Drizzle tends to be the most frequent form of precipitation over large areas of the world's oceans, particularly in the colder regions of the subtropics. These regions are dominated by shallow marine stratocumulus and trade wind cumulus clouds, which exist entirely within the marine boundary layer. Despite the low rates of surface accumulation, it has become apparent[to whom?] that drizzle exerts a major influence over the structure, coverage, and radiative properties of clouds in these regions.