Urban Heat Island

teens participating in a urban heat island effect exercise by the Robertson Branch Library

Why Do Scientists Care About the Urban Heat Island Effect?

The Urban Heat Island Effect (UHIE) is a phenomenon in which cities experience much warmer temperatures due to their high concentration of buildings, roads, and other developments. Of all the cities in California, Los Angeles has the worst UHIE, which leads to higher energy use by air conditioning, elevated air pollutants and greenhouse gasses, compromise of human health and comfort, and impaired water quality (source).

Trees and other plants can help reduce the UHIE by providing shade, releasing moisture, and removing air pollutants. Many of the benefits that trees provide are related to their size and the structure of their canopy. Understanding the current amount of tree canopy and the amount that could be established can be used to help communities plan.

image of the Urban Heat Island Effect kit with its content

What's in the Kit?

  • 1 Infrared thermometer (IRT)
  • 1 50 Meter tape measure
  • 1 Booklet “Pacific Coast Tree Finder”
  • 1 Sharpie + 1 Eraser
  • 1 Observation journal
  • 1 Instructions packet
  • 1 Mini GPS + 1 charging cord
  • 1 Spare better pouch
  • 1 DIY Clinometer activity set
  • Safety rules

Relevant Sustainable Development Goals (SDGs)

UN Sustainability Development Goal #3: Good Health and Well-being
UN Sustainability Development Goal #11: Sustainable Cities and Communities
UN Sustainability Development Goal #13: Climate Action
UN Sustainability Development Goal #16: Peace, Justice and Strong Institutions UN Sustainability Development Goal #17: Partnerships for the Goals

Next Generation Science Standards (NGSS) Alignment

Downloadable PDF


How to Help Scientists Collect Data

By participating in this project, everyone can help our city conduct a tree inventory and see how hot their neighborhood is compared to others. Along with scientists, people can develop and implement plans on how to cool areas in their communities. In order to provide scientists a better understanding of the impact of the UHIE on your study site, you will be collecting surface temperature, clouds, and tree height data for this NASA research.

General Setup

Step 1

Turn on Internet/Wi-Fi connectivity and location services/GPS tracking of your smart device (i.e., smartphone or tablet). You can also use Google Maps or download a free GPS-Map app for your iOS Apple or Android device.

Step 2

Go to the GLOBE Mission EARTH’s Urban Heat Island Effect (UHIE) page to learn more about UHIE and how to participate in NASA research.

Step 3

Download and launch the GLOBE Observer app.

Step 4

Follow the instructions in the app to create an account and sign in.

Step 5

Click the gear button at the bottom right of the screen to go to Account settings.

Step 6

Scroll down to GLOBE Teams. Click the 'Join a GLOBE Team' button and enter GLID5WFS for referral code to join Team LAPL (Los Angeles Public Library).

Step 7

Read the message on screen and tap Training Complete.

Step 8

Choose Allow or Not Allow for push notification from the GLOBE Observer app.

Step 9

Read through the Privacy and Terms of Use and select I Agree to proceed.

Measure, Collect and Record Surface Temperature of Your Study Site:

Step 10

Pick three Observation Spots in the same homogeneous area (i.e., an area with the same surfacing materials, such as grass, asphalt, concrete, etc.) within the same study site and mark them with the stake flags in the kit.

Helpful Tips:

  • These Observation Spots can be random and the distance between them depends on the size of the area you are studying.
  • The Spots should also be away from trees and buildings that create a shadow on the land and in locations that have not been recently disturbed by people or animal traffic.

Step 11

Use the UHIE data sheet (page 7) of the instructions packet to collect and record the latitude, longitude and elevation information of the center of the homogeneous area you picked, the observation date and (local) time, time zone. Use the “Comments” field to note the land cover type of your study site (e.g., grass, asphalt, concrete, etc.).

Step 12

Use the Infrared Thermometer (IRT) and measure the surface temperature in all three Observation Spots you picked. To measure, hold the IRT at arm’s length and point it straight down, click the button, then read it. Make sure to record your data in degrees Celsius (℃) on the data sheet.

Identify and Record Cloud and Sky Condition Data of Your Study Site:

Step 13

Use the GLOBE Clouds: Step by Step Guide and Cloud Identification Chart (page 11-14 of the instructions packet) to help you determine the type(s) of clouds and sky condition of your study site. Record the cloud and sky condition data on the data sheet (page 8).

Measure and Record Tree Height Data of the Trees at Your Study Site:

Step 14

Open the GLOBE Observer app, tap "Trees" protocol to collect tree height data at your study site.

Step 15

For the first-time user, read through the introduction by tapping Next. At the end of the introduction message, check the box "Do not show this again", if you do not want to go through the introduction screens again the next time you sign in.

Step 16

Select either "Metric" or "English" as your preferred system of measurement. In general, the metric system of measurement is preferred for scientific research worldwide.

Step 17

Input your height. The app will automatically estimate your average stride length and height of your eye level (or the height of the phone/mobile device you will be using to record tree height data). If you believe the estimated stride length is inaccurate, you can change it by clicking the “Edit” button. When you finished, click Next.

Step 18

You can click on the links to get more information about the app, tree height, and GLOBE. If you do not wish to see this screen again, click "Do not show this again" and click Next.

Step 19

Tap New Trees Observation and follow the instructions on screen to measure the tree(s) on your study site and record your observations.

Step 20

Select either "Metric" or "English" as your preferred system of measurement. In general, the metric system of measurement is preferred for scientific research worldwide.

Helpful Tip & Reminder:

Turn on the location services or GPS feature of your mobile device and the app will automatically enter the coordinates of your study site as well as the date and time of your observation. Location accuracy is critical to this research. If your position on the map looks incorrect, you can drag your location using two fingers to move the map to improve the accuracy.

Step 21 (Optional)

Use the tape measure in the kit and follow the instructions in the app to measure the tree’s circumference. Record the data and tap Finish.

Step 22

Review the measurement you collected and recorded. Tap the "edit" button to change the measurement if needed.

Step 23

Use the Comments box to note anything that could affect your observation (e.g., tree is on a slope, etc.) and/or any recent changes to the tree. When done, tap Finish.

Step 24

Tap "Send all tree data now" to submit your data.

Step 25

You can then either close the app or measure another tree that is within your study site.

Step 26

Please check and make sure all equipment and materials are in the kit backpack before returning.


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