Day 4

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Paper title Role of rural land cover and temporal dimension on the Surface Urban Heat Island intensity
Authors
  1. Alexandra Hurduc Instituto Dom Luiz - Faculdade de Ciências, Universidade de Lisboa Speaker
  2. Sofia L. Ermida Instituto Português do Mar e da Atmosfera (IPMA)
  3. Carlos DaCamara Instituto Dom Luiz - Faculdade de Ciências, Universidade de Lisboa
Form of presentation Poster
Topics
  • A5. Climate
    • A5.02 The role of Earth Observation in climate services
Abstract text Earth’s population is still growing. The percentage of population living in urban regions was only 30% in 1950, increasing to 55% in 2018. It is projected that 68% of the population will live in urban areas by 2050. As so many people live in urban environments, the topic of urban climate affecting quality of life and public health is of great importance. Several studies found that urban heat stress negatively affects population living in more urbanized regions.

The surface urban heat island (SUHI) effect occurs when an urban area is warmer than its surroundings. Usually, it is computed as the difference in temperature of the rural region relative to the urban core region. The present work uses Land Surface Temperature (LST) data, retrieved through the Meteosat Second Generation geostationary satellite with 3 km at nadir, every 15 minutes.

Paris, Madrid and Milan were chosen as case studies to evaluate how the SUHI varies along the day/year and how does the rural land cover affect the surface heat island intensity. We found diurnal and seasonal variability of SUHI between cities, as a result of different climates.
Results also show that computing the SUHI against different rural land covers results not only in different SUHI intensities but also in different diurnal and seasonal cycles due to the seasonality of the rural land cover. This has consequences when analyzing trends of SUHI for there is much land use and land cover change in the region surrounding cities. This implies that some of the variability and trends in SUHI may be attributed not only to the urban region but also the rural one.

The time dimension is also a key factor, as SUHI intensity and even signal can change throughout the day. Peak intensity may be reached at different times of day/year and poor temporal resolution may not capture/represent this dynamic behavior.

In summary, our results are twofold: (1) noticing the importance of rural land cover as an equal part in the urban/rural relationship in the SUHI topic and (2) stressing that low temporal resolution data, although useful for its spatial characteristics, only tells half the story when considering the SUHI variability.