Tag: Spatial Data Science and Technology

Refining cloud exclusion methods in tropical montane forest change detection with Landsat timeseries

Presenter: Sophia Shuler – Geography, Spatial Data Science and Technology

Faculty Mentor(s): Lucas Silva

Session: (In-Person) Poster Presentation

Satellite based remote sensing is one of the most accessible methods for implementing large-scale terrestrial change detection. However, cloud cover contamination of images is a frequent barrier to the use of change detection algorithms, particularly in places where cloud cover is frequent, such as in tropical mountains. In this project, I offer a method for cloud detection that can improve the quality of satellite image time series in tropical regions. Using both a cloud mask and a cloud index, I detected clouds in a set of Landsat-5 TM and Landsat-7 ETM+ time series from a tropical montane forest in Oaxaca, Mexico to a higher degree of accuracy than would be achieved by using the cloud mask alone. This method was used in sequence with the Breaks For Additive Season and Trend (BFAST) method in order to detect forest disturbances. After using a cloud index threshold of 2.8, the percentage of clouds detected increased from 91.8% to 94.4%. Additionally, this method yielded a 161% increase in the number of forest disturbances detected by BFAST. These results are applicable to change detection projects in regions with frequent cloud cover, where accuracy is limited by the climate conditions.

 

Evaluating Sources of Zinc Contamination within Eugene-Springfield Waterways

Presenter: Charlotte Klein − Environmental Science, Spatial Data Science and Technology

Faculty Mentor(s): Matt Polizzotto

Session: (In-Person) Poster Presentation

Stormwater runoff occurs when rainfall encounters impervious surfaces such as pavement and rooftops, instead of being absorbed into the ground. As runoff travels over these surfaces, pollutants are picked up and eventually make their way into natural waterways. In the Eugene-Springfield metro area, a specific stormwater pollutant of concern is zinc, which has been notably rising in local ambient water quality measurements taken by the city of Eugene over the past 20 years. As such, the causes and extent of elevated zinc levels within waterways in the Eugene-Springfield metro area are the focus of this study. Using 2019 as a case study year, data aggregation revealed similar zinc concentration patterns within the waterways of Springfield and Eugene. Literature review and spatial analysis identified zinc-based moss control products, tire and brake wear, and industrial discharges, as likely sources of zinc to the environment. This work adds to the understanding of municipal stormwater pollution in the Pacific Northwest and can lead to informed strategies for minimizing zinc loading to the environment.