ABoVE: Needle-Level Chlorophyll Fluorescence, Alaska and Idaho, USA, 2017 and 2019

Description

This dataset provides the results of in situ measurements of needle-level chlorophyll fluorescence (ChlF) obtained from a pulse amplitude modulated (PAM) fluorometer from evergreen needleleaf forested sites one in Alaska and one in Idaho. Measured light-adapted minimal fluorescence (Ft) is reported as the quantum yield of fluorescence and light-adapted variable fluorescence over maximal fluorescence (Fv/Fm) and is reported as the quantum yield of photosystem II. Also reported for both sites are two modeled irradiance products: (1) the top-of-canopy instantaneous irradiance (W/m2) and (2) needle-level irradiance (W/m2) that was modeled to account for shadow casting and canopy orientation in modulating direct radiation. Both products were modeled to be contemporaneous with ChlF observations. At the Idaho site only, needle-level irradiance (W/m2) was measured in situ with a handheld pyranometer. The Alaska field site is located in the northern latitudinal forest-tundra ecotone (FTE) near the Dalton Highway in Northern Alaska. Thirty-six Picea glauca (white spruce) trees were sampled on 2017-07-07 to 2017-07-08. The Idaho field site is located in a montane forest near McCall, Idaho. Ten selected Abies grandis (grand fir) trees were sampled on 2019-07-05 to 2019-07-06. Measurement of needle-level ChlF occurred during clear-sky conditions such that the canopies experienced a broad range of variability in sunlit-shading patterns across the day during these near-solstice periods.

Resources

Name Format Description Link
21 Search results for publications that cite this dataset by its DOI. https://scholar.google.com/scholar?q=10.3334%2FORNLDAAC%2F1785
21 ORNL DAAC Data Set Documentation https://daac.ornl.gov/ABOVE/guides/Chlorophyll_Fluorescence_Data.html
21 Data set Landing Page DOI URL https://doi.org/10.3334/ORNLDAAC/1785
21 ABoVE project site https://above.nasa.gov
33 ABoVE: Needle-Level Chlorophyll Fluorescence, Alaska and Idaho, USA, 2017 and 2019: Chlorophyll_Fluorescence_Data.pdf https://data.ornldaac.earthdata.nasa.gov/public/above/Chlorophyll_Fluorescence_Data/comp/Chlorophyll_Fluorescence_Data.pdf
21 This link allows direct data access via Earthdata login https://daac.ornl.gov/above/Chlorophyll_Fluorescence_Data/
34 Relationship between the quantum yields of fluorescence (Ft) and photosystem II (Fv/Fm) sampled P. glauca needles in Alaska (A) and A. grandis needles in Idaho (B). Modeled (A) and observed (B) irradiance is indicated in coloration of points; grey points in individual sampling period panels show observations from all periods for reference. Plots of sampling periods aligned with timing of satellite overpasses are outlined in green (A) and blue (B) boxes, respectively (Maguire et al., 2020). https://daac.ornl.gov/ABOVE/guides/Chlorophyll_Fluorescence_Data_Fig1.png

Tags

  • ecosystems
  • biosphere
  • vegetation
  • ecological-dynamics
  • earth-science

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