Plain Language Summary
Interplays between radiation, clouds and convection are well studied in
numerical simulations under idealized boundary conditions (e.g.,
spatially uniform sea surface temperatures, no wind shear, etc.).
However, it remains unclear how they interact with each other in more
realistic situations with the presence of sea surface temperature
gradients and a large-scale background circulation. In this study we
examine the impact of synoptic-scale radiative coupling on convective
organization, clouds, and precipitation extremes using a
~50 km resolution atmospheric general circulation model.
When synoptic-scale radiative coupling is disabled, we find that the
mean circulation and rainfall remain almost unaffected. However,
convection becomes less organized without radiative coupling, which is
due to the diminished spatial contrast in radiative cooling between dry
and moist regions. Also, both daily precipitation and mid-tropospheric
updrafts exhibit a reduction in the probability of their extreme values
when radiative coupling is disabled. In addition, we find that radiative
coupling can modulate the distribution of clouds and relative humidity.
These findings highlight the importance of synoptic-scale interactions
between radiation and convection even in realistic situations, and
motivates the comparison of model simulations and observations.