Research ArticleATMOSPHERIC SCIENCE

Pinpointing nitrogen oxide emissions from space

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Science Advances  13 Nov 2019:
Vol. 5, no. 11, eaax9800
DOI: 10.1126/sciadv.aax9800
  • Fig. 1 Tropospheric NO2 column over Riyadh as derived from TROPOMI.

    (A) Single overpass on 17 December 2017. Arrows indicate ECMWF wind vectors at 450 m above ground. Gray lines show motorways and trunk roads (20). Symbols mark city centers (o), PPs (Δ), and CPs (∇). See table S1 for plant locations and references. (B) Temporal average for December 2017 to October 2018.

  • Fig. 2 NOx budget over Riyadh for December 2017 to October 2018.

    (A) sinks S, (B) divergence D, and (C) top-down NOx emissions E = S + D. Numbers on top give spatial integrals for urban area (dashed rectangle) and greater area (250 × 250 km2). (D) Meridional sections of S, D, and E at 47.05°E (dotted rectangle), crossing PP9 and PP10.

  • Fig. 3 Separation of top-down emissions in point sources and residual city emissions.

    (A) Detected point source peaks Eps, identified as PP7 to P10 and CP1 and CP2. For each point source, a label provides i) the rank within the iterative peak fitting, ii) the total emission rate (in kg/s), and iii) the emission intensity (in g/kWh) resulting from division by PP capacity (table S1). (B) Residual city emissions EEps.

  • Fig. 4 NOx emissions over the South African Highveld.

    (A) Top-down emissions E averaged for December 2017 to October 2018. Gray lines show motorways and trunk roads. Symbols mark city centers (o), PPs (Δ), and a synthetic fuel plant (□). (B) Fitted point sources Eps. See table S2 for point source locations, references, and derived emissions.

  • Fig. 5 NOx emissions for Germany.

    (A) Top-down emissions E averaged for April to October 2018. Large cities (>106 inhabitants) and the lignite-fired PPs (>1 GW) are labeled. Smaller cities (>2 × 105 inhabitants) and the 100 largest point sources in Germany, as listed in E-PRTR, are shown by gray symbols (Δ, PP; ∇, CP; and □, other). Dashed rectangles indicate zoom regions. (B and C) Zooms of top-down emissions (left) and corresponding fitted point sources (right) for western and eastern PPs, respectively. (D) Correlation of fitted point source emissions to bottom-up values from E-PRTR for lignite PPs. See table S3 for details. Nr, Neurath; Na, Niederaußem; Jw, Jänschwalde; Bb, Boxberg; Ww, Weisweiler; Ld, Lippendorf; SP, Schwarze Pumpe.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/11/eaax9800/DC1

    Supplementary Text

    Fig. S1. Bottom-up emissions for Riyadh.

    Fig. S2. NOx budget for PPs over the South African Highveld.

    Fig. S3. NOx budget for Germany.

    Fig. S4. Mean NOx flux over Riyadh.

    Fig. S5. Illustration of the iterative peak fitting in 1D.

    Fig. S6. Impact of errors in wind fields.

    Table S1. Considered point sources around Riyadh.

    Table S2. Considered point sources in South Africa.

    Table S3. Considered point sources in Germany.

    References (2132)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text
    • Fig. S1. Bottom-up emissions for Riyadh.
    • Fig. S2. NOx budget for PPs over the South African Highveld.
    • Fig. S3. NOx budget for Germany.
    • Fig. S4. Mean NOx flux over Riyadh.
    • Fig. S5. Illustration of the iterative peak fitting in 1D.
    • Fig. S6. Impact of errors in wind fields.
    • Table S1. Considered point sources around Riyadh.
    • Table S2. Considered point sources in South Africa.
    • Table S3. Considered point sources in Germany.
    • References (2132)

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