WAVEWATCH-III source terms evaluation for optimizing hurricane wave modeling: A case study of Hurricane Ivan

Abstract. Using the third generation WAVEWATCH III wave model in an unstructured formulation, and driven by HARMONIE-AROME mesoscale model hourly winds with a 2.5 km horizontal resolution, we reproduce the winter storms of 2013/2014 and analyse their effect on the western coastline of Ireland. WAVEWATCH III was forced at its ocean boundaries by directional wave spectra obtained from the ECMWF ERA-Interim re-analysis dataset. The wave model has a high resolution grid (up to 225 m resolution in the nearshore) with around 20 000 nodes, producing an abundance of important wave parameters outputted hourly, enabling a high quality, high-resolution analysis of the winter storms of 2013/2014.

Download Full-text

Turbulence Variations in the Upper Troposphere in Tropical Cyclones from NOAA G-IV Flight-Level Vertical Acceleration Data

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-18-0148.1 ◽

2019 ◽

Vol 58 (3) ◽

pp. 569-583

Author(s):

John Molinari ◽

Michaela Rosenmayer ◽

David Vollaro ◽

Sarah D. Ditchek

Keyword(s):

Tropical Cyclones ◽

Radiative Forcing ◽

Vertical Acceleration ◽

Unstable Region ◽

Absolute Vorticity ◽

Upper Troposphere ◽

Hurricane Ivan ◽

The North ◽

Inertial Instability

AbstractThe NOAA G-IV aircraft routinely measures vertical aircraft acceleration from the inertial navigation system at 1 Hz. The data provide a measure of turbulence on a 250-m horizontal scale over a layer from 12.8- to 14.8-km elevation. Turbulence in this layer of tropical cyclones was largest by 35%–40% in the inner 200 km of radius and decreased monotonically outward to the 1000-km radius. Turbulence in major hurricanes exceeded that in weaker tropical cyclones. Turbulence data points were divided among three regions of the tropical cyclone: cirrus canopy; outside the cirrus canopy; and a transition zone between them. Without exception, turbulence was greater within the canopy and weaker outside the canopy. Nighttime turbulence exceeded daytime turbulence for all radii, especially within the cirrus canopy, implicating radiative forcing as a factor in turbulence generation. A case study of widespread turbulence in Hurricane Ivan (2004) showed that interactions between the hurricane outflow channel and westerlies to the north created a region of absolute vorticity of −6 × 10−5 s−1 in the upper troposphere. Outflow accelerated from the storm center into this inertially unstable region, and visible evidence for turbulence and transverse bands of cirrus appeared radially inward of the inertially unstable region. It is argued that both cloud-radiative forcing and the development of inertial instability within a narrow outflow layer were responsible for the turbulence. In contrast, a second case study (Isabel 2003) displayed strong near-core turbulence in the presence of large positive absolute vorticity and no local inertial instability. Peak turbulence occurred 100 km downwind of the eyewall convection.

Download Full-text

Parameterizing unresolved obstacles with source terms in wave modeling: A real-world application

Ocean Modelling ◽

10.1016/j.ocemod.2018.04.003 ◽

2018 ◽

Vol 126 ◽

pp. 77-84 ◽

Cited By ~ 5

Author(s):

Lorenzo Mentaschi ◽

Georgia Kakoulaki ◽

Michalis Vousdoukas ◽

Evangelos Voukouvalas ◽

Luc Feyen ◽

...

Keyword(s):

Real World ◽

Source Terms ◽

Wave Modeling ◽

Real World Application

Download Full-text

Unstructured global to coastal wave modeling for the Energy Exascale Earth System Model using WAVEWATCH III version 6.07

Geoscientific Model Development ◽

10.5194/gmd-14-2917-2021 ◽

2021 ◽

Vol 14 (5) ◽

pp. 2917-2938

Author(s):

Steven R. Brus ◽

Phillip J. Wolfram ◽

Luke P. Van Roekel ◽

Jessica D. Meixner

Keyword(s):

Earth System Model ◽

System Model ◽

Earth System ◽

Wave Modeling ◽

Wavewatch Iii ◽

Computational Costs ◽

System Models ◽

The Us ◽

Wave Models ◽

Earth System Models

Abstract. Wind-wave processes have generally been excluded from coupled Earth system models due to the high computational expense of spectral wave models, which resolve a frequency and direction spectrum of waves across space and time. Existing uniform-resolution wave modeling approaches used in Earth system models cannot appropriately represent wave climates from global to coastal ocean scales, largely because of tradeoffs between coastal resolution and computational costs. To resolve this challenge, we introduce a global unstructured mesh capability for the WAVEWATCH III (WW3) model that is suitable for coupling within the US Department of Energy's Energy Exascale Earth System Model (E3SM). The new unstructured WW3 global wave modeling approach can provide the accuracy of higher global resolutions in coastal areas at the relative cost of lower uniform global resolutions. This new capability enables simulation of waves at physically relevant scales as needed for coastal applications.

Download Full-text

Observation-Based Source Terms in the Third-Generation Wave Model WAVEWATCH III: Updates and Verification

Journal of Physical Oceanography ◽

10.1175/jpo-d-18-0137.1 ◽

2019 ◽

Vol 49 (2) ◽

pp. 489-517 ◽

Cited By ~ 27

Author(s):

Qingxiang Liu ◽

W. Erick Rogers ◽

Alexander V. Babanin ◽

Ian R. Young ◽

Leonel Romero ◽

...

Keyword(s):

Power Law ◽

Wave Spectrum ◽

Wave Model ◽

Wave Period ◽

Bulk Wave ◽

Third Generation ◽

Source Terms ◽

Frequency Wave ◽

Wavewatch Iii ◽

The Third

AbstractThe observation-based source terms available in the third-generation wave model WAVEWATCH III (i.e., the ST6 package for parameterizations of wind input, wave breaking, and swell dissipation terms) are recalibrated and verified against a series of academic and realistic simulations, including the fetch/duration-limited test, a Lake Michigan hindcast, and a 1-yr global hindcast. The updated ST6 not only performs well in predicting commonly used bulk wave parameters (e.g., significant wave height and wave period) but also yields a clearly improved estimation of high-frequency energy level (in terms of saturation spectrum and mean square slope). In the duration-limited test, we investigate the modeled wave spectrum in a detailed way by introducing spectral metrics for the tail and the peak of the omnidirectional wave spectrum and for the directionality of the two-dimensional frequency–direction spectrum. The omnidirectional frequency spectrum E(f) from the recalibrated ST6 shows a clear transition behavior from a power law of approximately f−4 to a power law of about f−5, comparable to previous field studies. Different solvers for nonlinear wave interactions are applied with ST6, including the Discrete Interaction Approximation (DIA), the more expensive Generalized Multiple DIA (GMD), and the very expensive exact solutions [using the Webb–Resio–Tracy method (WRT)]. The GMD-simulated E(f) is in excellent agreement with that from WRT. Nonetheless, we find the peak of E(f) modeled by the GMD and WRT appears too narrow. It is also shown that in the 1-yr global hindcast, the DIA-based model overestimates the low-frequency wave energy (wave period T > 16 s) by 90%. Such model errors are reduced significantly by the GMD to ~20%.

Download Full-text