On the link between the North Atlantic storm track and precipitation deuterium excess in Reykjavik

• Published in: Atmospheric Science Letters
• Main Author: Aemisegger, Franziska
• Other Authors: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Iceland; North Atlantic
• Online Access: http://dx.doi.org/10.1002/asl.865; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fasl.865; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/asl.865

This study establishes a robust process‐based dynamical link between the variability of the deuterium excess ( d ) in monthly winter precipitation in Reykjavik and the frequency of strong large‐scale ocean evaporation (SLOE) events in the subpolar North Atlantic. SLOE events are induced by cold advection in the rear of extratropical cyclones. The link between SLOE and d emerges from the fact that a substantial fraction of moisture that precipitates in Reykjavik in winter originates from SLOE events. It is shown that positive anomalies of monthly d co‐occur with positive anomalies in the frequency of SLOE events at the moisture source of Reykjavik precipitation. An intensification and a northeastwards shift of the North Atlantic storm track acts as a driver for the enhanced SLOE frequency in months with positive anomalies in d . This link also implies that in the subpolar North Atlantic, variations of d in monthly (or seasonal) precipitation reveal information about the storm track dynamics in the vicinity of Iceland. Potential implications of this finding for the interpretation of d as a proxy for the location and intensity of storm tracks are discussed.