Climate-related trends and meteorological conditions in the Porsanger fjord, Norway

Abstract

Summary Climate-related trends and meteorological conditions in the Porsanger fjord, in the vicinity of the Barents Sea, have been analyzed. Meteorological data include wind speed and direction, air temperature (AT) and precipitation from Era-Interim reanalysis (1986–2015) as well as local observations (2006–2015) from Honningsvaag and Lakselv. Statistically significant trends in annual AT means are 0.0485°C year−1 near the fjord mouth and 0.0416°C year−1 near the fjord head. Wind speed and precipitation data do not reveal any definite trends. Statistical analysis confirms the significant spatial variability of meteorological conditions in the fjord. For example, there are large differences in the annual AT cycle, with respective monthly means for January and July of −8.4 and 12.6°C at Lakselv (fjord head) and −2.5 and 10.1°C at Honningsvaag (fjord mouth). Strong wind events (>12 m s−1) are more frequent at Honningsvaag than at Lakselv. The annual cycle is characterized by stronger winds in winter and seasonality of wind direction. At Lakselv, the dominant wind directions in summer are: N, NNW and S and in winter: S and SSE. At Honningsvaag, the wind directions in summer present strong variability, no fixed pattern being pronounced, whilst the dominant sectors in winter are: S and SSW. Daily cycles in AT and wind speed are also observed. Precipitation at a given location can change by about 30% year-on-year and varies spatially. Estimates of terrigenous water discharge (derived from the E-HYPE model) reveal a seasonal cycle with the maximum discharge in late spring/early summer.