Abstract:

An annual cycle of atmospheric variations for 1989 in the Arctic had been simulated with WRF model with extension for polar climate. A severe cold bias was found around cold center in surface air temperature over the Arctic Ocean compared with results from ERA-Interim reanalysis. Four successive numerical experiments have been carried out to find out the reasons. The results show that, sea ice albedo scheme has the biggest influence in summer and the effect of cloud microphysics scheme is significant in both summer and winter. The effect of phase transition between ice and water has the biggest influence over the region near the sea ice edge in summer and gives little contribution to the improvement of the severe cold bias. The original rude consideration of albedo parameterization in surface process scheme is the main reason for the large simulated cold bias of cold center in summer. With another land surface scheme other than the one in control run, the cold biases of simulated surface air temperature over the Arctic Ocean is reduced greatly with a value up to 10 K at most, implying that land surface scheme is critical for polar climate simulation.

Key words: polar climate, numerical simulation, WRF