Characterization of ozone profiles derived from Aura TES and OMI radiances

Abstract

We present satellite based ozone profile estimates derived by combining radiances measured at thermal infrared (TIR) wavelengths from the Aura Tropospheric Emission Spectrometer (TES) and ultraviolet (UV) wavelengths measured by the Aura Ozone Monitoring Instrument (OMI). The advantage of using these combined wavelengths and instruments for sounding ozone over either instrument alone is improved sensitivity near the surface as well as the capability to consistently resolve the lower troposphere, upper troposphere, and lower stratosphere for scenes with varying geophysical states. For example, the vertical resolution of ozone estimates from either TES or OMI varies strongly by surface albedo and temperature. Typically, TES provides 1.6 degrees of freedom for signal (DOFS) and OMI provides less than 1 DOFS in the troposphere. The combination provides 2 DOFS in the troposphere with approximately 0.4 DOFS for near surface ozone (surface to 700 hPa). We evaluated these new ozone profile estimates with ozonesonde measurements and found that calculated errors for the joint TES and OMI ozone profile estimates are in reasonable agreement with actual errors as derived by the root-mean-square (RMS) difference between the ozonesondes and the joint TES/OMI ozone estimates. We also used a common a priori profile in the retrievals in order to evaluate the capability of different retrieval approaches on capturing near-surface ozone variability. We found that the vertical resolution of the joint TES/OMI ozone profile estimates shows significant improvements on quantifying variations in near-surface ozone with RMS differences of 49.9% and correlation coefficient of <i>R</i> = 0.58 for the TES/OMI near-surface estimates as compared to 67.2% RMS difference and <i>R</i> = 0.33 for TES and 115.8% RMS difference and <i>R</i> = 0.09 for OMI. This comparison removes the impacts of using the climatological a priori in the retrievals. However, it results in artificially large sonde/retrieval differences. The TES/OMI ozone profiles from the production code of joint retrievals will use climatological a priori and therefore will have more realistic ozone estimates than those from using a common a priori volume mixing ratio profile

Constraints on methane emissions in North America from future geostationary remote-sensing measurements

“…For the multi-spectral retrievals, a vertically resolved error covariance matrix is used. The error covariance for the multi-spectral retrieval is derived along with the averaging kernel using the approach described in Fu et al (2013) and references therein. The Jacobians for CH 4 and other trace gases affecting the observed radiances, from the near-IR and thermal IR, are combined along with noise estimates for both spectral regions that are based on TES and GOSAT radiances.…”

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

“…Ozone in the TIR has already been measured by several LEOs with sensitivity in the mid-troposphere, e.g. the Infrared Atmospheric Sounding Interferometer (IASI), see, for example Clerbaux et al (2009), sampling the lowermost troposphere in the TIR+UV combining both IASI (TIR) and GOME-2 (UV) (Cuesta et al, 2013) or both TES (Tropospheric Emission Spectrometer) and OMI (Ozone Monitoring Instrument) (Fu et al, 2013). The advantage of measuring in the VIS is to have ozone information at the Earth's surface for monitoring the AQ.…”

“…Liu et al, 2005), and instrument combinations thereof (e.g. Landgraf and Hasekamp, 2007;Worden et al, 2007;Natraj et al, 2011;Cuesta et al, 2013;Fu et al, 2013). In this paper, we build on the study of Claeyman et al (2011b) and consider the capabilities of the proposed MAGEAQ (Monitoring the Atmosphere from Geostationary orbit for European Air Quality) GEO mission that aimed to use thermal infrared (TIR) and visible (VIS) instruments onboard the same satellite (Peuch et al, 2009) to monitor ozone in the lowermost troposphere (surface and the 0-1 km height region) for AQ purposes.…”

Importance of interpolation and coincidence errors in data fusion

“…We analyze this problem 5 using simulated measurements of ozone profiles obtained in the ultraviolet and in the thermal infrared in the framework of the Sentinel 4 (S4) mission (ESA, 2017) of the Copernicus programme (http://www.copernicus.eu/main/sentinels). The advantages to use a multispectral approach for observing the ozone profile from space by synergism of atmospheric radiances in the thermal infrared and in the ultraviolet has been studied by Landgraf and Hasekamp (2007), Worden et al (2007), Fu et al (2013), Natraj et al, (2011), Cuesta et al (2013 and Costantino et al (2017). 10…”