Ozone profile and tropospheric ozone retrievals from the Global Ozone Monitoring Experiment: Algorithm description and validation

Abstract

[1] Ozone profiles are derived from back scattered radiance spectra in the ultraviolet (289-339 nm) measured by the Global Ozone Monitoring Experiment (GOME) using the optimal estimation technique. Tropospheric Column Ozone (TCO) is directly derived using the known tropopause to divide the stratosphere and troposphere. To optimize the retrieval and improve the fitting precision needed for tropospheric ozone, we perform extensive wavelength and radiometric calibrations and improve forward model inputs. The a priori influence of retrieved TCO is $15% in the tropics and increases to $50% at high latitudes. The dominant error terms are the smoothing errors, instrumental randomnoise errors, and systematic temperature errors. We compare our GOME retrievals with Earth-Probe Total Ozone Mapping Spectrometer (TOMS) Total column Ozone (TO), Dobson/Brewer (DB) TO, and ozonesonde TCO at 33 World Ozone and Ultraviolet Radiation Data Centre (WOUDC) stations between 71°S and 75°N during 1996-1999. The mean biases with TOMS and DB TO are within 6 DU (2%, 1 DU = 2.69 Â 10 16 molecules cm À2) at most of the stations. The retrieved Tropospheric Column Ozone (TCO) captures most of the temporal variability in ozonesonde TCO; the mean biases are mostly within 3 DU (15%) and the standard deviations (1s) are within 3-8 DU (13-27%). We also compare our retrieved ozone profiles above $15 km against Stratospheric Aerosol and Gas Experiment II measurements from 1996 to 1999. The mean biases and standard deviations are usually within 15%.

Tropospheric Ozone Assessment Report: Assessment of global-scale model performance for global and regional ozone distributions, variability, and trends

“…A more general issue with satellite measurements is that the instruments measure irradiances, which are then transformed into ozone abundances by a complex retrieval process that relies on various assumptions and models (Liu et al, 2005;Bowman et al, 2006). Although not applied to atmospheric chemistry observations, a recent innovation to deal with this issue is the development of instrument simulators for models.…”

Enhanced Mid-Latitude Tropospheric Column Ozone over East Asia: Coupled Effects of Stratospheric Ozone Intrusion and Anthropogenic Sources

“…We used the TCO dataset retrieved by Liu et al (2005Liu et al ( , 2006 for the period from 1995 through 2003. In the algorithm of Liu et al (2005), an ozone profile climatology (McPeters et al 2003) was used as a priori information, providing ozone mixing ratios at 61 levels from 0 to 60 km for each month and each 10 • latitude band.…”

“…In the algorithm of Liu et al (2005), an ozone profile climatology (McPeters et al 2003) was used as a priori information, providing ozone mixing ratios at 61 levels from 0 to 60 km for each month and each 10 • latitude band. The ozone profiles were derived from GOME measurements in the ultraviolet region (289-339 nm) using an optimal estimation technique.…”

“…Most recently, several studies derived TCO from Aura Microwave Limb Sounder (MLS) SCO and Ozone Monitoring Experiment (OMI) measurements by using spatial interpolation (Ziemke et al 2006), trajectory mapping (Schoeberl et al 2007), potential vorticity (Yang et al 2007), and data assimilation (Stajner et al 2008) to improve the spatial coverage of MLS data. Alternatively, Liu et al (2005Liu et al ( , 2006 derived TCO directly from the spectra obtained by the Global Ozone Monitoring Experiment (GOME).…”

“…As described above, East Asia is a one of the most significant areas for its high emissions of ozone precursors, and thus, detailed analysis of tropospheric ozone in this area is now required from the point of view of hemispheric transport of pollutants. Hayashida et al (2008) analyzed the TCO data derived from GOME sensor by Liu et al (2005) to examine the spatiotemporal variation in TCO over East Asia. Their analysis revealed that the enhanced TCO (E-TCO) belt was observed at mid-latitudes year-round.…”