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

Abstract. Long and consistent wave data are important for analysing wave climate variability and change. Moreover, such wave data 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 homogeneous 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 doi:10.1594/WDCC/coastDat-2_WAM–North_Sea Groll and Weisse(2016) or via the coastDat web-page http://www.coastdat.de.

Download Full-text

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

10.5194/essd-2017-36 ◽

2017 ◽

Cited By ~ 1

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.

Download Full-text

Interne Modellvariabilität von Ensemblesimulationen des gekoppelten Wellen- und Atmosphärenmodells GCOAST

10.5194/dach2022-137 ◽

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

Ziel dieser Studie (Wiese et al., 2020) ist, die Signifikanz des Einflusses des Wellenmodells auf das regionale Atmosph&#228;renmodell und die interne Modellvariabilit&#228;t sowohl des Atmosph&#228;renmodells, als auch des gekoppelten Systems bestehend aus Wellen- und Atmosph&#228;renmodell zu bestimmen. In einer vorhergehenden Studie wurde gezeigt, dass die Rauigkeit, die im Wellenmodell berechnet wird, gr&#246;&#223;er ist, als die Rauigkeit, die im Atmosph&#228;renmodell approximiert wird, was zu Unterschieden im Atmosph&#228;renmodell f&#252;hrt (Wiese et al. 2019). Hier soll nun untersucht werden, ob diese Unterschiede im Atmosph&#228;renmodell signifikant sind.&#160; Dazu werden Ensemblesimulation mit einem Referenz Setup (das Atmosph&#228;renmodell sendet den Wind an das Wellenmodell) und dem gekoppelten Setup (zus&#228;tzlich zum Windaustausch, sendet das Wellenmodell die Rauigkeitsl&#228;nge &#252;ber dem Meer zur&#252;ck an das Atmosph&#228;renmodell) durchgef&#252;hrt. Bei der Analyse der internen Modellvariabilit&#228;t zwischen beiden Ensembles zeigt sich, dass die interne Modellvariabilit&#228;t im gekoppelten Ensemble gegen&#252;ber dem Referenzensemble reduziert ist. Dieser Effekt tritt w&#228;hrend Extremereignissen am st&#228;rksten auf, ist aber auch bei einer generellen Analyse der internen Modellvariabilit&#228;t &#252;ber den gesamten Zeitraum sichtbar. Au&#223;erdem k&#246;nnen die Effekte der Kopplung von der internen Modellvariabilit&#228;t unterschieden werden, da die Effekte der Kopplung gr&#246;&#223;er sind, als die interne Modellvariabilit&#228;t. Diese Studie zeigt daher das Potential sowohl in operationellen Systemen als auch Systemen f&#252;r Klimastudien die Unsicherheit zu reduzieren, wenn das Wellenmodell mit dem Atmosph&#228;renmodell gekoppelt wird. Hinzu kommt, dass die Effekte der Kopplung klar von der internen Modellvariabilit&#228;t unterschieden werden k&#246;nnen, wodurch au&#223;erdem eine verbesserte &#220;bereinstimmung des gekoppelten Systems gegen&#252;ber dem Referenzensemble mit Beobachtungsdaten erzielt werden kann. In einem n&#228;chsten Schritt soll nun zus&#228;tzlich der Ozean gekoppelt und die Auswirkungen auf das gesamte System untersucht werden. &#160; Literatur: 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 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

Download Full-text

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

Atmosphere ◽

10.3390/atmos10070386 ◽

2019 ◽

Vol 10 (7) ◽

pp. 386 ◽

Cited By ~ 2

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.

Download Full-text