EMS Annual Meeting Abstracts
Vol. 20, EMS2023-240, 2023, updated on 06 Jul 2023
EMS Annual Meeting 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A new guidance on measuring, modelling and monitoring the canopy layer urban heat island

K. Heinke Schlünzen1, Sue Grimmond2, Alexander Baklanov3, Alberto Martilli4, Valéry Masson5, Shiguang Miao6, Chao Ren7, Matthias Roth8, and Iain Stewart9
K. Heinke Schlünzen et al.
  • 1Meteorological Institute, Universität Hamburg, Hamburg, Germany (heinke.schluenzen@uni-hamburg.de)
  • 2Department of Meteorology, University of Reading, UK
  • 3Science and Innovation Department, World Meteorological Organization (WMO), Geneva, Switzerland
  • 4Centro Investigaciones Energéticas, Medioambientales y Tecnológicas | CIEMAT · Spain
  • 5CNRM (Centre National de Recherches Météorologiques), Météo-France & CNRS, France
  • 6Institute of Urban Meteorology, China Meteorological Administration, Beijing, China
  • 7Faculty of Architecture, The University of Hong Kong, Hong Kong SAR, China
  • 8National University of Singapore, Department of Geography, Singapore
  • 9Global Cities Institute, University of Toronto, Toronto, Canada

Urbanization influences the local climate by changing the natural surface energy balance affecting the regional temperature field. One of the best-known and widely studied phenomenon is the canopy layer urban heat island (CL-UHI) which is found in cities of all sizes. Specifically, night-time temperatures are often higher in urban areas than in the surrounding rural areas. The CL-UHI characteristics differ between cities, within a city and with time of the day and the season. Climate change induced warming in cities is similar to that experienced in rural areas, but modified by the CL-UHI.

The CL-UHI is an additional heat burden on top of background anthropogenic warming, and therefore an increasing focus of urban planners. Given this development, and in response to the request of the 18th World Meteorological Congress (Resolutions 32 and 61), experts from WMO GAW (Global Atmosphere Watch) Urban Research Meteorology and Environment (GURME) initiated in 2020 an expert team inviting more than 30 world-wide experts to contribute to a guidance on measuring, modelling and monitoring the CL-UHI [1]. Topics include a clear definition of the CL-UHI and clarifications of what it is not, causes of the CL-UHI (e.g. meteorological and morphological influences), methods to assess the CL-UHI intensity (measurements, modelling approaches) as well as CL-UHI application examples. The guidance also explains why the CL-UHI mitigation is only part of an answer to reduce urban heat problems. The guidance will serve as a useful reference for meteorologists, climatologists, meteorological administrative staff, and others interested in the CL-UHI.

[1] WMO (2023): Guidance on Measuring, Modelling and Monitoring the Canopy Layer Urban Heat Island (CL-UHI).

K.H. Schlünzen, S. Grimmond, A. Baklanov (edts.), World Meteorological Organisation, WEATHER CLIMATE WATER. 2023 edition. WMO-No. 1292, pp.88.
https://library.wmo.int/doc_num.php?explnum_id=11537 last used 11.04.2023

How to cite: Schlünzen, K. H., Grimmond, S., Baklanov, A., Martilli, A., Masson, V., Miao, S., Ren, C., Roth, M., and Stewart, I.: A new guidance on measuring, modelling and monitoring the canopy layer urban heat island, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-240, https://doi.org/10.5194/ems2023-240, 2023.