Implications of employing detailed urban canopy parameters for mesoscale climate modelling: a comparison between WUDAPT and GIS databases over Vienna, Austria

Abstract

(no german version available) One of the major obstacles to using numerical weather prediction models for guidance on mitigating urban-ization's impact on local and regional climate is the lack of detailed and model ready morphological data at urban scale. TheWorld Urban Database and Access Portal Tool (WUDAPT) is a recent project developed to extract climate relevant informa-tion on urban areas, in the form of local climate zones (LCZs), out of remote sensing imagery. This description of the urbanlandscape has been tested and used for parameterization of different urban canopy models (UCM) for mesoscale studies. Asdetailed information is usually bounded within cities' centres, crowdsourced and remote sensing data offer the possibility tomove beyond the old barriers of urban climate investigations by studying the full range of variation from the urban core to theperiphery and its related impacts on local climate. Thus, for this study we sought to compare the relative impact of using theWUDAPT methodologyversusa simplified definition of the urban morphology extracted out of detailed GIS information toinitialize a regional weather model and compare the output against official and crowdsourced weather station networks. A casestudy over Vienna, Austria was conducted using the weather research forecasting (WRF) model, coupled with the buildingeffect parameterization and building energy models (BEP-BEM) in five distinct seasonal periods. Results demonstrated thatusing detailed GIS data to derive morphological descriptions of LCZs for mesoscale studies provided only a marginal overallimprovement over using the default WUDAPT parameters based on the ranges proposed by Stewart and Oke (2012). Thefindings also highlighted the importance of developing techniques that are better at capturing the morphological heterogeneityacross the entire urban landscape and thus improve our understandings of UCM performance over urban areas.

One of the major obstacles to using numerical weather prediction models for guidance on mitigating urban-ization's impact on local and regional climate is the lack of detailed and model ready morphological data at urban scale. TheWorld Urban Database and Access Portal Tool (WUDAPT) is a recent project developed to extract climate relevant informa-tion on urban areas, in the form of local climate zones (LCZs), out of remote sensing imagery. This description of the urbanlandscape has been tested and used for parameterization of different urban canopy models (UCM) for mesoscale studies. Asdetailed information is usually bounded within cities' centres, crowdsourced and remote sensing data offer the possibility tomove beyond the old barriers of urban climate investigations by studying the full range of variation from the urban core to theperiphery and its related impacts on local climate. Thus, for this study we sought to compare the relative impact of using theWUDAPT methodologyversusa simplified definition of the urban morphology extracted out of detailed GIS information toinitialize a regional weather model and compare the output against official and crowdsourced weather station networks. A casestudy over Vienna, Austria was conducted using the weather research forecasting (WRF) model, coupled with the buildingeffect parameterization and building energy models (BEP-BEM) in five distinct seasonal periods. Results demonstrated thatusing detailed GIS data to derive morphological descriptions of LCZs for mesoscale studies provided only a marginal overallimprovement over using the default WUDAPT parameters based on the ranges proposed by Stewart and Oke (2012). Thefindings also highlighted the importance of developing techniques that are better at capturing the morphological heterogeneityacross the entire urban landscape and thus improve our understandings of UCM performance over urban areas.