Spatially Explicit Correction of Simulated Urban Air Temperatures Using Crowdsourced Data.

Journal: Journal of applied meteorology and climatology
Published Date:

Abstract

Urban climate model evaluation often remains limited by a lack of trusted urban weather observations. The increasing density of personal weather sensors (PWSs) make them a potential rich source of data for urban climate studies that address the lack of representative urban weather observations. In our study, we demonstrate that carefully quality-checked PWS data not only improve urban climate models' evaluation but can also serve for bias correcting their output prior to any urban climate impact studies. After simulating near-surface air temperatures over London and south-east England during the hot summer of 2018 with the Weather Research and Forecasting (WRF) Model and its building Effect parameterization with the building energy model (BEP-BEM) activated, we evaluated the modeled temperatures against 402 urban PWSs and showcased a heterogeneous spatial distribution of the model's cool bias that was not captured using official weather stations only. This finding indicated a need for spatially explicit urban bias corrections of air temperatures, which we performed using an innovative method using machine learning to predict the models' biases in each urban grid cell. This bias-correction technique is the first to consider that modeled urban temperatures follow a nonlinear spatially heterogeneous bias that is decorrelated from urban fraction. Our results showed that the bias correction was beneficial to bias correct daily minimum, daily mean, and daily maximum temperatures in the cities. We recommend that urban climate modelers further investigate the use of quality-checked PWSs for model evaluation and derive a framework for bias correction of urban climate simulations that can serve urban climate impact studies.

Authors

  • Oscar Brousse
    Institute of Environmental Design and Engineering, University College London, London, United Kingdom.
  • Charles Simpson
    Institute of Environmental Design and Engineering, University College London, London, United Kingdom.
  • Owain Kenway
    Centre for Advanced Research Computing, University College London, London, United Kingdom.
  • Alberto Martilli
    Center for Energy, Environment and Technology (CIEMAT), Madrid, Spain.
  • E Scott Krayenhoff
    School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada.
  • Andrea Zonato
    Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
  • Clare Heaviside
    Institute of Environmental Design and Engineering, University College London, London, United Kingdom.

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