Characteristics and Scaling of the Stable Marine Internal Boundary Layer

The characteristics of a stable internal boundary layer (SIBL) offshore of Duck, North Carolina documented during CASPER‐EAST have been examined using surface layer‐resolving large eddy simulations. Under the influence of steady offshore winds, a SIBL develops over the coastal waters with its depth growing with the offshore advection time (TA) as ∼ TA . The SIBL includes an internal equilibrium layer above the surface where the heat and momentum fluxes linearly decrease with height and a transition layer aloft. The offshore area can be partitioned into three distinct zones, namely, a nearshore zone (NSZ, TA < Td/3), an intermediate offshore zone (IOZ, Td/3 < TA < Td), and a far‐offshore zone (FOZ, TA > Td), where Td is the vertically‐averaged turbulent dissipation time. The advection of turbulence from land plays a significant role in the momentum and scalar budgets over the NSZ. Consequently, the Monin‐Obukhov similarity theory (MOST) becomes invalid, and local similarity theory is applicable only above the SIBL in the NSZ. In the IOZ, the advection of turbulence from land is less important but still non‐negligible. As a result, while the dimensionless standard deviations of winds and potential temperature converge toward the MOST curves, the dimensionless gradients are smaller than their counterparts in the FOZ. In the FOZ, the advection from land becomes negligible, and MOST is applicable throughout the constant flux layer. Over the IOZ and the FOZ, LST works reasonably well within the SIBL.