The effects of the COVID-19 lockdowns on the composition  of the troposphere as seen by In-service Aircraft for a Global Observing System (IAGOS) at Frankfurt

Abstract. The European research infrastructure IAGOS (In-service Aircraft for a Global Observing System) equips commercial aircraft with a system for measuring atmospheric composition. A range of essential climate variables and air quality parameters are measured throughout the flight, from take-off to landing, giving high-resolution information in the vertical in the vicinity of international airports and in the upper troposphere–lower stratosphere during the cruise phase of the flight. Six airlines are currently involved in the programme, achieving a quasi-global coverage under normal circumstances. During the COVID-19 crisis, many airlines were forced to ground their fleets due to a fall in passenger numbers and imposed travel restrictions. Deutsche Lufthansa, a partner in IAGOS since 1994 was able to operate an IAGOS-equipped aircraft during the COVID-19 lockdown, providing regular measurements of ozone and carbon monoxide at Frankfurt Airport. The data form a snapshot of an unprecedented time in the 27-year time series. In May 2020, we see a 32 % increase in ozone near the surface with respect to a recent reference period, a magnitude similar to that of the 2003 heatwave. The anomaly in May is driven by an increase in ozone at nighttime which might be linked to the reduction in NO during the COVID-19 lockdowns. The anomaly diminishes with altitude becoming a slightly negative anomaly in the free troposphere. The ozone precursor carbon monoxide shows an 11 % reduction in MAM (March–April–May) near the surface. There is only a small reduction in CO in the free troposphere due to the impact of long-range transport on the CO from emissions in regions outside Europe. This is confirmed by data from the Infrared Atmospheric Sounding Interferometer (IASI) using retrievals performed by SOftware for a Fast Retrieval of IASI Data (SOFRID), which display a clear drop of CO at 800 hPa over Europe in March but otherwise show little change to the abundance of CO in the free troposphere.

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The Effects of the COVID-19 Lockdowns on the Composition of the Troposphere as Seen by IAGOS

10.5194/acp-2021-479 ◽

2021 ◽

Author(s):

Hannah Clark ◽

Yasmine Bennouna ◽

Maria Tsivlidou ◽

Pawel Wolff ◽

Bastien Sauvage ◽

...

Keyword(s):

Carbon Monoxide ◽

Quality Parameters ◽

Atmospheric Composition ◽

Free Troposphere ◽

Commercial Aircraft ◽

Range Transport ◽

Travel Restrictions ◽

Global Coverage ◽

Ozone Precursor ◽

The Impact

Abstract. The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System) equips commercial aircraft with a system for measuring atmospheric composition. A range of essential climate variables and air quality parameters are measured throughout the flight, from take-off to landing, giving high resolution information in the vertical in the vicinity of international airports, and in the upper-troposphere/lower-stratosphere during the cruise phase of the flight. Six airlines are currently involved in the programme, achieving a quasi-global coverage under normal circumstances. During the COVID-19 crisis, many airlines were forced to ground their fleets due to a fall in passenger numbers and imposed travel restrictions. Deutsche Lufthansa, a partner in IAGOS since 1994 was able to operate a IAGOS-equipped aircraft during the COVID-19 lockdown, providing regular measurements of ozone and carbon monoxide at Frankfurt airport. The data form a snapshot of an unprecedented time in the 27 year time-series. In May 2020, we see a 39 % increase in ozone near the surface with respect to the 26 year climatology, a magnitude similar to that of the 2003 heatwave. The anomaly in May is driven by an increase in ozone at nighttime which might be linked to the reduction of NO during the COVID-19 lockdowns. The anomaly diminishes with altitude becoming a slightly negative anomaly in the free troposphere. The ozone precursor carbon monoxide shows an 11 % reduction in MAM near the surface. There is only a small reduction of CO in the free troposphere due to the impact of long-range transport on the CO from emissions in regions outside Europe. This is confirmed by IASI-SOFRID CO retrievals which display a clear drop of CO at 800 hPa over Europe in March but otherwise show little change to the abundance of CO in the free troposphere.

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The influence of typhoons on atmospheric composition deduced from IAGOS measurements over Taipei

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-3945-2020 ◽

2020 ◽

Vol 20 (6) ◽

pp. 3945-3963

Author(s):

Frank Roux ◽

Hannah Clark ◽

Kuo-Ying Wang ◽

Susanne Rohs ◽

Bastien Sauvage ◽

...

Keyword(s):

Carbon Monoxide ◽

Relative Humidity ◽

Tropical Cyclones ◽

Marine Boundary Layer ◽

Chemical Species ◽

Atmospheric Composition ◽

Commercial Aircraft ◽

Regular Feature ◽

Mixing Ratios ◽

The Vertical Distribution

Abstract. The research infrastructure IAGOS (In-Service Aircraft for a Global Observing System) equips commercial aircraft with instruments to monitor the composition of the atmosphere during flights around the world. In this article, we use data from two China Airlines aircraft based in Taipei (Taiwan) which provided daily measurements of ozone, carbon monoxide and water vapour throughout the summer of 2016. We present time series, from the surface to the upper troposphere, of ozone, carbon monoxide and relative humidity near Taipei, focusing on periods influenced by the passage of typhoons. We examine landing and take-off profiles in the vicinity of tropical cyclones using ERA-5 reanalyses to elucidate the origin of the anomalies in the vertical distribution of these chemical species. Results indicate a high ozone content in the upper- to middle-troposphere track of the storms. The high ozone mixing ratios are generally correlated with potential vorticity and anti-correlated with relative humidity, suggesting stratospheric origin. These results suggest that tropical cyclones participate in transporting air from the stratosphere to troposphere and that such transport could be a regular feature of typhoons. After the typhoons passed Taiwan, the tropospheric column was filled with substantially lower ozone mixing ratios due to the rapid uplift of marine boundary layer air. At the same time, the relative humidity increased, and carbon monoxide mixing ratios fell. Locally, therefore, the passage of typhoons has a positive effect on air quality at the surface, cleansing the atmosphere and reducing the mixing ratios of pollutants such as CO and O3.

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Very high stratospheric influence observed in the free troposphere over the northern Alps – just a local phenomenon?

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-243-2020 ◽

2020 ◽

Vol 20 (1) ◽

pp. 243-266 ◽

Cited By ~ 4

Author(s):

Thomas Trickl ◽

Hannes Vogelmann ◽

Ludwig Ries ◽

Michael Sprenger

Keyword(s):

Stratospheric Ozone ◽

Atmospheric Composition ◽

Radiosonde Data ◽

Free Troposphere ◽

Stratospheric Intrusion ◽

Lidar Measurements ◽

Range Transport ◽

Summer Minimum ◽

Very High

Abstract. The atmospheric composition is strongly influenced by a change in atmospheric dynamics, which is potentially related to climate change. A prominent example is the doubling of the stratospheric ozone component at the Zugspitze summit station (2962 m a.s.l., Garmisch-Partenkirchen, Germany) between the mid-seventies and 2005, roughly from 11 to 23 ppb (43 %). Systematic efforts for identifying and quantifying this influence have been made since the late 1990s. Meanwhile, routine lidar measurements of ozone and water vapour carried out at Garmisch-Partenkirchen (German Alps) since 2007, combined with in situ and radiosonde data and trajectory calculations, have revealed that stratospheric intrusion layers are present on 84 % of the yearly measurement days. At Alpine summit stations the frequency of intrusions exhibits a seasonal cycle with a pronounced summer minimum that is reproduced by the lidar measurements. The summer minimum disappears if one looks at the free troposphere as a whole. The mid- and upper-tropospheric intrusion layers seem to be dominated by very long descent on up to hemispheric scale in an altitude range starting at about 4.5 km a.s.l. Without interfering air flows, these layers remain very dry, typically with RH ≤5 % at the centre of the intrusion. Pronounced ozone maxima observed above Garmisch-Partenkirchen have been mostly related to a stratospheric origin rather than to long-range transport from remote boundary layers. Our findings and results for other latitudes seem to support the idea of a rather high contribution of ozone import from the stratosphere to tropospheric ozone.

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Data assimilation of satellite-retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-5275-2015 ◽

2015 ◽

Vol 15 (9) ◽

pp. 5275-5303 ◽

Cited By ~ 53

Author(s):

A. Inness ◽

A.-M. Blechschmidt ◽

I. Bouarar ◽

S. Chabrillat ◽

M. Crepulja ◽

...

Keyword(s):

Carbon Monoxide ◽

Data Assimilation ◽

Nitrogen Dioxide ◽

Initial Conditions ◽

Stratospheric Ozone ◽

Lower Troposphere ◽

Atmospheric Composition ◽

Reactive Gases ◽

The Impact ◽

Total Column

Abstract. Daily global analyses and 5-day forecasts are generated in the context of the European Monitoring Atmospheric Composition and Climate (MACC) project using an extended version of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The IFS now includes modules for chemistry, deposition and emission of reactive gases, aerosols, and greenhouse gases, and the 4-dimensional variational data assimilation scheme makes use of multiple satellite observations of atmospheric composition in addition to meteorological observations. This paper describes the data assimilation setup of the new Composition-IFS (C-IFS) with respect to reactive gases and validates analysis fields of ozone (O3), carbon monoxide (CO), and nitrogen dioxide (NO2) for the year 2008 against independent observations and a control run without data assimilation. The largest improvement in CO by assimilation of Measurements of Pollution in the Troposphere (MOPITT) CO columns is seen in the lower troposphere of the Northern Hemisphere (NH) extratropics during winter, and during the South African biomass-burning season. The assimilation of several O3 total column and stratospheric profile retrievals greatly improves the total column, stratospheric and upper tropospheric O3 analysis fields relative to the control run. The impact on lower tropospheric ozone, which comes from the residual of the total column and stratospheric profile O3 data, is smaller, but nevertheless there is some improvement particularly in the NH during winter and spring. The impact of the assimilation of tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) is small because of the short lifetime of NO2, suggesting that NO2 observations would be better used to adjust emissions instead of initial conditions. The results further indicate that the quality of the tropospheric analyses and of the stratospheric ozone analysis obtained with the C-IFS system has improved compared to the previous "coupled" model system of MACC.

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Very high stratospheric influence observed in the free troposphere over the Northern Alps – just a local phenomenon?

10.5194/acp-2019-588 ◽

2019 ◽

Author(s):

Thomas Trickl ◽

Hannes Vogelmann ◽

Ludwig Ries ◽

Michael Sprenger

Keyword(s):

Stratospheric Ozone ◽

Atmospheric Composition ◽

Radiosonde Data ◽

Free Troposphere ◽

Stratospheric Intrusion ◽

Lidar Measurements ◽

Range Transport ◽

Summer Minimum ◽

Very High

Abstract. The atmospheric composition is strongly influenced by a change in atmospheric dynamics, which is potentially related to climate change. A prominent example is the doubling of the stratospheric ozone component at the summit station Zugspitze (2962 m a.s.l., Garmisch-Partenkirchen, Germany) between the mid-seventies and 2005, roughly from 11 ppb to 23 ppb (43 %). Systematic efforts for identifying and quantifying this influence have been made since the late 1990s. Meanwhile, routine lidar measurements of ozone and water vapour carried out at Garmisch-Partenkirchen (German Alps) since 2007, combined with in-situ and radiosonde data and trajectory calculations, have revealed that stratospheric intrusion layers are present on 84 % of the yearly measurement days. At Alpine summit stations the frequency of intrusions exhibits a seasonal cycle with a pronounced summer minimum that is reproduced by the lidar measurements. The summer minimum disappears if one looks at the free troposphere as a whole. The mid- and upper-tropospheric intrusion layers seem to be dominated by very long descent on up to hemispheric scale in an altitude range starting at about 4.5 km a.s.l. Without interfering air flows, these layers remain very dry, typically with RH ≤ 5 % at the centre of the intrusion. Pronounced ozone maxima observed above Garmisch-Partenkirchen have been mostly related to a stratospheric origin rather than to long-range transport from remote boundary layers. Our findings and results for other latitudes seem to support the idea of a rather high contribution of ozone import from the stratosphere to tropospheric ozone.

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Mapping carbon monoxide pollution from space down to city scales with daily global coverage

Atmospheric Measurement Techniques ◽

10.5194/amt-11-5507-2018 ◽

2018 ◽

Vol 11 (10) ◽

pp. 5507-5518 ◽

Cited By ~ 18

Author(s):

Tobias Borsdorff ◽

Joost aan de Brugh ◽

Haili Hu ◽

Otto Hasekamp ◽

Ralf Sussmann ◽

...

Keyword(s):

Carbon Monoxide ◽

Atmospheric Transport ◽

European Space Agency ◽

Total Carbon ◽

Atmospheric Composition ◽

Background Concentration ◽

Clear Sky ◽

Data Product ◽

Global Coverage ◽

The Individual

Abstract. On 13 October 2017, the European Space Agency (ESA) successfully launched the Sentinel-5 Precursor satellite with the Tropospheric Monitoring Instrument (TROPOMI) as its single payload. TROPOMI is the first of ESA's atmospheric composition Sentinel missions, which will provide complete long-term records of atmospheric trace gases for the coming 30 years as a contribution to the European Union's Earth Observing program Copernicus. One of TROPOMI's primary products is atmospheric carbon monoxide (CO). It is observed with daily global coverage and a high spatial resolution of 7×7 km2. The moderate atmospheric resistance time and the low background concentration leads to localized pollution hotspots of CO and allows the tracking of the atmospheric transport of pollution on regional to global scales. In this contribution, we demonstrate the groundbreaking performance of the TROPOMI CO product, sensing CO enhancements above cities and industrial areas and tracking, with daily coverage, the atmospheric transport of pollution from biomass burning regions. The CO data product is validated with two months of Fourier-transform spectroscopy (FTS) measurements at nine ground-based stations operated by the Total Carbon Column Observing Network (TCCON). We found a good agreement between both datasets with a mean bias of 6 ppb (average of individual station biases) for both clear-sky and cloudy TROPOMI CO retrievals. Together with the corresponding standard deviation of the individual station biases of 3.8 ppb for clear-sky and 4.0 ppb for cloudy sky, it indicates that the CO data product is already well within the mission requirement.

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Influence of trans-Pacific pollution transport on acyl peroxy nitrate abundances and speciation at Mount Bachelor Observatory during INTEX-B

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-9139-2007 ◽

2007 ◽

Vol 7 (3) ◽

pp. 9139-9181

Author(s):

G. M. Wolfe ◽

J. A. Thornton ◽

V. Faye McNeill ◽

D. A. Jaffe ◽

D. Reidmiller ◽

...

Keyword(s):

Boundary Layer ◽

Thermal Dissociation ◽

Mean Value ◽

Atmospheric Composition ◽

Ionization Mass ◽

Free Troposphere ◽

Pollution Transport ◽

Back Trajectories ◽

Mixing Ratios ◽

The Impact

Abstract. We present month-long observations of speciated acyl peroxy nitrates (APNs), including PAN, PPN, MPAN, APAN, and the sum of PiBN and PnBN, measured at the Mount Bachelor Observatory (MBO) as part of the INTEX-B collaborative field campaign during spring 2006. APN abundances, measured by thermal dissociation-chemical ionization mass spectrometry (TD-CIMS), are discussed in terms of differing contributions from the boundary layer and the free troposphere and in the context of previous APN measurements in the NE Pacific region. PAN mixing ratios range from 11 to 3955 pptv, with a mean value of 334 pptv for the full measurement period. PPN is linearly correlated with PAN (r2=0.96), with an average abundance of 6.5% relative to PAN; other APNs are generally <1% of PAN. Diurnal cycles and relationships of APNs with ozone reveal a gradient in hydrocarbon chemistry between the boundary layer and the free troposphere. On average, the highest levels of APNs, ozone and PPN/PAN are found in free tropospheric air masses, suggesting that this site is strongly influenced by distant pollution sources. To estimate the impact of long-range transport of Asian pollution on atmospheric composition at MBO, we perform a detailed analysis utilizing HYSPLIT back trajectories. This analysis suggests that trans-Pacific transport of Asian pollution leads to substantial increases in APN and ozone mixing ratios at MBO, especially when transport occurs via the free troposphere. The ensemble of trajectories indicate that Asian-influenced free tropospheric air was sampled in ~16% of our data and contained a median PAN mixing ratio double that of the full dataset.

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Assimilating Compact Phase Space Retrievals (CPSRs): Comparison with Independent Observations (MOZAIC in situ and IASI Retrievals) and Extension to Assimilation of Truncated Retrieval Profiles

10.5194/gmd-2018-19 ◽

2018 ◽

Author(s):

Arthur P. Mizzi ◽

David P. Edwards ◽

Jeffrey L. Anderson

Keyword(s):

Carbon Monoxide ◽

Phase Space ◽

Computational Cost ◽

Lower Troposphere ◽

Forecast Skill ◽

Atmospheric Composition ◽

Promising Alternative ◽

Independent Observations ◽

The Impact

Abstract. Assimilation of atmospheric composition retrievals presents computational challenges due to their high data volume and often sparse information density. Assimilation of compact phase space retrievals (CPSRs) meets those challenges and offers a promising alternative to assimilation of raw retrievals at reduced computational cost (Mizzi et al., 2016). This paper compares analysis and forecast results from assimilation of Terra/Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO) CPSRs with independent observations. We use MetOp-A/Infrared Atmospheric Sounding Interferometer (IASI) CO retrievals and Measurement of OZone, water vapor, carbon monoxide, and nitrogen oxides by in service AIrbus airCraft (MOZAIC) in situ CO profiles for our independent observation comparisons. Generally, the results confirm that assimilation of MOPITT CPSRs improved the WRF-Chem/DART analysis fit and forecast skill at a reduced computational cost (~ 35 % reduction) when compared to assimilation of raw or quasi-optimal retrievals (QORs). Comparison with the independent observations shows that assimilation of MOPITT CO generally improved the analysis fit and forecast skill in the lower troposphere but degraded it in the upper troposphere. We attribute that degradation to assimilation of MOPITT CO retrievals with a possible bias of ~ 14 % above 300 hPa. To discard the biased retrievals, in this paper we also extend CPSRs to assimilation of truncated retrieval profiles (as opposed to assimilation of full retrieval profiles). Those results show that not assimilating the biased retrievals: (i) resolves the upper tropospheric analysis fit degradation issue, (ii) has commensurate reductions in assimilation computation cost, and (iii) reduces the impact of assimilating the remaining unbiased retrievals because the total information content and vertical sensitivities are changed.

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Influence of trans-Pacific pollution transport on acyl peroxy nitrate abundances and speciation at Mount Bachelor Observatory during INTEX-B

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-5309-2007 ◽

2007 ◽

Vol 7 (20) ◽

pp. 5309-5325 ◽

Cited By ~ 52

Author(s):

G. M. Wolfe ◽

J. A. Thornton ◽

V. F. McNeill ◽

D. A. Jaffe ◽

D. Reidmiller ◽

...

Keyword(s):

Thermal Dissociation ◽

Mean Value ◽

Atmospheric Composition ◽

Ionization Mass ◽

Free Troposphere ◽

Pollution Transport ◽

Back Trajectories ◽

Mixing Ratios ◽

Full Dataset ◽

The Impact

Abstract. We present month-long observations of speciated acyl peroxy nitrates (APNs), including PAN, PPN, MPAN, APAN, and the sum of PiBN and PnBN, measured at the Mount Bachelor Observatory (MBO) as part of the INTEX-B collaborative field campaign during spring 2006. APN abundances, measured by thermal dissociation-chemical ionization mass spectrometry (TD-CIMS), are discussed in terms of differing contributions from the boundary layer (BL) and the free troposphere (FT) and in the context of previous APN measurements in the NE Pacific region. PAN mixing ratios range from 11 to 3955 pptv, with a mean value of 334 pptv for the full measurement period. PPN is linearly correlated with PAN (r2=0.96), with an average abundance of 6.5% relative to PAN; other APNs are generally <1% of PAN. Diurnal cycles and relationships of APNs with ozone reveal a gradient in hydrocarbon chemistry between the BL and the FT. On average, levels of APNs, ozone and PPN/PAN are substantially higher in FT air relative to BL air, suggesting that this site is strongly influenced by distant pollution sources. To estimate the impact of long-range transport of Asian pollution on atmospheric composition at MBO, we perform a detailed analysis utilizing HYSPLIT back trajectories. This analysis suggests that trans-Pacific transport of Asian pollution leads to substantial increases in APN and ozone mixing ratios at MBO, especially when transport occurs via the free troposphere. The ensemble of trajectories indicate that Asian-influenced free tropospheric air was sampled in ~16% of our data and contained a median PAN mixing ratio double that of the full dataset.

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Free troposphere ozone and carbon monoxide over the North Atlantic for 2001–2011

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-15377-2013 ◽

2013 ◽

Vol 13 (6) ◽

pp. 15377-15407 ◽

Cited By ~ 1

Author(s):

A. Kumar ◽

S. Wu ◽

M. F. Weise ◽

R. Honrath ◽

R. C. Owen ◽

...

Keyword(s):

Carbon Monoxide ◽

North Atlantic ◽

Measurement Data ◽

Free Troposphere ◽

Significance Level ◽

Mixing Ratios ◽

The North ◽

Source Regions ◽

The North Atlantic ◽

The Impact

Abstract. In-situ measurements of carbon monoxide (CO) and ozone (O3) at the Pico Mountain Observatory (PMO) located in the Azores, Portugal are analyzed together with results from atmospheric chemical transport modeling (GEOS-Chem) and satellite remote sensing (AIRS for CO and TES for O3) to examine the evolution of free-troposphere CO and O3 over the North Atlantic for 2001–2011. GEOS-Chem captured the seasonal cycles for CO and O3 well but significantly underestimated the mixing ratios of CO, particularly in spring. Statistically significant (using a significance level of 0.05) decreasing trends were found for both CO and O3 based on harmonic regression analysis of the measurement data. The best estimates of the trend for CO and O3 measurements are −0.31 &pm; 0.30 (2-σ) ppbv yr−1 and −0.21 &pm; 0.11 (2-σ) ppbv yr−1, respectively. Similar decreasing trends for both species were obtained with GEOS-Chem simulation results. The major factor contributing to the reported decrease in CO and O3 mixing ratios at PMO over the past decade is the decline in anthropogenic CO and O3-precursor emissions in regions such as North America and Europe. The increase in Asian emissions does not seem to outweigh the impact of these declines resulting in overall decreasing trends for both CO and O3. For O3, however, increase in atmospheric water vapor content associated with climate change also appears to be a contributing factor causing enhanced destruction of the O3 during transport from source regions. These hypotheses are supported by results from the GEOS-Chem tagged CO and tagged O3 simulations.

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