Wave-like ozone movements

The wave-like character of the total ozone variations is examined from the Aral Sea and Karaganda observatories in Middle Asia, and from Tromsa and Mu rmansk in the Arctic. The waves have a period of 10-20 days and an amplitud e of about 20-50 DU. They are seen practically every year when the ozone da ta do not contain too many gaps. In Middle Asia waves with the same periods are found in geopotential height and tropopause pressure variations. The o zone waves are caused by dynamic meteorological disturbances near the tropo pause, The passing of a wave crest in the pressure field causes the converg ence of ozone poor air under the tropopause and the divergence of ozone ric h air above the tropopause giving rise to a total ozone content decrease. T he passing of a wave trough stimulates the opposite process. By crosscorrel ation analysis the wave-like movement was determined as eastward for both p airs of stations with a velocity of 11 - 15 degrees/day. (C) 2000 Elsevier Science Ltd. All rights reserved.