We investigate how interactive surface feedbacks impact convective
clustering in a cloud resolving model coupled to a slab ocean, where
the domain-mean temperature is controlled with an adaptive Q-flux.
In the first investigation, with constant domain-mean
surface temperature, progressively thinner ocean layers slow the
onset of clustering by up to a month through surface feedback.
Enhanced solar radiation in nascent dry, cloud-free areas leads to
local surface warming, increasing latent heat fluxes in regions
distant from convection. Once the magnitude of humidity
anomalies increases, longwave emission dominates and the
ocean cools rapidly under the dry patches. In this stage the
surface feedback reverses and favors clustering.
In the second investigation using a 1 meter mixed layer, the ocean
undergoes a diurnal cycle in response to solar forcing, with a
diurnal range of 2.5$^o$C in the domain mean. This leads to
convective rainfall shifting from a weak broad nocturnal maximum to
a sharper afternoon peak. The consequent daytime anvil shielding
reduces the spatial SST variance, but the sharper rainfall peak
results from more concurrent convective towers, which are
distributed throughout the domain due to coldpools. This
reduces the upper tropospheric water vapor variance and causes a
slight delay in clustering onset, despite the reduced spatial SST
variance. We find that the onset time is deterministic when strong
forcing causes clustering to occur quickly (after 25 days), whereas
it is highly stochastic when surface feedback weakens the diabatic
forcing and delays clustering past 40 days.