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dc.contributor.authorMankoff, Kenneth D.
dc.contributor.authorGulley, Jason D.
dc.contributor.authorTulaczyk, Slawek M.
dc.contributor.authorCovington, Matthew D.
dc.contributor.authorLiu, Xiaofeng
dc.contributor.authorChen, Yunxiang
dc.contributor.authorBenn, Douglas I.
dc.contributor.authorGŁowacki, Piotr S.
dc.identifier.citationMankoff , K D , Gulley , J D , Tulaczyk , S M , Covington , M D , Liu , X , Chen , Y , Benn , D I & GŁowacki , P S 2017 , ' Roughness of a subglacial conduit under Hansbreen, Svalbard ' , Journal of Glaciology , vol. 63 , no. 239 , pp. 423-435 .
dc.identifier.otherPURE: 250199256
dc.identifier.otherPURE UUID: 90c333fa-3c42-4c60-9952-8889b48a12b0
dc.identifier.otherScopus: 85019544529
dc.identifier.otherWOS: 000401649100003
dc.identifier.otherORCID: /0000-0002-3604-0886/work/64697406
dc.descriptionK.M., J.G., X.L. and Y.C. were supported by the National Science Foundation (NSF) under Grant No. #1503928. Thefieldwork team (K.M., J.G., M.C.) were supported by the Norwegian Arctic Research Council and Svalbard Science Forum, RiS #6106. K.M. was also supported by the National Aeronautics and Space Administration (NASA)Headquarters under the NASA Earth and Space Science Fellowship Program – Grant NNX10AN83H, the University of California, Santa Cruz, and the Woods Hole Oceanographic Institution Ocean and Climate Change Institute post-graduate fellowship. Portions of this work were conducted while J.G. was supported by the NSF EAR Postdoctoral Fellowship (#0946767). S.T. was funded by NASA grant NNX11AH61G.en
dc.description.abstractHydraulic roughness exerts an important but poorly understood control on water pressure in subglacial conduits. Where relative roughness values are <5%, hydraulic roughness can be related to relative roughness using empirically-derived equations such as the Colebrook-White equation. General relationships between hydraulic roughness and relative roughness do not exist for relative roughness >5%. Here we report the first quantitative assessment of roughness heights and hydraulic diameters in a subglacial conduit. We measured roughness heights in a 125 m long section of a subglacial conduit using structure-from-motion to produce a digital surface model, and hand-measurements of the b-axis of rocks. We found roughness heights from 0.07 to 0.22 m and cross-sectional areas of 1-2 m2, resulting in relative roughness of 3-12% and >5% for most locations. A simple geometric model of varying conduit diameter shows that when the conduit is small relative roughness is >30% and has large variability. Our results suggest that parameterizations of conduit hydraulic roughness in subglacial hydrological models will remain challenging until hydraulic diameters exceed roughness heights by a factor of 20, or the conduit radius is >1 m for the roughness elements observed here.
dc.relation.ispartofJournal of Glaciologyen
dc.rights© The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.en
dc.subjectGlacier hydrologyen
dc.subjectSubglacial conduitsen
dc.subjectG Geography (General)en
dc.subjectGB Physical geographyen
dc.subjectEarth-Surface Processesen
dc.titleRoughness of a subglacial conduit under Hansbreen, Svalbarden
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Geography and Geosciencesen
dc.contributor.institutionUniversity of St Andrews. Geography & Sustainable Developmenten
dc.contributor.institutionUniversity of St Andrews. Bell-Edwards Geographic Data Instituteen
dc.description.statusPeer revieweden

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