Investigating GLOBE Air Quality using AerosolWatch

Lectures, lessons, and learning opportunities of all kinds are available online these days… luckily, air quality investigations can be, too! Publically available sources of air quality data, which can be accessed any time and anywhere, can be used in conjunction with or in lieu of the GLOBE Aerosols Protocol for students and teachers participating in the US Air Quality Student Research Campaign. This blog post will introduce a website called AerosolWatch, an online access point for satellite-based observations of aerosols, and factors that affect air quality (such as smoke and dust).


AerosolWatch displays visible satellite images, as well as satellite-based aerosol measurements, from two Geostationary Operational Environmental Satellite (GOES) satellites and two Visible Infrared Imaging Radiometer Suite (VIIRS) instruments. The VIIRS instruments are currently flying on board the Suomi NPP and NOAA-20 (polar orbiting) satellites. The AerosolWatch website updates every 10 minutes! The screenshot below shows an example of the GeoColor (visible) available from the NOAA-20 satellite. The most current GeoColor image available from the GOES-16 satellite is displayed by default when the website loads.

GOES-16 and GOES-17 are NOAA weather satellites. GOES-16 has imagery of most of the United States, but the westernmost parts of California, as well as Alaska and Hawaii, aren’t “seen” by GOES-16. GOES-17 has imagery (called ‘Layers’) of the western US and Pacific Ocean. The Suomi NPP and GOES-20 are polar orbiting satellites, jointly operated by NASA and NOAA. These satellites cross the equator approximately 14 times a day. The entire continental United States is visible from both of these satellites.

The AerosolWatch website has two sets of controls: the calendar and animation buttons across the top of the screen, and the drop-down menus on the right hand side.

To begin, use the calendar button - located at the top of the screen, to the left - to select a date of interest. Use the arrows at the top of the calendar that appears to move forward or backward in time, and click on the day you’d like to investigate. (See the animation to the left.) Note that any selections you’ve made – such as a specific type of imagery - reset to default when you change the date, so it’s a good idea to select the day you’re interested in before making any other changes!

When the date is changed, the time defaults to 1001 UTC, which is 5:00AM Eastern Standard Time (or 6:00AM Eastern Daylight Time). Change the time by clicking on the blue clock button at the top of the screen.

The animation to the right shows how to select a time range of satellite images to be displayed. If you only want one image to be displayed, choose the same Start Time and End Time. Once satellite images for the selected time range load, you can use the blue buttons at the top of the page to play an animation of the images you’ve selected, or step forward or backward in time. A note on selecting dates and times: The AerosolWatch website updates every 10 minutes, but not all the satellite imagery is updated at the same rate. Imagery for GOES-16 and GOES-17 is available in near real-time. Imagery from the VIIRS instruments may not be available for up to 24 hours.

After choosing a date and time of interest, select data – called ‘layers’ – that you are interested in seeing, using the drop down menus on the right hand side of the screen. It’s a good idea to turn ‘off’ the default layer – GOES-16 GeoColor – before selecting other layers. To add borders and names to the map, click on the ‘Labels Layer’ drop-down menu and add both the ‘Boundaries Layer’ and the ‘Labels Layer’. (See the animation to the left.) 

Layers that are particularly useful for investigating air quality are:

  • AOD: This stands for Aerosol Optical Depth, which is a similar measurement to what is measured by a Calitoo.
  • Smoke Dust Mask: This identifies and color codes areas of smoke and dust in the air.
  • Fire: Active fires, identified by VIIRS infrared instruments, appear as dots on the map.

Check out the screenshots below for examples of what the different layers look like together!

AOD over the western United States, August 25, 2020.

GeoColor satellite imagery and AOD over the western United States, August 25, 2020.

GeoColor satellite imagery and Smoke Dust Mask over the western United States, August 25, 2020.

If you have questions or need assistance, please contact the GLOBE AQ team at:

GLOBE Air Quality Team:

  • Dr. Margaret Pippin, NASA
  • Angie Rizzi, NASA/SSAI
  • Samantha Adams, Bronx Collaborative High School

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