The added value of a visible channel to a geostationary thermal infrared instrument to monitor ozone for air quality

Abstract

Abstract. Ozone is a tropospheric pollutant and plays a key role in determining the air quality that affects human wellbeing. In this study, we compare the capability of two hypothetical grating spectrometers onboard a geostationary (GEO) satellite to sense ozone in the lowermost troposphere (surface and the 0–1 km column). We consider one week during the Northern Hemisphere summer simulated by a chemical transport model, and use the two GEO instrument configurations to measure ozone concentration (1) in the thermal infrared (GEO TIR) and (2) in the thermal infrared and the visible (GEO TIR+VIS). These configurations are compared against each other, and also against an ozone reference state and a priori ozone information. In a first approximation, we assume clear sky conditions neglecting the influence of aerosols and clouds. A number of statistical tests are used to assess the performance of the two GEO configurations. We consider land and sea pixels and whether differences between the two in the performance are significant. Results show that the GEO TIR+VIS configuration provides a better representation of the ozone field both for surface ozone and the 0–1 km ozone column during the daytime especially over land.

The Ozone Monitoring Instrument: overview of 14 years in space

“…These products, as shown in Fig. 15, have been developed using either OMI measurements alone or in conjunction with other satellite measurements to improve sensitivity to near-surface ozone (e.g., Bowman, 2013;Cuesta et al, 2013;Hache et al, 2014) as summarized below. They have been used in tropospheric research (e.g., Sauvage et al, 2007;Ziemke et al, 2010;Cooper et al, 2014), for example to show evidence of decadal increases or trends in global tropospheric ozone, El Nino events during Aura (e.g., Chandra et al, 2009;Blunden and Ardnt, 2016), the 1-2 month Madden-Julian oscillation , and references therein), and urban pollution (Kar et al, 2010).…”

Formaldehyde column density measurements as a suitable pathway to estimate near‐surface ozone tendencies from space

“…However, under typical midlatitude conditions, O 3 in the planetary boundary layer (PBL, the mixed layer that extends 1–3 km above Earth's surface) can contribute anywhere from 10 to 50% to the total tropospheric column, and substantial variability in upper tropospheric O 3 can make it difficult to attribute changes in the total tropospheric column to changes in PBL O 3 [ Martins et al , ; Thompson et al , ]. Model simulations have suggested that multispectral retrieval techniques have the potential to derive a lower tropospheric or boundary layer O 3 column density, but these techniques cannot be implemented by using the current constellation of air quality‐relevant satellites [ Natraj et al , ; Zoogman et al , ; Hache et al , ].…”

Data assimilation: making sense of Earth Observation

“…Several OSSEs have been performed to assess the benefit of additions to the GOS to monitor air quality at the surface and lower troposphere (between the surface and ∼6 km), notably from GEO platforms. These OSSEs have tended to focus on measurements of ozone and CO (Edwards et al, 2009;Claeyman et al, 2011;Sellitto et al, 2013;Yumimoto, 2013;Hache et al, 2014;Zoogman et al, 2014); ozone is considered because it is a key lower tropospheric pollutant, and CO because it provides information on sources of pollution and transport processes in the lower troposphere. Other OSSEs for air quality have considered measurements of PM, another key tropospheric pollutant (Timmermans et al, 2009a,b).…”