04/08/2021
By Erica Gavin

The Kennedy College of Sciences, Department of Environmental, Earth and Atmospheric Sciences, invites you to attend a Master’s thesis defense by Tyler Harrington on “Decomposing Evapotranspiration's Control on North American Precipitation using the Community Earth System Model."

Candidate Name: Tyler Harrington
Degree: Master’s
Defense Date: Wednesday, April 21, 2021
Time: 10:30-11:30 a.m.
Location: Via Zoom
Thesis/Dissertation Title: Decomposing Evapotranspiration's Control on North American Precipitation using the Community Earth System Model

Committee Advisor: Chris Skinner, Environmental, Earth and Atmospheric Sciences, UMass Lowell
Committee Members:

  • Mathew Barlow, Environmental, Earth and Atmospheric Sciences, UMass Lowell,
  • Frank Colby, Environmental, Earth and Atmospheric Sciences, UMass Lowell

Brief Abstract:
Land surface evapotranspiration (ET) supplies a considerable amount moisture for precipitation over land masses (over 70% during the warm season in some regions). Land surface moisture is also highly susceptible to human activity including from irrigation systems, deforestation, and urban expansion. Understanding the source origins of land-based precipitation is therefore critical for sustaining freshwater resources. Terrestrial ET is comprised of three components: transpiration (T), canopy evaporation (C), and ground evaporation (E). Each ET component responds very differently to environmental conditions, so the sensitivities of each moisture flux vary depending on the local climate. Here we utilize the Community Earth System Model (CESM) enabled with online water tracing capabilities to determine the source origins of precipitation across the North American continent. Additionally, using newly implemented tracers, we are able to determine how each individual moisture flux contributes to precipitation characteristics. Important sources and sinks of land moisture are examined, as well as the vulnerabilities of different regions in North America based on the source origins of their precipitation.