GIS tool to predict photosynthetically active radiation in a Dry Valley

• Published in: Antarctic Science
• Main Authors: Acosta, Dimitri, Doran, Peter T., Myers, Madeline
• Format: Text
• Language: unknown
• Published: LSU Scholarly Repository 2020
• Subjects: ArcMap; Automated weather station; Digital elevation model; Ice-covered lakes; McMurdo Dry Valleys; R model; Taylor Valley; Antarc*; Antarctic
• Online Access: https://repository.lsu.edu/geo_pubs/576; https://doi.org/10.1017/S0954102020000218; https://repository.lsu.edu/context/geo_pubs/article/1575/viewcontent/576.pdf

© Antarctic Science Ltd 2020 Understanding primary productivity is a core research area of the National Science Foundation's Long-Term Ecological Research Network. This study presents the development of the GIS-based Topographic Solar Photosynthetically Active Radiation (T-sPAR) toolbox for Taylor Valley. It maps surface photosynthetically active radiation using four meteorological stations with ∼20 years of data. T-sPAR estimates were validated with ground-truth data collected at Taylor Valley's major lakes during the 2014-15 and 2015-16 field seasons. The average daily error ranges from 0.13 mol photons m-2 day-1 (0.6%) at Lake Fryxell to 3.8 mol photons m-2 day-1 (5.8%) at Lake Hoare. We attribute error to variability in terrain and sun position. Finally, a user interface was developed in order to estimate total daily surface photosynthetically active radiation for any location and date within the basin. T-sPAR improves upon existing toolboxes and models by allowing for the inclusion of a statistical treatment of light attenuation due to cloud cover. The T-sPAR toolbox could be used to inform biological sampling sites based on radiation distribution, which could collectively improve estimates of net primary productivity, in some cases by up to 25%.