Prolonged air contact with surface gives air {air mass}| same temperature and humidity as surface. Air masses {tropical mass} over Sahara Desert are warm and dry. Tropical masses in tropics are warm and wet. Air masses {polar mass} over plains of Canada or Siberia are cold and dry. Cold air masses make high pressure. High-pressure air masses can stay offshore, blocking east-west wind flow.
Physical Sciences>Earth Science>Atmosphere>Weather
5-Earth Science-Atmosphere-Weather
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Date Modified: 2022.0224