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.
N: 67.99 S: 44.91 E: -116.07 W: -149.75
|Temporal Extent:||Platform(s):||FIELD SURVEYS, Environmental Modeling|
|Data Center(s):||ORNL_DAAC||Instrument(s):||FLUOROMETERS, PYRANOMETERS, Computer|
Variables mapped on uniform space-time grid scales with completeness and consistency
|Project Short Name||Campaigns||Project Dates|
|ABoVE||No campaigns listed.||No dates provided.|
|Coverage Type||Zone Identifier||Geometry||Granule Representation|
ORNL DAAC User Services Office, P.O. Box 2008, MS 6407, Oak Ridge National Laboratory
Oak Ridge, Tennessee 37831-6407
There are no listed data contacts for this collection.
Format Type: Native
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