Ocean Color Hyperspectral Satellite Observations of Chlorophyll a Fluorescence, Phytoplankton Functional Types and Light Penetration Depth with SCIAMACHY
Aleksandra Wolanin1,2, Tilman Dinter1,2, Vladimir V. Rozanov1, Mariana Soppa2, John Philip Burrows1 and Astrid Bracher1,2, (1)University of Bremen, Institute of Environmental Physics, Bremen, Germany, (2)Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
Abstract:
Hyperspectral satellite data are a new exciting source of the top of atmosphere radiance signal, which can be used for novel algorithms aimed for observations of marine ecosystems. We have applied the hyperespectral data from the SCIAMACHY instrument to observe phytoplankton functional types (PFTs), chl a fluorescence and light penetration depth. The retrievals are based on the differential optical absorption spectroscopy (DOAS) and involve fitting spectral features of phytoplankton absorption and the filling in of the Fraunhofer lines by chl a fluorescence or vibrational Raman scattering. Here, we explain the method principles and show the retrievals' results in comparison to other multi-spectral satellite products. In addition, we stress the potential and the limitations of using the hyperspectral data, and show examples how developed retrievals can be used together with multispectral instruments to obtain synergistic products (PFTS), or further extended to observations of terrestrial vegetation (chl a fluorescence). The presented algorithms are generic, and in future will be applied to other hyperspectral instruments with similar (or better) spectral and radiometric performance, which will provide better spectral resolution and spatio-temporal coverage. References:
Bracher A et al. (2009) Quantitative observation of cyanobacteria and diatoms from space using PhytoDOAS on SCIAMACHY data. Biogeosciences 6: 751-764
Dinter T. et al. (2015) Retrieval of light availability in ocean waters utilizing signatures of vibrational Raman scattering in hyper-spectral satellite measurements. Ocean Science 11 , 373–389.
Wolanin A. et al. (2015a) Detecting CDOM fluorescence using high spectrally resolved satellite data: a model study. In: G. Lohmann, et al. (eds.), Towards an Interdisciplinary Approach in Earth System Science, Springer Earth System Sciences, Springer, Heidelberg, Germany. ISBN 978-3-319-13864-0, pages 109-121
Wolanin, A., Rozanov, V., Dinter, T., Noel, S., Vountas, M., Burrows, J., & Bracher, A. (2015b). Global retrieval of marine and terrestrial chlorophyll fluorescence at its red peak using hyperspectral top of atmosphere radiance measurements: Feasibility study and first results. Remote Sensing of Environment, 10.1016/j.rse.2015.05.018166 , 243–261.
