79-11Satellite Imaging and Sensing
As previously mentioned, NOAA’s AVHRR is primarily used for atmospheric applications but is also
ut
ilized
fo
r
la
nd
su
rface
ap
plications
. Ha
ving
a ne
ar-polar,
su
n-synchronous
or
bit
(a
t
83
3
km ab
ove
th
e
Ea
rth’s
su
rface),
th
e
AV
HRR
in
strument
pr
ovides
gl
obal
da
ta
wi
th
a 1.1 km sp
atial
re
solution
at na
dir,
an
d
in
cludes
v
e
ba
nds,
wi
th
da
ily
or tw
ice-daily
(f
or
th
ermal-IR)
co
verage
. Si
nce
19
78,
AV
HRR
da
ta
ar
e
av
ailable
at fu
ll
re
solution
(c
alled
Lo
cal
Ar
ea
Co
verage
[L
AC])
or su
bsampled
to 4 km (k
nown
as
Gl
obal
Ar
ea
Co
verage
[G
AC])
. Be
cause
of it
s
hi
gh
te
mporal
re
solution,
th
e
AV
HRR
in
strument
is ve
ry
us
eful
in ap
plications
su
ch
as o
od,
sto
rm,
or r
e
mo
nitoring,
as we
ll
as vo
lcanic
er
uption
. Be
cause
of
its GA