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Frequently
Asked Questions (FAQ)
Is CASA a replacement for
NEXRAD?
Not necessarily. CASA radars are designed to
complement the existing
NEXRAD network. However, the CASA network operates independently from NEXRAD and can be deployed as an independent system. During testing, CASA
radars will be
scanning primarily below 3km, areas generally not observed as well by
NEXRAD.
Can CASA radars track airplanes?
The network is designed to be
multi-purpose; however, the
goal of CASA is to concentrate exclusively on the design, fabrication
and use
of weather radar. Thus,
current R&D
is focused on weather radar and its applications.
How many CASA test beds will
there be and where will they be
located?
To achieve its strategic goals,
CASA will build five
end-to-end system testbeds. Known
as
Integrative Projects, these five IPs (IP1-IP5) will be located in Oklahoma, Houston,
and Puerto Rico. IP5 will be a 2nd
generation build
of IP1, and will be using the infrastructure from IP1 in Oklahoma.
Operations:
How do you operate the IP1
test bed? Continuously?
Periodically?
The test bed is operated
during specific field experiments or seasons. For example, during 2007 IP1 was operated continuously from April 7 - June 10 during our CASA Spring Experiment period.
Can the CASA radars be
"steered" manually?
The radars are designed to be
“steered” automatically, as a
function of the observed weather and end-user needs.
Thus, while the radars can be operated manually,
the system is designed as a functioning unit, with all four radars
operating
collaboratively. The
system is not
designed for manual operation of individual radars.
How long will the IP1
test bed be in operation?
IP1 will be in operation until
summer 2009. After that
time, the test bed will be readied
for the next testbed in Oklahom, IP5.
IP5 is scheduled to begin around 2010.
Do the CASA radars have dual
polarization capability?
Yes, the CASA radars have dual
polarization capability. In
fact, the Tier II (base) data includes
the dual polarization variables.
Is time-series data archived and available for download?
Tier I (spectral) data are
available upon
request. However,
such a request must be
made to the SOCC within 12 hours of the data being collected. The spectral data are
stored at each radar
node for 23 hours, and must be downloaded manually to a USB drive.
Can CASA be viewed by anyone in real-time?
The data from all four radars
of IP1 are displayed in
real-time in Google
Earth, OK-FIRST
and WDSS-II.
Do you have a central
operations facility for CASA? Where
is it located?
The Systems Operation Control
Center (SOCC) is the central
operations facility for IP1.
The SOCC is located in the National Weather Center on the campus of the University of Oklahoma.
Does CASA participate in
research field programs?
As a National Science
Foundation project, CASA
participates in research field programs that include the IP1 coverage
area. CASA was a participant in the CLASIC Field Program during 2007.
Will independent observations
(e.g., aircraft, UAVs) be
available to verify the CASA radars?
Specific aircraft and UAV data
collection are not currently
planned for verification of the CASA data.
However, CASA does use a
variety of existing
in situ and mobile platforms for data comparison.
Is CASA working with the
National Weather Service?
Yes, the NWS is an integral,
formal industrial partner of
CASA. The NWS is
key in aiding the
development of the scanning strategies and end-user interface design.
Why do CASA radars scan during clear-air conditions?
IP1 will be used to estimate clear-air moisture gradients using measurements of refractivity.
Do you integrate data from other
sensors with CASA radar data?
One advantage of the CASA
system design is the capability
through the WDSS-II platform to combine CASA data with existing radar,
in-situ,
satellite, and model output. CASA
integrates multiple data streams into the decision-making
process for
scanning.
When will the mechanically
scanning radars be replaced with
electronic scanning?
This has yet to be determined.
Technical:
Why is CASA using X-band radars?
One goal of CASA is to produce
a small, low-cost radar that
can be deployed on existing infrastructure such as cell phone towers. Because the antenna size
is directly related
to the wavelength, a 3-cm (X-band) radar was the natural choice.
How does CASA overcome the
severe attenuation associated
with X-band radars?
To overcome attenuation, a
network of radars is used. The
radars coordinate collaboratively
and adaptively to compensate for attenuation and improve upon existing
radar
system capabilities.
What is the nominal spatial
resolution in the CASA radar
coverage area?
Each radar has a range gate
of 100 m with an
effective beam width of 2.17 degrees. Azimuthal oversampling is done at 1.0 degrees.
How close to the ground will
the CASA radars be able to see?
The radars currently scan at 1, 2, 3, 5, 7, 9, 11, and 14 degree elevations.
How much networking bandwidth
is required for each radar?
Each radar produces moment
(base) and dual-pol data at a rate between
3 and 4 Megabytes per second.
Production:
How are the CASA radars
deployed operationally and who
operates them?
CASA is conducting the research, development and prototypes that form the foundation upon which a commercially-viable product can be created.
How expensive are the radars
now being built and deployed?
The hardware for each prototype
radar costs approximately
$300,000. However,
this does not include
the additional costs for infrastructure (tower and computing hardware)
and
operation (electricity, heating/cooling, and communications) or the
costs of
labor to design, build, install, and operate such equipment.
How expensive will the radars
be in production?
This is yet to be determined,
but will depend upon many
factors, including the number of radars produced, the type of radar
(magnetron
versus solid state), etc.
Who built the prototype
radars?
CASA built the prototype
radars; the
actual fabrication and assembling of the hardware took place at the University
of Massachusetts MIRSL
engineering laboratory. A
number of industrial and government
partners contributed to their development.
Who will build the production
radars?
This is yet to be determined.
What is the expected lifetime
for the IP1 radars?
The magnetron of the prototype
radars are expected to last
two years. These
can be replaced rather
easily, but in general the radars are expected to be used for about
three
years.
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