High-resolution intra-urban assessments of future heat events and heat waves for the city of Augsburg, Germany

Abstract

Under consideration of climate change, high-resolution (100 m × 100 m) assessments of heat events were performed for Augsburg, Southern Germany, for the extended summer season (May–September). Heat (anomaly) days were defined as days exceeding absolute (relative) temperature thresholds. The focus is on the assessment of how the number and duration of events change under future climate conditions and how e.g., green spaces or sealed areas affect the intra-urban structure of heat (anomaly) events. Assessments were performed under consideration of two Representative Concentration Pathways (RCP4.5 and RCP8.5). The method is based on a two-step statistical approach: a novel analog technique (Normal VECtor of circulation patterns, NVEC) to downscale large-scale information on point observation and a spatial model (Multiple Linear Regression, MLR) for estimating temperature patterns across the entire urban area. The model calibration and validation were performed by an urban meteorological network of 38 monitoring stations for air temperature. Results show that differences between RCP4.5 and RCP8.5 are only small until 2040. At the end of the 21st century, the number of heat days for RCP8.5 is four times higher than under consideration of RCP4.5 and 33 times higher than within the reference period (1970–2000) leading to more and longer lasting events.