Proposed standardized definitions for vertical resolution and uncertainty in the NDACC lidar ozone and temperature algorithms – Part 2: Ozone DIAL uncertainty budget

Abstract

Abstract. A standardized approach for the definition, propagation and reporting of uncertainty in the ozone differential absorption lidar data products contributing to the Network for the Detection for Atmospheric Composition Change (NDACC) database is proposed. One essential aspect of the proposed approach is the propagation in parallel of all independent uncertainty components through the data processing chain before they are combined together to form the ozone combined standard uncertainty. The independent uncertainty components contributing to the overall budget include random noise associated with signal detection, uncertainty due to saturation correction, background noise extraction, the absorption cross-sections of ozone, NO2, SO2, and O2, the molecular extinction cross-sections, and the number densities of the air, NO2, and SO2. The expression of the individual uncertainty components and their step-by-step propagation through the ozone DIAL processing chain are thoroughly estimated. All sources of uncertainty except detection noise imply correlated terms in the vertical dimension, which requires knowledge of the covariance matrix when the lidar signal is vertically filtered. In addition, the covariance terms must be taken into account if the same detection hardware is shared by the lidar receiver channels at the absorbed and non-absorbed wavelengths. The ozone uncertainty budget is presented as much as possible in generic form (i.e., as a function of instrument performance and wavelength) so that all NDACC ozone DIAL investigators across the network can estimate, for their own instrument and in a straightforward manner, the expected impact of each reviewed uncertainty component. In addition, two actual examples of full uncertainty budget are provided, using measurements from the tropospheric ozone DIAL located at the JPL-Table Mountain Facility, California, and measurements from the JPL stratospheric ozone DIAL located at Mauna Loa Observatory, Hawaii.

A method for quantifying near range point source induced O3 titration events using Co-located Lidar and Pandora measurements

“…Raws signals both analog and photon counting are background subtracted and range-squared before applying a single-pass Savitzky-Golay filter (Leblanc et al, 2016b, and references therein); the more points used in the filter, the lower the resolution. Analog and photon-count channels are merged together to provide a single optimized profile for range and signal-to-noise performance (Leblanc et al, 2016b;Zhang et al, 2014;Newsom et al, 2009). Ozone cross sections along with pressure and temperature information are used as part of the filter process to extract ozone mixing ratio as a function of altitude.…”

Combined UV and IR ozone profile retrieval from TROPOMI and CrIS measurements

“…For Table Mountain, where ozone profiles during daytime and nighttime are available, the vertical range is increased up to 25 km during the night. The overall precision reaches from 5 % in the free troposphere to up to 15 % above 20 km (Leblanc et al, 2016).…”

Tropospheric and stratospheric ozone profiles during the 2019 TROpomi vaLIdation eXperiment (TROLIX-19)

“…For all other times during the TROPOZ operation, the data have been averaged to 10 min, which is suitable under most clear sky conditions to retrieve ozone information within the entire troposphere. A brief description and community standardized definitions of the uncertainty budget of the lidar measurements presented in this paper can be found in Sullivan et al (2014), Leblanc et al (2016Leblanc et al ( , 2018. The maximum statistical uncertainties for the two GSFC lidars vary from night to night depending on atmospheric conditions and laser power fluctuations.…”