Development of a Modeling System for Urban Heat Islands: An Application to Athens and Thessaloniki, Greece

Abstract

The urban heat island (UHI) is one of the most well known forms of localized, inadvertent anthropogenic climate modification. The study of urban climate problems, such as the UHI, is possible through the implementation of numerical models. In this context, numerical weather prediction models are thought to be a significant supporting tool with a wide area of successful applications for studying the UHI effect. The current paper aims to present the development of a numerical modeling system that could be used for forecasting the UHI and its impacts on human thermal comfort. The modeling system is based on the meso-scale meteorological Weather Research and Forecasting (WRF) model. Major innovations include the incorporation of high resolution land use data, the use of satellite data for defining land surface parameters, and the development of a downscaling mask for increasing the spatial resolution. The modeling system was evaluated against ground-based data during selected dates in summer 2010 for the cities of Athens and Thessaloniki. The estimated average bias of the model in terms of air temperature simulation was found to approximate ±1°C.