Midlatitude tropospheric ozone columns derived from the Aura Ozone Monitoring Instrument and Microwave Limb Sounder measurements

Abstract

[1] Tropospheric ozone columns derived from differences between the Dutch-Finnish Aura Ozone Monitoring Instrument (OMI) measurements of the total atmospheric ozone column and the Aura Microwave Limb Sounder (MLS) measurements of stratospheric ozone columns are discussed. Because the measurements by these two instruments are not spatially coincident, interpolation techniques, with emphasis on mapping the stratospheric columns in space and time using the relationships between lower stratospheric ozone and potential vorticities (PV) and geopotential heights (Z), are evaluated. It is shown that this PV mapping procedure produces somewhat better agreement in comparisons with ozonesonde measurements, particularly in winter, than does simple linear interpolation of the MLS stratospheric columns or the use of typical coincidence criteria. The OMI/MLS derived tropospheric columns are calculated to be 4 Dobson units (DU) smaller than the sonde measured columns. This mean difference is consistent with the MLS (version 1.5) stratospheric ozone columns being high relative to Stratospheric Aerosol and Gas Experiment (SAGE II) columns by 3 DU. Standard deviations between the derived tropospheric columns and those measured by ozonesondes are 9 DU (30%) annually but they are just 6 DU (15%) in summer. Uncertainties in the interpolated MLS stratospheric columns are likely to be the primary cause of these standard deviations. An important advantage of the PV mapping approach is that it works well when MLS data are missing (e.g., when an orbit of measurements is missing). In the comparisons against ozonesonde measurements, it provides up to twice as many comparisons compared to the other techniques.

Tropospheric ozone column retrieval at northern mid-latitudes from the Ozone Monitoring Instrument by means of a neural network algorithm

“…Different techniques have been recently proposed to monitor tropospheric ozone from satellites including OMI: see, e.g. the methods proposed by Ziemke et al (2006a,b); Yang et al (2007); Schoeberl et al (2007); Stajner et al (2008); Liu et al (2010b). Three major techniques exist within this field.…”

Four‐dimensional variational assimilation of ozone profiles from the Microwave Limb Sounder on the Aura satellite

“…In addition, the biases between MLS and the operational observations have degraded the ozone analyses below 215 hPa. Recently, Ziemke et al [2006] and Yang et al [2007] used MLS ozone data to determine the tropospheric ozone columns together with the total ozone columns from the Aura Ozone Monitoring Instrument (OMI). Their results encourage us in the future to further explore the way to improve the tropospheric ozone analyses from the combined assimilation of the more accurate version 2.2 MLS data and the operational ozone observations through careful bias correction and observation selection such as excluding SBUV/2 data at certain layers.…”

“…It is also found that version 1.51 has slightly more ozone in the lower stratosphere (by a few percent) and less ozone in the upper stratosphere (by up to 10% at 1 hPa), when compared to the new (version 2.2) MLS data set [Froidevaux et al, 2008]. Moreover, a recent study by Yang et al [2007] shows that the stratospheric ozone columns of the version 1.51 data set are higher than SAGE II observations by about 3 Dobson units (DU). In the experiment, we only use version 1.51 data flagged as good.…”

“…[19] In contrast, in the lower stratosphere, SBUV/2 on NOAA-16 usually tends to underestimate ozone concentrations [Terao and Logan, 2007], while MLS version 1.51 have small positive biases [Yang et al, 2007;Froidevaux et al, 2008]. Since the SBUV/2 observations between 16 hPa and the surface layer are assimilated as a single partial ozone column, the systematic differences between SBUV/2 and MLS observations in the lower stratosphere can eventually lead to substantial underestimation of the tropospheric ozone, when they are assimilated together.…”

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

“…Since the late 1980s, TCO data have been derived by subtracting concurrent measurements of stratospheric column ozone (SCO) from total column ozone (Fishman et al 1986;Fishman and Larsen 1987;Fishman et al 1990), and these were further improved afterward (Fishman et al 2003;Chandra et al 2003). 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).…”