Comparison of coupled global ocean-sea ice model simulations with different grid-resolutions

Abstract

Arctic sea ice simulations are compared based on the coupled global ocean-sea ice models (GFDL MOM4p1-SIS) with different grid-resolutions. Horizontal grid intervals of the two models are 1 degree by 1 degree and 0.5 degree by 0.5 degree, respectively, except a higher resolution in the tropical region in both models. As a surface thermal and hydrological forcing CORE-NYF dataset (Large and Yeager, 2004) was applied. Global 1 degree model (GCM-1) was integrated for 1000 years and global 0.5 degree model (GCM-0.5) for 300 years. GCM-1 shows an increase of Arctic sea ice area in the initial warming-up stage of 40-50 years with the maximum of 10.95x1012 ㎡, while GCM-0.5 shows a more rapid increase with the larger maximum value (11.90x1012 ㎡). The time scale for reaching the quasi-steady state in the seasonal distributions of sea ice thickness and concentration are about order of 100 years in both the GCM-1 and GCM-0.5. Compared with the observation (recent 30 years average of HadISST) the two models show similar patterns in the distributions of sea ice concentration except several local areas. In March both GCM-1 and GCM-0.5 simulate higher concentrations of sea ice than the observation in the Bering Sea east of the Kamchatka Peninsula, eastern part of the Okhotsk Sea, east of the Greenland, and also in the Barents Sea and the Labrador Sea, which means that the present two GCMs simulate larger sea ice extent in the Norespectively, except a higher resolution in the tropical region in both models. As a surface thermal and hydrological forcing CORE-NYF dataset (Large and Yeager, 2004) was applied. Global 1 degree model (GCM-1) was integrated for 1000 years and global 0.5 degree model (GCM-0.5) for 300 years. GCM-1 shows an increase of Arctic sea ice area in the initial warming-up stage of 40-50 years with the maximum of 10.95x1012 ㎡, while GCM-0.5 shows a more rapid increase with the larger maximum value (11.90x1012 ㎡). The time scale for reaching the quasi-steady state in the seasonal distributions of sea ice thickness and concentration are about order of 100 years in both the GCM-1 and GCM-0.5. Compared with the observation (recent 30 years average of HadISST) the two models show similar patterns in the distributions of sea ice concentration except several local areas. In March both GCM-1 and GCM-0.5 simulate higher concentrations of sea ice than the observation in the Bering Sea east of the Kamchatka Peninsula, eastern part of the Okhotsk Sea, east of the Greenland, and also in the Barents Sea and the Labrador Sea, which means that the present two GCMs simulate larger sea ice extent in the Nor