Open AccessFine Vertical Resolution Radiative‐Convective Equilibrium Experiments: Roles of Turbulent Mixing on the High‐Cloud Response to Sea Surface Temperatures
Author(s) -
Ohno Tomoki,
Satoh Masaki,
Noda Akira
Publication year - 2019
Publication title -
journal of advances in modeling earth systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.03
H-Index - 58
ISSN - 1942-2466
DOI - 10.1029/2019ms001704
Subject(s) - radiative transfer , convection , atmospheric sciences , turbulence , cloud cover , environmental science , convective mixing , thermal diffusivity , cloud top , geology , mechanics , meteorology , climatology , cloud computing , physics , thermodynamics , optics , computer science , operating system
In this study, the vertical resolution dependency of the high‐cloud fraction response on the increase in sea surface temperature was investigated via radiative‐convective equilibrium simulations. We performed radiative‐convective equilibrium simulations for configurations with a wide range of vertical resolutions using a global nonhydrostatic model including explicit cloud microphysics. It was found that the high‐cloud cover almost monotonically decreased as the vertical resolution increased. We also found that the high‐cloud cover increased (decreased) as the sea surface temperature increased for higher (lower) vertical resolutions. Budget analyses of ice water condensate in transition states to equilibria were performed using the binned vertical profile method and revealed that the tendencies due to the turbulent mixing near convective cores were strongly dependent on the vertical resolution. Analyses of turbulent diffusivity profiles showed that the diffusivity tended to decrease as the vertical resolution increased. The vertical resolution dependency of turbulent mixing was related to frequently occurring weak stratification near the convective cores. We verified these findings via sensitivity experiments and determined that the contribution of the vertical resolution dependency of other processes was secondary. As substantial variability in vertical diffusivity has been reported in both models and observations, these results suggest that a more thorough understanding of turbulent mixing is needed to comprehend high‐cloud changes in warming climates better.