A43E-0330
Comparison of Eight Years Total Column Ozone Retrievals form Brewer and Dobson Spectrophotometers in South Pole

Thursday, 17 December 2015
Poster Hall (Moscone South)
Omid Moeini1, Keh-Harng Feng1, Charles T McElroy1, Robert D Evans2 and Irina V Petropavlovskikh3, (1)York University, Toronto, ON, Canada, (2)Earth System Research Laboratory - NOAA, Global Monitoring Division, Boulder, CO, United States, (3)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States
Abstract:
Total column ozone measured by a Brewer Mark III spectrophotometer (#85) from 2008 to 2015 is compared to the data obtained from three different Dobson spectrophotometers (#80, #82 and #42) that have been operating in parallel with the Brewer at the Amundsen-Scott Station near the South Pole. Measurements are made using either direct sunlight or light from the moon (up to 2 weeks per month). The result of the comparison was used to assess the performance of the two instrument types and determine the stability of the measurement systems.

Both instruments suffer from non-linearity due to the presence of instrumental stray light caused by the out-off-band radiations scattered from the optics within the instrument. Stray light results in an underestimated ozone column at large ozone path lengths. Since measurements made at the location of the station (Latitude 89.99o, Longitude -24.80o) have solar zenith angles of 66.5 degrees or greater, the issue of stray light is a particular concern.

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