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Event date: 11/10/2020 Export event

Learn How to Map the Urban Heat Island Effect with ARSET this November

Authors: Jonathan O’Brien, Sean Mccartney and Ana Prados (NASA)

Heat stress accounts for more than 600 deaths in the US annually (CDC). This problem is especially prevalent in urbanized areas. Why do more people per capita die of heat in the city than outside of it? There is an artificial weather phenomenon you may have heard about called the “urban heat island” effect. In essence, the effect is just as the name implies, an island of heat in urban areas. This is due to the impervious surfaces (e.g. paved roads, parking lots, and roofs) that cities are comprised of. These surfaces are especially good at trapping heat, but not so good at letting it go. Because of the way these surfaces trap heat, the ambient temperature in the city will often be higher than the surrounding areas, with the greatest difference in temperature occurring at night. This is important to note, since heat stroke susceptibility is dependent not just on the ambient temperature, but also a person’s ability to cool down effectively at night so their body can recover. This is one of the reasons the urban heat island effect is so dangerous.

An interesting fact is that satellites can observe the urban heat island from space by estimating the land surface temperature (LST). Land surface temperature is not the same as ambient temperature, and variations occur depending on the time of observation, but it is frequently used as a proxy for ambient temperature. If the surface of a stove is hot, it’s a good bet that whatever is sitting on top of it is pretty toasty too. To further refine the analysis, field temperature readings are usually collected by boots on the ground to validate and supplement the data collected from space. With these satellite observations we can create a temperature map of the city and the surrounding areas. These maps can be especially useful when paired with other data such as surface type or land cover and human data such as socioeconomic, demographic, and health variables. Through these types of analyses we can gain a holistic view of the heat situation on the ground and how it has changed over time.


With increasing urbanization and rising temperatures, this topic will only become more important in the future. If you are interested in getting in on the action and learning how to map out the urban heat island in your city, join the Applied Remote Sensing Training (ARSET) program for a three-part online training beginning on November 10. During the first session of this training series you will learn how to estimate LST in Google Earth Engine using Earth observations from Landsat. You will also be presented with background information on urban heat islands (UHI) and have a chance to familiarize yourself with satellites and sensors that can be used to map them. The second session of this series will introduce you to UHI case studies and go over methods for integrating in situ observations with satellite imagery for select US cities. The third and final session will cover long term mitigation strategies and present a case study of UHI and land cover in Huntsville, Alabama.

Sessions include guest speakers from NASA, USGS, NOAA, and Portland State University. There is no cost to participants and no prior experience is required. For more information or to register, visit


Building on the results of community heat mapping efforts 26 July 2019

Building on the results of community heat mapping efforts

Following successful completion of an urban heat mapping campaign in Portland, Oregon in 2016, the map produced through the community effort was used in a study on effective ways to cool the city's urban areas. The study, requested by the City of Portland, shows the substantial cooling effect of planting trees and vegetation in urban areas.

Citizen scientists take to the streets to map the hottest places in ten U.S. cities 24 July 2019

Citizen scientists take to the streets to map the hottest places in ten U.S. cities

With specially designed sensors mounted on their own cars, volunteers in each city will drive pre-planned routes, recording heat and humidity as they go. Scientists will stitch their results into a detailed map showing the hottest parts of each city.

National Geographic highlights NOAA-funded Urban Heat Island project with 2019 campaign set to kick off Saturday 24 July 2019

National Geographic highlights NOAA-funded Urban Heat Island project with 2019 campaign set to kick off Saturday

Developing an Early Warning System to Prevent Heat Illness

As three cities gear up to map urban heat islands on Saturday, this week National Geographic shared an article highlighting the NOAA-funded 2018 summer mapping campaign to help address extreme heat. The article includes the project’s map of Washington, DC, in August 2018 where temperatures spanned almost 17 degrees between the hottest and coolest areas of the city.

RCCC Heatwave Guide for Cities 24 July 2019

RCCC Heatwave Guide for Cities

This guide is intended to help city governments understand the heat risks they face, develop an early-warning system, work with partners to consolidate action plans, and adapt urban-planning practices.

Citizen Scientists Take to the Streets to Map the Hottest Places in Ten U.S. Cities 24 July 2019

Citizen Scientists Take to the Streets to Map the Hottest Places in Ten U.S. Cities

Citizen scientists will take to the streets during the hottest days this summer to map hot spots in ten different U.S. cities. The campaign is part of a NOAA-funded project to map places where buildings, asphalt, and other parts of urban environments can amplify high temperatures, putting people at heightened risk of heat illness during extreme heat events.



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NIHHIS is an integrated information system that builds understanding of the problem of extreme heat, defines demand for climate services that enhance societal resilience, develops science-based products and services from a sustained climate science research program, and improves capacity, communication, and societal understanding of the problem in order to reduce morbidity and mortality due to extreme heat.  NIHHIS is a jointly developed system by the Centers for Disease Control and Prevention (CDC) and the National Oceanic and Atmospheric Administration.

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