Impacts of anthropogenic and natural sources on free tropospheric ozone over the Middle East

Jiang, Zhe; Miyazaki, Kazuyuki; Worden, J.; Liu, Jane; Jones, Dylan B. A.; Henze, D. K.

doi:10.5194/acp-16-6537-2016

Cited by 12 publications

(10 citation statements)

References 38 publications

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“…For retrieval of O 3 from remote sensing measurements, the a priori knowledge is usually taken from an O 3 profile climatology, which provides average O 3 profiles and their variances. Most, if not all, total O 3 algorithms (e.g., Mateer et al, 1971;Klenk et al, 1982;Bhartia and Wellemeyer, 2002;Coldewey-Egbers et al, 2005;Eskes et al, 2005;Veefkind et al, 2006;Lerot et al, 2010Lerot et al, , 2014Loyola et al, 2011;Van Roozendael et al, 2006Wassmann et al, 2015) rely on an O 3 profile climatology to uniquely and completely specify the vertical distribution of a retrieved total column. Profile O 3 algorithms (e.g., Hoogen et al, 1999;Liu et al, 2005;Wei et al, 2010;Bhartia et al, 2013;Miles et al, 2015) based on the widely adopted optimal estimation (OE) inversion technique (Rodgers, 2000) require the a priori O 3 profiles and their covariances to constrain the retrievals from deviating too far from the a priori O 3 distributions.…”

Section: Profile Climatologymentioning

confidence: 99%

Ozone profile climatology for remote sensing retrieval algorithms

Yang

Liu

2019

Atmos. Meas. Tech.

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Abstract. New ozone (O3) profile climatologies are created from the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) O3 record between 2005 and 2016, within the period of Aura Microwave Limb Sounder (MLS) and Aura Ozone Monitoring Instrument (OMI) assimilation. These two climatologies consist of monthly mean O3 profiles and the corresponding covariances dependent on the local solar time, longitude (15∘), and latitude (10∘), which are parameterized by tropopause pressure and total O3 column. They are validated through comparisons, which show good agreements with previous O3 profile climatologies. Compared to a monthly zonal mean climatology, both tropopause- and column-dependent climatologies provide improved a priori information for profile and total O3 retrievals from remote sensing measurements. Furthermore, parameterization of the O3 profile with total column O3 usually reduces the natural variability of the resulting climatological profile in the upper stratosphere further than the tropopause parameterization, which usually performs better in the upper troposphere and lower stratosphere (UTLS). Therefore tropopause-dependent climatology is more appropriate for profile O3 retrieval for complementing the vertical resolution of backscattered ultraviolet (UV) spectra, while the column-dependent climatology is more suited for use in total O3 retrieval algorithms, with an advantage of complete profile specification without requiring ancillary information. Compared to previous column-dependent climatologies, the new MERRA-2 column-dependent climatology better captures the diurnal, seasonal, and spatial variations and dynamical changes in O3 profiles with higher resolutions in O3, latitude, longitude, and season. The new MERRA-2 climatologies contain the first quantitative characterization of O3 profile covariances, which facilitate a new approach to improve O3 profiles using the most probable patterns of profile adjustments represented by the empirical orthogonal functions (EOFs) of the covariance matrices. The MERRA-2 daytime column-dependent climatology is used in the combo O3 and SO2 algorithm for retrieval from the Earth Polychromatic Imaging Camera (EPIC) on board the Deep Space Climate Observatory (DSCOVR) satellite, the Ozone Mapping and Profiler Suite Nadir Mapper (OMPS-NM) on the Suomi National Polar Partnership (SNPP), and the Ozone Monitoring Instrument (OMI) on the Aura spacecraft.

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Section: Profile Climatologymentioning

confidence: 99%

Ozone profile climatology for remote sensing retrieval algorithms

Yang

Liu

2019

Atmos. Meas. Tech.

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“…The seven sites are chosen to represent two longitudinal and 3-4 latitudinal zones in Africa. The meteorological data include the NCEP/NCAR reanalysis I (Kalnay et al, 1996). The monthly wind fields are used to describe the climatology of atmospheric circulation during the study period from 1987 to 2006.…”

Section: The Hysplit Trajectory Model and Meteorological Datamentioning

confidence: 99%

Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

et al. 2018

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Abstract. In this study, we characterize the transport of ozone from Africa to Asia through the analysis of the simulations of a global chemical transport model, GEOS-Chem, from 1987 to 2006. The receptor region Asia is defined within 5–60∘ N and 60–145∘ E, while the source region Africa is within 35∘ S–15∘ N and 20∘ W–55∘ E and within 15–35∘ N and 20∘ W–30∘ E. The ozone generated in the African troposphere from both natural and anthropogenic sources is tracked through tagged ozone simulation. Combining this with analysis of trajectory simulations using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, we find that the upper branch of the Hadley cell connects with the subtropical westerlies in the Northern Hemisphere (NH) to form a primary transport pathway from Africa to Asia in the middle and upper troposphere throughout the year. The Somali jet that runs from eastern Africa near the equator to the Indian subcontinent in the lower troposphere is the second pathway that appears only in NH summer. The influence of African ozone mainly appears over Asia south of 40∘ N. The influence shows strong seasonality, varying with latitude, longitude, and altitude. In the Asian upper troposphere, imported African ozone is largest from March to May around 30∘ N (12–16 ppbv) and lowest during July–October around 10∘ N (∼ 2 ppbv). In the Asian middle and lower troposphere, imported African ozone peaks in NH winter between 20 and 25∘ N. Over 5–40∘ N, the mean fractional contribution of imported African ozone to the overall ozone concentrations in Asia is largest during NH winter in the middle troposphere (∼ 18 %) and lowest in NH summer throughout the tropospheric column (∼ 6 %). This seasonality mainly results from the collective effects of the ozone precursor emissions in Africa and meteorology and chemistry in Africa, in Asia and along the transport pathways. The seasonal swing of the Hadley circulation and subtropical westerlies along the primary transport pathway plays a dominant role in modulating the seasonality. There is more imported African ozone in the Asian upper troposphere in NH spring than in winter. This is likely due to more ozone in the NH African upper troposphere generated from biogenic and lightning NOx emissions in NH spring. The influence of African ozone on Asia appears larger in NH spring than in autumn. This can be attributed to both higher altitudes of the elevated ozone in Africa and stronger subtropical westerlies in NH spring. In NH summer, African ozone hardly reaches Asia because of the blocking by the Saharan High, Arabian High, and Tibetan High on the transport pathway in the middle and upper troposphere, in addition to the northward swing of the subtropical westerlies. The seasonal swings of the intertropical convergence zone (ITCZ) in Africa, coinciding with the geographic variations of the ozone precursor emissions, can further modulate the seasonality of the transport of African ozone, owing to the functions of the ITCZ in enhancing lightning NOx generation and uplifting ozone and ozone precursors to upper layers. The strength of the ITCZ in Africa is also found to be positively correlated with the interannual variation of the transport of African ozone to Asia in NH winter. Ozone from NH Africa makes up over 80 % of the total imported African ozone over Asia in most altitudes and seasons. The interhemispheric transport of ozone from southern hemispheric Africa (SHAF) is most evident in NH winter over the Asian upper troposphere and in NH summer over the Asian lower troposphere. The former case is associated with the primary transport pathway in NH winter, while the latter case is associated with the second transport pathway. The intensities of the ITCZ in Africa and the Somali jet can each explain ∼ 30 % of the interannual variations in the transport of ozone from SHAF to Asia in the two cases.

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“…Surface O 3 is produced in the atmosphere via photochemical processing of multiple precursors including volatile organic compounds (VOCs), carbon monoxide (CO) and nitrogen oxides (NO,NO 2 ). These precursors originate from both natural and anthropogenic sources (Vingarzan, 2004;Simon et al, 2014;Jiang et al, 2016). In addition to local production, transport of O 3 and its precursors from upwind regions and the upper atmosphere can also influence surface O 3 abundance.…”

Section: Introductionmentioning

confidence: 99%

“…Increases in solar radiation and air temperature can increase the rate of the chemical production of O 3 and modulate the biogenic emissions of O 3 precursors (Guenther, 1993;Sillman and Samson, 1995;Peñuelas and Llusià, 2001), especially over highly polluted regions (Ordónez et al, 2005;Rasmussen et al, 2012;Pusede et al, 2015). Increases in humidity can enhance the chemical destruction of O 3 and shorten its atmospheric lifetime (Johnson et al, 1999;Camalier et al, 2007). Therefore, changes in meteorological conditions on various spatial and temporal scales play key roles in determining the surface O 3 distribution.…”

Section: Introductionmentioning

confidence: 99%

Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

Liu

Ban-Weiss

et al. 2017

Atmos. Chem. Phys.

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Abstract. The response of surface ozone (O3) concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM). Idealized, spatially uniform sea surface temperature (SST) anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR) analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage between basin-scale SST variability and continental surface O3 pollution, which should be considered in regional air quality management.

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Impacts of anthropogenic and natural sources on free tropospheric ozone over the Middle East

Cited by 12 publications

References 38 publications

Ozone profile climatology for remote sensing retrieval algorithms

Ozone profile climatology for remote sensing retrieval algorithms

Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

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