Simultaneous assimilation of ozone profiles from multiple UV-VIS satellite instruments

Peet, Jacob C. A. van; A, Ronald van der; Kelder, H.; Levelt, P. F.

doi:10.5194/acp-18-1685-2018

Cited by 8 publications

(11 citation statements)

References 36 publications

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“…The ozone profiles from both instruments are retrieved with the optimal estimation technique. For GOME-2 the algorithm is described in van Peet et al (2014), while the OMI algorithm is described in Kroon et al (2011). The ozone profiles are assimilated into the global chemistry transport model TM5 (Tracer Model, version 5; e.g.…”

Section: Methodsmentioning

confidence: 99%

Deriving tropospheric ozone from assimilated profiles

Peet

2019

Atmos. Chem. Phys.

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We derived global tropospheric ozone (O 3 ) columns from GOME-2A (Global Ozone Monitoring Experiment) and OMI (Ozone Monitoring Instrument) O 3 profiles, which were simultaneously assimilated into the TM5 (Tracer Model, version 5) global chemistry transport model for the year 2008. The horizontal model resolution has been increased by a factor of 6 for more accurate results. To reduce computational cost, the number of model layers has been reduced from 44 to 31. The model ozone fields are used to derive tropospheric ozone, which is defined here as the partial column between mean sea level and 6 km altitude. Two methods for calculating the tropospheric columns from the free model run and assimilated O 3 fields are compared. In the first method, we calculate the residual between assimilated total columns and the partial model column between 6 km and the top of atmosphere. In the second method, we perform a direct integration of the assimilated O 3 fields between the surface and 6 km. The results are validated against tropospheric columns derived from ozone sonde measurements. Our results show that the residual method has too large a variation to be used reliably for the determination of tropospheric ozone, so the direct integration method has been used instead. The median global bias is smaller for the assimilated O 3 fields than for the free model run, but the large variation makes it difficult to make definitive statements on a regional or local scale. The monthly mean ozone fields show significant improvements and more detail when comparing the assimilated O 3 fields with the free model run, especially for features such as biomass-burning-enhanced O 3 concentrations and outflow of O 3 rich air from Asia over the Pacific.Published by Copernicus Publications on behalf of the European Geosciences Union.

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Section: Methodsmentioning

confidence: 99%

Deriving tropospheric ozone from assimilated profiles

Peet

2019

Atmos. Chem. Phys.

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“…We use the ozone profiles from the UV-VIS instruments GOME-2 (Callies et al, 2000;Munro et al, 2016) and OMI (Levelt et al, 2006) that are described in van Peet et al (2018). The ozone profiles from both instruments are retrieved with the optimal estimation technique.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the model covariance matrix is parameterised into a time independent correlation field and a time dependent uncertainty field. Due to the changes in resolution and meteorological fields, the correlation field had to be derived again according the same method as described in van Peet et al (2018). No other changes have been made to the assimilation algorithm.…”

Section: Methodsmentioning

confidence: 99%

Deriving tropospheric ozone from assimilated profiles

Peet¹,

A²

2019

Preprint

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Abstract. To derive global tropospheric O3 columns from satellite observations, O3 profiles retrieved from GOME-2A and OMI measurements were simultaneously assimilated into the TM5 global chemistry transport model for the year 2008. The horizontal model resolution has been increased by a factor of 6 for more accurate results, but to reduce computational cost, the number of model layers has been reduced from 44 to 31. The model ozone fields are used to derive tropospheric ozone, which is defined here as the partial column between mean sea level and 6&#8201;km altitude. Two methods for calculating the tropospheric columns from the free model run and assimilate O3 fields are compared. In the first method, we calculate the residual between assimilated total columns and the partial model column between 6&#8201;km and the top of atmosphere. In the second method, we perform a direct integration of the assimilated O3 fields between the surface and 6&#8201;km. The results are validated against tropospheric columns derived from ozone sonde measurements. It turned out that the residual method has a too large variation to be used reliably for the determination of tropospheric ozone, so the direct integration method has been used instead. The median global bias is smaller for the assimilated O3 fields than for the free model run, but the large variation makes it difficult to make definitive statements on a regional or local scale. The monthly mean ozone fields show significant improvements and more detail when comparing the assimilated O3 fields with the free model run, especially for features such as biomass burning enhanced O3 concentrations and outflow of O3 rich air from Asia over the Pacific.

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“…Each ozone profile is provided in volume-mixing ratio (VMR) and number density (ND) units on a fixed vertical grid with 20 levels ranging between 0 and 80 km, while the values of the 19 intermediate partial ozone column layers are provided as well. The RAL retrieval is a three-step process (Munro et al, 1998;Siddans, 2003;.…”

Section: L2 Uv-vis Retrieval Algorithmmentioning

confidence: 99%

“…and Peet et al (2018). The covariance matrices and the averaging kernel matrices from the L2 optimal estimation retrievals are thereby used.…”

Section: L3 Monthly Gridded Datamentioning

confidence: 99%

Quality assessment of the Ozone_cci Climate Research Data Package (release 2017) – Part 2: Ground-based validation of nadir ozone profile data products

et al. 2018

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Abstract. Atmospheric ozone plays a key role in air quality and the radiation budget of the Earth, both directly and through its chemical influence on other trace gases. Assessments of the atmospheric ozone distribution and associated climate change therefore demand accurate vertically resolved ozone observations with both stratospheric and tropospheric sensitivity, on both global and regional scales, and both in the long term and at shorter timescales. Such observations have been acquired by two series of European nadir-viewing ozone profilers, namely the scattered-light UV–visible spectrometers of the GOME family, launched regularly since 1995 (GOME, SCIAMACHY, OMI, GOME-2A/B, TROPOMI, and the upcoming Sentinel-5 series), and the thermal infrared emission sounders of the IASI type, launched regularly since 2006 (IASI on Metop platforms and the upcoming IASI-NG on Metop-SG). In particular, several Level-2 retrieved, Level-3 monthly gridded, and Level-4 assimilated nadir ozone profile data products have been improved and harmonized in the context of the ozone project of the European Space Agency's Climate Change Initiative (ESA Ozone_cci). To verify their fitness for purpose, these ozone datasets must undergo a comprehensive quality assessment (QA), including (a) detailed identification of their geographical, vertical, and temporal domains of validity; (b) quantification of their potential bias, noise, and drift and their dependences on major influence quantities; and (c) assessment of the mutual consistency of data from different sounders. For this purpose we have applied to the Ozone_cci Climate Research Data Package (CRDP) released in 2017 the versatile QA and validation system Multi-TASTE, which has been developed in the context of several heritage projects (ESA's Multi-TASTE, EUMETSAT's O3M-SAF, and the European Commission's FP6 GEOmon and FP7 QA4ECV). This work, as the second in a series of four Ozone_cci validation papers, reports for the first time on data content studies, information content studies and ground-based validation for both the GOME- and IASI-type climate data records combined. The ground-based reference measurements have been provided by the Network for the Detection of Atmospheric Composition Change (NDACC), NASA's Southern Hemisphere Additional Ozonesonde programme (SHADOZ), and other ozonesonde and lidar stations contributing to the World Meteorological Organisation's Global Atmosphere Watch (WMO GAW). The nadir ozone profile CRDP quality assessment reveals that all nadir ozone profile products under study fulfil the GCOS user requirements in terms of observation frequency and horizontal and vertical resolution. Yet all L2 observations also show sensitivity outliers in the UTLS and are strongly correlated vertically due to substantial averaging kernel fluctuations that extend far beyond the kernel's 15 km FWHM. The CRDP typically does not comply with the GCOS user requirements in terms of total uncertainty and decadal drift, except for the UV–visible L4 dataset. The drift values of the L2 GOME and OMI, the L3 IASI, and the L4 assimilated products are found to be overall insignificant, however, and applying appropriate altitude-dependent bias and drift corrections make the data fit for climate and atmospheric composition monitoring and modelling purposes. Dependence of the Ozone_cci data quality on major influence quantities – resulting in data screening suggestions to users – and perspectives for the Copernicus Sentinel missions are additionally discussed.

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Simultaneous assimilation of ozone profiles from multiple UV-VIS satellite instruments

Cited by 8 publications

References 36 publications

Deriving tropospheric ozone from assimilated profiles

Deriving tropospheric ozone from assimilated profiles

Deriving tropospheric ozone from assimilated profiles

Quality assessment of the Ozone_cci Climate Research Data Package (release 2017) – Part 2: Ground-based validation of nadir ozone profile data products

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