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ABoVE: Tundra Plant Leaf-level Spectral Reflectance

Submitted by ORNL DAAC Staff on 2022-07-18
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Schematic of FluoWat leaf clip operation for measuring leaf reflectance, transmittance, and upward and downward fluorescence (SIF). The leaf is placed in the clip and illuminated through the open port (A). Reflected and transmitted radiance are measured by attaching a fiber optic cable from the spectrometer to the top or bottom of the clip. To measure fluorescence spectra a low pass filter is placed across the illumination port (B). Two filters are applied in sequence, they block incident wavelengths above 650 nm and 700 nm, therefore any radiance measured in the longer wavelengths can come only from fluorescence.

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Leaf-level variables of high latitude plant samples collected near Fairbanks, Utqiagvik, and Toolik, Alaska, U.S., during the summers of 2019, 2020, and 2021.
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ABoVE: Landsat Vegetation Greenness Trends, 1985-2019

Submitted by ORNL DAAC Staff on 2022-07-18
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Change in greenness of boreal forest across the northern hemisphere between 2000 to 2019, estimated from an ensemble of vegetation indices derived from Landsat imagery. 

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Interannual trends in annual maximum vegetation greenness from 1985 to 2019 for recently undisturbed areas in the boreal forest biome.
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ABoVE: Projection of Permafrost Thaw

Submitted by ORNL DAAC Staff on 2022-07-10
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Changes in simulated permafrost dynamics. Simulated cumulative changes in (A and B) permafrost area for active layer thickness (ALT) less than 3 m from 2010-2299 and (C and D) the sensitivity of simulated changes in permafrost area to changes in mean annual air temperature for RCP4.5 (left column) and RCP8.5 (right column) model projections. 

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Model projections from 1901 to 2299 for the northern hemisphere permafrost domain.
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ACT-America: L2 Weighting Functions for Airborne Lidar CO2

Submitted by ORNL DAAC Staff on 2022-06-27
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Locations of ACT-America flights collecting MFLL carbon dioxide (CO2) measurements over eastern and central U.S. in 2016-2018.

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Vertical weighting function coefficients of the L2 remotely sensed column-average CO2 concentrations during Summer 2016, Winter 2017, Fall 2017, and Spring 2018.