Modelling spatiotemporal variations of the canopy layer urban heat island in Beijing at the neighbourhood scale
<p>Information on the spatiotemporal characteristics of Beijing's urban–rural near-surface air temperature difference, known as the canopy layer urban heat island (UHI), is important for future urban climate management strategies. This paper investigates the variation of near-surface air...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/13687/2021/acp-21-13687-2021.pdf |
| Summary: | <p>Information on the spatiotemporal characteristics of Beijing's
urban–rural near-surface air temperature difference, known as the canopy
layer urban heat island (UHI), is important for future urban climate
management strategies. This paper investigates the variation of near-surface
air temperatures within Beijing at a neighbourhood-scale resolution
(<span class="inline-formula">∼</span> 100 m) during winter 2016 and summer 2017. We perform
simulations using the urban climate component of the ADMS-Urban model with
land surface parameters derived from both local climate zone classifications
and OpenStreetMap land use information. Through sensitivity simulations, the
relative impacts of surface properties and anthropogenic heat emissions on
the temporal variation of Beijing's UHI are quantified. Measured UHI
intensities between central Beijing (Institute of Atmospheric Physics) and a
rural site (Pinggu) during the Atmospheric Pollution and Human Health in a
Chinese Megacity (APHH-China) campaigns, peak during the evening at
<span class="inline-formula">∼</span> 4.5 <span class="inline-formula"><sup>∘</sup></span>C in both seasons. In winter, the nocturnal
UHI is dominated by anthropogenic heat emissions but is underestimated by
the model. Higher-resolution anthropogenic heat emissions may capture the
effects of local sources (e.g. residential buildings and adjacent major
roads). In summer, evening UHI intensities are underestimated, especially
during heatwaves. The inability to fully replicate the prolonged release of
heat stored in the urban fabric may explain this. Observed negative daytime
UHI intensities in summer are more successfully captured when surface
moisture levels in central Beijing are increased. However, the spatial
correlation between simulated air temperatures and satellite-derived land
surface temperatures is stronger with a lower urban moisture scenario. This
result suggests that near-surface air temperatures at the urban
meteorological site are likely influenced by fine-scale green spaces that
are unresolved by the available land cover data and demonstrates the
expected differences between surface and air temperatures related to canopy
layer advection. This study lays the foundations for future studies of
heat-related health risks and UHI mitigation strategies across Beijing and
other megacities.</p> |
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| ISSN: | 1680-7316 1680-7324 |