Graduation Year

January 2014

Graduation Month

May

Document Type

Thesis

Degree Name

Bachelor of Science

School or Department

Geosciences

Major

Interdisciplinary Geosciences

Faculty Mentor

Anna Klene

Faculty Mentor Department

Geography

Faculty Reader(s)

Johnnie N. Moore

Keywords

climate change, permafrost, alaska

Subject Categories

Earth Sciences

Abstract

The Circumpolar Active Layer Monitoring (CALM) project has been observing permafrost (perennially frozen ground) and its overlaying active layer (which freezes and thaws annually) in northern Alaska’s Kuparuk River watershed and throughout the polar regions since the mid 1990’s to detect long-term responses to climatic change. The soil-surface temperature data is collected by thermistors that were positioned immediately below the surface of the ground at nine locations within a transect of 1-ha plots arranged from north to south across the region. Locations within each plot were individually selected to represent a full range of microsite conditions, with distinctions in vegetation, moisture, and microtopography. For my research, I have compared temperature measurements from three different generations of datalogger models from the same manufacturer deployed in pairs over 1-year durations from 2005-2006 and 2011-2012. Diagrams comparing daily soil-surface and air temperature differences between the different instrumentation models show systematic variations due to vegetation, air temperature, and moisture. The temporal variability in the differences between instrumentation is systematically related to seasonal cycles of temperature, with the largest differences being in the summer when the active layer thaws and is the most dynamic. Spatial variability within the plots was examined, showing that the larger temperature differences are at the warmer, drier sites. These instrumentation statistics were necessary to quantify the reliability and consistency of the 18-year CALM dataset. This dataset contributes to the greater understanding of our complicated climatic system, as the thickening of the active layer in Arctic regions may potentially discharge further greenhouse gases into the atmosphere, thus yielding a variety of ecological feedbacks and further intensification of climate change.

Honors College Research Project

Yes

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© Copyright 2014 Katrina Keleher