Relevance of mountain wave cooling for the formation of polar stratospheric clouds over Scandinavia: Mesoscale dynamics and observations for January 1997

The effect of mesoscale mountain wave‐induced temperature anomalies on the formation potential of polar stratospheric clouds above northern Scandinavia is analyzed with a one‐month mesoscale model integration. The simulation results are contrasted with synoptic‐scale analyses and compared with remote sensing and in situ observations. The mesoscale mass flux of air parcels with temperatures below the threshold for cloud formation through a control volume is compared with its synoptic‐scale counterpart. A classification of the synoptic‐scale flow into periods of large and small mountain wave activity in the stratosphere is proposed. The derived classification will be used for a climatology of stratospheric mountain wave activity above Scandinavia.