PACE Clouds Challenge Tips

The PACE Clouds Challenge is happening now. PACE scientist Dr. Andy Sayer would like observations and photos of the sky within 5 minutes of a PACE overpass. Here are three tips to help you collect your cloud observation.

timing

Tip #1: Timing Your Observation

Did you know that the GLOBE Observer app tells you when different satellites are over your location? We call this satellite flyover or overpass time. It is the exact time when certain satellites will be right above you, personalized for your location. 

The PACE Clouds Challenge is asking for observations and photos of the sky within 5 minutes of a PACE flyover. You can set notification alerts for the times when the PACE satellite will fly over your area. In the GLOBE Observer app, select Clouds then select the orange button that says Check Satellite Flyovers. Use the instructional video to set satellite flyover notifications. You can set the time and the days of the week you would like to get notifications. (For example, you can select to be alerted every day from 9am to 5pm). PLEASE NOTE - we would like observations only during daylight hours when you can easily see your sky.

Don't see PACE as an option for satellite notifications? Be sure to download the latest version of the app.

A GLOBE Clouds observation (up, north, south, west, and east photos) mapped to a sky view of the PACE satellite (green dot) passing overhead.

Here is a helpful schedule you could follow:

  • Set alerts for PACE overpasses in the GLOBE Observer app and you’ll be notified 15 minutes before the flyover.
  • About five minutes before the PACE flyover, go outside and start your Clouds observation.
  • Take all 6 photos even if you have something blocking your view of the sky. 
  • Remember to send in your observations! (View video tutorial)

Having trouble with satellite notifications on the app? You can use this website to generate overpass times for your location. Please click “ok” to the message about the Google Maps not loading correctly and find your location on the map. Note that your latitude and longitude do not need to be exact since the satellite covers a large area when flying overhead. 

photos

Tip #2: Include Your Photos

Dr. Sayer wants to identify whether each pixel in the PACE satellite image is a cloud or not. Your Up photo specifically will help answer this question. Here are some tips to help you collect all six photos:

  • Choose a safe place to make an observation. 
  • Try picking an area with an open view of the sky.
  • Take photographs in each cardinal direction (north, south, east, west) and up and down as directed by the GLOBE Observer app. It is important to submit all your photos, even if some are fully or partially blocked by trees, buildings, or even rain. Photos are an important data source.

A few lessons we’ve heard from volunteers:

  • Use the app's photo tool for capturing photos in all directions (north, south, east, west, up, down). This helps researchers to know the direction and angle the photo was taken.
  • Holding your phone with both hands gives you a more stable base and may help you better orient your camera.
  • When taking photos, rotate your body in a circle to find the letters that indicate the cardinal directions. 
  • Be sure your phone or device is not locked in portrait mode. If your phone is locked in portrait mode, you will notice that nothing happens when you turn your phone horizontally.  
  • Taking an  “Up” photo can be difficult if the Sun is directly above you. To avoid looking at the Sun, you can turn up your phone’s volume so that you can hear the shutter sound. Then point the camera straight upward until you hear the camera shutter sound. You can then lower the phone, click done, and review all the photos before going on to the next step.

The photos of submitted observations may take some time to process, so don’t worry if you don’t see them initially in the app. They should appear within a few days.

data

Tip #3: Data Quality

Your observations have the potential to impact and benefit the PACE mission. Collecting observations correctly can increase the probability of your data being used in research. Two potential issues can impact the PACE Clouds Challenge: technical problems with the app and hands or faces in submitted observations.

Technical problems – Some common app issues are described on the Frequently Asked Questions page.  If you experience other problems with the GLOBE Observer app, the GLOBE team is happy to help. Please reach out to us by tapping the “?” in the app or contact us through the GLOBE website. Please include information about the type of phone you are using, which version of the operating system is on the phone, and a description of the problem. 

Hands or Faces included in Photo Observations – All submitted observations pass through a computer vision algorithm to identify how much of the sky is visible in the photos. If you submit an observation with people’s faces or hands, we will not be able to include that data in the dataset shared with PACE scientists. They need to see as much of the sky as possible.

Examples of portions of the sky being removed because of distraction added to the photographs.

Avoid adding any distractions to the photographs, like hands or fingers, so that scientists can use your photographs in research. 

We value the time and effort you are putting into collecting these observations and want to help you ensure they are scientifically valuable. Thank you for being part of the GLOBE Program and for your observations to the PACE Clouds Challenge.