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Radar Interferometry
Measurement of Land
Subsidence in Phoenix,
Arizona
SAR Data
The Phoenix area has been
imaged extensively by
ERS-1/2 since mid-1992.
Shown below is an ERS-1 SAR
image of Phoenix acquired on
August 8, 1995. The
image represents the
radiometrically uncalibrated
amplitude computed from the
complex image.
Features readily visible are
the Phoenix metropolitan
area in the lower half of
the image, Lake Pleasant
just left of center, the
White Tank Mountains in the
lower left corner, and the
agricultural area just right
of the White Tank Mountains.
Phoenix ERS radar
image
An ERS-1/2 one-day tandem
interferogram reveals the
topography of the area.
Each cycle through the color
wheel represents
approximately 160 meters of
topographic relief.
The urban areas are situated
in the valleys in the
southern portion of the
interferogram.
Phoenix topography
interferogram
A geocoded three-year
differential interferogram
from May 14, 1995 to
February 23, 1998 contains
phase signatures associated
with subsidence as well as
differential atmospheric
artifacts. Each cycle
through the color wheel
represents 2.8 cm of surface
motion or differential path
length delay along the radar
line-of-sight.
Temporal decorrelation
occurs over the agricultural
areas in the southern part
of the interferogram.
Phoenix geocoded
differential interferogram
Results
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