Michael Mommert
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Mommert
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Michael
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michael.mommert@unisg.ch
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+41 71 224 2615
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  • Publication
    Toward Global Estimation of Ground-Level NO2 Pollution With Deep Learning and Remote Sensing
    (IEEE, 2022-03-21)
    Scheibenreif, Linus Mathias
    ;
    Mommert, Michael
    ;
    Borth, Damian
    Air pollution is a central environmental problem in countries around the world. It contributes to climate change through the emission of greenhouse gases, and adversely impacts the health of billions of people. Despite its importance, detailed information about the spatial and temporal distribution of pollutants is complex to obtain. Ground-level monitoring stations are sparse, and approaches for modeling air pollution rely on extensive datasets which are unavailable for many locations. We introduce three techniques for the estimation of air pollution to overcome these limitations: 1) a baseline localized approach that mimics conventional land-use regression through gradient boosting; 2) an OpenStreetMap (OSM) approach with gradient boosting that is applicable beyond regions covered by detailed geographic datasets; and 3) a remote sensing-based deep learning method utilizing multiband imagery and trace-gas column density measurements from satellites. We focus on the estimation of nitrogen dioxide (NO2), a common anthropogenic air pollutant with adverse effects on the environment and human health. Our local baseline model achieves strong results with a mean absolute error (MAE) of 5.18 ± 0.16 μg/m3 NO2. Substituting localized inputs with OSM leads to a degraded performance (MAE 7.22 ± 0.14) but enables NO2 estimation at a global scale. The proposed deep learning model on remote sensing data combines high accuracy (MAE 5.5 ± 0.14) with global coverage and heteroscedastic uncertainty quantification. Our results enable the estimation of surface-level NO2 pollution with high spatial resolution for any location on Earth. We illustrate this capability with an out-of-distribution test set on the US westcoast. Code and data are publicly available.
    Type: journal article
    Journal: IEEE Transactions on Geoscience and Remote Sensing
    Volume: 60
    Issue: 4705914
    URL: https://ieeexplore.ieee.org/document/9738606
    DOI: 10.1109/TGRS.2022.3160827
    URI: https://www.alexandria.unisg.ch/handle/20.500.14171/108867
    Scopus© Citations 10
  • Publication
    Distinguishing multicellular life on exoplanets by testing Earth as an exoplanet
    (Cambridge University Press, 2020-10)
    Doughty, Christopher E.
    ;
    Abraham, Andrew J.
    ;
    Windsor, James
    ;
    Mommert, Michael
    ;
    Gowanlock, Michael
    ;
    Robinson, Tyler
    ;
    Trilling, David E.
    Can multicellular life be distinguished from single cellular life on an exoplanet? We hypothesize that abundant upright photosynthetic multicellular life (trees) will cast shadows at high sun angles that will distinguish them from single cellular life and test this using Earth as an exoplanet. We first test the concept using unmanned aerial vehicles at a replica moon-landing site near Flagstaff, Arizona and show trees have both a distinctive reflectance signature (red edge) and geometric signature (shadows at high sun angles) that can distinguish them from replica moon craters. Next, we calculate reflectance signatures for Earth at several phase angles with POLDER (Polarization and Directionality of Earth's reflectance) satellite directional reflectance measurements and then reduce Earth to a single pixel. We compare Earth to other planetary bodies (Mars, the Moon, Venus and Uranus) and hypothesize that Earth's directional reflectance will be between strongly backscattering rocky bodies with no weathering (like Mars and the Moon) and cloudy bodies with more isotropic scattering (like Venus and Uranus). Our modelling results put Earth in line with strongly backscattering Mars, while our empirical results put Earth in line with more isotropic scattering Venus. We identify potential weaknesses in both the modelled and empirical results and suggest additional steps to determine whether this technique could distinguish upright multicellular life on exoplanets.
    Type: journal article
    Journal: International Journal of Astrobiology
    DOI: 10.1017/S1473550420000270
    URI: https://www.alexandria.unisg.ch/handle/20.500.14171/111732
    Scopus© Citations 1