3-D radiative interactions for non-orthogonal surfaces within a regular grid of a microscale atmospheric model

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985807%3A_____%2F23%3A00576327" target="_blank" >RIV/67985807:_____/23:00576327 - isvavai.cz</a>

Result on the web

<a href="https://virtual.oxfordabstracts.com/#/event/3742/submission/382" target="_blank" >https://virtual.oxfordabstracts.com/#/event/3742/submission/382</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

3-D radiative interactions for non-orthogonal surfaces within a regular grid of a microscale atmospheric model

Original language description

ZÁKLADNÍ ÚDAJE: 11th International Conference on Urban Climate. Titles. Sydney: ICUC, 2023, č. článku 382. [ICUC 2023: International Conference on Urban Climate /11./. 28.08.2023-01.09.2023, Sydney]. ABSTRAKT: Spatial discretization using a regular grid is a standard approach for all kinds of atmospheric models. PALM is an open-source HPC-enabled modular atmospheric modelling system that is able to capture the most relevant physical processes in the complex urban boundary layer. One of the most important urban processes is the radiative interaction among urban surfaces in 3-D. In PALM, these are simulated explicitly by the Radiative transfer model (RTM), which utilises the same discretization by a regular grid and the same data structures and parallelization approach as the model core, and that makes it tightly integrated and highly scalable. However, it can be demonstrated that the discretization of arbitrarily oriented surfaces using only orthogonal grid surface elements may lead to biases that cannot be eliminated by increasing the model resolution. E.g. an idealised street canyon oblique to the grid axes is discretized by artificial steps that increase the total area of the walls by a resolution-independent coefficient. It also introduces artificial reflections among the steps which decrease the effective albedo of the walls. The latest version of RTM introduces a system for representing and modelling radiation among arbitrarily oriented surface elements in such a way that it avoids these biases while preserving its high computational efficiency and scalability. It keeps the discretization by the regular grid and the level of detail corresponding to the grid resolution. It also allows a combination of slanted and orthogonal surface elements without a significant performance penalty to the latter. The presentation will describe the system in detail and demonstrate the results of its performance and scalability testing, as well as validation and sensitivity testing on idealised cases. The research was supported by project TO01000219 “TURBAN” (Norway Grants, Technology Agency of the Czech Republic). HPC support: Czech Ministry of Education, e-INFRA CZ (90140).

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

<a href="/en/project/TO01000219" target="_blank" >TO01000219: Turbulent-resolving urban modeling of air quality and thermal comfort</a><br>

Continuities

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

Publication year

2023

Confidentiality

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