1University of Maryland Baltimore County UMBC-JCET Joint Center for Earth Systems and Technology and NASA Goddard Space Flight Center Greenbelt, Greenbelt, MD 20771, USA
2NOAA Earth System Research Laboratory, 325 Broadway, Boulder, CO 80305, USA
3Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder 80309, USA
4Goddard Earth Sciences Technology & Research (GESTAR) Columbia, Columbia, MD 21046, USA
Received: 20 Jan 2015 – Discussion started: 20 Mar 2015
Abstract. A comparison of retrieved total column ozone (TCO) amounts between the Pandora #34 spectrometer system and the Dobson #061 spectrophotometer from direct-sun observations was performed on the roof of the Boulder, Colorado, NOAA building. This paper, part of an ongoing study, covers a 1-year period starting on 17 December 2013. Both the standard Dobson and Pandora TCO retrievals required a correction, TCOcorr = TCO (1 + C(T)), using a monthly varying effective ozone temperature, TE, derived from a temperature and ozone profile climatology. The correction is used to remove a seasonal difference caused by using a fixed temperature in each retrieval algorithm. The respective corrections C(TE) are CPandora = 0.00333(TE-225) and CDobson = -0.0013(TE-226.7) per degree K. After the applied corrections removed most of the seasonal retrieval dependence on ozone temperature, TCO agreement between the instruments was within 1 % for clear-sky conditions. For clear-sky observations, both co-located instruments tracked the day-to-day variation in total column ozone amounts with a correlation of r2 = 0.97 and an average offset of 1.1 ± 5.8 DU. In addition, the Pandora TCO data showed 0.3 % annual average agreement with satellite overpass data from AURA/OMI (Ozone Monitoring Instrument) and 1 % annual average offset with Suomi-NPP/OMPS (Suomi National Polar-orbiting Partnership, the nadir viewing portion of the Ozone Mapper Profiler Suite).
Revised: 02 Jul 2015 – Accepted: 07 Jul 2015 – Published: 24 Aug 2015
Herman, J., Evans, R., Cede, A., Abuhassan, N., Petropavlovskikh, I., and McConville, G.: Comparison of ozone retrievals from the Pandora spectrometer system and Dobson spectrophotometer in Boulder, Colorado, Atmos. Meas. Tech., 8, 3407-3418, doi:10.5194/amt-8-3407-2015, 2015.