An Assessment of the Energy Balance Bowen Ratio Method to Quantify Optical Turbulence in the Maritime Environment

The interactions between Earth's surface and atmosphere are crucial to understanding their impact on surface layer optical turbulence, specifically the temperature structure function (C-T(2)) and refractive index structure function (C-n(2)). The Energy Balance Bowen Ratio (EBBR) - the ratio of sensible heat flux to latent heat flux - has shown promising capabilities to calculate sensible heat flux, a key component for computing C-T(2) and C-n(2). Sensible heat as calculated via the Bowen Ratio inherently accounts for moisture content and evaporation as it apportions the balance of sensible heat to latent heat in the ratio. Thus it better permits the calculation of C-T(2) and C-n(2) via a single equation only dependent on temperature and sensible heat in any stability condition as compared to "ground truth" sonic anemometer turbulence values during daylight and nighttime hours at various land sites. The Bulk Aerodynamic method relies on standard meteorological observations but requires stability corrections based on underlying assumptions with this approach. Researchers have shown success of Bulk Aerodynamic methods and similarity theory to predict C-n(2) in the maritime surface layer, but many adjustments for weakness in stable conditions (air warmer than the water) are necessary. In this study, field data from a marine wave boundary layer test site allow for assessments of both the EBBR and Aerodynamic methods to quantify maritime surface layer turbulence, and the results compared to sonic anemometer and DELTA C-n(2) values.