Ground to Satellite

Connecting GLOBE to Satellite Data

GLOBE Satellite Match connects volunteers' ground observations with spaceborne data collected at the same time and location, creating an augmented dataset that provides researchers with more comprehensive collocated measurements, while giving participants personalized insights comparing their view to space.

While NASA Earth-observing satellites provide global coverage, their unique top-down vantage point can struggle to resolve complex atmospheric and land features, such as thin cirrus clouds, white clouds over snow, or fine-scale surface details. GLOBE ground-based observations fill these critical spatial and temporal gaps, providing essential ground-truth data that complements satellite measurements.

Matching NASA Satellite Data to GLOBE Observations

GLOBE works with several NASA satellite missions to connect your local, on-the-ground observations with space-based satellite data taken at the exact same time and location. By combining these two vantage points, on-the-ground volunteers and NASA researchers work together to create a complete, top-to-bottom snapshot of our Earth. Plus, volunteers receive a personalized NASA "Satellite Comparison" email placing their view side-by-side with the satellite's view.
 

Active Satellite Matches: Clouds & Land Cover

The satellite match process currently integrates GLOBE Clouds and Land Cover observations with specific Earth-observing satellites:

Clouds: Ground observations of sky cover, cloud types, opacity, and atmospheric conditions are matched to both geostationary and polar-orbiting satellites. Geostationary matches from GOES, Meteosat, Himawari provide rapid temporal comparisons, while matches to low-Earth orbit (LEO) satellites pair ground reports with advanced sensors on missions such as PACE, NOAA-20 (JPSS), and the broader Earth Observing System constellation.

Land Cover: Photographs and land cover classifications collected through the GLOBE Observer app are collocated with multispectral surface imagery from Landsat 8 and 9 (30-meter resolution) as well as Sentinel-2 (10-meter resolution). These matched pairs assist in verifying surface reflectance algorithms, tracking land cover transitions, and resolving urban heat island boundaries.

As new NASA Earth science missions launch and additional GLOBE protocols are integrated into satellite matching, we will continue to unlock new multi-sensor comparison capabilities for future research.

For Participants: How to Match Your Observation with a Satellite

Making an observation while a satellite passes overhead creates a direct link between your ground report and NASA data. Here is how you can time your observations and track down your matched data:

Time Your Observation to a Satellite

  1. Check Satellite Flyovers: Open the Clouds/Land Cover tool in the GLOBE Observer app and tap “Check Satellite Flyovers” on the screen.
  2. Set Custom Alerts: Calculate exact overpass times for your location and enable 15-minute reminder notifications so you can head outside right as a satellite passes above. This short video tutorial will show you how to turn on satellite flyover notifications for your current location.

Where to Find Your Matched Data

  • Personalized Comparison Emails: All Land Cover observations and any Clouds observations that are timed to a satellite passing overhead can receive a personalized email from the NASA Langley Research Team. This email includes a link to side-by-side comparison tables showing your GLOBE observation and relevant satellite data and imagery. 
  • My Observations Page:  Log in to your account on the app or website to view your complete observation history, check match statuses, and review past submission records.
  • GLOBE Visualization System (Data Vis): Explore your observations on an interactive global map. Filter by protocol, layer satellite data over ground reports, and see how your localized observation fits into global weather patterns alongside reports from citizens worldwide.

For Researchers: Access Matched Earth Science Datasets

GLOBE provides researchers, data analysts, and communities with open access to collocated GLOBE and spaceborne sensor datasets. The merged datasets pair field observations directly with collocated satellite measurements.

Data Access Points

  • Pre-Packaged Datasets: Access to annual global CSV files for collocated clouds data is available through the GLOBE Community Data page on Zenodo. These datasets pair ground-observed cloud parameters with collocated satellite variables (including cloud fraction, phase, altitude, and opacity). You can also download Special Event & Challenge Datasets. These targeted subsets were collected during specialized research efforts, such as Solar Eclipse campaigns, Cloud Challenges, and atmospheric phenomenon studies like the "Terminator Problem."
  • Advanced Data Access Tool (ADAT) & API: For custom spatial, temporal, or multi-protocol queries, use the Advanced Data Access Tool or query the GLOBE API directly to stream collocated data into your analytical workflows.
  • Data Documentation & Citations: Review the GLOBE Data User Guide for data dictionary definitions, satellite matching algorithms, quality assurance annotations, and recommended dataset citations for publication.