Each of the four towers can collapse to a form suitable
for travel and expand to deployment configuration within 30 minutes. The objective is to gather high-fidelity time
histories of the wind velocity as the storm passes over the instruments.
This data at 5 and 10 meter elevations provide an important element for
engineers working to mitigate damage from extreme winds.
To see a short movie illustrating a tower setup, choose
large versions of video taken during Isabel.
Anatomy of a Portable Wind Tower
The four portable towers systems were constructed during 1998-1999.
They are designed to function in up to 200 mph wind gusts. Click on the
picture below to see the components of the tower in detail.
Click on the Tower Picture to Enlarge
(or see PDF)
Strength and Stability
The main tower is built from a structural steel lattice,
bolstered by structural steel tubing that connects the tower to its
All computer, generator and battery enclosures are built from 16 gauge
steel or diamond-plated aluminum. Wiring for power and data is
encased in conduit for maximum protection.
Strength is complemented with several measures to
stabilize the towers in high winds. The towers resist sliding and
overturning from impinging wind loads through the following design
the 5500 lbs of self-weight
the outrigger system, which places the supports of the
tower 20 ft away from the center of the tower. This kind of
configuration is analogous to pushing an upright person over. If the
person keeps their feet close together, this task is easy. As the
farther apart the person spreads their feet, however, the more difficult
this task becomes. Engineers refer to this principle as resistance
to overturning moment
The instruments include two 3-axis fixed anemometer arrays at 5 and 10
meter elevations, and a vane anemometer at the 10 meter elevation.
Environmental variables (barometric pressure, temperature, relative
humidity, rainfall) are also collected onboard.
Two onboard computer systems read data from the instruments and save files
every 15 minutes. The first system samples at 100 Hz (Hz =
sample/second) and writes
results to two hard drives in the CPU. The second system, running on
a laptop and the Tower XP software (in LabVIEW), pulls data at 10 Hz.
The data is post-processed and uploaded to the web, where emergency
managers and meteorological agencies (eg, NOAA) can access the data.
More information about the real-time data acquisition may be found in the
Current/Future Efforts section
of the FCMP website.
An onboard gasoline generator powers a system of UPS batteries to provide power
to computers and powered instruments. The tower system can operate
for 24-36 hours before the generators must be refueled.
to the Tower System:
The 2003 season will see the introduction of two important new additions
to the portable tower hurricane data collection system.
1) Real Time data transmission to a web site
2) Additional 5-meter satellite towers to deployed around each main tower.
Details of these new additions are found on the
Current / Future Efforts page
Data Sets Collected
The FCMP teams have been
deploying for landfalling tropical storms and hurricanes since 1998. Tower
data has been collected for the following storms.
Dennis, Floyd and Irene
Charley, Frances, Ivan and Jeanne
Dennis, Katrina, Rita and Wilma
More details are provided on the
Collected Data page on this site.
Pictures of these deployments can be found at the