DOI: 10.5194/tc-14-769-2020
论文题名: The seasonal evolution of albedo across glaciers and the surrounding landscape of Taylor Valley, Antarctica
作者: Bergstrom A. ; Gooseff M.N. ; Myers M. ; Doran P.T. ; Cross J.M.
刊名: Cryosphere
ISSN: 19940416
出版年: 2020
卷: 14, 期: 3 起始页码: 769
结束页码: 788
语种: 英语
英文关键词: ablation
; albedo
; desert
; energy budget
; glacier dynamics
; landscape structure
; meltwater
; MODIS
; radiometer
; seasonal variation
; shortwave radiation
; Antarctica
; East Antarctica
; McMurdo Dry Valleys
; Taylor Valley
英文摘要: 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 °C, 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. © Author(s) 2020. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164406
Appears in Collections: 气候变化与战略
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作者单位: Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80305, United States; Department of Civil Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, CO 80305, United States; Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, United States; Department of Geology, Portland State University, Portland, OR 97201, United States
Recommended Citation:
Bergstrom A.,Gooseff M.N.,Myers M.,et al. The seasonal evolution of albedo across glaciers and the surrounding landscape of Taylor Valley, Antarctica[J]. Cryosphere,2020-01-01,14(3)