Date of Award

June 2018

Degree Name

Master of Arts (MA)

Department

Geography

Advisor(s)

Susan Millar

Keywords

cryosphere, particulate matter, snow albedo, urban snow

Subject Categories

Social and Behavioral Sciences

Abstract

This thesis examines the spatial distribution of particulate matter in snow around a mid-size, midlatitude city. Particulates are small, light absorbing impurities that are produced from the incomplete combustion of carbon-based fuel. When deposited on the snowpack, these particles reduce snow albedo and accelerate melt. Two experiments were designed to explore the distribution and effect of urban particulate emissions on snow surrounding Syracuse, NY (43.049897, -76.149102, pop: 149,000). The “directional study” examined the relationship between distribution and cross-city prevailing wind, while, the “transect study” examined the variability of particulate concentration with distance from a busy interstate highway. Fifteen sites were sampled over two winter seasons (2016-2017 and 2017-2018). Eight sites were located in the suburbs roughly aligned to the cardinal directions with respect to the city, one site was located within the city boundaries and six sites were located on a transect across I-90. Snow temperature, air temperature, wind speed/direction and albedo were recorded at each site. A snow core was collected for laboratory analysis using the Light Meter Filter Analysis method and two photos were taken of the snow surface for a second albedo analysis using ImageJ. At the city-scale, trend analyses show that particulate concentration decreases from W to E across the urban center and albedo increases from NW to SE. The small westerly shift between albedo and particulate trend analysis may be explained by a slight difference in measurement parameters. Albedo analysis measures the effect of particulates on the snow surface since the end of snow accumulation. Particulate concentration, however, measures the total quantity of particulates in the entire snowpack. Both analyses align with the WSW to NW prevailing wind that is responsible for the formation of lake effect snow from Lake Ontario and Lake Erie. That said, the observed distribution was found to be opposite expectations. This is likely a result of wind circulation patterns within the urban core. At the local-scale, high particulate concentration/low albedo was found adjacent to the interstate highway. Results show that the concentration does not necessarily decrease with distance from vehicle emissions. Instead, particulate distribution is altered by the presence of any obstacles within 600m of the highway. Snow surface photo analysis was able to determine the relative albedo of each site but not actual albedo value. Despite this, the photo analysis method looks promising for future citizen science based studies of particulate matter. Overall, findings suggest that urban particulate distribution in midlatitude snow is altered by city morphology and proximity to local emission sources. Future research is necessary to examine how this distribution affects climatic processes in the midlatitudes.

Access

Open Access

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