WMOD00307

• Title: A Proposal for Cooperative Weather Research Between the Santa Barbara County Water Agency and the US Department of Interior Bureau of Reclaimation in the Context of the Weather Damage Modification Program through the State of CA 2002-2003 Winter Season
• Date: 10/17/2002
• State: CA
• Weather Modification - Doc Type: Report

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The Rosemount RT105 is a de-iced platinum resistance-type total temperature sensor for high
performance aircraft applications where accurate total temperature measurements are required.
The sensing element consists of platinum wire having 500 ohms resistance at 00 Celsius and is
hermetically sealed within two concentric tubes. The sensing element is protected from small
foreign particles such as sand, ice and insects. The sensor features a de-icing heater which
dissipates 270 watts under in-flight conditions with 28 volts DC applied. The WMI-RT105 is
interfaced with the WMI-DAS-300 and will display temperatures from -500 C to 500 C.

Dew Point Temperature
The dew point Sensor is a complete optical dew point system for monitoring in-flight
atmospheric dew and frost points. It is the only aircraft instrument that provides two stages of
thermoelectric cooling. It can reach frost points between - 600 and-700C, depending on
mounting configuration and operating conditions. No auxiliary coolants are required. Included
in the WMI-137 system are a water-excluding inlet probe and a pressure tap for monitoring static
pressure. A digital display with resolution to 0.1 oC is provided as well as an analog D.C. voltage
output that is interfaced with the WMI-DAS-200 for display and recording purposes.

Atmospheric Pressure
Atmospheric pressure is provided by the same Setra S-270 pressure transducer mentioned
previously (see position, above).

Liquid Water Content
The Droplet Measurement Technologies (DMT) LWC-100 consists of a control unit, a power
supply, and a sensor head. The sensor head holds the wire-wound element between two prongs
that position it three inches away from the outside skin when mounted on an aircraft. The
sensing element, in conjunction with a remotely mounted power supply, is interfaced with the
display module. The display is mounted within the WMI-DAS-200 and is interfaced with the
computer for recording and disrlaying liquid water content measurements. The LWC-100 is
capable of measuring 0 to 5 g m- of liquid water.

Cloud Droplet Spectra
The Forward Scattering Spectrometer Probe (FSSP) is a one-dimensional laser probe that
provides sizing of particles up to 47 microns. The probe outputs a parallel digital size code along
with a strobe pulse for each acceptable particle encountered. The output is interfaced with the
WMI-DAS-200 for collecting, displaying and recording the data provided. The format of the
displays can easily be tailored to the users preference. The available ranges of the FSSP are
controlled by the WMI-DAS-200 and can easily be selected by the user.

The probe is contained inside a rugged seven-inch diameter cylinder with hemisphere end caps
on both ends resulting in a main body length of 31 inches. The sensing unit extends out from the
forward end cap that must be oriented into the direction of flight. The FSSP has four
overlapping size ranges with each size range divided into fifteen linear size intervals providing
up to 60 size channels in the 0.5 to 45 micron range. Laser and detector alignment is achieved
with spring-loaded x-y screw adjustments. The FSSP's He-Ne (632.8nm) laser tube has an
extruded aluminum envelope and is configured in high order multimode. The probe electronics

Weather Damage Modification Program 35