Date of Award
Plants -- Effect of drought on -- Sierra Nevada (Calif. and Nev.), Atmospheric carbon dioxide -- Sierra Nevada (Calif. and Nev.), Droughts -- California
Remote sensing is a widely used technique for studying Earth systems, including ecosystem response to global warming. With the recent California drought, remote sensing gives an opportunity to study large-scale CO2 flux changes over time due to insufficient water uptake by plant life. In this study three flux towers were used, to correlate Net Ecosystem Exchange (NEE = PRI * NDVI * PAR), gathered from remote sensing data, and measurements of CO2 flux from in-situ flux towers over an area of 8,149 km2 in the Sierra Nevada Range. To estimate CO2 from NEE, two linear regressions were used which correlated with the temperature stress response of plants (>23.5 and 2 values of 0.81 and 0.83 respectively. Per-pixel CO2 flux was estimated for flights between 2011 (pre drought) and 2015 (during drought). This study showed a 25% (4.8 g / min) decrease in net carbon fixation between September 2011 and October 2014 over 34 km2. Also seen was a decrease in net carbon fixation over 7,737 km2 of 90.2% (18,863 g / min) between June 2013 to June 2015. Of the 411.6 km2 affected by the 2013 Rim Fire, this study showed a decrease in net carbon fixation of 85.5% (1,574 g / min) between June 2013 and June 2015. It is estimated that the entire Rim Fire (1,041 km2) could have caused a total decrease in net carbon fixation totaling 3,982 grams per minute from 2013 to 2015.
Mazzi, Jessica, "The Impact of Drought on the Sierra Nevada Range: Using Remote Sensing Data to Estimate Large-Scale Carbon Dioxide Flux" (2016). University Honors Theses. Paper 240.