The mesoscale atmospheric model WRF is used over three Svalbard glaciers. The simulations are done with a setup of the model corresponding to the state-of-the-art model for polar conditions, Polar WRF, and it was validated using surface observations. The ERA-Interim reanalysis was used for boundary forcing and the model was used with three nested smaller domains, 24 and 8 km, and 2.7 km resolution. The model was used for a two-year period as well as for a more detailed study using 3 summer and winter months. In addition sensitivity tests using finer horizontal and vertical resolution in the boundary layer and using different physics schemes were performed. Temperature and incoming short- and long-wave radiation were skillfully simulated, with lower agreement between measured and modelled wind speed. Increased vertical resolution improved the frequency distributions of the wind speed and the temperature. The choice of different physics schemes only slightly changed the model results. The polar-optimized microphysics scheme outperformed a slightly simpler microphysics scheme, but the two alternative and more sophisticated PBL schemes improved the model score. A PBL scheme developed for very stable stratifications (QNSE) proved to be better in the winter.

A 20-year dataset of weekly precipitation observations in Ny-Alesund, Svalbard, was analysed to assess atmospheric wet deposition of nitrogen. Mean annual total nitrogen deposition was 74 mg N/(m(2) yr) but exhibited large interannual variability and was dominated by highly episodic "strong" events, probably caused by rapid transport from European sources. The majority (90%) of precipitation samples were defined as "weak" (< 2mgN/m(2)) and contributed an annual baseline of similar to 17 mg N/(m(2) yr), whereas 10% of precipitation samples were defined as "strong" (>2mgN/m(2)) and additionally contributed up to 225 mg N/(m(2) yr). Nitrate deposition largely occurred in samples within the solid-precipitation season (16 September-2 June), and ammonium deposition occurred equally in both solid and liquid seasons. Trends of reactive nitrogen emissions from Europe are uncertain, and increasing cyclonic activity over the North Atlantic caused by a changing climate might lead to more strong deposition events in Svalbard.