The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica
The McMurdo Dry Valleys (MDVs) of Antarctica are a polar desert ecosystem consisting of alpine glaciers, ice-covered lakes, streams, and expanses of vegetation-free rocky soil. Because average summer temperatures are close to 0 Cel., the MDV ecosystem in general, and glacier melt dynamics in particu...
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ftportlandstate:oai:pdxscholar.library.pdx.edu:geology_fac-1162 2023-05-15T13:52:19+02:00 The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica Bergstrom, Anna Gooseff, Michael N. Doran, Peter T. Cross, Julian M. 2020-01-01T08:00:00Z application/pdf https://pdxscholar.library.pdx.edu/geology_fac/161 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1162&context=geology_fac unknown PDXScholar https://pdxscholar.library.pdx.edu/geology_fac/161 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1162&context=geology_fac Geology Faculty Publications and Presentations Glacier mass balance Glaciers -- Environmental aspects Geology Glaciology text 2020 ftportlandstate 2022-01-09T19:55:58Z The McMurdo Dry Valleys (MDVs) of Antarctica are a polar desert ecosystem consisting of alpine glaciers, ice-covered lakes, streams, and expanses of vegetation-free rocky soil. Because average summer temperatures are close to 0 Cel., the MDV ecosystem in general, and glacier melt dynamics in particular, are both closely linked to the energy balance. A slight increase in incoming radiation or change in albedo can have large effects on the timing and volume of meltwater. However, the seasonal evolution or spatial variability of albedo in the valleys has yet to fully characterized. In this study, we aim to understand the drivers of landscape albedo change within and across seasons. To do so, a box with a camera, GPS, and shortwave radiometer was hung from a helicopter that flew transects four to five times a season along Taylor Valley. Measurements were repeated over three seasons. These data were coupled with incoming radiation measured at six meteorological stations distributed along the valley to calculate the distribution of albedo across individual glaciers, lakes, and soil surfaces. We hypothesized that albedo would decrease throughout the austral summer with ablation of snow patches and increasing sediment exposure on the glacier and lake surfaces. However, small snow events (< 6mm water equivalent) coupled with ice whitening caused spatial and temporal variability of albedo across the entire landscape. Glaciers frequently followed a pattern of increasing albedo with increasing elevation, as well as increasing albedo moving from east to west laterally across the ablation zone. We suggest that spatial patterns of albedo are a function of landscape morphology trapping snow and sediment, longitudinal gradients in snowfall magnitude, and wind-driven snow redistribution from east to west along the valley. We also compare our albedo measurements to the MODIS albedo product and found that overall the data have reasonable agreement. The mismatch in spatial scale between these two datasets results in variability, which is reduced after a snow event due to albedo following valley-scale gradients of snowfall magnitude. These findings highlight the importance of understanding the spatial and temporal variability in albedo and the close coupling of climate and landscape response. This new understanding of landscape albedo can constrain landscape energy budgets, better predict meltwater generation on from MDV glaciers, and how these ecosystems will respond to changing climate at the landscape scale. Text Antarc* Antarctica McMurdo Dry Valleys polar desert Portland State University: PDXScholar Austral McMurdo Dry Valleys Taylor Valley ENVELOPE(163.000,163.000,-77.617,-77.617) |
institution |
Open Polar |
collection |
Portland State University: PDXScholar |
op_collection_id |
ftportlandstate |
language |
unknown |
topic |
Glacier mass balance Glaciers -- Environmental aspects Geology Glaciology |
spellingShingle |
Glacier mass balance Glaciers -- Environmental aspects Geology Glaciology Bergstrom, Anna Gooseff, Michael N. Doran, Peter T. Cross, Julian M. The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica |
topic_facet |
Glacier mass balance Glaciers -- Environmental aspects Geology Glaciology |
description |
The McMurdo Dry Valleys (MDVs) of Antarctica are a polar desert ecosystem consisting of alpine glaciers, ice-covered lakes, streams, and expanses of vegetation-free rocky soil. Because average summer temperatures are close to 0 Cel., the MDV ecosystem in general, and glacier melt dynamics in particular, are both closely linked to the energy balance. A slight increase in incoming radiation or change in albedo can have large effects on the timing and volume of meltwater. However, the seasonal evolution or spatial variability of albedo in the valleys has yet to fully characterized. In this study, we aim to understand the drivers of landscape albedo change within and across seasons. To do so, a box with a camera, GPS, and shortwave radiometer was hung from a helicopter that flew transects four to five times a season along Taylor Valley. Measurements were repeated over three seasons. These data were coupled with incoming radiation measured at six meteorological stations distributed along the valley to calculate the distribution of albedo across individual glaciers, lakes, and soil surfaces. We hypothesized that albedo would decrease throughout the austral summer with ablation of snow patches and increasing sediment exposure on the glacier and lake surfaces. However, small snow events (< 6mm water equivalent) coupled with ice whitening caused spatial and temporal variability of albedo across the entire landscape. Glaciers frequently followed a pattern of increasing albedo with increasing elevation, as well as increasing albedo moving from east to west laterally across the ablation zone. We suggest that spatial patterns of albedo are a function of landscape morphology trapping snow and sediment, longitudinal gradients in snowfall magnitude, and wind-driven snow redistribution from east to west along the valley. We also compare our albedo measurements to the MODIS albedo product and found that overall the data have reasonable agreement. The mismatch in spatial scale between these two datasets results in variability, which is reduced after a snow event due to albedo following valley-scale gradients of snowfall magnitude. These findings highlight the importance of understanding the spatial and temporal variability in albedo and the close coupling of climate and landscape response. This new understanding of landscape albedo can constrain landscape energy budgets, better predict meltwater generation on from MDV glaciers, and how these ecosystems will respond to changing climate at the landscape scale. |
format |
Text |
author |
Bergstrom, Anna Gooseff, Michael N. Doran, Peter T. Cross, Julian M. |
author_facet |
Bergstrom, Anna Gooseff, Michael N. Doran, Peter T. Cross, Julian M. |
author_sort |
Bergstrom, Anna |
title |
The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica |
title_short |
The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica |
title_full |
The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica |
title_fullStr |
The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica |
title_full_unstemmed |
The Seasonal Evolution of Albedo across Glaciers and the Surrounding Landscape of Taylor Valley, Antarctica |
title_sort |
seasonal evolution of albedo across glaciers and the surrounding landscape of taylor valley, antarctica |
publisher |
PDXScholar |
publishDate |
2020 |
url |
https://pdxscholar.library.pdx.edu/geology_fac/161 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1162&context=geology_fac |
long_lat |
ENVELOPE(163.000,163.000,-77.617,-77.617) |
geographic |
Austral McMurdo Dry Valleys Taylor Valley |
geographic_facet |
Austral McMurdo Dry Valleys Taylor Valley |
genre |
Antarc* Antarctica McMurdo Dry Valleys polar desert |
genre_facet |
Antarc* Antarctica McMurdo Dry Valleys polar desert |
op_source |
Geology Faculty Publications and Presentations |
op_relation |
https://pdxscholar.library.pdx.edu/geology_fac/161 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1162&context=geology_fac |
_version_ |
1766256598108340224 |