GLOBE Observer Tips and Tricks

Making Cloud Observations: Tips and Tricks Using the GLOBE Observer App

The GLOBE Observer app (available for iPhones and Android devices) is a new, step-by-step way to submit cloud observations to NASA. Use your GLOBE sign-in information to sync your observations with your GLOBE data entry. 

Here are some simple tips and tricks on how to better identify clouds while using the app. Your latitude, longitude, and time of day with be filled in automatically by the app!



1. What does your sky look like?

Is your sky completely clear with no contrails? Are there clouds or is the sky obscured that it makes it difficult to make any observation? This is the first question you will encounter in the app. 

Tip: Be sure to be in an area that doesn't have buildings to obscure your view. Also, be sure to look at clouds slightly above the horizon! You may see clouds really far away in the horizon, but they will be hard to distinguish. Focus on those in your area.

Trick: Scan the sky for contrails. Some are short lived and can last for a very short amount of time. Explore pictures of different types of contrails

What is an obscured sky? This question is asking if there is rain, snow, dust, fog, smoke, haze, volcanic ash, ocean spray, or blowing sand that is making it hard to get a clear view of the clouds. NOTE: fog is a low-level cloud, AND an obscuration!



2. What is your sky color and visibility? Presence of aerosols or particles in the sky

Sky color and visibility are indicators of the amount of aerosols or particles in the sky. CAUTION: NEVER LOOK DIRECTLY AT THE SUN!!!!

Sky color is best when there are no clouds present. It is easy to confuse a white-ish sky with really thin high clouds. 

Tip: Report sky color when the sky is clear of clouds (0-10% cloud cover). 

Trick: Look for the bluest part of the sky and report that color!

Sky visibility is looking at how many aerosols or particles in the sky are near the ground. 

Tip: Visibility is hard at dusk or at night. Only report it during the day.

Trick: Find a landmark in the distance and estimate the visibility. 


3. What cloud types do you see? 

Identifying cloud types comes easier with practice. Cloud images like those in the app help. Below are some simple descriptions taken from the Elementary GLOBE book about clouds

Teachers: Check out a suggested lesson plan about cloud types identification. 

Tip: You can use the size of the puffy cumulus clouds compared to your fist to figure out height. See Dr. Lin Chambers tips to distinguish between cloud types. NOTE: fog is a low-level cloud, AND an obscuration!

Trick: A dichotomous key (or simple yes/no questions) is really helpful. Check out Dr. Tina Cartwright's foldable dichotomous key pictured below.

dichotomous cloud key


  4. How much of the sky is covered by clouds? 

First, the app will ask you to estimate total cloud cover or how much of the sky is covered by clouds no matter the type of cloud. Then, the app will ask you to estimate how many clouds are at each level (low, medium, high). 

Not all clouds are created equal, and knowing how many there are at each level is important.  

Tip: First, look at all clouds together and report the best percentage based on the example pictures. Be sure to include contrails in this first look. Then, look at the estimated level and make your best guess at the amounts. 

Trick: Look at the amount of clouds in each cardinal direction (North, South, East, West) and then make your total estimate.




5. What is opacity?

Not all clouds are created equal, and that includes how they interact with energy. Do all clouds cast shadows? No, each cloud type interacts differently with the energy coming from the Sun. Opacity, or how the cloud looks, gives us an idea of how they are interacting with the Sun's light. 

Tip: Use the description below to estimate opacity. Estimate a general appearance instead of each individual cloud.

Opacity General Appearance
Opaque Gray
Translucent Bright white 
Transparent Milky bluish white

Trick: Look at the middle of the clouds. The edges of clouds might look slightly different.


6. What are the surface conditions?

Surface conditions are very important since satellites looking at Earth can have a hard time seeing the difference between clouds and snow, for example.

Tips and tricks: Some of these can be tricky, especially if you have trees with leaves and others without leaves. Always report the average.

NOTE: a pond is an example of standing water.

Surface measurements are for people that have instrumentation at hand to make those measurements. Feel free to skip these if needed. Learn more how to properly measure this information using GLOBE's Atmosphere E-Training options



7. Taking pictures of the sky.

The app will ask you if you would like to take pictures of the sky. The app will help you take the images at the right spot at each cardinal direction, up and down. Just move the phone until the letter or word is inside the circle. The app will automatically take the picture!

Tip: It is easier, at least for me, to hold my phone with both hands.

Trick:  Pictures of the "Up" direction can be tricky if the sun is right above you. If your phone is unmuted, you can move your phone while facing up until you hear the picture being taken. 

NOTE: this is not a good picture of the sky since I'm inside my office :)


8. Would you like to receive a satellite match email from NASA?

The NASA cloud team matches GLOBE Observer cloud observations to corresponding satellite data. If your cloud observation is matched to satellite data, you will receive a Satellite Match email from NASA within 1 week of submitting your report.

For more information, visit the Satellite Comparison page.

Tip : Make your cloud observation +/- 15 minutes of when a satellite will fly over your location : satellite overpass calculator. The app already enables you to receive emails from NASA to participate.


We hope to receive your cloud/sky observations! Reach out to the GLOBE Clouds team at any time through our contact page.