Assessment of Circulation Weather Types around Svalbard and their Impact on the Ny-Ålesund Atmospheric Column

Meteorological conditions in Ny-Ålesund (NYA), Svalbard, are influenced by the large-scale atmospheric circulation patterns, such as southerly or northerly advection as well as cyclonic or anticyclonic circulation regimes. We classify the prevailing synoptic circulation into a number of recurrent circulation weather types (CWT), to quantify their influence on local atmospheric column properties and their contribution to the observed Arctic amplification in NYA.

We construct a 45+ year CWT catalogue for NYA based on hourly 850 hPa geopotential fields from ERA5 reanalysis data using a modified Jenkinson-Collison classification. This catalogue is combined with long-term observational records from the AWIPEV radiosonde programme and the Baseline Surface Radiation Network (BSRN) in NYA.

Composite analyses reveal a pronounced directional and seasonal dependence of near-surface temperature, longwave net radiation and humidity on the prevailing CWT. Trends in CWT frequency indicate an increased occurrence of southerly advection in winter and autumn, which contributes to the enhanced warming in NYA in these seasons. Conversely, a higher frequency of northerly CWT in spring is associated with the observed cooling, particularly in March.

Consequently, CWT analysis and their long-term trends quantify the influence of synoptic circulation to atmospheric conditions in NYA and contribute to the explanation of the observed seasonal changes in the Svalbard region.

 

This work was supported by the DFG funded Transregio-project TRR 172 “Arctic Amplification (AC)³“.