B100-07
Monitoring changes over time in thaw pond size with unmanned aerial systems (UAS): connections to ebullitive methane emissions
Tuesday, 15 December 2020: 09:05
Virtual
Sophia A Burke1, Michael W Palace2, Alexandra Contosta3, Clarice R Perryman4, Kathryn A Bennett5, Katherine Rocci6, Jessica DelGreco2, Christina Herrick7, Patrick M Crill8 and Ruth K Varner9, (1)Institute for the Study of Earth, Oceans, and Space, Durham, NH, United States, (2)University of New Hampshire, Dept. of Earth Sciences and Earth Systems Research Center, Durham, NH, United States, (3)University of New Hampshire Main Campus, Institute for the Study of Earth, Oceans and Space, Durham, NH, United States, (4)University of New Hampshire Main Campus, Durham, NH, United States, (5)University of New Hampshire Main Campus, Earth Sciences, Durham, NH, United States, (6)Colorado State University, Graduate Degree Program in Ecology, Fort Collins, CO, United States, (7)University of New Hampshire, Earth Systems Research Center, Durham, NH, United States, (8)Stockholm University, Stockholm, Sweden, (9)University of New Hampshire, Durham, NH, United States
Abstract:
Permafrost soils contain a large amount of carbon (C), and these areas are rapidly warming in response to climate change. Thawing of these C-rich regions can lead to the development of small water bodies called thaw ponds, which are known sources of the radiatively important trace gas methane (CH
4) to the atmosphere. Unmanned aerial systems (UAS) allow for frequent monitoring of pond size across the growing season. Long-term monitoring of thaw pond size, environmental variables and CH
4 emissions can help determine controls on CH
4 flux from these thaw features.
We used two different UASs equipped with simple RGB cameras to collect a total of 144 images of seven thaw ponds located in Stordalen Mire, Sweden over five growing seasons (2014 – 2018). From each image, two polygons were defined, one representing where thaw has occurred (referred to as a pond edge polygon) and the other representing where the water collected within the pond (a water polygon). We also monitored CH4 ebullitive flux and environmental variables.
Pond size increased overall across the study period, though each pond showed a varying degree of change. Comparison of the area of these ponds to the measured ebullitive emissions indicated that the largest ebullitive flux emitted over the growing season was from ponds of intermediate size (100-150 m2). However, we attribute this finding less to pond size and more to the sedge-dominated, deep, and hydrologically isolated characteristics of these intermediate ponds, as compared to larger, more hydrologically connected ponds and smaller ponds with fewer sedges. Our study shows the value of using UASs for monitoring pond size which in tandem with monitoring physical characteristics, allows us to better understand the variability in CH4 emissions in these dynamic systems.
