EGU2020-3129, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-3129
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Linking the variability of PM10 in Europe to the position of the extratropical jet

Carlos Ordóñez1, Jose M. Garrido-Perez1,2, Ricardo García-Herrera1,2, and David Barriopedro2
Carlos Ordóñez et al.
  • 1Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física de la Tierra y Astrofísica, Madrid, Spain
  • 2Instituto de Geociencias (IGEO, CSIC-UCM), Madrid, Spain

We have investigated the impact of the polar jet on the winter PM10 (particulate matter with aerodynamic diameter ≤ 10 μm) concentrations in Europe during a 10-year period. For this purpose, we have computed the daily latitude and strength of the jet by using reanalysis wind fields in the lower troposphere over the eastern North Atlantic (0°–15° W). Then we have extracted daily average surface PM10 observations at ~440 sites from the European air quality database (AirBase).

Four preferred jet positions have been identified over the 0°–15° W sector in winter: southern (south of 41° N), central-southern (between 41° N and 51° N), central-northern (between 51° N and 63° N) and northern (north of 63° N). They exert a stronger influence than the jet strength on the mean PM10 levels. Consequently, we have examined whether the full distribution of PM10 and the occurrence of PM10 extremes (exceedances of the local winter 95th percentiles) are also linked to the jet position.

The northern position is associated with enhanced PM10 concentrations (on average ~9 μg m−3 above the mean values) and threefold increases in the odds of PM10 extremes over northwestern / central Europe. Comparable increases have been found in southern Europe when the jet is in its central-northern position. In both cases, the rise in the PM10 concentrations is associated with blocking of the zonal flow over those regions and the impact on PM10 extremes is maximised for time lags of around 1–2 days. On the other hand, the mean sea level pressure (SLP) patterns of the central-southern jet position resemble a positive phase of the winter North Atlantic Oscillation (NAO), yielding large PM10 decreases (on average around −9 μg m−3) in northwestern / central Europe. Similarly, the southern jet position results in low PM10 concentrations in southern Europe.

These results demonstrate that winter near-surface PM10 concentrations in Europe are strongly sensitive to the jet latitude, with implications for future projections of air pollution. As there is no consensus on the future evolution of the North Atlantic jet in a warming climate, different responses among model simulations could be relevant to understand discrepancies in their climate change projections of PM10 and other pollutants.

How to cite: Ordóñez, C., Garrido-Perez, J. M., García-Herrera, R., and Barriopedro, D.: Linking the variability of PM10 in Europe to the position of the extratropical jet, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3129, https://doi.org/10.5194/egusphere-egu2020-3129, 2020

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  • CC1: Association with climate variability? , Meiyun Lin, 30 Apr 2020

    Very interesting results! Do you notice any associations of the four preferred jet locations with climate variability such as NAO or ENSO? You may be interested in our paper that demonstrated the role of ENSO and associated jet stream structure (not just location) on springtime high surface ozone events over the western United States: 

    , A.M. Fiore, L.W. Horowitz, A.O. Langford, S. J. Oltmans, D. Tarasick, H.E. Reider (2015): Climate variability modulates western US ozone air quality in spring via deep stratospheric intrusionsNature Communications, 6, 7105, doi:10.1038/ncomms8105

    Meiyun (

    • CC2: Reply to CC1, Meiyun Lin, 30 Apr 2020

      Correction: 

      , A.M. Fiore, L.W. Horowitz, A.O. Langford, S. J. Oltmans, D. Tarasick, H.E. Reider (2015): Climate variability modulates western US ozone air quality in spring via deep stratospheric intrusionsNature Communications, 6, 7105, doi:10.1038/ncomms8105

      • AC2: Reply to CC2 by Meiyun Lin, Carlos Ordóñez, 30 Apr 2020

        I was aware of your paper but have not read it yet! I will have a look at it as soon as I have the time, thanks!

    • AC1: Reply to CC1 by Meiyun Lin, Carlos Ordóñez, 30 Apr 2020

      Thanks for the comment, Meiyun.

      We haven't examined the associations of the preferred jet locations with modes of climate variability. That has been done before and we were mainly interested in the impact on the concentrations of air pollutants.

      The first three modes of climate variability affecting western Europe are the North Atlantic Oscillation (NAO), the East Atlantic Pattern (EA) and the Scandinavian Pattern (SCAND) (see e.g. Cassou and Cattiaux, 2016). Woollings et al. (2010) introduced the jet algorithm that we adapted and also examined some of those relationships. The abstract in Woolling's paper says: "the NAO and the EA both describe combined changes in the latitude and speed of the jet stream. It is therefore necessary, but not always sufficient, to consider both the NAO and the EA in identifying changes in the jet stream". There are also more recent papers by Woollings and other authors examining similar types of relationships. I am not familiar with any work investigating the role of ENSO, although I am not an expert.

      I should note that Woollings et al. (2010) identified the jet over a large region in the north Atlantic (0-60 W) and detected three preferred jet positions in winter. In our case, we reduced the region to the East Atlantic (0-15 W) in order to maximise the impact on the PM10 concentrations. We found four preferred winter jet locations over that sector so any connections with modes of climate variability might be different from those found by Woollings and other analyses. For instance, one of our jet positions (central southern jet) resembles a positive NAO and is associated with negative PM anomalies over most of western Europe. On the other hand, our northern jet location is a typical situation of blocked zonal flow and therefore yields positive PM anomalies over the same region. See more details in Ordóñez et al. (2019).

      Finally, there have been some papers on the relationships between European PM concentrations and the NAO and here we show a link to the jet latitude. However, we have found even stronger associations of PM10 with the occurrence of high-latitude blocks and subtropical ridges, with R-squared values up to ~0.8 for wintertime mean values over some parts of central Europe (Garrido-Perez et al., 2017). Unfortunately, there are not many long-term observations of PM in Europe, so it would be good to reexamine some of these relationships with models. I agree with you that one should have a look at the role of different parameters describing the jet structure. There is indeed considerable spread in future projections of some of those parameters (e.g. Peings et al., 2018), which could have an impact on future air quality projections too.

      Cassou, C. and J. Cattiaux (2016): Disruption of the European climate seasonal clock in a warming world, Nature Climate Change, http://dx.doi.org/10.1038/nclimate2969

      Garrido-Perez J.M., Ordóñez C., García-Herrera R. (2017): Strong signatures of high-latitude blocks and subtropical ridges in winter PM10 over Europe. Atmospheric Environment, 167, 49-60. doi:10.1016/j.atmosenv.2017.08.004.

      Ordóñez C., Barriopedro D., García-Herrera R. (2019): Role of the position of the North Atlantic jet in the variability and odds of extreme PM10 in Europe. Atmospheric Environment, 210, 35-46. doi:10.1016/j.atmosenv.2019.04.045.

      Peings et al. (2018): Projected squeezing of the wintertime North-Atlantic jet, Environmental Research Letters, Volume 13, Number 7

      Woollings, T., Hannachi, A., Hoskins, B., 2010. Variability of the North Atlantic eddy-driven jet stream. Q. J. R. Meteorol. Soc. 136, 856–868. https://doi.org/10.1002/qj.625.