Townsend, Philip (Phil): University of Wisconsin (Project Lead)
Project Funding:
2017 - 2020
NRA: 2016 NASA: Utilization of Airborne Visible/Infrared Imaging Spectrometer- Next Generation Data from an Airborne Campaign in India-AVRSNG
Funded by NASA
Abstract:
Imaging spectroscopy exhibits great potential for mapping foliar functional traits that are impractical or expensive to regularly measure on the ground, and are essentially impossible to characterize comprehensively across space. Knowledge of the variability in such traits is critical to understanding vegetation productivity, as well as responses to climatic variability, disturbances, pests and pathogens. In places where ground-measured trait data are sparse – such as India – imaging spectroscopy offer the capacity to fill gaps in our knowledge of global variation in foliar traits between and within biomes. In India, such data are important to understanding environmental drivers of variation in vegetation function, especially in biodiversity hotspots threatened by a range of change agents. Application of imaging spectroscopy algorithms to map foliar traits globally requires the development of “universal” algorithms that work across phenology, vegetation types, locations and years. Existing models that meet these requirements – such as those of Singh et al. (2015) for temperate forests – need to be tested in new regions and vegetation communities to ensure that the models are stable and transferable, as well as to identify gaps in coverage needed to improve those models. Such testing will help ensure that relatively robust models that operate well globally within or among physiognomic types (e.g. forests) are available for future global hyperspectral missions, such as HyspIRI. Here we propose the application of models developed by Singh et al. (2015) and new ones in development in the Townsend Lab in support of NEON’s cross-site mapping activities to the imagery collected over Indian forests as part of the 2015-2016 joint NASA-ISRO AVIRIS-NG campaign in India. By linking to other trait-mapping work, this will enhance ongoing efforts to develop cross-biome trait retrieval models for future spaceborne imaging spectrometers such as EnMap or HyspIRI. We will partner with Dr. N.S.R. Krishnayya at The Maharaja Sayajirao (M.S.) University of Baroda, whose team collected foliar samples for validation at three of the forest sites imaged during the AVIRIS-NG campaign. We will collect additional foliar samples in ~January 2018 (approximately 2-year anniversary of the original acquisition) at these three sites and another one site having matching vegetation for further evaluation. Data will be used for both validation and chemometric (partial least-squares) model refinement. Our proposed sites fall along a series of climatic (rainfall, temperature) and phenological gradients in the Western Ghats of India, identified by multiple organizations as one of the world’s premier biodiversity hotspots. We will use the results of our functional trait mapping to assess how forests across these regions vary functionally with well-characterized environmental gradients, both through empirical analyses and using coupled biophysical-radiative transfer model. The proposed project leverages a number of related efforts underway by the project participants.
More details may be found in the following project profile(s):
