Use of Satellite Images for Observational and Quantitative Analysis of Urban Heat Islands Around the World

Abstract

Urban heat island intensity (UHU) is calculated as the spatially averaged temperature difference between an urban and its surrounding rural area. This concept, however, provides an umbrella for a range of diversified ideas that include the temperature difference between the densely developed urban area and least developed area or between two different built-up areas. There are also averages for the season, for the year, for multiple years, etc., and UHll quoted for the day and another for the night. The objective of this work is to examine the urban heat island effect for cities around the world, using readily available data. The innovation is in using data from the Landsat satellites for different cities previously not studied. Thermal images of the Earth were obtained and analyzed to produce suiface-temperature maps. These maps showed that the temperature in the urban environments were significantly higher than the temperature in the surrounding countryside, a defining characteristic of urban heat island. Eurthermore, the urban and rural areas in the images were separated and analyzed individually to quantitatively measure the temperature difference. It was found that the UHII could be 0.3-5.1 °C for the eleven cities investigated. Miami and Shenzen are two cities which seem to have been missed in previous studies because they were limited in their scope and responsibilities, and their methods required much more resources for the longer term studies. It is not the claim here that a UHl is definitively established by the analysis presented of the Landsat satellite data. The present work demonstrates the use of a possible planning tool in terms of understanding where urban areas may be subjected to additional heat. Our use of the method shows that a UHI is probably taking place at the time of observation, and precautionary notices should be sent out to the community to take preventative measures to ensure their health and wellbeing. The minimal resources required is the demonstration shown by our work of the usefulness of this method.

Convergence of microclimate in residential landscapes across diverse cities in the United States

“…The microclimate patterns described here were evident even within the context of the broader citywide UHI pattern of heating in urban relative to rural locations. For example, previous research in most of our selected cities showed that urbanized areas were significantly warmer at night compared with areas outside of the city boundaries (Brazel et al 2000;Zhang et al 2004;Imhoff et al 2010;Wong and Chaudhry 2012;Kenward et al 2014). The native sites used in this study were located within the same geographic range as residential sites, and in some cases the two were closely intermingled within the urban matrix (see Supplemental Fig.…”

Smart Glass and Its Potential in Energy Savings

“…On the action item to reduce urban heating effects, (4) above, many cities in developed countries have heat island problems [18][19][20][21][22]. Additionally, many cities in fast growing economies, e.g., China, are developing heat island problems [23][24][25][26].…”

Recommendations for Energy Water Nexus Problems

“…That such seasonal flash floods would become more recursive and severe as global warming pro gresses, followed by severe seasonal water shortages due to lower volume flows downstream of the Himalayas, require solutions which are more permanent than mud dams. Climate change and its effects have been studied by Wong and researchers [21][22][23][24], According to Vidal [25], India plans for 292 dams on rivers ris ing in the Himalayas. Vidal stated that India, Nepal, Bhutan and Pakistan are in a "water grab" in the Himalayas, as they look for new sources of electricity to power their economies.…”