Status: this preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Continuing the MLS water vapor record with OMPS LP
Michael D. Himes,Natalya A. Kramarova,Krzysztof Wargan,Sean M. Davis,and Glen Jaross
Abstract.
Stratospheric water vapor (SWV) plays an important role in atmospheric chemistry, dynamics, and radiative forcing. Satellite measurements by the Aura Microwave Limb Sounder (MLS), SciSat-1 Atmospheric Chemistry Experiment (ACE), and Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station have provided key constraints on SWV for the past decades. MLS provides the best geographical coverage among these instruments, but it approaches the end of its life cycle in the coming years, which will result in a data desert for satellite-based SWV measurements given that ACE and SAGE III only measure at a few dozen geolocations per day. The Ozone Mapping and Profiler Suite Limb Profiler (OMPS LP) is flying aboard the Suomi National Polar-orbiting Partnership (SNPP) and NOAA-21 satellites and is planned for additional platforms in the coming years. While not designed to measure SWV, it shows weak sensitivity to it, particularly in the wake of the Hunga eruption's significant injection of water vapor into the stratosphere. By utilizing the frequent co-locations between OMPS LP and MLS measurements, we developed a neural network-based approach to retrieve SWV from SNPP OMPS LP radiances between 11.5–40.5 km. We find that the LP SWV profiles typically agree with MLS within 5 %, and agreement with ACE and SAGE III is typically within 10 %. We show that the SNPP-trained model is applicable to NOAA-21 OMPS LP without retraining, though minor differences in radiances between the instruments results in a ~5 % bias under most conditions. Our results suggest that OMPS LP can continue the global water vapor record in the lower stratosphere into the 2030s, though continued independent measurements by satellite and balloon-borne instruments will be key to verifying the stability of our approach for quantifying decadal-scale SWV variability.
Received: 30 Sep 2025 – Discussion started: 07 Oct 2025
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Measurement Techniques.
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Stratospheric water vapor (SWV) influences various atmospheric processes. While the Ozone Mapping and Profiler Suite Limb Profiler (OMPS LP) was not designed to measure SWV, we utilized near-coincident measurements by the Aura Microwave Limb Sounder (MLS) and OMPS LP to develop a machine learning method to measure SWV between 11.5–40.5 km. The LP-derived SWV closely agrees with MLS. Our results suggest OMPS LP can continue the global water vapor record after MLS measurements cease in 2026.
Stratospheric water vapor (SWV) influences various atmospheric processes. While the Ozone...
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