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Chapter 30
Space-borne hyper-spectral imagers are under development at present for
various missions. These include MERIS on ENVISAT, HSI on the Lewis
Test Satellite, ARIES on an Australian platform (with the support of CSIRO
and commercial mining user groups), or MODIS on the NASA Terra platform. Additional information on these instruments is provided in Tables 2A
and 2B below.
Particularly, IS allows the distinction of species in the water, in the vegetation canopy (biochemistry), as well as applications in surface mineralogy
and petrography. Table 1 provides an example survey of such applications
and the corresponding useful spectral regions, though with inadequate spectral resolution. While the early push-broom type IS developments (FLI in
Canada, ROSIS at DSS) covered the visible/NIR spectrum (VNIR) only,
more recent developments typically include short wavelengths IR channels
(SWIR)—both operating in the reflected sunlight spectral range. Somewhat
less emphasis has been given to the thermal infrared (IR: 3–12
).
The primary mission emphasis is widely dependent on the IS IFOV and
TFOV, and will be mainly focused on:
energy and water fluxes
water quality, organic and inorganic inlets (on global scale with medium
resolution IS, on regional scale high resolution IS)
land surface processes and changes (see Fig. 1 as example), particularly
for:
– vegetation status, health/stress, multi-temporal BRDF measurements
along- and across-track
– soil condition, surface minerals
– coastal and inland water bodies for narrow FOV IS, global ocean monitoring for wide FOV IS
– carbon cycle detailing
– detection of indicators for the effect of traces gases and aerosols (see
Fig. 2 for the Etna) on the environment (e.g., vegetation, glacier melting).