2016/05/30 by L. Carone, Rony Keppens, R. Keppens +1
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Atmospheric circulation #Atmospheric sciences #Climatology #Geology #Geology and Paleoclimatology Research #High-pressure geophysics and materials #Optics #Physics #Planet #Radiative transfer #Rossby wave #Tidal locking #Zonal and meridional #astro-ph.EP
paper · pdf · doi:10.1093/mnras/stw1265
25 pages, 21 figures, accepted by MNRAS
openalex publication_date 2016/05/30 · arxiv created 2016/05/31 · arxiv updated 2016/06/01 · openalex created_date 2022/05/12 · openalex updated_date 2026/08/05
We investigate how nightside cooling and surface friction affect surface temperatures and large-scale circulation for tidally locked Earth-like planets. For each scenario, we vary the orbital period between Prot = 1 and 100 d and capture changes in climate states. We find drastic changes in climate states for different surface friction scenarios. For very efficient surface friction (ts,fric = 0.1 d), the simulations for short rotation periods (Prot ≤ 10 d) show predominantly standing extratropical Rossby waves. These waves lead to climate states with two high-latitude westerly jets and unperturbed meridional direct circulation. In most other scenarios, simulations with short rotation periods exhibit instead dominance by standing tropical Rossby waves. Such climate states have a single equatorial westerly jet, which disrupts direct circulation. Experiments with weak surface friction (ts,fric = 10–100 d) show decoupling between surface temperatures and circulation, which leads to strong cooling of the nightside. The experiment with ts,fric = 100 d assumes climate states with easterly flow (retrograde rotation) for medium and slow planetary rotations Prot = 12–100 d. We show that an increase of nightside cooling efficiency by one order of magnitude compared to the nominal model leads to a cooling of the nightside surface temperatures by 80–100 K. The dayside surface temperatures only drop by 25 K at the same time. The increase in thermal forcing suppresses the formation of extratropical Rossby waves on small planets (RP = 1REarth) in the short rotation period regime (Prot ≤ 10 d).