{"title":"Improved processing methods for eddy covariance measurements in calculating sensible heat fluxes at glacier surfaces","authors":"Cole Lord-May, Valentina Radić","doi":"10.1017/jog.2024.39","DOIUrl":null,"url":null,"abstract":"<p>Bulk aerodynamic methods have been shown to perform poorly in computing turbulent heat fluxes at glacier surfaces during shallow katabatic winds. Katabatic surface layers have different wind shear and flux profiles to the surface layers for which the bulk methods were developed, potentially invalidating their use in these conditions. In addition, eddy covariance-derived turbulent heat fluxes are unlikely to be representative of surface conditions when eddy covariance data are collected close to the wind speed maximum (WSM). Here we utilize two months of eddy covariance and meteorological data measured at three different heights (1 m, 2 m, and 3 m) at Kaskawulsh Glacier in the Yukon, Canada, to re-examine the performance of bulk methods relative to eddy covariance-derived fluxes under different near-surface flow regimes. We propose a new set of processing methods for one-level eddy covariance data to ensure the validity of calculated fluxes during highly variable flows and low-level wind speed maxima, which leads to improved agreement between eddy covariance-derived and modelled fluxes across all flow regimes, with the best agreement (correlation >0.9) 1 m above the surface. Contrary to previous studies, these results show that adequately processed eddy covariance data collected at or above the WSM can provide valid estimates of surface heat fluxes.</p>","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Glaciology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1017/jog.2024.39","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOGRAPHY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Bulk aerodynamic methods have been shown to perform poorly in computing turbulent heat fluxes at glacier surfaces during shallow katabatic winds. Katabatic surface layers have different wind shear and flux profiles to the surface layers for which the bulk methods were developed, potentially invalidating their use in these conditions. In addition, eddy covariance-derived turbulent heat fluxes are unlikely to be representative of surface conditions when eddy covariance data are collected close to the wind speed maximum (WSM). Here we utilize two months of eddy covariance and meteorological data measured at three different heights (1 m, 2 m, and 3 m) at Kaskawulsh Glacier in the Yukon, Canada, to re-examine the performance of bulk methods relative to eddy covariance-derived fluxes under different near-surface flow regimes. We propose a new set of processing methods for one-level eddy covariance data to ensure the validity of calculated fluxes during highly variable flows and low-level wind speed maxima, which leads to improved agreement between eddy covariance-derived and modelled fluxes across all flow regimes, with the best agreement (correlation >0.9) 1 m above the surface. Contrary to previous studies, these results show that adequately processed eddy covariance data collected at or above the WSM can provide valid estimates of surface heat fluxes.
期刊介绍:
Journal of Glaciology publishes original scientific articles and letters in any aspect of glaciology- the study of ice. Studies of natural, artificial, and extraterrestrial ice and snow, as well as interactions between ice, snow and the atmospheric, oceanic and subglacial environment are all eligible. They may be based on field work, remote sensing, laboratory investigations, theoretical analysis or numerical modelling, or may report on newly developed glaciological instruments. Subjects covered recently in the Journal have included palaeoclimatology and the chemistry of the atmosphere as revealed in ice cores; theoretical and applied physics and chemistry of ice; the dynamics of glaciers and ice sheets, and changes in their extent and mass under climatic forcing; glacier energy balances at all scales; glacial landforms, and glaciers as geomorphic agents; snow science in all its aspects; ice as a host for surface and subglacial ecosystems; sea ice, icebergs and lake ice; and avalanche dynamics and other glacial hazards to human activity. Studies of permafrost and of ice in the Earth’s atmosphere are also within the domain of the Journal, as are interdisciplinary applications to engineering, biological, and social sciences, and studies in the history of glaciology.