TEMPO Science Team Reprocesses Gridded Ozone Total Column Level 3 Version 04

TEMPO O3TOT L3 V04 data originally had a grid of 0.04 degrees (latitude) x 0.02 degrees (longitude). However, the TEMPO Science Team has updated the processing algorithm to 0.02 degrees x 0.02 degrees. They made this change to keep the O3TOT L3 resolution consistent with the previous version of TEMPO O3TOT L3 data files and to make it consistent with other TEMPO Level 3 products, including nitrogen dioxide (NO₂), formaldehyde (HCHO), and clouds (CLDO4). 

Switching the TEMPO O3TOT L3 V04 data to the 0.02 degrees x 0.02 degrees grid may result in different values compared to those in the existing 0.04 degrees (latitude) x 0.02 degrees (longitude) files due to how the interpolation method will impact the different pixel size. This may lead to small changes in individual grid values, spatial patterns, coverage, and aggregated statistics. Array dimensions will also change, so user applications that assume the current grid structure may need to be updated. 

TEMPO O3TOT Level 2 V04 data files are not be affected by this reprocessing.   

The TEMPO Science Team replaced TEMPO O3TOT L3 V04 products for the following date ranges: 

• August 2, 2023  to September 7, 2023 
• July 15, 2024  to August 15, 2024 
• September 17, 2025  to April 1, 2026  

Forward processing of TEMPO O3TOT L3 V04 data began on April 2, 2026. Existing TEMPO O3TOT L3 V04 data were overwritten. This reprocessing occurred between April 2-6, 2026.

If you have previously downloaded TEMPO O3TOT L3, the science team recommends to redownload the new data to replace the previous download.

Please note that the reprocessed data have the same filenames as the previous data on the coarser grid (that are being overwritten); therefore, you will not be able to determine which files are new by looking at the filename. Reprocessed files can be identified by the production date time and Science Data Processing Center (SDPC) version variables in the metadata.

Identifying files in Earthdata Search

In Earthdata Search, users can view the metadata by opening the TEMPO_O3TOT_L3_V04 collection. Each granule has a three-dot menu on the top right. Click on that menu, and then click “View details” to display the metadata. View the "productionDateTime" variable to view the production date. The revised data will have an April 2026 date; the old data will have dates between September 2025 and April 1, 2026.

Identifying files by looking at the file itself

Open the file in a file viewer such as Panoply. In the global attributes, view the production_date_time and sdpc_version variables.

• "productionDateTime" production_date_time: this will be an April 2026 date; the old data will have dates between September 2025 and April 1, 2026
• sdpc_version will be "TEMPO_SDPC_v4.8.3"; the old data state TEMPO_SDPC_v4.6.1

The TEMPO O3TOT user guide has been updated to reflect this change and can be found on the TEMPO O3TOT L3 V04 collection page.