A Time Series of NDVI at a High Arctic Peatland

• Main Author: Maraldo, Daniel
• Other Authors: Loisel, Julie
• Format: Thesis
• Language: unknown
• Published: 2023
• Subjects: Peatlands; Arctic Greening; NDVI; Canada; Satellite Imagery; Arctic; Climate change; Ice; permafrost
• Online Access: https://hdl.handle.net/1969.1/200186

Arctic greening has been studied as a significant and accelerating environmental change throughout the past few decades; however, most studies focus on greening across scales as large as the entire terrestrial Arctic and lack smaller-scale observations of vegetation at individual sites. Conducting such studies on peatlands is especially important, considering Arctic peatlands’ potential to act as an immense source of atmospheric carbon should they degrade as permafrost thaw accelerates. Additionally, while remote sensing studies cannot quantify any vegetation trends with complete accuracy, I aimed to prove the effectiveness of open-source, free satellite imagery in displaying the existence and strength of such trends. I produced a time series of NDVI at a well-studied catchment basin in the Canadian High Arctic, to illuminate trends of greening since the start of the 21st century. I compiled and analyzed MODIS imagery from peak growing seasons starting in 2000 until 2022. Without any in situ data to qualify the results from my analysis, I found a statistically significant trend in NDVI throughout the past 22 years; with in situ data, this data could be considered when mapping related physical attributes when trying to further quantify environmental changes at the site. Additionally, I found that, despite the inherent flaws of remote sensing’s accuracy when collecting data, remote sensing datasets with low resolution are effective in uncovering trends as long as the temporal resolution is high; with daily image products from a platform like MODIS, outliers of snow, ice, and cloud cover can be accounted for, which sensors like Landsat and Sentinel could not despite higher spatial resolution. Greening is likely to continue at this site with climate change, and future studies are warranted to observe the cascading effects of warming and permafrost thaw on vegetation cover in peatlands.