Abstract:

The modeled atmospheric circulations around the Arctic region during the period of 17-19, July, 2005 and 20-24, December, 2007 with the Polar MM5 are presented, respectively. The numerical analyses indicated there were two fluctuation modes existed over the Pole both in summer and winter season. There was an Iceland low additionally in summer simulation instead of a high pressure system existed around the Iceland in winter. And this high pressure system extended to the Greenland. Two upper-air observations from the Arctic are used to verify the simulated atmospheric state for the variables of temperature and wind. The model is found to reproduce the observed atmospheric state with smaller biases and larger correlation coefficients for the variables considered. Moreover, the mesoscale model reflected evident diurnal cycles for the temperature at height of 2m, sensible heat and latent heat fluxes at station Barrow in July; and the inversed temperature at Barrow was also simulated by the model, effectively. In winter, T2m and turbulent fluxes took on the characteristics of anti-phase state. The Arctic landuse was the heat and moisture source of the atmosphere, although the amplitude of fluxes in winter was far less than the state of summer.

Key words: Numerical simulation