Greenland and the Northern Hemispheric winter circulation

The impact of Greenland’s orography on the general circulation is investigated. Two 10 year simulations are conducted using the NCAR Community Climate Model (CCM3), run at T106 horizontal resolution; A control simulation and a simulation where Greenland’s orography is set to sea level. A comparison of the two simulations indicates that Greenland has a significant impact on the general circulation at middle and high latitudes on the Northern Hemisphere. The storm tracks over the North Atlantic are shifted northward in the presence of the mountain. The difference fields of sea level pressure, geopotential height and temperature have a wave-like pattern that extends around the earth. The first wave of this pattern is linked to the blocking and diversion of cold low level air masses west of Greenland. The result is a trough on the upstream side of the mountain. Thus, Greenland’s impact on the general circulation is fundamentally different from the impact of the Rocky Mountains and the Tibetan Plateau where a trough is created downstream of the mountains.