Event Title

Quantifying dominant heat fluxes in arctic rivers

Presenter Information

Tyler King
Bethany Neilson

Location

Eccles Conference Center

Event Website

http://water.usu.edu

Start Date

1-4-2014 5:10 PM

End Date

1-4-2014 5:15 PM

Description

Quantifying dominant heat fluxes in arctic rivers is necessary to understanding impacts that climate change will have on high latitude freshwater ecosystems. The presence of a seasonally thawing river-bed, minimal hill slope storage, and 24 hour sun are three indicators that river energy balances differ between arctic and temperate rivers. We develop an understanding of an arctic river energy balance through data collection and explicit process-based heat flux modelling. We hypothesized that arctic and temperate rivers are subject to the same heat fluxes, but that the relative importance of these fluxes may differ given the disparity in climate and hillslope hydrology. We further anticipated that the most important heat fluxes are solar radiation, heat loss through bed conduction early in the season, and lateral inflows. Data collected along the Kuparuk River (70°N, 149°W) during the open water season of 2013 indicate net longitudinal gains in heat, discharge and specific conductance with the exception of a thermal and conductive reset over a large surficial ice sheet (known as an Aufeis feature). Also, lateral inflow effects, diurnal trends, and temperature-discharge dependence are more pronounced in lower order portions of the river. Preliminary modeling results indicate that: 1) surface heat fluxes dominate the energy balance throughout the system; 2) the Aufeis feature serves as an effective boundary condition reset within the watershed; 3) the required model detail is inversely proportional to stream order for channel geometry and temperature/discharge of lateral inflows; and 4) lateral inflows must be accounted for within the model. Based on these findings, future work will focus on further refining river geometry and isolated lateral inflow effects in the low order portion of the basin.

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Apr 1st, 5:10 PM Apr 1st, 5:15 PM

Quantifying dominant heat fluxes in arctic rivers

Eccles Conference Center

Quantifying dominant heat fluxes in arctic rivers is necessary to understanding impacts that climate change will have on high latitude freshwater ecosystems. The presence of a seasonally thawing river-bed, minimal hill slope storage, and 24 hour sun are three indicators that river energy balances differ between arctic and temperate rivers. We develop an understanding of an arctic river energy balance through data collection and explicit process-based heat flux modelling. We hypothesized that arctic and temperate rivers are subject to the same heat fluxes, but that the relative importance of these fluxes may differ given the disparity in climate and hillslope hydrology. We further anticipated that the most important heat fluxes are solar radiation, heat loss through bed conduction early in the season, and lateral inflows. Data collected along the Kuparuk River (70°N, 149°W) during the open water season of 2013 indicate net longitudinal gains in heat, discharge and specific conductance with the exception of a thermal and conductive reset over a large surficial ice sheet (known as an Aufeis feature). Also, lateral inflow effects, diurnal trends, and temperature-discharge dependence are more pronounced in lower order portions of the river. Preliminary modeling results indicate that: 1) surface heat fluxes dominate the energy balance throughout the system; 2) the Aufeis feature serves as an effective boundary condition reset within the watershed; 3) the required model detail is inversely proportional to stream order for channel geometry and temperature/discharge of lateral inflows; and 4) lateral inflows must be accounted for within the model. Based on these findings, future work will focus on further refining river geometry and isolated lateral inflow effects in the low order portion of the basin.

http://digitalcommons.usu.edu/runoff/2014/2014Posters/23