Tropical tropospheric ozone columns from nadir retrievals of GOME-1/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A (1996–2012)

Leventidou, Elpida; Eichmann, Kai‐Uwe; Weber, Mark; Burrows, J. P.

doi:10.5194/amt-9-3407-2016

Cited by 12 publications

(23 citation statements)

References 53 publications

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“…Regional positive tropospheric ozone trends of similar magnitude were also observed in other studies (e.g. Lelieveld et al, 2004;Beig and Singh, 2007;Kulkarni et al, 2010;Cooper et al, 2014;Ebojie et al, 2016;Heue et al, 2016). On the other hand, tropospheric O 3 decreases by ∼ 3 DU decade −1 over the Caribbean Sea and parts of the North Pacific Ocean, and by less than 2 DU decade −1 over some regions of the southern Pacific Ocean.…”

Section: Seasonal Tropospheric O 3 Trendssupporting

confidence: 86%

“…parts of the Arabian sea (D), south Africa and the southern African outflow (H), parts of India (B), and north south America (C) agree well with results of Lelieveld et al (2004), Beig and Singh (2007), Kulkarni et al (2010), Ebojie et al (2016) and Heue et al (2016) who also observed an increasing ozone trend over these regions. Although, Ebojie et al (2016) observe a decreasing trend of −0.5 DU decade −1 in tropospheric ozone over northeast Africa (D).…”

Section: Areasupporting

confidence: 83%

“…Various studies have been performed in urban and rural sites using in situ data in order to estimate tropical tropospheric ozone trends. Lelieveld et al (2004) noticed an increase in surface ozone of the order of 0.4 ppbv yr −1 over the northeastern tropical Atlantic, 0.4 ppbv yr −1 over the southeastern tropical Atlantic and a smaller trend of 0.1 ppbv decade −1 over the southwestern tropical Atlantic Ocean, based on ship-borne measurements . Oltmans et al (2013) observed an increase of 3.8 % decade −1 (0.16 ppbv yr −1 ) in surface ozone in Mauna Loa, Hawaii (19.5 • N) in the North Pacific since 1974 and a smaller insignificant trend of the order of 0.7 % decade −1 (0.01 ppbv yr −1 ) in American Samoa (−14.5 • S) after 1976.…”

Section: Introductionmentioning

confidence: 96%

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Harmonisation and trends of 20-year tropical tropospheric ozone data

Leventidou¹,

Weber²,

Eichmann³

et al. 2018

Atmos. Chem. Phys.

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Abstract. Using a convective-cloud differential (CCD) method, developed in-house and applied to retrievals of total ozone and cloud data from three European satellite instruments (viz. GOME/ERS-2, 1995–2003; SCIAMACHY/Envisat, 2002–2012 and GOME-2/MetOp-A, 2007–2015), monthly mean tropical tropospheric columns of ozone (TTCO) have been retrieved, which are in good agreement with ozonesondes (biases less than 6 DU). As small differences in TTCO between the individual instruments were evident, it was necessary to develop a scheme to harmonise the three datasets into one consistent time series starting from 1996 until 2015. Correction offsets (biases) between the instruments using SCIAMACHY as intermediate reference have been calculated and six different harmonisation or merging scenarios have been evaluated. Depending on the merging approach, the magnitude, pattern and uncertainty in the trends strongly vary. The harmonisation or merging represents an additional source of uncertainty in the trends (2 DU decade−1 on average, in most of the cases exceeding the uncertainty from the regression). For studying further details on tropospheric ozone trends on various spatial scales in the tropics, we stick with one preferred merged dataset that shows best agreement with ozonesondes. In this merged dataset, no correction was applied for GOME, and mean biases with respect to SCIAMACHY in the overlapping period (2007–2012) were calculated and applied for GOME-2 in each grid box (2.5°  × 5°). In contrast with other studies we found that the tropospheric trend averaged over the tropics (−15° S to 15° N) is not statistically significant. The mean tropospheric ozone trend equals −0.2 ± 0.6 DU decade−1 (2σ). Regionally, tropospheric ozone has a statistically significant increase of ∼  3 DU decade−1 over southern Africa ( ∼ 1.5 % yr−1), the southern tropical Atlantic ( ∼ 1.5 % yr−1), southeastern tropical Pacific Ocean ( ∼ 1 % yr−1), and central Oceania ( ∼ 2 % yr−1) and by ∼ 2 DU decade−1 over central Africa (2–2.5 % yr−1) and south India ( ∼ 1.5 % yr−1). On the other hand, tropospheric O3 decreases by ∼ 3 DU decade−1 over the Caribbean Sea and parts of the North Pacific Ocean ( ∼ 2 % yr−1), and by less than 2 DU decade−1 over some regions of the southern Pacific and Indian oceans ( ∼ 0.5–1 % yr−1).

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Section: Seasonal Tropospheric O 3 Trendssupporting

confidence: 86%

Section: Areasupporting

confidence: 83%

Section: Introductionmentioning

confidence: 96%

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Harmonisation and trends of 20-year tropical tropospheric ozone data

Leventidou¹,

Weber²,

Eichmann³

et al. 2018

Atmos. Chem. Phys.

Self Cite

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“…Regionally the strongest trends were found in a band from central northern Africa eastwards to SE Asia, and in a band stretching from northern Brazil eastwards to central Africa. In the near future, additional long-term (20-years or more) composites of tropical TCO using multiple satellite instruments will be available for tropical ozone trend quantification (Leventidou et al, 2016; J. Ziemke, personal communication).…”

Section: The Global View From Satellitesmentioning

confidence: 99%

Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation

Gaudel

Cooper

Ancellet

et al. 2018

Elementa: Science of the Anthropocene

335

367

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The Tropospheric Ozone Assessment Report (TOAR) is an activity of the International Global Atmospheric Chemistry Project. This paper is a component of the report, focusing on the present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Utilizing the TOAR surface ozone database, several figures present the global distribution and trends of daytime average ozone at 2702 non-urban monitoring sites, highlighting the regions and seasons of the world with the greatest ozone levels. Similarly, ozonesonde and commercial aircraft observations reveal ozone’s distribution throughout the depth of the free troposphere. Long-term surface observations are limited in their global spatial coverage, but data from remote locations indicate that ozone in the 21st century is greater than during the 1970s and 1980s. While some remote sites and many sites in the heavily polluted regions of East Asia show ozone increases since 2000, many others show decreases and there is no clear global pattern for surface ozone changes since 2000. Two new satellite products provide detailed views of ozone in the lower troposphere across East Asia and Europe, revealing the full spatial extent of the spring and summer ozone enhancements across eastern China that cannot be assessed from limited surface observations. Sufficient data are now available (ozonesondes, satellite, aircraft) across the tropics from South America eastwards to the western Pacific Ocean, to indicate a likely tropospheric column ozone increase since the 1990s. The 2014–2016 mean tropospheric ozone burden (TOB) between 60˚N–60˚S from five satellite products is 300 Tg ± 4%. While this agreement is excellent, the products differ in their quantification of TOB trends and further work is required to reconcile the differences. Satellites can now estimate ozone’s global long-wave radiative effect, but evaluation is difficult due to limited in situ observations where the radiative effect is greatest.

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“…The cloud albedo is fixed at 0.8 in both cloud algorithms. For S5P the cloud data will be calculated using the OCRA/ROCINN algorithm, which is also based on the O 2 A-band (Schuessler et al, 2014;Loyola et al, 2010). The TROPOMI offline total ozone data product will be retrieved with the GODFIT algorithm.…”

Section: Godfit Total Ozone Retrievalmentioning

confidence: 99%

Trends of tropical tropospheric ozone from 20 years of European satellite measurements and perspectives for the Sentinel-5 Precursor

et al. 2016

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Abstract. In preparation of the TROPOMI/S5P launch in early 2017, a tropospheric ozone retrieval based on the convective cloud differential method was developed. For intensive tests we applied the algorithm to the total ozone columns and cloud data of the satellite instruments GOME, SCIAMACHY, OMI, GOME-2A and GOME-2B. Thereby a time series of 20 years (1995–2015) of tropospheric column ozone was generated. To have a consistent total ozone data set for all sensors, one common retrieval algorithm, namely GODFITv3, was applied and the L1 reflectances were also soft calibrated. The total ozone columns and the cloud data were input into the tropospheric ozone retrieval. However, the tropical tropospheric column ozone (TCO) for the individual instruments still showed small differences and, therefore, we harmonised the data set. For this purpose, a multilinear function was fitted to the averaged difference between SCIAMACHY's TCO and those from the other sensors. The original TCO was corrected by the fitted offset. GOME-2B data were corrected relative to the harmonised data from OMI and GOME-2A. The harmonisation leads to a better agreement between the different instruments. Also, a direct comparison of the TCO in the overlapping periods proves that GOME-2A agrees much better with SCIAMACHY after the harmonisation. The improvements for OMI were small. Based on the harmonised observations, we created a merged data product, containing the TCO from July 1995 to December 2015. A first application of this 20-year record is a trend analysis. The tropical trend is 0.7 ± 0.12 DU decade−1. Regionally the trends reach up to 1.8 DU decade−1 like on the African Atlantic coast, while over the western Pacific the tropospheric ozone declined over the last 20 years with up to 0.8 DU decade−1. The tropical tropospheric data record will be extended in the future with the TROPOMI/S5P data, where the TCO is part of the operational products.

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Tropical tropospheric ozone columns from nadir retrievals of GOME-1/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A (1996–2012)

Cited by 12 publications

References 53 publications

Harmonisation and trends of 20-year tropical tropospheric ozone data

Harmonisation and trends of 20-year tropical tropospheric ozone data

Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation

Trends of tropical tropospheric ozone from 20 years of European satellite measurements and perspectives for the Sentinel-5 Precursor

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