Three-dimensional mapping of the water cycle and D/H on Mars with ALMA
Abstract
Using ALMA, we mapped the vertical distribution of the water D/H across a broad range of terrains and times of days and local seasons on Mars. The observations were done in March/2016 and targeted four lines of isotopic water (H2O, HDO, H218O, H217O), and one line of isotopic carbon monoxide (C17O) used for establishing the thermal structure. The observations allowed us to investigate and separate how the D/H evolves on the planet, since fractionation processes induced by cloud formation would lead to notable variations of D/H along the column.Isotopic measurements are per-se excellent tracers of water loss/evolution on Mars (Villanueva et al. 2015), yet some of the recently observed variations are striking and reveal a far more complex scenario for the processes acting on the Martian water cycle. They are perhaps indicative of sub-surface water reservoirs interacting with the atmosphere, but the IR measurements did not resolve the vertical structure, limiting the untangling of climatological effects (e.g., cloud formation, Rayleigh distillation).We will present 3D maps of water and D/H and will discuss possible scenarios to explain the observations, in particular, in the context of the upper-atmosphere D/H MAVEN measurements.Villanueva, G. L., Mumma, M. J., Novak, R. E., et al. 2015, Science, 348, 218
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #48
- Pub Date:
- October 2016
- Bibcode:
- 2016DPS....4840401V