Spatial / Temporal Coverage
- Spatial Coverage: 70N to 70S
- Spatial Resolution: .5km vertical
- Temporal Coverage: 03/17/2017 – Present
- Temporal Resolution: 1 file per event
- Ozone (solar and lunar)
- Aerosol Extinction Profiles
- Water Vapor
- Nitrogen Dioxide (solar and lunar)
- Nitrogen Trioxide (lunar)
Science Data Processing
The Level 1 and 2 science products are derived from the Level 0 data by algorithms running in the SAGE III/ISS Science Computing Facility (SCF) located at NASA Langley Research Center (LaRC). External ancillary data sources needed to proceed with Level 1 and 2 processing are: observation time/location and pressure/temperature profiles of the neutral atmosphere. GPS time and ISS position/velocity are standard products provided by ISS and are incorporated into the nominal SAGE III/ISS payload data stream. At the advice of the pre-flight ROSES selected Science Utilization Team, the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) is used for temperature/pressure profiles of the neutral atmosphere. This is the same ancillary source used in creating the SAGE II V7 record. MERRA-2 is generally available three weeks after the end of the preceding month. Once the necessary ancillary information is available, processing a month of occultations is complete within a day or so.
The mission team reviews the results to assess the overall quality and remove any obvious failures, which are rare, not flagged by automated checks of data consistency, or stressing cases that are used for product improvement. Cleared data are then posted to the LaRC Distributed Active Archive Center (DAAC) for public distribution. These steps are usually completed within the required 10 days from receipt of the necessary inputs.
The SAGE III/ISS SCF processing system architecture consists of two Linux-based servers that act as a data storage and production pair. The complete system has two of these pairs: one performs the standard processing on a monthly cadence; the other pair is for research/development processing and supplying redundant capabilities during reprocessing campaigns, such as for the initial release of version 5.1 products. There are also three Linux-based development servers that primarily act as development servers, though they also hold a copy of the raw, level 0, and intermediate files, and can act as backup servers for production. These development servers are also used for analysis, testing, and validation of the Level 1 and Level 2 data products. All seven of these servers have been verified to produce identical results between various stages of processing.
The SAGE III/ISS Team is proud to announce the second official release of SAGE III/ISS products that are suitable for use in both validation and research studies for data products as described in the associated Data Product User’s Guide DPUG. The nominal monthly release of new SAGE III/ISS events will be processed by the V5.2 algorithm starting with March 2021. Version 5.1 remains publicly available for events from June 2017 through February 2021. This statement applies to SAGE III/ISS Version 5.2 Solar Level 1B, Solar Level 2, and Lunar Level 2 data products. The SAGE III/ISS Team recommends using Version 5.2 instead of Version 5.1 because of the modifications and improvements mentioned below.
Version 5.2 improvements and bug fixes recovered 311 more solar events (increase of 1.0%) compared to v5.1; 104 more lunar events (increase of 4.3%) compared to v5.1; improvements and the number of water vapor profiles withheld by QA was reduced from 570 (v5.1) to 30 (v5.2).
Read more about SAGE III data:
SAGE III/ISS First Atmospheric Data Release
SAGE III/ISS Lunar Data Release
SAGE III/ISS Observes 2017 British Columbia Wildfires
SAGE III Instrument Observes Aerosol Spike from Australian Fires
SAGE III Sees California Wildfire Effects in Stratosphere