Remote sensing of rivers: applications for streamflow and carbon flux estimations

Abstract

Rivers are drivers of Earth's hydrologic and biogeochemical cycles-transporting water and materials to the world's oceans. Understanding changes in global hydrology as a result of climate-induced impacts is difficult due to the decline of globally available insitu measurements, nonexistent data in remote regions of the world, and geopolitical limitations. Advancements in remote sensing have provided means to combat these challenges, allowing for the derivation of river quantity and quality parameters. Using remote sensing to derive river discharge time series, we contribute to methodologies and insights to three key research challenges related to globally important rivers and associated fluxes. In the first chapter, we analyze how the Surface Water and Ocean Topography (SWOT) mission and its irregular sampling frequency may impact the observed hydrology in rivers, and provide insight into leveraging future SWOT data. We find the irregular SWOT orbit may be better suited for larger, more stable rivers, and the hydrology of smaller, flashier rivers may be more sensitive to fewer observations. In the second chapter, we demonstrate the potential of satellite gravimetry and altimetry for estimating river discharge time series and focus on the differences that arise from process-based approaches. Our results suggest greater limitations of regionalized GRACE/GRACE-FO for river discharge derivations particularly in arctic rivers, as well as limitations using satellite altimetry where river channel dynamics are complex (e.g., Amazon). The last chapter combines remotely sensed river discharges with measurements of dissolved organic carbon concentrations for extended records of carbon flux estimates globally. We highlight the significance of capturing peak discharge events using remote sensing methods, and further examine how LOADEST models vary within reaches. The insights of this research contribute advancements toward a greater understanding of remote sensing tools for evaluating river discharge time series and subsequent applications for filling gaps in constituent flux estimations. part of such a motivating, thoughtful, and hilarious group of brilliant people. You make research fun! I never would have thought to take this journey four years ago without the encouragement of my undergraduate advisor at Union College, Dr. Mason Stahl. Thank you, Mason, for continuing to instill confidence and curiosity in young researchers. Thank you to all of the students in the Beighley and Stubbins Lab groups. Thank you to Wesley,