Cavanaugh, Kyle: UCLA (Project Lead)
Project Funding:
2015 - 2017
NRA: 2014 NASA: HyspIRI Preparatory Airborne Activities and Associated Science: Coral Reef and Volcano Research
Funded by NASA
Abstract:
Coral reefs are one of the most ecologically and economically important ecosystems in the world. However, degradation of coral reefs is increasing due to a combination of local- and global-scale stressors. There is a great deal of uncertainty as to the scale and trajectory of this degradation because the biological record of coral reef extent and health is limited. In order to better understand the patterns of reef degradation and the processes behind it, researchers need observations of coral reef extent and health on regional to global scales. This need is mentioned specifically in the NRC’s 2007 report, “Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond”, and in the HyspIRI mission science questions (specifically vq6 and cq1). The proposed research will use remotely sensed and simulated radiance data to show (1) that retrieval of benthic composition and coral bleaching is uniquely enabled by HyspIRI-like data, and (2) that this capacity will improve our understanding of the causes of coral bleaching. We will achieve these two technical and scientific objectives by performing the following tasks: Task 1:Use data with HyspIRI-like spectral characteristics to extract information on coral reef benthic composition and coral reef bleaching extent. Task 2: Use simulated top-of-atmosphere radiance data to characterize the practical limits on discrimination of coral reef benthic composition and coral bleaching as a function of instrument spectral characteristics, atmospheric conditions, instrument noise, and water column properties. Task 3: Assess the implications of HyspIRI’s planned 60-m spatial resolution by determining how sensor resolution impacts estimates of benthic composition and coral bleaching. Develop methods to utilize available high-resolution imagery to enhance the retrieval of benthic composition and bleaching from 60-m HyspIRI imagery. Task 4: Assess the environmental drivers and thresholds associated with coral bleaching events. In order to clearly demonstrate the unique capabilities of HypIRI-like imagery, we will perform similar analyses on simulated Landsat OLI reflectance to allow for a direct comparison of HypIRI and OLI capabilities. The proposed research will take place in the Hawaiian Islands, where we have high-resolution bathymetry and extensive in situ data for evaluation of benthic composition and bleaching in HyspIRI-like AVIRIS imagery. Limited additional in situ data on benthic composition and bleaching will be acquired coincident with the AVIRIS overflights. Spectral unmixing of imaging spectrometer (Task 1) data will require limited collection of in situ reflectance measurements of benthic components. These reflectance spectra will also be used in the spectral simulations (Task 2). The proposed research is poised to take advantage of any bleaching events that occur in 2016, but is not dependent upon the occurrence of a bleaching event. We already have sufficient data on benthic composition and bleaching (associated with a major bleaching event that occurred in Hawaii in 2014) that we can use to assess the environmental drivers and thresholds of coral bleaching (Task 4). This is just the type of data that would be uniquely enabled by HyspIRI (Task 1).
Publications:
Bell, T. W., Okin, G. S., Cavanaugh, K. C., Hochberg, E. J. 2020. Impact of water characteristics on the discrimination of benthic cover in and around coral reefs from imaging spectrometer data. Remote Sensing of Environment. 239, 111631. DOI: 10.1016/j.rse.2019.111631
Clare, J., McKinney, S. T., DePue, J. E., Loftin, C. S. 2017. Pairing field methods to improve inference in wildlife surveys while accommodating detection covariance. Ecological Applications. 27(7), 2031-2047. DOI: 10.1002/eap.1587
Doughty, C. L., Cavanaugh, K. C., Hall, C. R., Feller, I. C., Chapman, S. K. 2017. Impacts of mangrove encroachment and mosquito impoundment management on coastal protection services. Hydrobiologia. 803(1), 105-120. DOI: 10.1007/s10750-017-3225-0
Kelleway, J. J., Cavanaugh, K., Rogers, K., Feller, I. C., Ens, E., Doughty, C., Saintilan, N. 2017. Review of the ecosystem service implications of mangrove encroachment into salt marshes. Global Change Biology. 23(10), 3967-3983. DOI: 10.1111/gcb.13727
More details may be found in the following project profile(s):
