provinces facing the Cantabrian Sea), recorded between 1988 and 2018 are analysed. Furthermore, the circulation patterns responsible for heavy snowfall in the region were studied. The analysis of the daily synoptic patterns of the geopotential height and temperature at 500 and 850 hPa pressure level and mean sea‐level pressure showed that a trough was present over the Iberian Peninsula, close to it, and a low appeared over the Mediterranean Sea or Central Europe.