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

Ziemke, J. R.; Douglass, Anne R.; Oman, Luke D.; Strahan, S. E.; Duncan, B. N.

doi:10.5194/acp-15-8037-2015

Cited by 43 publications

(37 citation statements)

References 53 publications

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“…It is notable that we do not find any sites that show significance of a 7-day cycle (Altshuler et al, 1995;Marr and Harley, 2002;Beirle et al, 2003). Application of this approach to longer time series may also allow the investigation of other characteristic timescales such as North Atlantic Oscillation (NAO) or El Niño-Southern Oscillation (ENSO) (Ziemke et al, 2015).…”

Section: Annual and Daily Cyclesmentioning

confidence: 96%

Spectral analysis of atmospheric composition: application to surface ozone model–measurement comparisons

2016

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Abstract. Models of atmospheric composition play an essential role in our scientific understanding of atmospheric processes and in providing policy strategies to deal with societally relevant problems such as climate change, air quality, and ecosystem degradation. The fidelity of these models needs to be assessed against observations to ensure that errors in model formulations are found and that model limitations are understood. A range of approaches are necessary for these comparisons. Here, we apply a spectral analysis methodology for this comparison. We use the LombScargle periodogram, a method similar to a Fourier transform, but better suited to deal with the gapped data sets typical of observational data. We apply this methodology to long-term hourly ozone observations and the equivalent model (GEOS-Chem) output. We show that the spectrally transformed observational data show a distinct power spectrum with regimes indicative of meteorological processes (weather, macroweather) and specific peaks observed at the daily and annual timescales together with corresponding harmonic peaks at one-half, one-third, etc., of these frequencies. Model output shows corresponding features. A comparison between the amplitude and phase of these peaks introduces a new comparison methodology between model and measurements. We focus on the amplitude and phase of diurnal and seasonal cycles and present observational/model comparisons and discuss model performance. We find large biases notably for the seasonal cycle in the mid-latitude Northern Hemisphere where the amplitudes are generally overestimated by up to 16 ppbv, and phases are too late on the order of 1-5 months. This spectral methodology can be applied to a range of model-measurement applications and is highly suitable for Multimodel Intercomparison Projects (MIPs).

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Section: Annual and Daily Cyclesmentioning

confidence: 96%

Spectral analysis of atmospheric composition: application to surface ozone model–measurement comparisons

2016

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“…DOI: https://doi. org/10.1525/elementa.265.f8 (Sun et al 2014;Ziemke et al, 2015), but this has not been demonstrated for CCMs. A single CCM study, using observed SSTs, reproduced the tropical ozone response to ENSO variability but not shorter timescales related to the MJO (Ziemke et al, 2015).…”

Section: State Of Knowledgementioning

confidence: 99%

“…org/10.1525/elementa.265.f8 (Sun et al 2014;Ziemke et al, 2015), but this has not been demonstrated for CCMs. A single CCM study, using observed SSTs, reproduced the tropical ozone response to ENSO variability but not shorter timescales related to the MJO (Ziemke et al, 2015). Over northern mid-latitudes, ENSO events can affect the interannual variability of hemispheric pollution transport by modulating the strength and position of the subtropical jet stream, particularly in the Pacific-North America sector (Trenberth et al, 1998;Koumoutsaris et al, 2008;Li and Lau, 2012;Lin et al, 2014).…”

Section: State Of Knowledgementioning

confidence: 99%

Tropospheric Ozone Assessment Report: Assessment of global-scale model performance for global and regional ozone distributions, variability, and trends

Young

Naik

Fiore

et al. 2018

Elementa: Science of the Anthropocene

255

274

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The goal of the Tropospheric Ozone Assessment Report (TOAR) is to provide the research community with an up-to-date scientific assessment of tropospheric ozone, from the surface to the tropopause. While a suite of observations provides significant information on the spatial and temporal distribution of tropospheric ozone, observational gaps make it necessary to use global atmospheric chemistry models to synthesize our understanding of the processes and variables that control tropospheric ozone abundance and its variability. Models facilitate the interpretation of the observations and allow us to make projections of future tropospheric ozone and trace gas distributions for different anthropogenic or natural perturbations. This paper assesses the skill of current-generation global atmospheric chemistry models in simulating the observed present-day tropospheric ozone distribution, variability, and trends. Drawing upon the results of recent international multi-model intercomparisons and using a range of model evaluation techniques, we demonstrate that global chemistry models are broadly skillful in capturing the spatio-temporal variations of tropospheric ozone over the seasonal cycle, for extreme pollution episodes, and changes over interannual to decadal periods. However, models are consistently biased high in the northern hemisphere and biased low in the southern hemisphere, throughout the depth of the troposphere, and are unable to replicate particular metrics that define the longer term trends in tropospheric ozone as derived from some background sites. When the models compare unfavorably against observations, we discuss the potential causes of model biases and propose directions for future developments, including improved evaluations that may be able to better diagnose the root cause of the model-observation disparity. Overall, model results should be approached critically, including determining whether the model performance is acceptable for the problem being addressed, whether biases can be tolerated or corrected, whether the model is appropriately constituted, and whether there is a way to satisfactorily quantify the uncertainty.

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“…The response is highly linear in the tropics, so La Niña conditions produce an antisymmetric response (DeWeaver and Nigam, 2002). This influence on tropical tropospheric ozone has been observed in satellite data (e.g., Chandra et al, 1998;Thompson et al, 2001;Ziemke et al, 2010Ziemke et al, , 2015 and ground-based measurements (e.g., Fujiwara et al, 1999;Lee et al, 2010). Both chemical transport models (CTMs) driven by analyzed meteorology and free-running models have simulated this impact of ENSO on the tropical ozone (e.g., Sudo and Takahashi, 2001;Zeng and Pyle, 2005;Doherty et al, 2006;Oman et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

2016

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Abstract. We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude and spatial distribution of the El Niño Southern Oscillation (ENSO) influence on tropospheric column ozone (TCO) into the middle latitudes. This study provides the first explicit spatially resolved characterization of the ENSO influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Niño 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Niño 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, ENSO related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9-year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Niño influence on tropospheric ozone in the middle latitudes.

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

Cited by 43 publications

References 53 publications

Spectral analysis of atmospheric composition: application to surface ozone model–measurement comparisons

Spectral analysis of atmospheric composition: application to surface ozone model–measurement comparisons

Tropospheric Ozone Assessment Report: Assessment of global-scale model performance for global and regional ozone distributions, variability, and trends

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

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