Environmental Engineering Reference
In-Depth Information
Figure 9.1 Spectacular view of Sarychev Volcano (Matua Island, Kuriles)
June 12, 2009 (Astronaut photograph ISS020-E-9048, Nikon D2XS digital
camera, 400 mm lens). Photo by NASA Earth Observatory, with permission
( http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=38985 ) . A black
and white version of this
figure will appear in some formats. For the colour
version, please refer to the plate section .
temporal (daily) resolution data, and can be useful for observing episodes of
heightened activity at speci
lm
and digital images of eruptions, taken from the International Space Station (ISS,
52ยบ orbital inclination), with resolution of a few meters, is an under-exploited,
if qualitative, volcanological asset. Typically, ISS data opportunities cluster in
episodes of 3 - 5-day intervals for any given target volcano, depending on latitude
( Figure 9.1 ).
c volcanoes. A unique archive of hand-held
9.2.2 Mapping missions
In orbital mapping missions, earth-observing instruments typically operate at a
nearly 100% duty cycle. That is, they are nearly always on, and nadir-looking,
thus foregoing the need to aim observing instruments at particular targets, and
greatly simplifying operations. Synoptic mapping missions in polar orbit with
low (1 km/pixel) to moderate (250 m/pixel) spatial resolutions permit relatively
frequent repeat observations, at least one image per day, and often many more,
depending on geocentric latitude. Synoptic mapping missions in geostationary
(GEO), circular high Earth orbit (HEO), or high elliptical orbits (Molniya), may
return data on a minute-by-minute basis across a hemisphere; however, data are
returned at relatively low (e.g. 1 - 4 km/pixel) spatial resolutions for unclassi
ed
civil applications.
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