Picturing SIF: field readiness and initial results from a novel SIF imaging instrument
Abstract
Solar-induced fluorescence (SIF) is an important proxy of photosynthesis and correlates with gross primary productivity at the canopy scale across a range of ecosystems. Recent innovations in hyper-spectral imagery are improving the spatial resolution of the quantification of SIF. Here, we perform initial calibration and testing of a novel SIF device, the high-resolution chlorophyll fluorescence imager (Headwall Photonics, Fitchburg, MA, USA). The instrument has a spectral passband of 670-780 nm, a full width at half maximum of 0.1-0.2 nm, and a spectral sampling interval of 0.051 nm/pixel. Previous studies showed that its large signal to noise ratio (120:1) allowed for improved quantification of absolute SIF and deeper O2-A and O2-B absorption bands as well as improved relationships with leaf-level SIF measurements when compared with broader-band instruments. While the imager was initially developed for airborne and satellite deployments, here we present initial recommendations to prepare and deploy the instrument on a rotating tripod in the field. The imaging capacity allows for concurrent survey of different parts of the same ecosystem, including top of canopy and understory, or individual leaves within the same canopy, but also presents unique challenges related to field ruggedness of the overall system, calibration, and image-distortion. We plan to build an open-source signal and image processing package in Python for the analysis of these data. Here, we present initial results of a deployment within an agricultural field and explore the effect of sun and instrument viewing angles and sensitivity of the instrument to small variations in SIF.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B25H1574R