Daily Ozonesonde Launches at Barrow, Alaska During ARCTAS: April 1-21, 2008.

Daily ozonesondes were launched from the NOAA/ESRL Barrow Observatory (71.32N, 156.6W) from April 1- 21, 2008 during the ARCTAS spring campaign (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites). Barrow was one of 13 sites in Canada and the U.S. launching daily ozonesondes (http://croc.gsfc.nasa.gov/arcions/) to look at springtime polar transport, tropospheric ozone budgets, and provide comparisons with the Tropospheric Emission Spectrometer (TES) satellite overpasses. Total column ozone from the ozonesondes were 3.9 +/- 3.5% higher than the Barrow Dobson spectrophotometer. Prelaunch surface checks showed the ozonesonde to be consistently within +/- 0.6 ppbv of the Barrow surface Thermo Environmental Instruments (TEI) ozone monitor. The daily Barrow ozonesonde launches also provided a look at the vertical extent of an Arctic springtime surface ozone depletion event. These events are believed to be due to the springtime increase of natural halogen compounds, such as bromine and chlorine that react with ozone. The ozonesondes and the surface ozone measurements at Barrow Observatory showed one event when surface ozone dropped and remained at 3-6 ppbv for 2 days from April 15 to April 17. The low ozone extended from the surface to 210-260 meters altitude where ozone increased abruptly to 40-50 ppbv. The Chukchi Sea in the Arctic Ocean surrounds Barrow Observatory to the west, north, and east, with level tundra or permafrost to the south. However, the very low ozone was measured while the wind was coming from a relatively narrow west/northwest direction.