Archive - Researcher of the Month

Dr. Tracy Twine

Tracy Twine, is an Assistant Professor in the Department of Atmospheric Sciences at UIUC, and is an affiliate with CWACES. Dr. Twine received her B.S. in Meteorology from The Pennsylvania State University in 1994, her M.S. in Atmospheric and Oceanic Sciences from University of Wisconsin-Madison in 1998, and her Ph.D. in 2004, also from University of Wisconsin-Madison.

Dr. Twine also conveys outside experience to UIUC and CWACES. After obtaining her B.S. degree, she worked for two years with the Boreal Ecosystem Atmosphere Study (BOREAS) at NASA Goddard Space Flight Center, a collaborative effort among many agencies including NASA, and NOAA, among other international organizations. The goal was to study water, energy, and carbon exchange over the boreal forest in northern Saskatchewan and Manitoba. In calculating the carbon budget, scientists figured a missing "sink" of carbon existed somewhere, and they hypothesized that this was in the boreal forest. The result was a multi-scale examination of all environmental facets of the forest. For this project, Dr. Twine was part of the information staff, compiling large amounts of information into a database. Through this experience, she met world-renown scientists, including Professor John Norman, who would become her Master's advisor.

The title for her Master's thesis was, "Underestimation of eddy covariance fluxes over a grassland," which presented results from the Southern Great Plains Hydrology Experiment (SGP), a field project in Oklahoma. She investigated the hydrology below the soil combined with how the grassland interacted with the atmosphere. After completing this project, Dr. Twine continued to examine the interactions between vegetation and the atmosphere, with her Ph.D. dissertation, "Investigating the effects of land cover change and climate variability on the land surface hydrology of the Mississippi River Basin." As a student of Professor Jon Foley, she utilized the Integrated Biosphere Simulator (IBIS), a land surface ecosystem model that simulates the physics of the land surface and vegetation growth, and may be coupled with larger global climate models (GCMs). Dr. Twine used IBIS on the Mississippi River basin, to examine how land cover change has affected hydrology, specifically the energy and water balance. The model was first run on the basin using its natural vegetation (trees and grassland), followed by a run using a crop model, which simulates major crops grown in the basin (corn, soybeans, winter wheat, and spring wheat), using maps to determine the coverage areas of the appropriate crops. Dr. Twine found the effects upon energy and water balance were dependent on a specific crop, the specific vegetation removed from an area, and season. The introduction of crops in the basin had significant effects on the major sub-basins of the Mississippi River basin, however, anomalies of opposite sign caused little change in total outflow of the Mississippi River. Runoff increased when trees were removed from the eastern part of the basin and replaced with crops, while it decreased in the drier, western portions of the basin when crops replaced grasslands, as a result of increased evapotranspiration from the plants. Dr. Twine expanded upon this work during her postdoctoral research at the Center for Sustainability and the Global Environment (SAGE), University of Wisconsin, where she attempted to validate the IBIS model with remote sensing information of vegetation greenness.