Temporal Variability of Titan’s Middle-atmospheric Zonal Winds from Southern Fall to Late Winter (2016–2023)
10 affiliations
- 1Astrochemistry Laboratory
- 2Catholic University of America
- 3Aeolis Research
- 4Yale University
- 5University of Bristol
- 6Space Telescope Science Institute
- 7California Institute of Technology
- 8The Open University
- 9Ulster University
- 10Southwest Research Institute
Abstract
Previous ALMA observations have revealed unexpectedly strong and rapid variations in Titan’s high-altitude equatorial zonal winds, which present a challenge to our understanding of this moon’s atmospheric dynamics. Here we report further measurements of Titan’s zonal wind field at middle atmospheric altitudes ≈200–490 km, based on ALMA observations of spatially and spectrally resolved CH ₃ CN emission between 2016 and 2023 (corresponding to a solar longitude L s = 81 . ° 6 – 156 . ° 4 , spanning Titan’s late southern autumn to late winter). These observations indicate substantial, ongoing, rapid temporal variability of Titan’s zonal winds, on timescales as short as ≈1 Earth month ( 0 . ° 9 in L s ). The strongest variability is at (near-)equatorial latitudes where the zonal winds are fastest (up to 240 ± 26 m s ⁻¹ ), with repeated ∼40 m s ⁻¹ fluctuations occurring between L s = 146 . ° 0 – 156 . ° 4 . The observed longer-term trends are qualitatively well-reproduced by two independent, state-of-the-art general circulation models (GCMs), which match the observed decrease in zonal wind speeds over a broad range of latitudes between L s = 81 . ° 6 – 146 . ° 0 , followed by a more moderate increase between L s = 146 . ° 0 – 156 . ° 4 . The wind speeds at mid-to-high latitudes (∼−45° south) are also typically reasonably well reproduced by the GCMs (differing by ≲30%). However, the equatorial wind speeds are up to a factor of ∼2 faster than model predictions (with the greatest discrepancy around solstice; L s ≈ 90°). Rapid temporal variability of the retrieved zonal winds indicates the presence of strong atmospheric instabilities that are not well reproduced by models, suggesting a need for future GCM improvements.
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BibTeX
@article{cordiner2026temporal,
title = {{Temporal Variability of Titan’s Middle-atmospheric Zonal Winds from Southern Fall to Late Winter (2016–2023)}},
author = {Martin A. Cordiner and Yuan Lian and Juan M. Lora and Nicholas A. Lombardo and Lucy Wright and Jonathon Nosowitz and Richard Cosentino and Nicholas A. Teanby and Conor A. Nixon and Alexander E. Thelen and Claire E. Newman and Steven B. Charnley and Eliot F. Young},
journal = {The Planetary Science Journal},
year = {2026},
month = oct,
doi = {10.3847/psj/aeb004},
url = {https://iopscience.iop.org/article/10.3847/PSJ/aeb004},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Temporal Variability of Titan’s Middle-atmospheric Zonal Winds from Southern Fall to Late Winter (2016–2023)
AU - Martin A. Cordiner
AU - Yuan Lian
AU - Juan M. Lora
AU - Nicholas A. Lombardo
AU - Lucy Wright
AU - Jonathon Nosowitz
AU - Richard Cosentino
AU - Nicholas A. Teanby
AU - Conor A. Nixon
AU - Alexander E. Thelen
AU - Claire E. Newman
AU - Steven B. Charnley
AU - Eliot F. Young
PY - 2026
DA - 2026/10/26
JO - The Planetary Science Journal
DO - 10.3847/psj/aeb004
UR - https://iopscience.iop.org/article/10.3847/PSJ/aeb004
AB - Previous ALMA observations have revealed unexpectedly strong and rapid variations in Titan’s high-altitude equatorial zonal winds, which present a challenge to our understanding of this moon’s atmospheric dynamics. Here we report further measurements of Titan’s zonal wind field at middle atmospheric altitudes ≈200–490 km, based on ALMA observations of spatially and spectrally resolved CH ₃ CN emission between 2016 and 2023 (corresponding to a solar longitude L s = 81 . ° 6 – 156 . ° 4 , spanning Titan’s late southern autumn to late winter). These observations indicate substantial, ongoing, rapid temporal variability of Titan’s zonal winds, on timescales as short as ≈1 Earth month ( 0 . ° 9 in L s ). The strongest variability is at (near-)equatorial latitudes where the zonal winds are fastest (up to 240 ± 26 m s ⁻¹ ), with repeated ∼40 m s ⁻¹ fluctuations occurring between L s = 146 . ° 0 – 156 . ° 4 . The observed longer-term trends are qualitatively well-reproduced by two independent, state-of-the-art general circulation models (GCMs), which match the observed decrease in zonal wind speeds over a broad range of latitudes between L s = 81 . ° 6 – 146 . ° 0 , followed by a more moderate increase between L s = 146 . ° 0 – 156 . ° 4 . The wind speeds at mid-to-high latitudes (∼−45° south) are also typically reasonably well reproduced by the GCMs (differing by ≲30%). However, the equatorial wind speeds are up to a factor of ∼2 faster than model predictions (with the greatest discrepancy around solstice; L s ≈ 90°). Rapid temporal variability of the retrieved zonal winds indicates the presence of strong atmospheric instabilities that are not well reproduced by models, suggesting a need for future GCM improvements.
SN - 2632-3338
ER -