scholarly journals Global ozone–CO correlations from OMI and AIRS: constraints on tropospheric ozone sources

2013 ◽  
Vol 13 (4) ◽  
pp. 8901-8937 ◽  
Author(s):  
P. S. Kim ◽  
D. J. Jacob ◽  
X. Liu ◽  
J. X. Warner ◽  
K. Yang ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Transport Model ◽  
General Structure ◽  
Deep Convection ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Data Set ◽  
Tropical Regions ◽  
Ozone Maximum ◽  
Regression Slopes

Abstract. We present a global data set of free tropospheric ozone–CO correlations with 2° × 2.5° spatial resolution from the Ozone Monitoring Instrument (OMI) and Atmospheric Infrared Sounder (AIRS) satellite instruments for each season of 2008. OMI and AIRS have near daily global coverage of ozone and CO respectively and observe coincident scenes with similar vertical sensitivities. The resulting ozone–CO correlations are highly statistically significant (positive or negative) in most regions of the world, and are less noisy than previous satellite-based studies that used sparser data. We interpret the observed ozone–CO correlations with the GEOS-Chem chemical transport model to infer constraints on ozone sources. Driving GEOS-Chem with different meteorological fields generally shows consistent ozone–CO correlation patterns, except in some tropical regions where the correlations are strongly sensitive to model transport error associated with deep convection. GEOS-Chem reproduces the general structure of the observed ozone–CO correlations and regression slopes (dO3/dCO), although there are some large regional discrepancies. We examine the model sensitivity of dO3/dCO to different ozone sources (combustion, biosphere, stratosphere, and lightning NOx) by correlating the ozone change from that source to CO from the standard simulation. The model reproduces the observed positive dO3/dCO in the extratropical Northern Hemisphere in spring–summer, driven by combustion sources. Stratospheric influence there is also associated with a positive dO3/dCO because of the interweaving of stratospheric downwelling with continental outflow. The well-known ozone maximum over the tropical South Atlantic is associated with negative dO3/dCO in the observations; this feature is reproduced in GEOS-Chem and supports a dominant contribution from lightning to the ozone maximum. A~major model discrepancy is found over the Northeast Pacific in summer-fall where dO3/dCO is positive in the observations but negative in the model, for all ozone sources. We suggest that this reflects a model overestimate of lightning at northern mid-latitudes combined with an underestimate of the East Asian CO source.

scholarly journals Global ozone–CO correlations from OMI and AIRS: constraints on tropospheric ozone sources

2013 ◽  
Vol 13 (18) ◽  
pp. 9321-9335 ◽  
Author(s):  
P. S. Kim ◽  
D. J. Jacob ◽  
X. Liu ◽  
J. X. Warner ◽  
K. Yang ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Transport Model ◽  
General Structure ◽  
Deep Convection ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Data Set ◽  
Tropical Regions ◽  
Ozone Maximum ◽  
Regression Slopes

Abstract. We present a global data set of free tropospheric ozone–CO correlations with 2° × 2.5° spatial resolution from the Ozone Monitoring Instrument (OMI) and Atmospheric Infrared Sounder (AIRS) satellite instruments for each season of 2008. OMI and AIRS have near-daily global coverage of ozone and CO respectively and observe coincident scenes with similar vertical sensitivities. The resulting ozone–CO correlations are highly statistically significant (positive or negative) in most regions of the world, and are less noisy than previous satellite-based studies that used sparser data. Comparison with ozone–CO correlations and regression slopes (dO3/dCO) from MOZAIC (Measurements of OZone, water vapour, carbon monoxide and nitrogen oxides by in-service AIrbus airCraft) aircraft profiles shows good general agreement. We interpret the observed ozone–CO correlations with the GEOS (Goddard Earth Observing System)-Chem chemical transport model to infer constraints on ozone sources. Driving GEOS-Chem with different meteorological fields generally shows consistent ozone–CO correlation patterns, except in some tropical regions where the correlations are strongly sensitive to model transport error associated with deep convection. GEOS-Chem reproduces the general structure of the observed ozone–CO correlations and regression slopes, although there are some large regional discrepancies. We examine the model sensitivity of dO3/dCO to different ozone sources (combustion, biosphere, stratosphere, and lightning NOx) by correlating the ozone change from that source to CO from the standard simulation. The model reproduces the observed positive dO3/dCO in the extratropical Northern Hemisphere in spring–summer, driven by combustion sources. Stratospheric influence there is also associated with a positive dO3/dCO because of the interweaving of stratospheric downwelling with continental outflow. The well-known ozone maximum over the tropical South Atlantic is associated with negative dO3/dCO in the observations; this feature is reproduced in GEOS-Chem and supports a dominant contribution from lightning to the ozone maximum. A major model discrepancy is found over the northeastern Pacific in summer–fall where dO3/dCO is positive in the observations but negative in the model, for all ozone sources. We suggest that this reflects a model overestimate of lightning at northern midlatitudes combined with an underestimate of the East Asian CO source.

scholarly journals Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

2013 ◽  
Vol 13 (8) ◽  
pp. 21455-21505
Author(s):  
E. Emili ◽  
B. Barret ◽  
S. Massart ◽  
E. Le Flochmoen ◽  
A. Piacentini ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Chemical Transport ◽  
Free Troposphere ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Global Chemical Transport Model ◽  
The Impact

Abstract. Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. In this study we examine the impact of assimilating ozone observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI) in a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE). The assimilation of the two instruments is performed by means of a variational algorithm (4-D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozone-sondes measurements to verify the presence of observations and model biases. It is found that the IASI Tropospheric Ozone Column (TOC, 1000–225 hPa) should be bias-corrected prior to assimilation and MLS lowermost level (215 hPa) excluded from the analysis. Furthermore, a longer analysis of 6 months (July–August 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (Root Mean Square Error, RMSE) of the modeled ozone columns from 30% to 15% in the Upper-Troposphere/Lower-Stratosphere (UTLS, 70–225 hPa) and from 25% to 20% in the free troposphere. The positive effect of assimilating IASI tropospheric observations is very significant at low latitudes (30° S–30° N), whereas it is not demonstrated at higher latitudes. Results are confirmed by a comparison with additional ozone datasets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be little sensitive to the assimilation parameters and the model chemical scheme, due to the high frequency of satellite observations compared to the average life-time of free-troposphere/low-stratosphere ozone.

scholarly journals Intercomparison methods for satellite measurements of atmospheric composition: application to tropospheric ozone from TES and OMI

2010 ◽  
Vol 10 (1) ◽  
pp. 1417-1456 ◽  
Author(s):  
L. Zhang ◽  
D. J. Jacob ◽  
X. Liu ◽  
J. A. Logan ◽  
K. Chance ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Kernel Smoothing ◽  
Transport Model ◽  
Atmospheric Composition ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Satellite Measurements ◽  
In Situ Data ◽  
In Situ Method

Abstract. We analyze three different methods to validate and intercompare satellite measurements of atmospheric composition, and apply them to tropospheric ozone retrievals from the Tropospheric Emission Spectrometer (TES) and the Ozone Monitoring Instrument (OMI). The first method (in situ method) uses in situ vertical profiles for absolute instrument validation; it is limited by the sparseness of in situ data. The second method (CTM method) uses a chemical transport model (CTM) as an intercomparison platform; it provides a globally complete intercomparison with relatively small noise added by model error. The third method (averaging kernel smoothing method) involves smoothing the retrieved profile from one instrument with the averaging kernel matrix of the other; it also provides a global intercomparison but dampens the actual difference between instruments and adds noise from the a priori. Application to a full year (2006) of TES and OMI data shows mean positive biases of 5.3 parts per billion volume (ppbv) (10%) for TES and 2.8 ppbv (5%) for OMI at 500 hPa relative to in situ data from ozonesondes. We show that the CTM method (using the GEOS-Chem CTM) closely approximates results from the in situ method while providing global coverage. It reveals that differences between TES and OMI are generally less than 10 ppbv (18%), except at northern mid-latitudes in summer and over tropical continents. The CTM method allows for well-constrained CTM evaluation in places where the satellite observations are consistent. We thus find that GEOS-Chem underestimates tropospheric ozone in the tropics, reflecting a combination of possible factors, and overestimates ozone in the northern subtropics and southern mid-latitudes, likely because of excessive stratospheric influx.

scholarly journals Tropospheric ozone variability in the tropics from ENSO to MJO and shorter timescales

2015 ◽  
Vol 15 (5) ◽  
pp. 6373-6401
Author(s):  
J. R. Ziemke ◽  
A. R. Douglass ◽  
L. D. Oman ◽  
S. E. Strahan ◽  
B. N. Duncan
Keyword(s):  
Tropospheric Ozone ◽  
Climate Model ◽  
Transport Model ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Longwave Radiation ◽  
Chemical Transport Model ◽  
Enso Variability ◽  
Primary Driver ◽  
The Tropics

Abstract. Aura OMI and MLS measurements are combined to produce daily maps of tropospheric ozone beginning October 2004. We show that El Ni no Southern Oscillation (ENSO) related inter-annual change in tropospheric ozone in the tropics is small compared to combined intra-seasonal/Madden–Julian Oscillation (MJO) and shorter timescale variability by a factor ~ 3–10 (largest in the Atlantic). Outgoing Longwave Radiation (OLR) indicates further that deep convection is the primary driver of the observed tropospheric ozone variability from ENSO down to weekly timescales. We compare tropospheric ozone and OLR satellite observations with two simulations: (1) the Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) that uses observed sea surface temperatures and is otherwise free-running, and (2) the NASA Global Modeling Initiative (GMI) chemical transport model (CTM) that is driven by Modern-Era Retrospective Analysis for Research and Applications (MERRA) analyses. It is shown that the CTM-simulated ozone accurately matches measurements for timescales from ENSO to intra-seasonal/MJO and even 1–2 week periods; however (though not unexpected) the CCM simulation reproduces ENSO variability but not shorter timescales. These analyses suggest that using a model to delineate temporal/spatial properties of tropospheric ozone and convection in the tropics will require that the model reproduce the non-ENSO variability that dominates.

scholarly journals Trends in Global Tropospheric Ozone Inferred from a Composite Record of TOMS/OMI/MLS/OMPS Satellite Measurements and the MERRA-2 GMI Simulation

2018 ◽  
Author(s):  
Jerry R. Ziemke ◽  
Luke D. Oman ◽  
Sarah A. Strode ◽  
Anne R. Douglass ◽  
Mark A. Olsen ◽  
...  
Keyword(s):  
East Asia ◽  
Tropospheric Ozone ◽  
Transport Model ◽  
Central Africa ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Satellite Measurements ◽  
Ozone Trends ◽  
Ne Pacific

Abstract. Past studies have suggested that ozone in the troposphere has increased globally throughout much of the 20th century due to increases in anthropogenic emissions and transport. We show by combining satellite measurements with a chemical transport model that during the last four decades tropospheric ozone does indeed indicate increases that are global in nature, yet still highly regional. Satellite ozone measurements from Nimbus-7 and Earth Probe Total Ozone Mapping Spectrometer (TOMS) are merged with ozone measurements from Aura Ozone Monitoring Instrument/Microwave Limb Sounder (OMI/MLS) to determine trends in tropospheric ozone for 1979–2016. Both TOMS (1979–2005) and OMI/MLS (2005–2016) depict large increases in tropospheric ozone from the Near East to India/East Asia and further eastward over the Pacific Ocean. The 38-year merged satellite record shows total net change over this region of about +6 to +7 Dobson Units (DU) (i.e., ~ 15–20 % of average background ozone), with the largest increase (~ 4 DU) occurring during the 2005–2016 Aura period. The Global Modeling Initiative (GMI) chemical transport model with time-varying emissions is included to evaluate tropospheric ozone trends for 1980–2016. The GMI simulation for the combined record also depicts greatest increases of +6 to +7 DU over India/east Asia, identical to the satellite measurements. In regions of significant increases in TCO the trends are a factor of 2–2.5 larger for the Aura record when compared to the earlier TOMS record; for India/east Asia the trends in TCO for both GMI and satellite measurements are ~ +3 DU-decade−1 or greater during 2005–2016 compared to about +1.2 to +1.4 DU-decade−1 for 1979–2016. The GMI simulation and satellite data also reveal a tropospheric ozone increase of ~ +4 to +5 DU for the 38-year record over central Africa and the tropical Atlantic Ocean. Both the GMI simulation and satellite-measured tropospheric ozone during the latter Aura time period show increases of ~ +3 DU-decade−1 over the NH Atlantic and NE Pacific.

scholarly journals Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

2014 ◽  
Vol 14 (1) ◽  
pp. 177-198 ◽  
Author(s):  
E. Emili ◽  
B. Barret ◽  
S. Massart ◽  
E. Le Flochmoen ◽  
A. Piacentini ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Intercontinental Transport ◽  
Global Chemical Transport Model ◽  
The Impact

Abstract. Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. We consider a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE) in combination with a linear ozone chemistry scheme to examine the impact of assimilating observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI). The assimilation of the two instruments is performed by means of a variational algorithm (4D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozonesonde measurements to verify the presence of observations and model biases. Furthermore, a longer analysis of 6 months (July–December 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (root mean square error, RMSE) of the modeled ozone columns from 30 to 15% in the upper troposphere/lower stratosphere (UTLS, 70–225 hPa). The assimilation of IASI tropospheric ozone observations (1000–225 hPa columns, TOC – tropospheric O3 column) decreases the RMSE of the model from 40 to 20% in the tropics (30° S–30° N), whereas it is not effective at higher latitudes. Results are confirmed by a comparison with additional ozone data sets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be insensitive to the assimilation parameters. We conclude that the combination of a simplified ozone chemistry scheme with frequent satellite observations is a valuable tool for the long-term analysis of stratospheric and free-tropospheric ozone.

scholarly journals Trends in global tropospheric ozone inferred from a composite record of TOMS/OMI/MLS/OMPS satellite measurements and the MERRA-2 GMI simulation

2019 ◽  
Vol 19 (5) ◽  
pp. 3257-3269 ◽  
Author(s):  
Jerry R. Ziemke ◽  
Luke D. Oman ◽  
Sarah A. Strode ◽  
Anne R. Douglass ◽  
Mark A. Olsen ◽  
...  
Keyword(s):  
East Asia ◽  
Tropospheric Ozone ◽  
Transport Model ◽  
Central Africa ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Satellite Measurements ◽  
Ozone Trends ◽  
Ne Pacific

Abstract. Past studies have suggested that ozone in the troposphere has increased globally throughout much of the 20th century due to increases in anthropogenic emissions and transport. We show, by combining satellite measurements with a chemical transport model, that during the last four decades tropospheric ozone does indeed indicate increases that are global in nature, yet still highly regional. Satellite ozone measurements from Nimbus-7 and Earth Probe Total Ozone Mapping Spectrometer (TOMS) are merged with ozone measurements from the Aura Ozone Monitoring Instrument/Microwave Limb Sounder (OMI/MLS) to determine trends in tropospheric ozone for 1979–2016. Both TOMS (1979–2005) and OMI/MLS (2005–2016) depict large increases in tropospheric ozone from the Near East to India and East Asia and further eastward over the Pacific Ocean. The 38-year merged satellite record shows total net change over this region of about +6 to +7 Dobson units (DU) (i.e., ∼15 %–20 % of average background ozone), with the largest increase (∼4 DU) occurring during the 2005–2016 Aura period. The Global Modeling Initiative (GMI) chemical transport model with time-varying emissions is used to aid in the interpretation of tropospheric ozone trends for 1980–2016. The GMI simulation for the combined record also depicts the greatest increases of +6 to +7 DU over India and East Asia, very similar to the satellite measurements. In regions of significant increases in tropospheric column ozone (TCO) the trends are a factor of 2–2.5 larger for the Aura record when compared to the earlier TOMS record; for India and East Asia the trends in TCO for both GMI and satellite measurements are ∼+3 DU decade−1 or greater during 2005–2016 compared to about +1.2 to +1.4 DU decade−1 for 1979–2005. The GMI simulation and satellite data also reveal a tropospheric ozone increases in ∼+4 to +5 DU for the 38-year record over central Africa and the tropical Atlantic Ocean. Both the GMI simulation and satellite-measured tropospheric ozone during the latter Aura time period show increases of ∼+3 DU decade−1 over the N Atlantic and NE Pacific.

scholarly journals Simultaneous assimilation of satellite NO<sub>2</sub>, O<sub>3</sub>, CO, and HNO<sub>3</sub> data for the analysis of tropospheric chemical composition and emissions

2012 ◽  
Vol 12 (20) ◽  
pp. 9545-9579 ◽  
Author(s):  
K. Miyazaki ◽  
H. J. Eskes ◽  
K. Sudo ◽  
M. Takigawa ◽  
M. van Weele ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Transport Model ◽  
Chemical Species ◽  
Chemical Compounds ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Data Set ◽  
Chemical Coupling ◽  
Data Assimilation System ◽  
Assimilation System

Abstract. We have developed an advanced chemical data assimilation system to combine observations of chemical compounds from multiple satellites. NO2, O3, CO, and HNO3 measurements from the Ozone Monitoring Instrument (OMI), Tropospheric Emission Spectrometer (TES), Measurement of Pollution in the Troposphere (MOPITT), and Microwave Limb Sounder (MLS) satellite instruments are assimilated into the global chemical transport model CHASER for the years 2006–2007. The CHASER data assimilation system (CHASER-DAS), based on the local ensemble transform Kalman filter technique, simultaneously optimizes the chemical species, as well as the emissions of O3 precursors, while taking their chemical feedbacks into account. With the available datasets, an improved description of the chemical feedbacks can be obtained, especially related to the NOx-CO-OH-O3 set of chemical reactions. Comparisons against independent satellite, aircraft, and ozonesonde data show that the data assimilation results in substantial improvements for various chemical compounds. These improvements include a reduced negative tropospheric NO2 column bias (by 40–85%), a reduced negative CO bias in the Northern Hemisphere (by 40–90%), and a reduced positive O3 bias in the middle and upper troposphere (from 30–40% to within 10%). These changes are related to increased tropospheric OH concentrations by 5–15% in the tropics and the Southern Hemisphere in July. Observing System Experiments (OSEs) have been conducted to quantify the relative importance of each data set on constraining the emissions and concentrations. The OSEs confirm that the assimilation of individual data sets results in a strong influence on both assimilated and non-assimilated species through the inter-species error correlation and the chemical coupling described by the model. The simultaneous adjustment of the emissions and concentrations is a powerful approach to correcting the tropospheric ozone budget and profile analyses.

Tropospheric ozone over the Indian subcontinent from 2000 to 2015: Data set and simulation using GEOS-Chem chemical transport model

2019 ◽  
Vol 219 ◽  
pp. 117039 ◽  
Author(s):  
Liji M. David ◽  
A.R. Ravishankara ◽  
Jared F. Brewer ◽  
Bastien Sauvage ◽  
Valerie Thouret ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Transport Model ◽  
Indian Subcontinent ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Data Set

scholarly journals Intercomparison methods for satellite measurements of atmospheric composition: application to tropospheric ozone from TES and OMI

2010 ◽  
Vol 10 (10) ◽  
pp. 4725-4739 ◽  
Author(s):  
L. Zhang ◽  
D. J. Jacob ◽  
X. Liu ◽  
J. A. Logan ◽  
K. Chance ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Kernel Smoothing ◽  
Transport Model ◽  
Atmospheric Composition ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Satellite Measurements ◽  
In Situ Data ◽  
In Situ Method

Abstract. We analyze the theoretical basis of three different methods to validate and intercompare satellite measurements of atmospheric composition, and apply them to tropospheric ozone retrievals from the Tropospheric Emission Spectrometer (TES) and the Ozone Monitoring Instrument (OMI). The first method (in situ method) uses in situ vertical profiles for absolute instrument validation; it is limited by the sparseness of in situ data. The second method (CTM method) uses a chemical transport model (CTM) as an intercomparison platform; it provides a globally complete intercomparison with relatively small noise from model error. The third method (averaging kernel smoothing method) involves smoothing the retrieved profile from one instrument with the averaging kernel matrix of the other; it also provides a global intercomparison but dampens the actual difference between instruments and adds noise from the a priori. We apply the three methods to a full year (2006) of TES and OMI data. Comparison with in situ data from ozonesondes shows mean positive biases of 5.3 parts per billion volume (ppbv) (10%) for TES and 2.8 ppbv (5%) for OMI at 500 hPa. We show that the CTM method (using the GEOS-Chem CTM) closely approximates results from the in situ method while providing global coverage. It reveals that differences between TES and OMI are generally less than 10 ppbv (18%), except at northern mid-latitudes in summer and over tropical continents. The CTM method further allows for CTM evaluation using both satellite observations. We thus find that GEOS-Chem underestimates tropospheric ozone in the tropics due to possible underestimates of biomass burning, soil, and lightning emissions. It overestimates ozone in the northern subtropics and southern mid-latitudes, likely because of excessive stratospheric influx of ozone.

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