1. Atmospheric and air-water interface characterisation spectral bands
Atmospheric and air-water interface characterisation spectral bands. The greyed spectral bands already occur in Table 2.2..
Design Considerations for an Aquatic Ecosystem Earth Observing System: Does this cover your requirements?
A.G. Dekker & N. Pinnel (Eds) with: Gege, P., Briottet, X., Court, A., Peters, S.W.M., Turpie, K., Sterckx, C., Costa, M., Giardino, C., Brando, V.E., Braga, F., Bergeron, M., Heege, T. and Pflug, B.
Oceans & Atmosphere
Inland, estuarine, near-coastal waters, benthic and shallow water bathymetry EO applications
There are a lot of terrestrial, ocean and atmospheric EO sensors….but none specifically designed for where ~60% of the world’s population lives and ~ 60 trillion U$ of GDP is produced….
What would be the generic specifications for a global aquatic ecosystem EO mapping system that provides relevant information for inland water bodies, transitional water bodies to coasts, and seagrass, macro-algae and coral reef ecosystems?
Water column, substratum and depth properties measureable by EO:
Chlorophyll-a, phaeophytin; CP-cyanin & CP-erythrin; phytoplankton functional types; total suspended matter; particle size distributions; coloured dissolved organic matter; transparency/ turbidity/vertical attenuation of light; bathymetry (depth of substrate); bottom relief (topography). If spectrally & spatially discriminable!: Coral reefs, rocky reefs, seagrasses, macro-algae, benthic micro-algae, intertidal rock platforms and beaches and mudflats, saltmarsh, mangroves, floodplains and freshwater macrophytes; (biomass?)
Spectral Resolution Considerations:
Radiometric Resolution Constraints:
Theoretical maximal SNR for an imaging spectrometry earth observing sensor with pixel size of 17 and 33 m, spectral sampling interval of 8 nm with a lens aperture of 300 mm in a 400 km orbit. The radiance was calculated using Ahmad (2010) with a sun zenith angle of 42°. Typical radiance from PACE Ocean Color Instrument (Meister et al., 2011)
Spatial Resolution Considerations:
Ground Sampling Distance requirements showing resolvable size class, cumulative number and area coverage of the world’s lakes (using Verpoorter et al. (2014) dataset for lakes) and Pavelsky et al. (2012) dataset for rivers (Courtesy E.L. Hestir & Mark Matthews)).
Calculated using a box of 3 x 3 pixels sufficient to resolve the specified lake size and 3 x 1 pixels for widths of river reaches
Lakes and Reservoirs Size Class
Required GSD
% Total Area
Total Number
≥ km2
33 m 90 ~
≥ km2
15 m
100 ~
River Reach Size Class
% Total Reaches
Total Number of Reaches
≥ 0.10 km 12 ~
≥ 0.05 km
17 m 24 ~
NB: 0.3 to 10 m spatial resolution covered for e.g. benthic habitat mapping by commercial and S-2 sensors
Recommended minimum set of spectral bands for extracting information from remote sensing reflectance spectra of optically deep and shallow waters.
In conclusion spectral & spatial resolution are prime drivers with radiometric resolution subsequently to be as high as possible. Temporal resolution is a function of nr of satellites and orbit choices.
Are these specifications correct?
Do we need hyperspectral sensors or multispectral sensors and if so: what bands are crucial?
Do we need a suite of EO sensors with varying spectral, spatial and radiometric sensitivity
What amount of satellites do we need in which orbits (polar, equatorial, geostationary?)
Please provide us with your expertise, ideas, innovations…. or
Temporal Resolution Considerations:
Hourly: such as algal blooms, flood events with associated influxes of high nutrient, high coloured dissolved organic matter and suspended sediment loads into reservoirs, estuaries or coastal seas or with tidal or wind driven events.
Daily: e.g. pollution events, dredging effects etc.
Weekly: e.g. coral bleaching events (Healthy coloured coral -> bleached coral -> dead coral or recovered coral)
Seasonally to yearly to longer term: e.g. successions of phytoplankton functional types or emergence, florescence and decay of macrophytes.
This may be achieved through a combination of polar, equatorial and geostationary satellite sensors
Atmospheric and air-water interface characterisation spectral bands.
Dekker, A.G & Pinnel, N., Gege, P., Briottet, X., Court, A., Peters, S.W.M., Turpie, K., Sterckx, C., Costa, M., Giardino, C., Brando, V.E., Braga, F., Bergeron, M., Heege, T. and Pflug, B. (2018) Feasibility Study for an Aquatic Ecosystem Earth Observing System; Dekker, A.G., and Pinnel, N. (Eds), CEOS Report, CSIRO, Canberra, Australia: pp 195;
Acknowledgements
This work was supported by CSIRO, DLR, NASA, ONERA, TNO, Water Insight, VITO, Un. Victoria (CA), CNR, EOMAP, SatDek.
See CEOS report for references and more detailed considerations for: temporal, spatial, spectral resolution and radiometric resolution, geolocational accuracy, sun glint avoidance and polarisation sensitivity
Dr Arnold G. Dekker