Full implementation of non-orthogonal surfaces within the PALM model

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985807%3A_____%2F25%3A00638182" target="_blank" >RIV/67985807:_____/25:00638182 - isvavai.cz</a>

Result on the web

<a href="https://meetingorganizer.copernicus.org/ICUC12/ICUC12-723.html" target="_blank" >https://meetingorganizer.copernicus.org/ICUC12/ICUC12-723.html</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Full implementation of non-orthogonal surfaces within the PALM model

Original language description

ZÁKLADNÍ ÚDAJE: ICUC12 Abstracts. Rotterdam: ICUC, 2025, č. článku 723.. [ICUC 2025: International Conference on Urban Climate /12./. 07.07.2025-11.07.2025, Rotterdam & online]. ABSTRAKT: The orthogonal 3D grid used in PALM and other atmospheric models brings challenges in representing resolved obstacles (such as terrain or buildings) with non-orthogonal surfaces. The simple binary form of representation, in which each grid cell is either entirely atmospheric or obstacle, causes aliasing effects (artificial stairs). It has been demonstrated that this leads to significant biases in radiation, surface energy balance and fluid dynamics. The newly introduced PALM slanted surface option involves new methods in the Radiative Transfer Model (RTM) and the surface-related modules in PALM, and it enables a more faithful representation of non-orthogonal surfaces while preserving the PALM’s Arakawa-C model grid without inducing significant performance penalty. For surface-atmospheric interactions, the cut-cell approach is used. In the RTM, a new representation of surface elements is introduced for both raytracing in the preprocessing phase and radiosity-based interactions in the time-stepping phase of the simulation. The format of the input data had to be extended to accommodate the representation of the slanted surfaces. The open-source input processor PALM-GeM is able to prepare slanted surface PALM inputs using various geographic data. Validation and benchmarking results from synthetic and real-case scenarios are presented. The slanted surface model is also being prepared for wind tunnel validation.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10509 - Meteorology and atmospheric sciences

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů