Evaluation of Ocean-Wave Dependence of Sea Surface Roughness Using Wave-Boundary Layer Model

2008 ◽  
Vol 55 ◽  
pp. 41-45
Author(s):  
Naoto KIHARA ◽  
Shuji ISHIHARA ◽  
Hiromaru CHI
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Sea Surface ◽  
Ocean Wave ◽  
Layer Model ◽  
Wave Boundary Layer ◽  
Boundary Layer Model ◽  
Sea Surface Roughness ◽  
Wave Boundary

scholarly journals The use of a wave boundary layer model in SWAN

2017 ◽  
Vol 122 (1) ◽  
pp. 42-62 ◽  
Author(s):  
Jianting Du ◽  
Rodolfo. Bolaños ◽  
Xiaoli Guo Larsén
Keyword(s):  
Boundary Layer ◽  
Layer Model ◽  
Wave Boundary Layer ◽  
Boundary Layer Model ◽  
Wave Boundary

scholarly journals Wave boundary layer model in SWAN revisited

Ocean Science ◽  
2019 ◽  
Vol 15 (2) ◽  
pp. 361-377 ◽  
Author(s):  
Jianting Du ◽  
Rodolfo Bolaños ◽  
Xiaoli Guo Larsén ◽  
Mark Kelly
Keyword(s):  
Boundary Layer ◽  
Source Function ◽  
Source Terms ◽  
Layer Model ◽  
Wave Boundary Layer ◽  
Boundary Layer Model ◽  
Wind Input ◽  
Wave Induced ◽  
The Impact ◽  
Wave Boundary

Abstract. In this study, we extend the work presented in Du et al. (2017) to make the wave boundary layer model (WBLM) applicable for real cases by improving the wind-input and white-capping dissipation source functions. Improvement via the new source terms includes three aspects. First, the WBLM wind-input source function is developed by considering the impact of wave-induced wind profile variation on the estimation of wave growth rate. Second, the white-capping dissipation source function is revised to be not explicitly dependent on wind speed for real wave simulations. Third, several improvements are made to the numerical WBLM algorithm, which increase the model's numerical stability and computational efficiency. The improved WBLM wind-input and white-capping dissipation source functions are calibrated through idealized fetch-limited and depth-limited studies, and validated in real wave simulations during two North Sea storms. The new WBLM source terms show better performance in the simulation of significant wave height and mean wave period than the original source terms.

Implementation of the wave boundary layer model in the OpenIFS model

2020 ◽  
Author(s):  
Nefeli Makrygianni ◽  
Jean R. Bidlot ◽  
Michaela Bray ◽  
Shunqi Pan
Keyword(s):  
Boundary Layer ◽  
Drag Coefficient ◽  
Roughness Length ◽  
Coupled Model ◽  
Extreme Conditions ◽  
Layer Model ◽  
Wave Boundary Layer ◽  
Boundary Layer Model ◽  
Wind Input ◽  
Wave Boundary

<p>For more than 30 years, many studies have been carried out to improve the understanding of the air-sea interaction and its impact on the predictions of atmospheric and the oceanic processes. It is well understood that the accuracy in predictions of the wind-driven waves is highly dependent on the source input and dissipation terms. The Wave Boundary Layer (WBL) approach for the estimation of surface stress has previously been used to improve the wind and wave simulations under extreme conditions. However, until recently the WBL was only used to determine the roughness length (z<sub>0</sub>) and drag coefficient (C<sub>d</sub>), but not to alter the wind input source function in wave models. In this study, the wave boundary layer model (WBLM) was implemented in the OpenIFS coupled model as source functions as suggested by Du et al. (2017, 2019). The new wind input and dissipation terms are then tested using numerical model simulations, with a particular focus on the contribution of the high frequency tail in the source input function.  The comparison of the results of this study with published results hints at better performance of the model on the estimation of the roughness length and drag coefficient. This should improve predictions of the significant wave height and wind speeds, especially under extreme conditions.</p><p>Corresponding Author: Nefeli Makrygianni ([email protected])</p>

scholarly journals Reduced Sea-Surface Roughness Length at a Coastal Site

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 991
Author(s):  
Yuncheng He ◽  
Jiyang Fu ◽  
Pak Wai Chan ◽  
Qiusheng Li ◽  
Zhenru Shu ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Atmospheric Boundary Layer ◽  
Roughness Length ◽  
Sea Surface ◽  
Marine Atmospheric Boundary Layer ◽  
Coastal Site ◽  
Surface Roughness Length ◽  
Sea Surface Roughness ◽  
Roughness Lengths

Sea-surface roughness length is a key parameter for characterizing marine atmospheric boundary layer. Although aerodynamic roughness lengths for homogeneous land and open water surfaces have been examined extensively, the extension of relevant knowledge to the highly inhomogeneous coastal area is problematic due to the complex mechanisms controlling coastal meteorology. This study presented a lidar-based observational analysis of sea-surface roughness length at a coastal site in Hong Kong, in which the wind data recorded from March 2012 to November 2015 were considered and analyzed. The results indicated the turning of wind near the land-sea boundary, leading to a dominative wind direction parallel to the coastline and an acceleration in wind. Moreover, the roughness lengths corresponding to two representative azimuthal sectors were compared, in which the roughness lengths for the onshore wind sector (i.e., 120°–240°) appear to be larger than the constant value (z0 = 0.2 mm) recommended in much existing literature, whereas the values for the alongshore wind sector (i.e., 60°–90°) are significantly smaller, i.e., about two orders of magnitude less than that of a typical sea surface. However, it is to be noted that the effect of atmospheric stability, which is of crucial importance in governing the marine atmospheric boundary layer, is not taken into account in this study.

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