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MaximumShearStress 2010-2014


Metadata
File Identifier: 9EAB8C7D-6389-4BD5-889B-289F925C05C7
Metadata Language: English
: utf8
Resource Type: Service
Responsible Party:
Individual Name: Ulrike Kleeberg
Organisation Name: HZG Helmholtz-Zentrum Geesthacht
Role: Point Of Contact
Contact Info:
E-Mail Address: ulrike.kleeberg@hzg.de
Metadata Date: 2017-01-11
Metadata Standard Name: INSPIRE Metadata Implementing Rules: Technical Guidelines based on EN ISO 19115 and EN ISO 19119
Metadata Standard Version: V. 1.2
Service Identification
Abstract: The map shows the spatial distribution of time-averaged maximum bed shear stress generated by the combined action of waves and currents in the southern North Sea. The current data were calculated by the TRIM model. The wave data were calculated by the WAM model. The time-averaging period is over the years 2010 to 2014. The skin-friction bed shear-stress (or bottom friction) is the frictional force exerted on unit area of sea bed generated by currents and/or waves. It is usually given in “Newton per m2”. The skin-friction bed shear-stress t is an important quantity for sediment transport purposes (Soulsby 1997). So it may be assumed that t also represents a relevant impact on benthic fauna. According to Soulsby (1997), “the bed shear stresses beneath combined waves and currents are enhanced beyond the values which would result from a simple linear addition of the wave-alone and current-alone stresses. This occurs because of a non-linear interaction between the wave and current boundary layers.” The bed shear stresses generated by the combined action of waves and currents are commonly represented (a) by the mean and (b) by the maximum bed shear stress during a wave cycle. The map shows the maximum bed shear stress tCW.MAX. The most important task of tCW.MAXin a sediment transport model is the erosion of bottom sediment. The spatial distribution of tCW.MAXin the southern North Sea shows the characteristics of both the current bed shear stress tCand the wave bed shear stress tW. The high values of tCW.MAXin the Southern Bight and along the English coast are due to high tCvalues (resulting from strong tidal currents), while the high values of tCW.MAXin shallow areas (e.g. Dogger Bank) are due to high tWvalues.
Purpose: The map shows the spatial distribution of time-averaged maximum bed shear stress generated by the combined action of waves and currents in the southern North Sea. The current data were calculated by the TRIM model for the years 2010 to 2014
Thumbnail:
Browse Graphic: https://coastmap.hzg.de/server/rest/directories/thumbs/MaximumShearStress_thumb_2010_2014.png
Citation:
Title: MaximumShearStress 2010-2014
Date:
Date: 2017-01-12
Date Type: Publication Date
Identifier: 9EAB8C7D-6389-4BD5-889B-289F925C05C7-DI
Individual Name: Ulrike Kleeberg
Organisation Name: HZG Helmholtz-Zentrum Geesthacht
Role: Point Of Contact
Contact Info:
E-Mail Address: ulrike.kleeberg@hzg.de
Point Of Contact:
Individual Name: Ulrike Kleeberg
Organisation Name: HZG Helmholtz-Zentrum Geesthacht
Role: Point Of Contact
Contact Info:
Country: DE
E-Mail Address: ulrike.kleeberg@hzg.de
Keyword Collection:
Keyword: oceanographyKey2
Keyword: NOAH
Keyword: shear stress
Keyword: Live Data and Maps
Service Type: ESRI ArcGIS Mapping Service
Service type version: 1.1.3
Extent:
West Bounding Longitude: -3
East Bounding Longitude: 10
North Bounding Latitude: 58
South Bounding Latitude: 48
Constraints: none
Legal Constraints:
Access Constraints: Intellectual Property Rights
Use Constraints: Intellectual Property Rights
Distribution
Distribution Format:
Format Name: ArcGIS Service
Format Version: 10.3
Transfer Options:
URL: https://coastmap.hzg.de/server/rest/services/NOAH_geoDB/MaximumShearStress_2010_2014/MapServer
Protocol:
Application Profile:
Function: Information
Transfer Options:
URL: https://coastmap.hzg.de/server/services/NOAH_geoDB/MaximumShearStress_2010_2014/MapServer/WMSServer?
Protocol:
Application Profile:
Function: Information
Quality
Scope: Dataset
Conformance Result:
Validation Performed: true
Explanation: none
Specification:
Title: INSPIRE Directive 2007/2/EC
Date:
Date: 2010-07-02
Date Type: Creation Date
Lineage: Concerning the quality of the median grain-size data see the appropriate section of the median grain-size map. The WAM model is a state-of-the-art spectral wave model. The quality of its results depends primarily on the quality of the wind forcing and on the correctness of the bathymetry. Wind forcing is simulated with the regional climate model COSMO-CLM (Groll et al. 2013), the first non-hydrostatic atmosphere model of the German Weather Service (DWD). This atmosphere model is at the leading edge of research and development. TRIM is a 3-dimensional fully baroclinic model. It calculates sea surface elevation, three velocity components, temperature and salinity. In addition it calculates the vertical eddy diffusivity by using the public domain turbulence model GOTM. TRIM is a state-of-the-art model - the quality of its results depends primarily on a correct bathymetry and correct boundary conditions (e.g. wind velocity above the water surface, water elevation at the seaward boundaries). TRIM uses the results of the REgional atmosphere MOdel REMO (Feser et al. 2001) to drive current velocities and water temperatures at the water surface. The formula used for calculating tCW.MAX from the near-bed current and wave velocities were derived by Soulsby (1997). Soulsby tested several relevant theories and models against a data set of 131bed shear stresses which were measured both in the laboratory and in the field. He finally derived a formula “DATA2” which can be regarded as the “model of choice” as the “DATA2” formula is reliable and robust.
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