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Abstract Drag coefficient parameterizations, which are largely developed from homogenous deep ocean data, are ineffective nearshore where conditions are nonuniform. This is problematic because operational forecast accuracy depends upon reliable quantification of air–sea momentum transfer. This is especially important for storms which threaten coastal life and property. To help fill this knowledge gap, direct flux measurements were collected from the beach and pierhead in Duck, North Carolina, as part of the During Nearshore Event Experiment (DUNEX). The footprint analysis shows these fluxes were sourced in the surfzone and offshore, representing very different conditions. During a weeklong storm, wind speeds and significant wave heights were 20 m s⁻¹and 4 m, leading to a broad, vigorous surfzone. The drag coefficient in the surfzone was twice the offshore value, explained by increased roughness due to wind stress and bathymetric changes. The Charnock parameter is well predicted by wave age, but it is expected this is site-specific due to unique bathymetry. A horizontal wind speed gradient was observed and attributed to the high surfzone roughness. The wavelengths of the turbulent eddies in the surfzone were smaller than offshore or predicted by universal scaling. This research offers novel insights that can contribute to a crucial collective effort to develop robust coastal flux models, leading to improved forecasting. Significance StatementWhen wind blows over the ocean, the energy associated with its motion is moved from the air into water. This energy transfer helps grow waves and drive currents which, via many pathways, alter the characteristics of the upper ocean and lower atmosphere. In turn, this affects weather and climate, so it is critical this energy exchange is accounted for in forecasts. Energy transfer is reasonably well understood in the deep ocean, but not nearshore where conditions are nonuniform and change quickly, especially in storms where very few measurements are made. To remedy this, data were collected in May 2022 during a storm in Duck, North Carolina, which had wind speeds of 20 m s⁻¹and 4-m wave heights. The extreme conditions created a very wide and energetic surfzone. Wind measurements were made on the beach and approximately 500 m offshore. Due to the rough surface, twice the energy was transferred from the air into the ocean in the surfzone than offshore and the wind speed decreased as it crossed the surfzone. Finally, the wavelengths of the wind that transfer energy into the ocean are much smaller than offshore or predicted by previous research. 

Aluminum-doped porous silicon was produced by a molten salt reaction. 

Power semiconductor devices are utilized as solid-state switches in power electronics systems, and their overarching design target is to minimize the conduction and switching losses. However, the unipolar figure-of-merit (FOM) commonly used for power device optimization does not directly capture the switching loss. In this Perspective paper, we explore three interdependent open questions for unipolar power devices based on a variety of wide bandgap (WBG) and ultra-wide bandgap (UWBG) materials: (1) What is the appropriate switching FOM for device benchmarking and optimization? (2) What is the optimal drift layer design for the total loss minimization? (3) How does the device power loss compare between WBG and UWBG materials? This paper starts from an overview of switching FOMs proposed in the literature. We then dive into the drift region optimization in 1D vertical devices based on a hard-switching FOM. The punch-through design is found to be optimal for minimizing the hard-switching FOM, with reduced doping concentration and thickness compared to the conventional designs optimized for static FOM. Moreover, we analyze the minimal power loss density for target voltage and frequency, which provides an essential reference for developing device- and package-level thermal management. Overall, this paper underscores the importance of considering switching performance early in power device optimization and emphasizes the inevitable higher density of power loss in WBG and UWBG devices despite their superior performance. Knowledge gaps and research opportunities in the relevant field are also discussed.