03158nas a2200181   4500008004100000245011200041210006900153260001200222300001200234490000700246520256300253100002402816700002502840700002002865700002102885700002202906856004802928       2020                        eng d00aThe seasonal evolution of albedo across glaciers and the surrounding landscape of Taylor Valley, Antarctica0 aseasonal evolution of albedo across glaciers and the surrounding  c03/2020  a769-7880 v143 a<p>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&thinsp;∘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 (&lt;6&thinsp;mm 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.</p>1 aBergstrom, Anna, J.1 aGooseff, Michael, N.1 aMyers, Madeline1 aDoran, Peter, T.1 aCross, Julian, M.  uhttps://www.the-cryosphere.net/14/769/2020/02017nas a2200133   4500008004100000245011800041210006900159260005700228490000900285520149000294100002001784700002101804856005801825       2019                        eng d00aSpatiotemporal impact of snow on underwater photosynthetically active radiation in Taylor Valley, East Antarctica0 aSpatiotemporal impact of snow on underwater photosynthetically a  aBaton Rouge, LAbLouisiana State Universityc08/20190 vM.S.3 a<p>The role of snow on underwater photosynthetically active radiation (UW PAR) in the McMurdo Dry Valleys (MDVs) has been understudied due to lack of a detailed snowfall record. Research has shown that a relationship between snow cover and UW PAR exists, but the extent has never been evaluated in great detail. Although annual snowfall values in the MDVs are low (3 to 50 mm water equivalent annually), trends of increasing snowfall on the continent under future warming conditions could lead to an increased role for snow in regulating UW PAR (and associated primary productivity). Here, I discuss evidence from the snowfall record, surface PAR, and UW PAR, of the influence of snowfall on UW PAR in the major lakes of Taylor Valley. This study aims to quantify the spatiotemporal impact of lake ice snow packs on UW PAR in Taylor Valley from field surveys, long-term UW PAR, and meteorological data. Lake Fryxell has the strongest seasonality to precipitation, which decreases inland. On average, Lake Fryxell also has the most days with snow cover on the lake ice. Lake Hoare is experiencing an increase in Fall snow persistence since the 2007 snow year. Snow less than 0.5 mm snow water equivalent (SWE) can suppress UW PAR by 40%. The calendar day that snow falls often determines whether phototrophs will switch from photosynthesis to respiration, which suggests the importance to seasonality in determining the impact of snow on photoautotrophs and lake-wide carbon budget.</p>1 aMyers, Madeline1 aDoran, Peter, T.  uhttps://digitalcommons.lsu.edu/gradschool_theses/4965