Rice University team releases WISO-SAT: water vapor deuterium data from eight satellites, 2002–2024
Eight satellite instruments measured the deuterium share in atmospheric water vapor in different formats. The open WISO-SAT database puts them on common monthly grids.
A team led from Rice University has published WISO-SAT, an open database of monthly deuterium (δD) and moisture concentration retrievals from eight satellite missions covering 2002–2024, according to a paper in Scientific Data doi.org
Scientific Datadoi.orgOpen source ↗. The work was led by Mampi Sarkar and Sylvia Dee. Eleven co-authors in the United States, the Netherlands, Germany and Norway took part, including scientists at NASA's Jet Propulsion Laboratory.
Eight instruments, one format
The database combines data from SCIAMACHY, GOSAT, GOSAT-2, TROPOMI, TES, AIRS, CrIS and IASI. Before this work the records covered different periods and altitudes and were stored in inconsistent formats, which complicated comparison.
Four of the instruments read thermal radiation from the atmosphere and return a rough vertical profile of the isotope ratio. The other four read reflected sunlight and return a single value for the whole air column, weighted toward the lowest layers. The authors kept these two kinds of product separate rather than blending them.
The data are distributed as instrument-specific gridded NetCDF files at 1° × 1° and 5° × 5° resolution. A 1° cell is about 111 kilometers on a side at the equator. The products include bias correction across platforms and uncertainty estimates doi.org
Scientific Datadoi.orgOpen source ↗. The files are posted on the Zenodo archive together with the preprocessing code and example notebooks for applying model-satellite averaging kernels and regression-based bias correction.
Validation and limits
The authors warn that satellites see the lower atmosphere poorly. In dry or polar air, retrievals drift toward the starting guess built into the retrieval software.
They checked two instruments against water vapor sampled on nine Atlantic research cruises. One instrument averaged about 23 parts per thousand higher than the ship measurements, the other about 18 parts per thousand lower. Against 25 long-term land stations, the second instrument showed an average difference of 67 parts per thousand, with variation around that average roughly twice as large. A statistical correction based on ground data removed the average offsets and improved agreement.
The corrections rest on small samples, and one proved unreliable when individual stations were removed. The surface checks covered only the two profile instruments. The sunlight-based column products have not been compared with the surface in the database; for that the authors point users to ground-based column measurements and aircraft profiles.
The dataset is intended for evaluating isotope-enabled climate models and for process studies of moisture transport, rain formation, evaporation and atmospheric rivers doi.org
Scientific Datadoi.orgOpen source ↗. The archive is a first version, and its processing code is public so that other groups can grid their own satellite data in the same way.
