HysIS: Hyspectral Imaging Satellite
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- 1st hyperspectral imaging satellite.
- It observes earth’s surface in 3 different ranges including visible, near infrared and shortwave infrared regions in 55 spectral or colour bands.
- Enables us to do a ‘CATSCAN’ equivalent of Earth surface.
- Application
- Agriculture, forestry, coastal zones, inland waters, soil, oil and minerals mapping and military surveillance
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Hyperspectral Imaging v/s Multi-Spectral Imaging: Concept
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- We have seen the basics of spectroscopy in previous section.
- Multi-spectral scanners include sensors capable of detecting absorption, emission and scattering (reflection and refraction) of different lights (visible and invisible). Doing this gives more details about the object and thereby help in differentiating between chemical composition.
- Hyperspectral imaging is an advanced version of multi-spectral imaging. Only difference is it includes sensors capable of sensing a contiguous band of light thereby giving sharp details.
- While multispectral scanners are useful to differentiate minerals, hyperspectral sensors help in even quantifying individual materials.
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NISAR
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Planned launch: late-2023 early-2024
- Joint active remote sensing satellite of NASA-ISRO, thus all-weather, day-and-night, cloud penetrating.
- Short for NASA-ISRO Synthetic Aperture Radar satellite
- 2 radar frequencies (S band and L band)
- Uses advanced technique called interferometric synthetic aperture radar (InSAR)
- InSAR: superimposes multiple reflected light beams to cause interference helping in construction of 3-d topographic maps. Time-series images of such topographic maps help in observing surface motion and change.
Capabilities
- 3-10 m spatial resolution
- Global coverage of land and ice cover every 12 days. (cryosphere)
- Can study of slow motion of earth’s crust with the help InSAR
- Study of biomass
Applications
- Earthquakes and vulcanology
- Distribution of carbon stocks in terrestrial biomass: Global warming applications
- Vulnerability of wetlands by studying the extent of inundation
- Geomorphology, movement of sea ice and hydrology
- Movement of glaciers and icesheets thereby climate change
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