Stratocumulus

Stratocumulus clouds are low, horizontally extensive cloud layers that commonly form in cool and stable marine boundary layers. They are especially important in eastern subtropical and equatorial oceans where they strongly modulate surface radiation and boundary-layer moisture.

How they form

Marine stratocumulus typically forms when cool ocean surfaces maintain a shallow marine boundary layer capped by a strong temperature inversion. Turbulent mixing below the inversion supplies moisture upward, while the inversion prevents deep vertical development. The result is a persistent low-cloud deck rather than deep convective towers.

Climatic role

• They reflect a large fraction of incoming solar radiation.
• They often indicate a shallow Marine boundary layer capped by a temperature inversion.
• They can produce drizzle or maintain persistent cloud immersion without large rain totals.

Because of their radiative importance, stratocumulus clouds are a major control on ocean-atmosphere coupling and a recurring source of uncertainty in climate modeling.

In the Galapagos

During the Garua season, cool SSTs and a strong inversion favor persistent stratocumulus over and around the Galapagos Islands. This low-cloud regime is central to cloud frequency patterns, Occult precipitation, and ecoclimatic moisture gradients.

Relevance for diagnostics and models

Capturing stratocumulus well requires a good representation of SST gradients, inversion structure, boundary-layer turbulence, and surface fluxes. That makes it an important test case for regional models such as WRF in the Galapagos context.

See also: Garua, Marine boundary layer, Temperature inversion, Cloud frequency in the Galapagos, Ecoclimatic cloud zonation in the Galapagos