Development of new remote sensing retrievals for snow/ice characteristics and phytoplankton properties
This dissertation introduces two new remote sensing retrieval methods for snow and ice characteristics and phytoplankton properties. A synergistic usage might be a promising advanced application to investigate ice algae in high latitudes. The retrievals exploit the discrimination power of emissivity...
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| Other Authors: | , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://refubium.fu-berlin.de/handle/fub188/22598 https://doi.org/10.17169/refubium-404 https://nbn-resolving.org/urn:nbn:de:kobv:188-refubium-22598-3 |
| Summary: | This dissertation introduces two new remote sensing retrieval methods for snow and ice characteristics and phytoplankton properties. A synergistic usage might be a promising advanced application to investigate ice algae in high latitudes. The retrievals exploit the discrimination power of emissivity and phytoplankton absorption, scattering, and fluorescence due to specific dependency of the properties on object and wavelength. The cryospheric algorithm sorts three surface emissivities, which are converted from remotely sensed thermal infra-red (TIR) brightness temperatures from Advanced Along-Track Spectro-Radiometer (AATSR) 11 μm and 12 μm bands in nadir and forward view, in a classification scheme. The scheme is based on measurements of Hori et al. (2006) and discriminates between fine, medium, coarse grained snow and suncrust and ice. Depending on the physical surface temperature wet areas are detected. Invalid pixels mostly occur at topographically complex areas and due to collocation of the two views. Scenes in Antarctica and Greenland exhibit classified pixels between 60% to 90%. Phytoplankton is characterized with Total Algae Peak Integration Retrieval (TAPIR) linking the local reflectance maximum in the chlorophyll-a fluorescence domain from 650 nm to 730 nm with the local chlorophyll-a absorption maximum at 670 nm a670. Radiative transfer simulations show high sensitivity on chlorophyll-a absorption, phytoplankton scattering and chlorophylla fluorescence, which are combined in a670 in TAPIR. The peak’s shape, magnitude and spectral location is mainly influenced from those properties which are considered by a spectral peak integration in the retrieval. TAPIR functions are retrieved for several hyper-spectral instruments such as Environmental Mapping and Analysis Program (EnMAP) and can be applied to multi-spectral sensors, e.g. Ocean and Land Colour Imager (OLCI), with a fitting function. An application of both algorithms to Lake Erie at the Canadian/American border reveals good performance of TAPIR for ... |
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