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: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2020
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Taylor Valley; Fryxell; Hoare; Lake Fryxell; Lake Hoare; Antarctic Science
• Online Access: http://dx.doi.org/10.1017/s0954102020000218; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102020000218

Abstract 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%.