Project Funding: 2013 - 2017

NRA: 2011 NASA: HyspIRI Preparatory Airborne Activities and Associated Science and Applications   

Funded by NASA

Abstract:
As identified as a national research priority by the NRC Decadal Survey report, key objectives of the HyspIRI mission satellite are to detect and monitor changes in physiological functioning and map changes in species composition. The expanded and related objectives are principally described in HyspIRI science Documents VQ2, VQ3, and CQ4. To address these objectives, we ask the question: to what extent are functional types consistent with biochemical diversity at the canopy scale? Our main objective is to advance scientific understanding of the relationship between conventional plant functional types (PFT(c)), which are described by growth form and phenology, and physiologically important biochemical components at the canopy scale (Chl a, b, carotenoids, water, nitrogen, carbon); and assess the viability of a PFT definition in terms of remotely sensed canopy biochemistry. We address this objective through three sub-objectives: (1) Identify whether associations of different biochemical compositions match conventional plant functional types and their groups. (2) Evaluate the clustering of remotely sensed biophysical and biochemical properties in relation to PFT(c)s. Does biochemical variability (natural clustering in multivariate spectral space) correspond with PFT distributions? To what extent do PFT differences influence retrieved biochemical concentrations? And (3) Test the potential for complete automation of the radiative transfer model inversion to retrieve canopy chemistry products from HyspIRI spectra. This study will significantly improve understanding of how biochemical composition varies with physiognomically identified PFTs. Results will lead to better understanding of variables related to physiological functioning for climate and ecosystem models. Consequently, it will produce data that corresponds more accurately to realized physiological activity, leading to improved monitoring of ecosystem feedbacks to the climate system and reduced uncertainty in predicting future climate conditions. We will evaluate retrieval of canopy chemistry using an improved version of the radiative transfer PROSPECT-5 leaf optical properties model with the SAIL family of canopy models for the three proposed HyspIRI California transects expected to be collected in different seasons in 2013 and 2014. We will concentrate on retrieval of quantitative estimates of physiologically active canopy chemistry components (chlorophyll a and b, carotenoids, water and ligno-cellulose dry matter) that are relevant for fluxes of carbon and water with the atmosphere. Additionally we will use Partial Least Squares (PLS) method for estimating nitrogen and Gitelson s 3-band method for retrieval of anthocyanin. Leaf reflectance and transmission will be made on leaves for chemical analysis using an ASD integrating sphere or the ASD leaf probe and our Fieldspec-3 spectrometers. We will concentrate field evaluations at sites with presumed different PFTs, primarily located at flux tower sites or others where information about species composition and physiological activity are independently available and at any additional sites where concurrent HyspIRI related field activities are conducted. Field data will be used to evaluate chemistry retrieval from corresponding AVIRIS and MASTER data. Lab chemistry measured from sites crossed by the HyspIRI flightlines combined with airborne canopy temperatures will be used as independent measures of apparent canopy stress to evaluate detected chemistry. We will test the potential for complete automation of the radiative transfer processing procedures used to retrieve canopy chemistry products. The automation of these processing procedures are necessary to ensure that canopy chemistry products can be routinely produced and made available to a broad range of HyspIRI end users.

Publications:

Huesca, M., Garcia, M., Roth, K. L., Casas, A., Ustin, S. L. 2016. Canopy structural attributes derived from AVIRIS imaging spectroscopy data in a mixed broadleaf/conifer forest. Remote Sensing of Environment. 182, 208-226. DOI: 10.1016/j.rse.2016.04.020

Miraglio, T., Adeline, K., Huesca, M., Ustin, S., Briottet, X. 2019. Monitoring LAI, Chlorophylls, and Carotenoids Content of a Woodland Savanna Using Hyperspectral Imagery and 3D Radiative Transfer Modeling. Remote Sensing. 12(1), 28. DOI: 10.3390/rs12010028

Roth, K. L., Casas, A., Huesca, M., Ustin, S. L., Alsina, M. M., Mathews, S. A., Whiting, M. L. 2016. Leaf spectral clusters as potential optical leaf functional types within California ecosystems. Remote Sensing of Environment. 184, 229-246. DOI: 10.1016/j.rse.2016.07.014

More details may be found in the following project profile(s):

• NASA Biological Diversity & Ecological Conservation (BDEC) Project Profile