Are the Dry Valleys Getting Wetter? A Preliminary Assessment of Wetness Across the Mcmurdo Dry Valleys Landscape

Open Access
Author:
Langford, Zachary Lance
Graduate Program:
Civil Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 07, 2013
Committee Members:
  • Dr Michael Gooseff, Thesis Advisor
  • Peggy Ann Johnson, Thesis Advisor
  • Alfonso Ignacio Mejia, Thesis Advisor
Keywords:
  • Remote Sensing
  • Snow Hydrology
  • Streams
Abstract:
Liquid water is scarce across the landscape of the McMurdo Dry Valleys (MDV), Antarctica and is associated with soils that are adjacent to streams and lakes, during the annual thaw season. However, seeps, water tracks, and wet patches have been observed at several other locations as well. The source of water for these is likely generated by a combination of infiltration from melting snowpacks, melting of pore ice at the ice table beneath the water tracks, and melting of buried segregation ice formed during winter freezing. We are using high resolution (<1m pixel) remote sensing data gathered several times per week in the MDV region to determine the spatial and temporal distribution of wet soils. We assess the spatial consistency with which these wet soils occur for the 2008-2009 to 2011-2012 austral summers with complete coverage and partial coverage for 2003-2004 and 2006-2007 austral summers using a land cover classification. We also quantify the soil moisture of wetted soils using an artificial neural network (ANN). The ANN utilizes field radiometer data to retrieve estimates of surface moisture based on the spectral measurements and soil moisture samples collected during the 2010-2011 field season. The remote sensing based analyses of the wetted soils have shown the magnitude to vary greatly and how topography and regional microclimates influence the wetted soils in the MDV. The 2010-2011 austral summer provided the most wetted soil area, 10.21 km2, and 2008-2009 covered the least, 5.38 km2. The ANN soil moisture distribution in the MDV shows values ranging from 0.36 % to over 19 %. We suggest that wet soils are a significant component of this cold desert land system and ecosystem.