Jason Horne -- PhD Qualifying Exam

(Penn State, Department of Meteorology and Atmospheric Science)

"What is the impact of turfgrass on urban carbon dioxide fluxes?"

What GR Homepage PhD Qualifying Exam
When Nov 29, 2023
from 09:30 am to 12:00 pm
Where 529 Walker Building
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Adviser: Ken Davis

Climate mitigations require the quantification of urban greenhouse gas (GHG) emissions. Urban systems mix anthropogenic and biogenic GHG fluxes. Disaggregation of these fluxes is necessary to understand urban systems. One vegetative community common in these urban environments is turfgrass. We compare measurements from two urban flux towers over turfgrass lawns. Turfgrass flux towers in Indianapolis show a photosynthetic drawdown in the winter when vegetation is commonly assumed to be dormant. We use data from these towers to create a new turfgrass Plant Functional Type (PFT) parameter set for the Vegetation Photosynthesis and Respiration Model (VPRM). The new turfgrass PFT enables VPRM to simulate photosynthetic activity during winter. Our results show no previously used PFT parameter set can accurately model the observed turfgrass CO2 fluxes, and less managed lawns like cemeteries need differing parameters than heavily managed lawns like golf courses. Using these results, we explore daily and seasonal variability in turfgrass fluxes and their impact, integrated across the city, on total urban carbon dioxide (CO2) fluxes. This study illustrates the importance of representing turfgrass as a unique PFT when quantifying urban GHG fluxes.