Ice thickness variability in the Arctic Ocean between 1954-1990, results from a coupled ocean-ice-atmosphere column model

The interannual variation of the Arctic Ocean ice thickness during the period 1954-1990 is investigated by using a coupled ocean-ice-atmosphere column model. The model is forced by poleward energy flux in the atmosphere from NCEP/NCAR reanalysis data, ice export from satellite observations, cloudiness, and precipitation observed at the Russian North Pole drift stations. During the period 1977-1986 the model ice thickness decreased from 3.2 m to 2.0 m. The decrease is mainly caused by extra melting due to larger poleward energy flux in summer, and reduced ice growth in winter as a result of both increased cloudiness and energy flux. Precipitation and ice export are of less importance. A sensitivity study shows that the NCEP/NCAR data is accurate enough with respect to stochastic errors to ensure that the thinning is not caused by forcing errors. It is also shown that the poleward energy flux during summer is the dominant factor for regulating the ice thickness. The column model gives different results compared to other model studies using 2D ice models, especially towards the end of the period. Possible reasons for this disparity are discussed.