Using surface relief classes with LCZs for an improved heat island methodology: Demonstration in a small Brazilian city

Source abstract

The Local Climate Zone (LCZ) classification has standardized the treatment of built form and land-cover controls on urban temperature patterns, yet the framework does not explicitly treat the role of surface relief. This study addresses the need to incorporate surface relief features in each LCZ to support a deeper understanding of local thermal climates in and around cities. To this end, we propose a statistical approach based on LCZ relief classes to select representative sites and evaluate spatiotemporal characteristics of urban heat island magnitudes and intra-urban temperature differences. We demonstrate the approach using nighttime air temperature data collected along mobile survey routes in a small Brazilian city with relatively simple relief. Results show that LCZ relief classes improve recognition of thermal contrasts within urban and non-urban landscapes, revealing clear clusters of air-temperature values and heat island patterns across distinct landform units. We found consistently warmer and comparable conditions among representative urban sites on the plateau, whereas built-up areas across other landform units at lower elevations (slope and step) exhibited temperature regimes influenced by localized relief. Explicit treatment of local topography through LCZ relief classes also improves site metadata documentation, thereby strengthening the physical interpretation of inter-city heat island magnitudes and inter-zone temperature contrasts at a regional scale. Further research is required in cities with more complex topographies at both meso- and local scales, allowing a pathway toward more consistent practices in the analysis, interpretation, and communication of urban temperature effects.