Differentiating carbon sinks versus sources on a university campus using synergistic UAV NIR and visible signatures.

This research proposes a framework for quantitatively differentiating carbon sinks versus sources, utilizing synergistic NIR (near-infrared) and visible signatures acquired from UAV (unmanned aerial vehicle). UAV NIR and visible imagery acquired at 70-m flying altitude identified the major types of carbon sinks versus sources, such as vegetation and constructed surfaces (e.g., road and buildings) for representative section of the university campus at the level of almost field-survey standpoint. Our findings show that the NIR reflectance for the sink was distributed in the range of 9.46-44.65%, whereas the emission sources had shown NIR response, ranging from 16.74 to 22.67%. The visible green reflectance showed a significantly higher range for emission sources (23.6-52.3%) than the sink (13.50-26.74%). The emission source in visible red showed a wider range of reflectance (17.05-38.49%), while the sink was observed in the narrow range of 9.36-17.75%. It was confirmed that synergistically combining NIR and visible signatures offers a viable method for measuring and comparing campus-wide carbon sinks versus sources due to extremely hyper-spatial resolution. It is anticipated that this research will be used as a valuable reference to investigate hyper-localized carbon sources and sinks in university campuses as cities within cities.