Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation

1. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation Team: PI: K. Fred Huemmrich (University of Maryland Baltimore County) Co-Is: Craig Tweedie (UTEP) Petya Campbell (UMBC) Joanna Joiner (NASA/GSFC) Yasuko Yoshida (SSAI) Betsy Middleton (NASA/GSFC) Science Objectives: • Determine in situ relationships between solar induced fluorescence (SIF) and vegetation photosynthetic capacity for different high latitude species under a range of environmental conditions • Collect measurements in tundra and boreal forest sites near NEON flux towers in Barrow and Caribou-Poker Creeks • Scale observations from leaf-level to the plot/canopy level • Apply relationships to the landscape level across the ABoVE domain using satellite data • Use satellite imagery to describe SIF spatial variability along with diurnal, seasonal and multi-year changes, derive gross primary productivity (GPP) and describe its variability

2. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation Background • Photons absorbed by a chlorophyll molecule may follow three pathways: • - photochemistry, • - heat loss (nonphotochemical quenching, NPQ), or • - Chlorophyll fluorescence (ChlF) ChlF may provide a better description of seasonal productivity in evergreen boreal forests than reflectance indices

3. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation Issues Significant differences in ChlF emission spectra for Deciduous and Conifer leaves ChlF signal is very small compared to reflected radiance

4. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation Methodology Collect measurements in tundra and boreal forest sites near NEON flux towers in Barrow and Caribou-Poker Creeks to examine diurnal to seasonal variability Leaf Level Measurements The MONITORING-PAM (MoniPAM) for automated measurements of ChlF, relative electron transport rates and photochemical yields of photosystem II. The FloWat leaf clip to measure in situ ChlF emission spectra Li-Cor 6400 to measure photosynthesis.

5. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation Methodology Canopy Level Measurements Spatial variability measured with QEPro spectrometers along transects sampled through the growing season. Ecosystem CO2 fluxes from NEON flux towers using eddy covariance techniques. FLoX (Dual FLuorescence boX) makes automated measures of canopy SIF and spectral reflectance

6. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation Methodology Regional Measurements Daily SIF retrievals from TROPOMI over the ABoVE domain

7. Clarifying Linkages between Canopy SIF and Physiological Function for High Latitude Vegetation PI: K. Fred Huemmrich, University of Maryland Baltimore County karl.f.huemmrich@nasa.gov Science Objectives Methodology - Determine in situ relationships between SIF and photosynthetic capacity under different environmental conditions - Collect measurements in tundra and boreal forest sites - Scale observations from leaf-level to plot/canopy level - Apply relationships to the landscape level across the ABoVE domain using satellite data - Use satellite imagery to describe SIF variability, derive gross primary productivity (GPP) and describe its variability Utilize signals from Solar Induced Fluorescence (SIF) and spectral reflectance to improve descriptions of high latitude ecosystem productivity and seasonality Impacts on ABoVE Science: Fieldwork SIF retrieved from satellite can improve assessment of growing season length and ecosystem productivity, providing new insights into the relationships between season length, productivity, carbon balance, and other critical feedback processes for ecosystems across the ABoVE domain. 2019 Barrow – ground/lab measurements 2020 Near Barrow NEON flux tower – ground measurements and automated sensors (FLoX and MoniPAM) 2021 Near Caribou-Poker Creeks NEON flux tower – ground measurements and automated sensors (FLoX and MoniPAM) CoIs:C. Tweedie (UTEP) ctweedie@utep.edu, P. Campbell (UMBC) petya.k.campbell@nasa.gov, J. Joiner (NASA/GSFC) joanna.joiner-1@nasa.gov, Y. Yoshida (SSAI) yasuko.yoshida-1@nasa.gov E. Middleton (NASA/GSFC) elizabeth.m.middleton@nasa.gov Acknowledgements This work is supported by NASA grant 80NSSC19M0110. 5/19