Arctic Air Masses

Arctic Air Masses

 

air masses forming over the arctic. They are characterized by low temperatures and low humidity and are very clear. As a result of cyclone activity, arctic air masses may be displaced to lower latitudes, where they cause a drop in the temperature. Intrusions of arctic air masses are most frequently observed in the region between Iceland and Greenland, over the Kara Sea, the East Siberian Sea, and in the area of Alaska. In their movement to the south in Eurasia, arctic air masses may reach as far as the Mediterranean, the plains of Middle Asia, and Siberia, but they are contained by mountain chains (the Alps, the Caucasus Mountains, and others); in North America, they may advance unhindered as far as Florida. The properties of arctic air masses change when they are displaced to lower latitudes depending on the state of the surface features. The ground temperatures in fresh intrusions of arctic air masses in winter are higher than in stable continental anticyclones; however, with time the temperatures drop under the influence of the strongly chilled surface of the continent. Spring incursions of arctic air masses over the warmed surface of a land mass are accompanied by the formation of convective clouds and precipitation in the form of rain. In the summer, arctic air masses are quickly warmed over the continents, and their relative humidity decreases quickly. Frequent recurrence of arctic intrusions in the steppe zone leads to droughts.

S. P. KHROMOV

References in periodicals archive ?
A sharp cold snap in Kyrgyzstan is due to the Arctic air masses, Kyrgyzhydromet reported on January 24.
Other factors that often play a role in the winter weather include the Arctic Oscillation, which influences the number of arctic air masses that penetrate into the South and create nor'easters on the East Coast, and the Madden-Julian Oscillation, which can affect the number of heavy rain events in the Pacific Northwest.
Because chinooks occur in winter, they often displace arctic air masses just east of the Rockies, causing dramatic warming episodes that may quickly raise temperatures by 30 or 40 degrees.
Since the polar vortex normally retains the cold Arctic air masses up above the Arctic Circle, its weakening allows the cold air to invade lower latitudes.
Spring is trying to come, but cold, arctic air masses keep finding their way out of Canada.
These arctic air masses can be persistent, so a shadow is a clue that it's going to be cold for a while.
Since this region of the southwestern Yukon is located at the convergence of the coastal and Arctic air masses, climate change could lead to increased variability in winter temperatures and precipitation (Northern Climate ExChange, 2006).
Todd Crawford, "While the late January pattern will be characterized by more frequent visits from Arctic air masses, our objective model guidance suggests that the recent pattern flip to a northeastern Pacific ridge may be temporary, possibly driven by the recent strong pulse of the Madden-Julian Oscillation.