The first summertime observations of surface ozone have been made in the Pamir mountains, Central Asia. Measurements of the O 3 concentrations were performed at six valley sites situated in the Northern Pamirs at altitudes of 1500–4000m above sea level. The peculiarities of the diurnal ozone variations and the processes responsible for them are analysed. The observed diurnal variations are common to all sites, considerable and show a minimum in the night (5–10ppb) and a maximum in the daytime (up to 35ppb). The character of the diurnal cycles is typical for valley sites and is associated closely with mesoscale mechanisms – mountain‐valley circulation and local temperature regime. The low night‐time O 3 concentrations are caused by dry ozone deposition to the ground under nocturnal temperature inversions and by strong O 3 destruction in the air streaming to the valley with downslope wind. Due to the low level of anthropogenic factors in the Pamir valleys, there was no experimental evidence of the significant contribution of the local photochemical O 3 production to detected ozone concentrations. It is believed that measured daytime ozone concentrations are representative of lower tropospheric background ozone ones. The rarely studied short‐term ozone variations observed during the measuring campaign are also presented.
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Document Type: Research Article
Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria
Research Institute of Physics, University of St.Petersburg, Uljanovskaja St, 198904 Starii Petergoph, St Petersburg, Russia
Publication date: 2005-08-20
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