scholarly journals The Impact of the Two-Way Coupling between Wind Wave and Atmospheric Models on the Lower Atmosphere over the North Sea

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 386 ◽  
Author(s):  
Anne Wiese ◽  
Emil Stanev ◽  
Wolfgang Koch ◽  
Arno Behrens ◽  
Beate Geyer ◽  
...  
Keyword(s):  
North Sea ◽  
Wind Wave ◽  
Wave Model ◽  
Lower Atmosphere ◽  
Small Scale ◽  
Coupled Simulation ◽  
The North ◽  
Induced Drag ◽  
The North Sea ◽  
Wave Induced

The effects of coupling between the atmospheric model of the Consortium for Small-Scale Modelling-Climate Limited-area Modelling (CCLM) and the wind wave model (WAM) on the lower atmosphere within the North Sea area are studied. Due to the two-way coupling between the models, the influences of wind waves and the atmosphere on each other can be determined. This two-way coupling between these models is enabled through the introduction of wave-induced drag into CCLM and updated winds into WAM. As a result of wave-induced drag, different atmospheric parameters are either directly or indirectly influenced by the wave conditions. The largest differences between the coupled and reference model simulation are found during storm events as well as in areas of steep gradients in the mean sea level pressure, wind speed or temperature. In the two-way coupled simulation, the position and strength of these gradients vary, compared to the reference simulation, leading to differences that spread throughout the entire planetary boundary layer and outside the coupled model area, thereby influencing the atmosphere over land and ocean, although not coupled to the wave model. Ultimately, the results of both model simulations are assessed against in situ and satellite measurements, with a better general performance of the two-way coupled simulation with respect to the observations.

scholarly journals An atmosphere–wave regional coupled model: improving predictions of wave heights and surface winds in the southern North Sea

Ocean Science ◽  
2017 ◽  
Vol 13 (2) ◽  
pp. 289-301 ◽  
Author(s):  
Kathrin Wahle ◽  
Joanna Staneva ◽  
Wolfgang Koch ◽  
Luciana Fenoglio-Marc ◽  
Ha T. M. Ho-Hagemann ◽  
...  
Keyword(s):  
North Sea ◽  
German Bight ◽  
Wind Wave ◽  
Surface Wind ◽  
Wave Model ◽  
Atmospheric Model ◽  
Induced Drag ◽  
Wave Heights ◽  
Wave Induced ◽  
The Impact

Abstract. The coupling of models is a commonly used approach when addressing the complex interactions between different components of earth systems. We demonstrate that this approach can result in a reduction of errors in wave forecasting, especially in dynamically complicated coastal ocean areas, such as the southern part of the North Sea – the German Bight. Here, we study the effects of coupling of an atmospheric model (COSMO) and a wind wave model (WAM), which is enabled by implementing wave-induced drag in the atmospheric model. The numerical simulations use a regional North Sea coupled wave–atmosphere model as well as a nested-grid high-resolution German Bight wave model. Using one atmospheric and two wind wave models simultaneously allows for study of the individual and combined effects of two-way coupling and grid resolution. This approach proved to be particularly important under severe storm conditions as the German Bight is a very shallow and dynamically complex coastal area exposed to storm floods. The two-way coupling leads to a reduction of both surface wind speeds and simulated wave heights. In this study, the sensitivity of atmospheric parameters, such as wind speed and atmospheric pressure, to the wave-induced drag, in particular under storm conditions, and the impact of two-way coupling on the wave model performance, is quantified. Comparisons between data from in situ and satellite altimeter observations indicate that two-way coupling improves the simulation of wind and wave parameters of the model and justify its implementation for both operational and climate simulations.

Interne Modellvariabilität von Ensemblesimulationen des gekoppelten Wellen- und Atmosphärenmodells GCOAST

2021 ◽  
Author(s):  
Anne Wiese ◽  
Joanna Staneva ◽  
Ha Thi Minh Ho-Hagemann ◽  
Sebastian Grayek ◽  
Wolfgang Koch ◽  
...  
Keyword(s):  
North Sea ◽  
Internal Model ◽  
Wind Wave ◽  
Lower Atmosphere ◽  
Atmospheric Models ◽  
Ensemble Simulations ◽  
The North ◽  
The North Sea ◽  
Model Variability ◽  
The Impact

<p>Ziel dieser Studie (Wiese et al., 2020) ist, die Signifikanz des Einflusses des Wellenmodells auf das regionale Atmosphärenmodell und die interne Modellvariabilität sowohl des Atmosphärenmodells, als auch des gekoppelten Systems bestehend aus Wellen- und Atmosphärenmodell zu bestimmen. In einer vorhergehenden Studie wurde gezeigt, dass die Rauigkeit, die im Wellenmodell berechnet wird, größer ist, als die Rauigkeit, die im Atmosphärenmodell approximiert wird, was zu Unterschieden im Atmosphärenmodell führt (Wiese et al. 2019). Hier soll nun untersucht werden, ob diese Unterschiede im Atmosphärenmodell signifikant sind.  Dazu werden Ensemblesimulation mit einem Referenz Setup (das Atmosphärenmodell sendet den Wind an das Wellenmodell) und dem gekoppelten Setup (zusätzlich zum Windaustausch, sendet das Wellenmodell die Rauigkeitslänge über dem Meer zurück an das Atmosphärenmodell) durchgeführt. Bei der Analyse der internen Modellvariabilität zwischen beiden Ensembles zeigt sich, dass die interne Modellvariabilität im gekoppelten Ensemble gegenüber dem Referenzensemble reduziert ist. Dieser Effekt tritt während Extremereignissen am stärksten auf, ist aber auch bei einer generellen Analyse der internen Modellvariabilität über den gesamten Zeitraum sichtbar. Außerdem können die Effekte der Kopplung von der internen Modellvariabilität unterschieden werden, da die Effekte der Kopplung größer sind, als die interne Modellvariabilität. Diese Studie zeigt daher das Potential sowohl in operationellen Systemen als auch Systemen für Klimastudien die Unsicherheit zu reduzieren, wenn das Wellenmodell mit dem Atmosphärenmodell gekoppelt wird. Hinzu kommt, dass die Effekte der Kopplung klar von der internen Modellvariabilität unterschieden werden können, wodurch außerdem eine verbesserte Übereinstimmung des gekoppelten Systems gegenüber dem Referenzensemble mit Beobachtungsdaten erzielt werden kann. In einem nächsten Schritt soll nun zusätzlich der Ozean gekoppelt und die Auswirkungen auf das gesamte System untersucht werden.</p> <p> </p> <p>Literatur:</p> <p>Wiese A, Stanev E, Koch W, Behrens A, Geyer B and Staneva J (2019) The Impact of the Two-Way Coupling between Wind Wave and Atmospheric Models on the Lower Atmosphere over the North Sea. Atmosphere. 10(7):386. doi: 10.3390/atmos10070386</p> <p>Wiese A, Staneva J, Ho-Hagemann HTM, Grayek S, Koch W and Schrum C (2020) Internal Model Variability of Ensemble Simulations With a Regional Coupled Wave-Atmosphere Model GCOAST. Front. Mar. Sci. 7:596843. doi: 10.3389/fmars.2020.596843</p>

scholarly journals A multi-decadal wind-wave hindcast for the North Sea 1949–2014: coastDat2

2017 ◽  
Author(s):  
Nikolaus Groll ◽  
Ralf Weisse
Keyword(s):  
Climate Variability ◽  
North Sea ◽  
Wind Wave ◽  
Wave Model ◽  
Wave Climate ◽  
Climate Variability And Change ◽  
Data Set ◽  
Wave Hindcast ◽  
The North ◽  
The North Sea

Abstract. Long and consistent wave data are important for analysing wave climate variability and change. Moreover, such statistics are also needed in coastal and offshore design and for addressing safety-related issues at sea. Using the third-generation spectral wave model WAM a multi-decadal wind-wave hindcast for the North Sea covering the period 1949–2014 was produced. The hindcast is part of the coastDat database representing a consistent and homogenous met-ocean data set. It is shown that despite not being perfect, data from the wave hindcast are generally suitable for wave climate analysis. In particular comparisons of hindcast data with in situ and satellite observations show on average a reasonable agreement while a tendency towards overestimation of the highest waves could be inferred. Despite these limitations, the wave hindcast still provides useful data for assessing wave climate variability and change as well as for risk analysis, in particular when conservative estimates are needed. Hindcast data are stored at the World Data Center for Climate (WDCC) and can be freely accessed using the https://doi.org/10.1594/WDCC/coastDat-2_WAM-North_Sea (Groll and Weisse, 2016) or via the coastDat web-page http://www.coastdat.de.

Effects of wave-induced forcing on a circulation model of the North Sea

2016 ◽  
Vol 67 (1) ◽  
pp. 81-101 ◽  
Author(s):  
Joanna Staneva ◽  
Victor Alari ◽  
Øyvind Breivik ◽  
Jean-Raymond Bidlot ◽  
Kristian Mogensen
Keyword(s):  
North Sea ◽  
Circulation Model ◽  
The North ◽  
The North Sea ◽  
Wave Induced

scholarly journals The North Sea Andrea storm and numerical simulations

2014 ◽  
Vol 14 (6) ◽  
pp. 1407-1415 ◽  
Author(s):  
E. M. Bitner-Gregersen ◽  
L. Fernandez ◽  
J. M. Lefèvre ◽  
J. Monbaliu ◽  
A. Toffoli
Keyword(s):  
Numerical Simulations ◽  
North Sea ◽  
Rogue Wave ◽  
Grid Point ◽  
Wave Model ◽  
Wave Statistics ◽  
The North ◽  
Nonlinear Phase ◽  
Spectral Wave Model ◽  
The North Sea

Abstract. A coupling of a spectral wave model with a nonlinear phase-resolving model is used to reconstruct the evolution of wave statistics during a storm crossing the North Sea on 8–9 November 2007. During this storm a rogue wave (named the Andrea wave) was recorded at the Ekofisk field. The wave has characteristics comparable to the well-known New Year wave measured by Statoil at the Draupner platform 1 January 1995. Hindcast data of the storm at the nearest grid point to the Ekofisk field are here applied as input to calculate the evolution of random realizations of the sea surface and its statistical properties. Numerical simulations are carried out using the Euler equations with a higher-order spectral method (HOSM). Results are compared with some characteristics of the Andrea wave record measured by the down-looking lasers at Ekofisk.

scholarly journals Impact of additional small-scale survey data on the geostatistical analyses of demersal fish species in the North Sea

2005 ◽  
Vol 69 (4) ◽  
pp. 587-602 ◽  
Author(s):  
Gerd Peter Zauke ◽  
Vanessa Stelzenmüller ◽  
Siegfried Ehrich
Keyword(s):  
Survey Data ◽  
North Sea ◽  
Fish Species ◽  
Demersal Fish ◽  
Small Scale ◽  
The North ◽  
The North Sea

scholarly journals JOINT OFFSHORE WIND FIELD MONITORING WITH SPACEBORNE SAR AND PLATFORM-BASED DOPPLER LIDAR MEASUREMENTS

2015 ◽  
Vol XL-7/W3 ◽  
pp. 959-966 ◽  
Author(s):  
S. Jacobsen ◽  
S. Lehner ◽  
J. Hieronimus ◽  
J. Schneemann ◽  
M. Kühn
Keyword(s):  
North Sea ◽  
Wind Field ◽  
Wind Farm ◽  
Offshore Wind ◽  
Small Scale ◽  
Doppler Lidar ◽  
Wind Fields ◽  
The North ◽  
Spatial Coverage ◽  
The North Sea

The increasing demand for renewable energy resources has promoted the construction of offshore wind farms e.g. in the North Sea. While the wind farm layout consists of an array of large turbines, the interrelation of wind turbine wakes with the remaining array is of substantial interest. The downstream spatial evolution of turbulent wind turbine wakes is very complex and depends on manifold parameters such as wind speed, wind direction and ambient atmospheric stability conditions. <br><br> To complement and validate existing numerical models, corresponding observations are needed. While in-situ measurements with e.g. anemometers provide a time-series at the given location, the merits of ground-based and space- or airborne remote sensing techniques are indisputable in terms of spatial coverage. Active microwave devices, such as Scatterometer and Synthetic Aperture Radar (SAR), have proven their capabilities of providing sea surface wind measurements and particularly SAR images reveal wind variations at a high spatial resolution while retaining the large coverage area. Platform-based Doppler LiDAR can resolve wind fields with a high spatial coverage and repetition rates of seconds to minutes. In order to study the capabilities of both methods for the investigation of small scale wind field structures, we present a direct comparison of observations obtained by high resolution TerraSAR-X (TS-X) X-band SAR data and platform-based LiDAR devices at the North Sea wind farm alpha ventus. We furthermore compare the results with meteorological data from the COSMO-DE model run by the German Weather Service DWD. Our study indicates that the overall agreement between SAR and LiDAR wind fields is good and that under appropriate conditions small scale wind field variations compare significantly well.

scholarly journals An atmosphere-wave regional coupled model: improving predictions of wave heights and surface winds in the Southern North Sea

2016 ◽  
Author(s):  
Kathrin Wahle ◽  
Joanna Staneva ◽  
Wolfgang Koch ◽  
Luciana Fenoglio-Marc ◽  
Ha T. M. Ho-Hagemann ◽  
...  
Keyword(s):  
North Sea ◽  
German Bight ◽  
Surface Wind ◽  
Model Performance ◽  
Coupled Model ◽  
Wave Model ◽  
Induced Drag ◽  
Wave Heights ◽  
Wave Induced ◽  
The Impact

Abstract. Reduction of wave forecasting errors is a challenge especially in dynamically complicated coastal ocean areas as the southern part of the North Sea area – the German Bight. Coupling of different models is a favoured approach to address this issue as it accounts for the complex interactions of waves, currents and the atmosphere. Here we study the effects of coupling between an atmospheric model and a wind wave model, which in the present study is enabled through an introduction of wave induced drag in the atmosphere model. This, on one side, leads to a reduction of the surface wind speeds, and on the other side, to a reduction of simulated wave heights. The sensitivity of atmospheric parameters such as wind speed, and atmospheric pressure to wave-induced drag, in particular under storm conditions, is studied. Additionally, the impact of the two-way coupling on wave model performance is investigated. The performance of the coupled model system has been demonstrated for extreme events and calm conditions. The results revealed that the effect of coupling results in significant changes in both wind and waves. The simulations are compared to data from in-situ and satellite observations. The results indicate that the two-way coupling improves the agreement between observations and simulations for both wind and wave parameters in comparison to the one-way coupled model. In addition, the errors of the high-resolution German Bight wave model compared to the observations have been significantly reduced in the coupled model. The improved skills resulting from the proposed method justifies its implementations for both operational and climate simulations.

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