xi AGU_2015_abstract..

AGU 2015 abstract to be submitted to B064: Photosynthesis and respiration at leaf, ecosystem,
regional, or global scales: constraints, measurements and modeling
(More information about this session could be found on the next page.)
Title: Solar-Induced Fluorescence (SIF) Captured by California Laboratory for Atmospheric Remote
Sensing (CLARS)
Authors: Xi Xi, Thomas J. Pongetti, Run-Lie Shia, Stanley P. Sander, Yuk L. Yung, Christian
Frankenberg, David Schimel
Solar-induced fluorescence (SIF) is emitted from the core of the photosynthetic apparatus and can serve
as a direct indicator of photosynthetic efficiency. It could be exploited for large scale monitoring of plant
health, which is crucial for studies in ecosystem, carbon cycle, agriculture, and other related fields. In this
study, we use Fourier Transform Spectrometers at California Laboratory for Atmospheric Remote
Sensing (CLARS) to measure high-resolution spectra near the oxygen A band. Measurement campaigns
conducted in recent two years provide weeks of measurements that capture the diurnal variations of SIF
from a variety of species including grasses and oak trees. Stationed on the top of Mount. Wilson in
Southern California, CLARS is capable of monitoring SIF over the nearby mountains and the Los
Angeles basin. This study aims to demonstrate that instruments at CLARS are capable of capturing SIF
with high precision over different times of day. The high spatiotemporal variations of SIF are unique
features of the CLARS measurements. The results have implications for the proposed constellation of
geostationary satellites that are designed to capture SIF at regional scales.
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B064: Photosynthesis and respiration at leaf, ecosystem, regional, or global
scales: constraints, measurements and modeling
Session Description:
Photosynthesis and respiration are two coupled processes operating under fundamentally
different mechanisms. While net biosphere-atmosphere CO2 exchange is routinely measured at
the ecosystem scale, the gross photosynthetic and respiratory fluxes are only loosely constrained
at ecosystem, regional, and global scales. Uncertainty in the responses of photosynthesis and
respiration to the environment at these scales is a major source of uncertainty in predictions of
biosphere-atmosphere feedbacks under climate change.
Advances have been made in developing methods to partition the measurable flux difference into
photosynthetic and respiratory components. For example, eddy covariance CO2 flux partitioning,
COS, SIF, isotopes, and PRI have all shown potential to derive process-specific information. We
propose a session of measuring and modeling photosynthesis and respiration at any scale from
the ecosystem to the globe to review recent advances in photosynthesis and respiration. We
especially invite studies introducing novel methods that push the boundaries of carbon
cycle science.
Primary Convener:
Ian T Baker, Colorado State University, Atmospheric Sciences, Fort Collins, CO, United States
Roisin Commane, Harvard University, Cambridge, MA, United States, Ying Sun, University of
Texas at Austin, Austin, TX, United States and Georg Wohlfahrt, University of Innsbruck,
Institute of Ecology, Innsbruck, Austria
A - Atmospheric Sciences
GC - Global Environmental Change
H - Hydrology
Index Terms:
0414 Biogeochemical cycles, processes, and modeling [BIOGEOSCIENCES]
0426 Biosphere/atmosphere interactions [BIOGEOSCIENCES]
0428 Carbon cycling [BIOGEOSCIENCES]
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