EESS talk on "In situ and in orbit: Optical properties of surface waters"
Event details
| Date | 23.03.2021 |
| Hour | 12:15 › 13:00 |
| Speaker | Dr Daniel Odermatt,Tenure Track Group leader, Remote Sensing Group, Dept. of Surface Waters, EAWAG |
| Location |
ZOOM
Online
|
| Category | Conferences - Seminars |
Abstract:
The maturing of optical satellite Earth observation technologies is closely linked to the development of field spectroradiometers that measure comparable parameters in situ. For surface water applications, the most comprehensive reference datasets are acquired by above-surface spectroradiometers mounted on jetties or buoys. These datasets consist of accurate reflectance measurements, which are used for satellite sensor vicarious calibration by all major space agencies.
The Thetis profiler next to the LéXPLORE platform in Lake Geneva is currently limited to below-surface reflectance measurements, but it simultaneously acquires absorption and scattering properties. This provides an unprecedented basis for the interpretation of reflectances, including vertical gradients of several bio-physical indicators at sub-diel scale. It furthermore allows for an optical closure via radiative transfer simulations, and hence a detailed description of reflectance measurement uncertainties. In this manner, we can optimize the measurements’ comparability with daily observations by the Sentinel-3 satellites, and thereby mitigate the technical limitations of below-surface measurements.
Based on Thetis measurements as well as longer but less comparable water quality monitoring time series, we currently develop daily primary productivity estimates for Switzerland’s largest 20 lakes. The productivity estimated by a bio-optical model, and the underlying chlorophyll-a and Secchi depth estimates from 300 m resolution Sentinel-3 data are made available in www.datalakes-eawag.ch, within a few hours after acquisition.
We envision a similar system for Sentinel-2 based 20 m turbidity estimates in smaller lakes and at higher elevations, where ground reference measurements and other ancillary data is currently missing. While preparing to acquire such measurements during the next two summers, we compiled an inventory of more than 1200 lakes that formed in the Swiss Alps since the Little Ice, as a result of the ongoing deglaciation.
Short biography:
Daniel Odermatt is a Tenure Track Group Leader in the Surface Waters department at Eawag. He’s a geographer and glaciologist who is specialized in optical Earth observation. He received his Ph.D. from the University of Zurich for a thesis on water quality remote sensing. As a Marie-Curie IAPP postdoctoral fellow and company founder, Daniel spent more than five years in the private industry where he developed, on behalf of the European Space Agency (ESA), global scale satellite Earth observation applications for biodiversity conservation and sustainable development. He recently developed an open source Python library (https://gitlab.com/eawag-rs/sencast) to carry on such applications with ESA’s Sentinel satellite data. At closer range, Daniel is exploiting bio-optical measurements and modeling for Swiss lakes.
The maturing of optical satellite Earth observation technologies is closely linked to the development of field spectroradiometers that measure comparable parameters in situ. For surface water applications, the most comprehensive reference datasets are acquired by above-surface spectroradiometers mounted on jetties or buoys. These datasets consist of accurate reflectance measurements, which are used for satellite sensor vicarious calibration by all major space agencies.
The Thetis profiler next to the LéXPLORE platform in Lake Geneva is currently limited to below-surface reflectance measurements, but it simultaneously acquires absorption and scattering properties. This provides an unprecedented basis for the interpretation of reflectances, including vertical gradients of several bio-physical indicators at sub-diel scale. It furthermore allows for an optical closure via radiative transfer simulations, and hence a detailed description of reflectance measurement uncertainties. In this manner, we can optimize the measurements’ comparability with daily observations by the Sentinel-3 satellites, and thereby mitigate the technical limitations of below-surface measurements.
Based on Thetis measurements as well as longer but less comparable water quality monitoring time series, we currently develop daily primary productivity estimates for Switzerland’s largest 20 lakes. The productivity estimated by a bio-optical model, and the underlying chlorophyll-a and Secchi depth estimates from 300 m resolution Sentinel-3 data are made available in www.datalakes-eawag.ch, within a few hours after acquisition.
We envision a similar system for Sentinel-2 based 20 m turbidity estimates in smaller lakes and at higher elevations, where ground reference measurements and other ancillary data is currently missing. While preparing to acquire such measurements during the next two summers, we compiled an inventory of more than 1200 lakes that formed in the Swiss Alps since the Little Ice, as a result of the ongoing deglaciation.
Short biography:
Daniel Odermatt is a Tenure Track Group Leader in the Surface Waters department at Eawag. He’s a geographer and glaciologist who is specialized in optical Earth observation. He received his Ph.D. from the University of Zurich for a thesis on water quality remote sensing. As a Marie-Curie IAPP postdoctoral fellow and company founder, Daniel spent more than five years in the private industry where he developed, on behalf of the European Space Agency (ESA), global scale satellite Earth observation applications for biodiversity conservation and sustainable development. He recently developed an open source Python library (https://gitlab.com/eawag-rs/sencast) to carry on such applications with ESA’s Sentinel satellite data. At closer range, Daniel is exploiting bio-optical measurements and modeling for Swiss lakes.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Janet Hering, Director, EAWAG