Spatial patterns of shallow clouds: Challenging the concept of defined regimes

Tropical shallow clouds are a major source of uncertainty in Earth's climate sensitivity, especially through their spatial arrangement, which global climate models do not represent. Efforts to understand their organization have partly relied on classifying observed scenes, identifying four patterns as archetypal regimes. Here we analyze geostationary satellite imagery of the western tropical Atlantic using the L‐function, a tool based on point pattern theory that quantifies cloud organization across spatial scales. Classical examples of the four patterns show distinct L‐function fingerprints, revealing their characteristic clustering and regularity scales and aiding physical interpretation. Yet, when evaluating many scenes at fixed spatial scales, the L‐function distribution lacks the distinct modes expected from discrete regimes. This is corroborated by analyses of other organization indices employing diverse approaches, from inter‐cloud nearest‐neighbor distances to fractal analysis. Implications for the parameterization of mesoscale cloud organization in climate models are discussed.