Raw sunlight dimming through the atmosphere (newer version)
What it measures. Profiles of how much sunlight passed through Earth's atmosphere during a single sunrise or sunset, recorded by altitude.
How it's made. A raw, low-level (Level 1B) product from the SAGE III instrument on the International Space Station, which looks at sunlight as it skims through the atmosphere's edge.
How & where you'd use it. A building-block input that feeds into higher-level products identifying upper-atmosphere gases and aerosols; not typically used on its own. A few March 2024 events are flagged as unreliable.
What's measured
Coverage & cadence
- Time span2017-06-07 → 2024-11-30
- Measured byISS (SAGE III)
- Processing levelLevel 1B
- Spatial extent-180, -90, 180, 90
- FormatsHDF5
- StatusCOMPLETE
What you can do with it
- Map air pollutants — NO₂, aerosols, ozone
- Track greenhouse gases and Earth's energy budget
- Feed weather and air-quality analysis
Official description
Data quality notice: The SAGE III/ISS team recommends against using data from events 2024030913SS, 2024030915SS, and 2024030917SS. These events were affected by line-of-sight blockage from a docked spacecraft which undermined the data quality. Typically, such events are withheld by a quality assurance process. g3bt_53 is the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station (ISS) (SAGE III/ISS) Level 1B Solar Event Transmission Data (HDF5) V053 data product. It contains pixel group transmission profiles for a single solar event. Launched on February 19, 2017 on a SpaceX Falcon 9 from Kennedy Space Center, the Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS), the second instrument from the SAGE III project, is externally mounted on the International Space Station (ISS). This ISS-based instrument uses a technique known as occultation, which involves looking at the light from the Sun or Moon as it passes through Earth’s atmosphere at the edge, or limb, of the planet to provide long-term monitoring of ozone vertical profiles of the stratosphere and mesosphere. The data provided by SAGE III/ISS includes other key components of atmospheric composition and their long-term variability, focusing on the study of aerosols, nitrogen dioxide, nitrogen trioxide, and water vapor. SAGE data has historically been used by the World Meteorological Organization to inform their periodic assessments of ozone depletion. These new observations from the International Space Station will continue the SAGE team's contributions to ongoing scientific understanding of the Earth's atmosphere. Several improvements predominately the ozone, nitrogen dioxide and aerosol products are realized in the version 6.0 data product and cause it to be recommended over version 5.3. These improvements include: filling transmission gaps (caused mainly by sunspots) leading to several hundred more events, additional term in L1 uncertainty, updated ozone absorption cross-section database, more robust covariance computation of aerosol uncertainty. Version 6.0 also has incorporated aerosol flags and particle size distribution information which were previously available in separate files. Further details can be found in the version 6.0 release notes.
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="g3bt",
version="53",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from LARC_CLOUD Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package. Official links
- How to cite ASDC data VIEW RELATED INFORMATION
- SAGE III/ISS Version 5.30 DPUG (Data Product User's Guide) VIEW RELATED INFORMATION
- NASA Open Source Agreement for Computer Software VIEW RELATED INFORMATION
- SAGE III/ISS Version 5.30 Release Notes VIEW RELATED INFORMATION
- Earthdata Search for g3bt_53 (NASA Application to search, discover, visualize, refine, and access NASA Earth Observation data) GET DATA
- Virtual Directory for g3bt_53 GET DATA
- SAGE III Algorithm Theoretical Basis Document (ATBD) Transmission Level 1B Products VIEW RELATED INFORMATION
- SAGE III Algorithm Theoretical Basis Document (ATBD) Solar and Lunar Algorithm VIEW RELATED INFORMATION