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Title: Collaborative Research On Ecophysiological Controls On Amazonian Precipitation Seasonality And Variability

Abstract

We developed and deployed a robust and accurate instrumentation package for measurement of solar induced chlorophyll fluorescence (SIF) from above a plant canopy. The sensor collects light from identical up and down facing hemispheric collectors. A fiber optic transmits the collected light (selected by a rotatable prism) to spectrometers located at the base of the tower. Spectra of the down welling and upwelling light were collected alternatively and stored for later analysis. SIF was retrieved by a spectral unmixing approach using high resolution spectra in the 730-760 nm band. Most other ground-based sensors base their analysis on O2-alpha band (760-780 nm) for SIF retrieval. We found that the former gave identical results when the atmosphere was clear, but the former was more stable in the cloudy conditions that often prevailed in the Amazon. The mechanical design and software developed for the system are available on request. The sensor was mounted near the top of an 80 m tower at K34 near Manaus in the Brazilian Amazon Forest. The sensor system proved weather-tight and functioned flawlessly over the time of deployment. Our experiment was cut short at 6 months by failure of air conditioning infrastructure at the tower. We found thatmore » SIF emitted by canopy was remarkably stable when scaled by the downwelling photosynthetically active radiation or the upwelling near infrared light. We detected a 3.4% increase in SIF over the course of the dry season. This finding is consistent with the observation that several trees in the field of view flushed new leaves in the dry season. We saw no evidence of drought stress or photo damage of the forest canopy during our study.« less

Authors:
ORCiD logo;
Publication Date:
Research Org.:
Carnegie Inst. of Washington, Washington, DC (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1570388
Report Number(s):
101519
DOE Contract Number:  
SC0011113
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; SIF (Solar induced chlorophyll fluorescence); Photosynthesis; Gross Primary Productivity; Water Stress; Canopy dynamics

Citation Formats

Berry, Joseph, and Kornfeld, Ari. Collaborative Research On Ecophysiological Controls On Amazonian Precipitation Seasonality And Variability. United States: N. p., 2019. Web. doi:10.2172/1570388.
Berry, Joseph, & Kornfeld, Ari. Collaborative Research On Ecophysiological Controls On Amazonian Precipitation Seasonality And Variability. United States. doi:10.2172/1570388.
Berry, Joseph, and Kornfeld, Ari. Tue . "Collaborative Research On Ecophysiological Controls On Amazonian Precipitation Seasonality And Variability". United States. doi:10.2172/1570388. https://www.osti.gov/servlets/purl/1570388.
@article{osti_1570388,
title = {Collaborative Research On Ecophysiological Controls On Amazonian Precipitation Seasonality And Variability},
author = {Berry, Joseph and Kornfeld, Ari},
abstractNote = {We developed and deployed a robust and accurate instrumentation package for measurement of solar induced chlorophyll fluorescence (SIF) from above a plant canopy. The sensor collects light from identical up and down facing hemispheric collectors. A fiber optic transmits the collected light (selected by a rotatable prism) to spectrometers located at the base of the tower. Spectra of the down welling and upwelling light were collected alternatively and stored for later analysis. SIF was retrieved by a spectral unmixing approach using high resolution spectra in the 730-760 nm band. Most other ground-based sensors base their analysis on O2-alpha band (760-780 nm) for SIF retrieval. We found that the former gave identical results when the atmosphere was clear, but the former was more stable in the cloudy conditions that often prevailed in the Amazon. The mechanical design and software developed for the system are available on request. The sensor was mounted near the top of an 80 m tower at K34 near Manaus in the Brazilian Amazon Forest. The sensor system proved weather-tight and functioned flawlessly over the time of deployment. Our experiment was cut short at 6 months by failure of air conditioning infrastructure at the tower. We found that SIF emitted by canopy was remarkably stable when scaled by the downwelling photosynthetically active radiation or the upwelling near infrared light. We detected a 3.4% increase in SIF over the course of the dry season. This finding is consistent with the observation that several trees in the field of view flushed new leaves in the dry season. We saw no evidence of drought stress or photo damage of the forest canopy during our study.},
doi = {10.2172/1570388},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {10}
}