Reproduction of the large-scale state of water and sea ice in the Arctic Ocean in 1948–2002: Part I. Numerical model

Abstract

This paper completes a series of studies conducted with a numerical model of low spatial resolution for the area of the North Atlantic and Arctic Ocean north of 65° N without including Hudson Bay to reproduce the monthly mean state in 1948–2002. The paper gives a detailed description of the physical formulation of the problem, the approximations and parametrizations that were employed, and the parameters of atmospheric and oceanic external forcings. Generally, the author follows the requirements of the protocol of the Arctic Ocean Model Intercomparison Project (AOMIP). The paper analyzes the main monthly mean characteristics: ice thickness, ice-drift velocity, snow thickness, velocity of currents, and temperature and salinity, which were derived as multiyear averages over 1958–2002. A good reproduction of the following sea-ice characteristics is noted: ice thickness, propagation area, ice concentration, and drift velocity. For example, the annual mean ice-drift velocity is about 3.33 cm/s, which is consistent with the data obtained from drifting buoys, which yield an annual mean ice-drift velocity of 3.65 cm/s. At the same time, there are problems of reproducing the observed snow-thickness distribution. The use of parametrizations of horizontal turbulence of the Neptune-Effect type and eddy transfer for a scalar makes it possible to conserve the cyclonic circulation in the Atlantic water layer although the low spatial resolution gives no way of explicitly reproducing the narrow topographic jet. In conclusion, we briefly discuss the main unsolved problems and, primarily, the problem of reproducing the freshwater content. The model and further versions of it will be used in the European Commission project DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-Term Environmental Studies) to assess the sensitivity of the Arctic Ocean to the parameters of external forcing and to evaluate the role of tides in the formation of the Arctic Ocean’s climate.