Understanding how greenhouse gases and pollutants move through the atmosphere is essential for predicting and mitigating their effects. We present the Boundary Layer Dispersion and Footprint Model (BLDFM), which solves the three-dimensional steady-state advection-diffusion equation in Eulerian form using a numerical approach based on the Fourier, linear shooting, and exponential integrator methods. In contrast to analytical Gaussian plume or stochastic Lagrangian models, this approach avoids several asymptotic assumptions required for closed-form solutions, such as the slender-plume approximation and power-law profiles. BLDFM relies solely on a steady-state Reynolds-averaged advection-diffusion equation with K-theory closure and horizontally homogeneous profiles that depend only on height. BLDFM is modular, decoupling the turbulence closure from the transport solver. The flexibility and modularity of the model may enable a wide range of applications, including climate impact studies, industrial emissions monitoring, and spatial flux attribution. We verify the numerical solver against an analytical test case and find excellent agreement. We also compare BLDFM with the well-established Kormann and Meixner (2001) footprint model (KM01), based on the analytical Gaussian plume. The results show overall good agreement, but some differences in the fetch of the footprints, attributed to KM01's neglect of streamwise turbulent mixing. Our results demonstrate the potential of BLDFM as a useful tool for atmospheric scientists, biogeochemists, ecologists, and engineers.
", "doi": "10.5194/gmd-19-6259-2026", "issn": "1991-9603", "publisher": "European Geosciences Union", "publication": "Geoscientific Model Development", "publication_date": "2026-07-13", "series_number": "13", "volume": "19", "issue": "13", "pages": "6259-6272" }, { "id": "authors:f4rwj-g8a38", "collection": "authors", "collection_id": "f4rwj-g8a38", "cite_using_url": "https://authors.library.caltech.edu/records/f4rwj-g8a38", "type": "article", "title": "Variability of local gravity wave spectra from data of a high-resolution icosahedral-grid global model", "author": [ { "family_name": "Proch\u00e1zkov\u00e1", "given_name": "Zuzana", "orcid": "0000-0002-1095-4436" }, { "family_name": "Mahmoudi", "given_name": "Erfan" }, { "family_name": "Chew", "given_name": "Ray", "orcid": "0000-0001-6454-8401", "clpid": "Chew-Ray-W" }, { "family_name": "Dolaptchiev", "given_name": "Stamen", "orcid": "0000-0002-2410-3739" }, { "family_name": "Stephan", "given_name": "Claudia Christine", "orcid": "0000-0001-5736-1948" }, { "family_name": "V\u00f6lker", "given_name": "Georg Sebastian", "orcid": "0000-0003-3658-8515" }, { "family_name": "Achatz", "given_name": "Ulrich", "orcid": "0000-0002-5065-5633" } ], "abstract": "Atmospheric gravity waves influence the general circulation through transport of energy and momentum. Even with increasing computing capacities, parametrisation of their effects is still needed. Here, we diagnose gravity wave spectra from the data of a high-resolution ICON simulation on subdomains defined by a low-resolution ICON grid. A unique methodology is applied that avoids unnecessary interpolations and filters the data by projection on the linearised gravity wave modes, providing precise and detailed information about the gravity wave spectra. The dependence of these spectra on latitude is then studied, highlighting the importance of the zonal wind direction in the shape of the spectra. Finally, we see that the spectra can be highly simplified by using tens to hundreds of principal components, which is a key property allowing for an increase in efficiency of current gravity wave parametrisations.
", "doi": "10.5194/acp-26-9541-2026", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2026-07-08", "series_number": "13", "volume": "26", "issue": "13", "pages": "9541-9558" } ]