The Hydrological Cycle and Circulation of Tidally-Locked Planets with a Finite Moisture Inventory
Abstract
Tidally-locked planets express a range of climate regimes distinct from those found in our solar system. Their atmospheres are often dominated by planetary-wide overturning circulations and super- rotating jets. In this paper we explore the hydrological cycle of such planets and how it might depend on the total inventory of condensate. To this end we use a set of idealised GCM simulations to probe the response of the hydrological cycle to the surface moisture budget in their atmospheres. We find that for low moisture inventories the climate quickly develops a barren day side and a moist night side where the moisture is trapped, as might be expected. For higher moisture inventories the drying of the day side is significantly delayed by the development of a substellar lake just east of the substellar point, which is sustained by the presence of a local thunderstorm-like convective system that persists even after the lake disappears. The timescales for the lake to disappear are millennia, suggesting that even a weak transfer of moisture through surface processes could maintain a moist day side. We also find that adjusting the threshold at which the evaporative rate becomes constrained by the remaining surface liquid depth modifies the longevity of the lake and surrounding day side conditions. These findings have implications for understanding a diverse range of planetary climates and habitability, given the distribution of moisture and presence of a substellar lake.
Related
- Atmospheric dynamics and variability of periodically irradiated tidally locked planets
- ARRAKIHS: The observability of tidally stripped satellites in a Milky Way-like halo
- Tidally perturbed pulsations in OO Dra
- Tidally Perturbed Pulsations in OO Dra
- Eppur binaria non è esclusa: Pulsations in CZ Tuc appear to be tidally excited by its veiled companion
BibTeX
@misc{williams2026hydrological,
title = {{The Hydrological Cycle and Circulation of Tidally-Locked Planets with a Finite Moisture Inventory}},
author = {Daniel A. Williams and Geoffrey K. Vallis and Stephen I. Thomson and William J. M. Seviour},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.13517},
eprint = {2610.13517},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.13517},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Hydrological Cycle and Circulation of Tidally-Locked Planets with a Finite Moisture Inventory
AU - Daniel A. Williams
AU - Geoffrey K. Vallis
AU - Stephen I. Thomson
AU - William J. M. Seviour
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.13517
UR - https://arxiv.org/abs/2610.13517
AB - Tidally-locked planets express a range of climate regimes distinct from those found in our solar system. Their atmospheres are often dominated by planetary-wide overturning circulations and super- rotating jets. In this paper we explore the hydrological cycle of such planets and how it might depend on the total inventory of condensate. To this end we use a set of idealised GCM simulations to probe the response of the hydrological cycle to the surface moisture budget in their atmospheres. We find that for low moisture inventories the climate quickly develops a barren day side and a moist night side where the moisture is trapped, as might be expected. For higher moisture inventories the drying of the day side is significantly delayed by the development of a substellar lake just east of the substellar point, which is sustained by the presence of a local thunderstorm-like convective system that persists even after the lake disappears. The timescales for the lake to disappear are millennia, suggesting that even a weak transfer of moisture through surface processes could maintain a moist day side. We also find that adjusting the threshold at which the evaporative rate becomes constrained by the remaining surface liquid depth modifies the longevity of the lake and surrounding day side conditions. These findings have implications for understanding a diverse range of planetary climates and habitability, given the distribution of moisture and presence of a substellar lake.
ER -