Climate Impacts on Regional Boreal Forest Productivity Inferred from Solar-Induced Chlorophyll Fluorescence

Daniel Muccio,  University of Michigan,  drmuccio@umich.edu (Presenter)
Gretchen Keppel-Aleks,  University of Michigan,  gkeppela@umich.edu
Nicholas Parazoo,  JPL,  nicholas.c.parazoo@jpl.nasa.gov

The uptake of carbon by the land via photosynthesis, also known as Gross Primary Productivity (GPP), may differ across Arctic continents. Previous studies have shown increased vegetation greening in Eurasia relative to North America, with an associated relative increase in Net Ecosystem Exchange (NEE) amplification. Amplification of NEE in boreal and arctic ecosystems, due to a changing seasonal cycle of atmospheric carbon dioxide concentration, implies that the component fluxes of NEE, namely GPP and the release of carbon via respiration, are changing. We seek to determine whether variations in GPP are driven by top-down climate conditions across high latitude boreal forests in both Eurasia and North America. Understanding the sensitivity of GPP to climate and how these sensitivities may differ across regions of the globe will help us gain insight into what is affecting the uptake of carbon and the future of the net carbon sink in the Arctic Boreal Zone. To investigate these impacts, we use a global spatially contiguous solar-induced chlorophyll fluorescence (CSIF) data product from a multi-year, multi-platform satellite record, which has been shown to correlate strongly with tower-based GPP. We found that max and mean air temperature is highly correlated with CSIF variations in boreal forests during the late spring and early summer, but temperature explains less of the variance later in the growing season. With regards to soil moisture, we performed lagged correlations and a case study to show that both SIF and soil moisture may influence each other throughout the growing season. Singular Value Decomposition showcases both a redistribution of productivity and patterns in soil moisture related to wet (dry) years and the drawdown (replenishment) of soil moisture throughout a growing season. Lastly, the amplitude of interannual variability in CSIF across the growing season in boreal forests is comparable even though Eurasia evergreen needleleaf forests show a long-term trend in CSIF 2-3 times larger than North America evergreen needleleaf forests and Eurasia deciduous needleleaf forests.

Poster Location ID: 1-49

Presentation Type: Poster

Session: Poster Session 1

Session Date: Tue (May 9) 5:00-7:00 PM

CCE Program: Other