New Satellite Matches Page

NASA Cloud Satellite Comparisons

satellite comparison table that summarizes a persons report of sky and clouds and what the satellite detected.

 

What is a Satellite Comparison?

 

One of the most exciting moments in making a cloud observation is receiving your NASA “Satellite Comparison” personalized email. The email includes data about your observation, time and location, and it compares it to satellite data obtained at approximately the same time at your location.

 

Image of earth and satellite

Why is a Satellite Comparison Important?


Satellites can only capture a top-down view of our planet. We need your ground observations to complement what the satellite cannot see, for example, cloud bases, ground cover, and multiple cloud layers.

GLOBE observations aligned to satellite data are important because:

  • You expand the reach of scientists who are limited in time, number, and money.
  • You are contributing to a database that has been growing for over 2 decades. A long-term data set is crucial for scientists to see patterns and change over time.
  • You add another layer of perspective helping scientists to better understand the effects of clouds on our Earth.

How Can You Receive a Satellite Comparison Email?

 

  • If there’s a satellite measurement made over your location at the same time you make your observation, you’ll receive a satellite comparison email aligning your observation to the corresponding satellite data.
  • While observations are useful at any time, your ground reports can help verify satellite measurements if you take your observations during a satellite overpass. You may be able to time your observation to the overpass times by checking the satellite overpass schedule to find out when specific satellites will be passing over your location. Another option would be the geostationary satellite which typically views an entire hemisphere simultaneously, so you don’t need to match to a specific overpass time.

 

 

Your Role:

We want to match your ground observations of clouds with Earth observing satellites. Review how to make and submit cloud observations with the cloud protocol or the eTraining slides. Some satellites are always observing the same location of the Earth while others are observing the entire planet. Your location is important to determine when to best make your observations. Visit the Satellite Overpass Schedule to see when to best make your ground observations.

All observations matched to satellite data are used in research. In the "Cloud Research" video NASA scientist Dr. Brant Dodson explains how your observations are used in research and the importance of your GLOBE cloud observations.

 

Satellite Match Email:

Observations that coincide with satellite observations will receive a ‘match’ email. The satellite match email summarizes both ground and satellite observations. Ground cloud observations help NASA better understand satellite data even though they may not agree. Discrepancies should be investigated but do not imply an error on the part of the observer. The NASA GLOBE Clouds team prepared this "Satellite Matching" video that explains how to read the satellite match table and how to identify discrepancies between the satellite and your observations.

 

GLOBE Clouds and Satellite Matched Data:

 

When a GLOBE Clouds observation is taken within 15 minutes of a satellite overpass, the data are matched to NASA satellite data for further analysis. The GLOBE Clouds data and matching satellite data are provided as CSV files in the GLOBE Observer webpage. These data files include all cloud data received by GLOBE and matched to satellite data by the NASA Langley Research Center’s GLOBE Clouds team.

 

Note: Version 2.0 data includes additional satellite matches after a correction to the code used for matching, an error pointed out by a regular GLOBE Observer contributor. The window before or after a satellite overpass to match with ground data was incorrectly set at 0.15 hours (9 minutes) rather than the full 15 minutes (0.25 hours) intended. All data starting from 2017-01-01 has been reprocessed using the new code, resulting in an additional 54,000+ satellite matches, a 36% increase.