Traditional methods of carbon monitoring in mountainous regions are challenged by complex terrain. Recently, solar-induced fluorescence (SIF) has been found to be an indicator of gross primary production (GPP), and the increased availability of remotely sensed SIF provides an opportunity to estimate GPP across the Western United States. Although the empirical linkage between SIF and GPP is strong, the current mechanistic understanding of this linkage is incomplete and depends upon changes in leaf biochemical processes in which absorbed sunlight leads to photochemistry, heat (via nonphotochemical quenching [NPQ]), fluorescence, or tissue damage. An improved mechanistic understanding is necessary to leverage SIF observations to improve representation of ecosystem processes within land surface models. Here we included an improved fluorescence model within the Community Land Model, Version 4.5 (CLM 4.5), to simulate seasonal changes in SIF at a subalpine forest in Colorado. We found that when the model accounted for sustained NPQ, this provided a larger seasonal change in fluorescence yield leading to simulated SIF that more closely resembled the observed seasonal pattern (Global Ozone Monitoring Experiment-2 [GOME-2] satellite platform and a tower-mounted spectrometer system). We found that an acclimation model based on mean air temperature was a useful predictor for sustained NPQ. Although light intensity was not an important factor for this analysis, it should be considered before applying the sustained NPQ and SIF to other cold climate evergreen biomes. More leaf-level fluorescence measurements are necessary to better understand the seasonal relationship between sustained and reversible components of NPQ and to what extent that influences SIF.
1.Univ Utah, Sch Biol Sci, Salt Lake City, UT 84112 USA 2.Univ Helsinki, Inst Atmospher & Earth Syst Res Forest Sci, Opt Photosynth Lab, Helsinki, Finland 3.CALTECH, Jet Prop Lab, Pasadena, CA USA 4.CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA 5.Brown Univ, Dept Earth Environm & Planetary Sci, Providence, RI 02912 USA 6.Univ Calif Los Angeles, Joint Inst Reg Earth Syst Sci & Engn, Los Angeles, CA USA 7.Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA USA 8.Heidelberg Univ, Inst Environm Phys, Heidelberg, Germany 9.Bowdoin Coll, Dept Biol, Brunswick, ME 04011 USA 10.Univ Colorado, Dept Geog, Boulder, CO 80309 USA 11.Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA 12.Univ Utah, Dept Atmospher Sci, Salt Lake City, UT USA 13.Univ Virginia, Dept Environm Sci, Clark Hall, Charlottesville, VA 22903 USA
Recommended Citation:
Raczka, Brett,Porcar-Castell, A.,Magney, T.,et al. Sustained Nonphotochemical Quenching Shapes the Seasonal Pattern of Solar-Induced Fluorescence at a High-Elevation Evergreen Forest[J]. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES,2019-01-01,124(7):2005-2020