Extreme Atmospheric Moistening and Drying Events at Ny‐Ålesund and Their Relation to Weather Systems

Abstract Understanding the role of water vapor in Arctic amplification requires a detailed evaluation of its spatio‐temporal variability. In this work, we use an integrated water vapor (IWV) data set from a ground‐based microwave radiometer at Ny‐Ålesund, Svalbard, covering 2012–2024, to characterize temporal IWV variability. We also identify extreme atmospheric moistening and drying events based on a new detection method and relate them to large‐scale circulation patterns and airmass pathways. IWV exhibits a pronounced annual cycle with values ranging from 0.6 to 33 kg . While absolute IWV variability within a month is smaller in winter than in summer, relative variability is nearly twice as large. We identified 352 extreme moistening and 371 extreme drying events, accounting for 20% of the study period. Extreme drying occurs primarily through continuous drying, whereas extreme moistening events include a higher fraction of consecutive moistening episodes and therefore last longer. Most events occur on synoptic time scales of 1–3 days. Extreme moistening events are linked to large‐scale circulation patterns that facilitate the advection of moist airmasses toward Svalbard from southeasterly to westerly directions, which account for 52% of all moistening events. Extreme drying occurs under similar circulation patterns, but is mainly linked to a reduction in the poleward moisture transport due to an eastward shift of the prevailing pressure centers. 45% of extreme drying events follow directly after an extreme moistening event. Given the comprehensive ground‐based observations available at Ny‐Ålesund, the identified events provide a useful framework to study their impact on clouds, precipitation, radiation, and surface conditions.