Sponsor
Portland State University. Department of Environmental Science and Management
First Advisor
Kelly Gleason
Term of Graduation
Fall 2024
Date of Publication
12-12-2024
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Environmental Science and Management
Department
Environmental Science and Management
Language
English
Subjects
Black Carbon, Burn Severity, Forest Fire Impacts on Hydrology, Postfire Snowpack Dynamics, Radiative Forcing, Snow Albedo Recovery
Physical Description
1 online resource (ix, 67 pages)
Abstract
Burned forests that remain standing following fire release light-absorbing particles (LAPs), including black carbon (BC), into winter snowpacks, reducing snow surface albedo and accelerating snowmelt timing for decades postfire. Although the role of LAPs in seasonal snow has been extensively studied, the spatiotemporal variability of LAPs' contributions to snowmelt relative to time-since-fire and burn severity remains unknown. This study aimed to quantify the spatiotemporal variability of forest fire effects on LAPs in snow and associated snow albedo in the Triple Divide region of western Wyoming, headwaters of the Colorado, Columbia, and Missouri rivers. Using geochemical analysis and radiative transfer modeling, we measured BC concentrations across a chronosequence of eight burned forests, examining how fire age and burn severity impact snowpack albedo. We hypothesized that radiative forcing due to BC in snow would be highest immediately after fire in high-severity burned forests and that snow albedo in burned areas would gradually recover to resemble open meadow conditions over decades. Our results confirmed that BC concentrations were highest in high-severity burned forests, peaking at 154.5 ppb in surface snow and remaining elevated for up to 20 years postfire. Elevated BC concentrations also extended beyond burned perimeters into adjacent unburned forests and open meadows. Seasonal analysis showed that near-surface samples in February had the highest mean BC concentration, reaching 78.4 ppb. Radiative forcing values were greatest in high-severity burned forests, peaking at 54.2 W/m², which indicates significant energy absorption and likely accelerated snowmelt in these regions.
Rights
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Persistent Identifier
https://archives.pdx.edu/ds/psu/43007
Recommended Citation
Zapata Villegas, Monica Vanesa, "Recovery of Black Carbon Concentrations in Burned Forests in Wyoming, USA" (2024). Dissertations and Theses. Paper 6756.