russell betsuie environmental team supervisor gila river indian community department of...

METEOROLOGICAL INSTRUMENTATION

Russell Betsuie Environmental Team Supervisor

Gila River Indian Community Department of Environmental Quality


Gila River Indian Community Akimel O’odham (Pima) & Pee Posh (Maricopa) Located in Central Arizona, adjacent to Phoenix in

Maricopa & Pinal counties Established in 1859 by Executive Order 374,000 acres Population 15,500 people (on reservation)

+ 1, Keith’s baby daughter


Meteorological Sensors Overview Wind speed Wind Direction Ambient temperature Relative humidity Barometric pressure Precipitation gauge

Brief overview Solar radiation Fuel moisture / Fuel temperature

Meteorological Tower Data Logger Documentation

Other information


Wind Speed Sensor Propeller

Lightweight material Magnetically induced AC sine

wave output voltage Met Card

Frequency directly proportional to wind speed

Translator output is an analog voltage

Voltage applied to Data Logger Voltage In Card


Wind Speed Sensor Cup assembly

Chopper wheel directly coupled to speed sensor which interrupts light path of optic link

Pulse frequency proportional to wind speed

Met Card

Translator output is an analog voltage

Voltage applied to data logger Voltage In Card


Met One 010C Wind Speed Sensor Cover remove showing the

light chopper disk that produces the pulse frequency

Detector light assembly Electronic board


Sine wave

Time

+

+

-

Hz (Hertz) is cycles per second

Use sensor unit specs for range

Wind Speed Sensor Frequencies

Pulsed frequency


Voltage Signal Voltage Signal

1 Volt

999.3 Hz =100 MPH

Full Scale

If 1.0 volt = 100 Mile per hour then 0.5 volts = 50.0 MPH

0.5 Volt 552.2 Hz =50 MPH

Change is proportional

Basic Signal Concept


Wind direction Sensor Lightweight vane material

Wind vane directly coupled to potentiometer

Potentiometer produce an analog output voltage

Voltage is proportional to vane angle (wind direction)

Voltage is applied to translator or data logger

Voltage In Card


Wind direction Sensor Lightweight material

Airfoil shape Polyurethane Directly coupled to potentiometer Potentiometer produce an analog

output voltage Voltage proportional to vane angle

(wind direction) Voltage is applied to translator or

data logger Voltage In Card


Voltage Degrees Voltage Degrees

1 Volt 360 Degrees

Full Scale

If 1.0 volt = 360 degrees then 0.5 volts = 180 Degrees

0.5 Volts 180 Deg.

Change is proportional

Basic Analog Concept


Ultra Sonic Wind speed and direction

sensor combined Solid state Analog and Digital output No moving parts

Less maintenance No calibration required


RM Young Vane Alignment Rod

Notch and box will always face true south with rod pointing to true north

Met One Cross-arm

Notch on direction sensor face south with cross arm pointing south / true north


Compass will show magnetic north Set wind direction sensor to true north Each area has declination to use for correction to true

north Eastern part of U.S. declination is positive Western part of U.S. declination is negative

Web site www.ngdc.noaa.gov/seg/geomag/jsp/struts/calcDeclination

http://www.ngdc.noaa.gov/seg/geomag/jsp/struts/calcDeclination


Ambient Temperature Sensor High impedance thermistors or thermocouple

Cold temperature will increase sensor resistance Hot Temperature will decrease sensor resistance

Relative Humidity Sensor Measure water vapor contents of atmosphere

Works based on capacitive change Integrated Sensor unit

Advantage 2 sensors in one sensor (cost)

Disadvantage If temperature or relative humidity component is damaged.

Sensor must be replace sacrificing other sensor data


2 types of Radiation Shields 1. Multi-plate Radiation Shield

White aluminum housing with disk plates

Protect sensors from rain and from direct sun rays

Allows air flow through plates to sensor located in center of shield


2. Fan Aspirated Radiation Shield White coating on aluminum and white material housing Protect sensors from rain and from direct sun rays Fan produce continuous ambient air flow through shield and

sensor Prevents convective heat transfer to sensor Requires more cleaning of housing and replacement of fan


Fuel moisture /fuel temperature sensor Basically a temperature and humidity sensor

Used for applications such as fire management Can help determine fire danger levels Used for determining fuel moisture & fuel

temperature of area. Mounted over fuel bed Typical fuels may be forest material: timber,

brushes & also trash


Barometric pressure sensors Outside & Inside Sensors Detect atmospheric pressure Typically a solid-state pressure

transducer Internal electronic circuitry Analog output voltage


Precipitation gauge Measures amount of rain fall Tipping bucket located below funnel Rain droplets collects in tipping

bucket Tipping action activates switch Switch closure sends signal to

translator box or data logger Important to level bucket, some

buckets have a internal bubble level


Solar radiation sensor Solar Pyranometer

Detects amount of solar radiation from sun (sunlight)

Complements ozone data Complements fuel stick data

Operation Detector element: black & white Different rates of absorption Temperature differential Be aware of obstruction that may

effect data Shade from trees or buildings Night light from street lights


Tower 10 x the distance of the height of obstruction (tree drip line, buildings) May not be ideal location due to:

Security Access Power Accessible

Reference: EPA Quality Assurance Handbook for Pollution Measurement Systems: Volume IV Meteorological Measurements


Three Type of Met Towers 10 meter height (30 feet) Grounding kit Lowering clearance free of electrical lines Set hinge base correctly for lowering Concrete base or attach to structure and/or guy

wiring. Secure kids from climbing tower

1. Free Standing Tower Popular Needs clearance for lowering down Pre-plan for location of base tower

Courtesy: Aluma Tower Company Inc.


2. Telescoping Tower No clearance for lowering

Tower stay in vertical position Top sections lowers into lower

section Hand or Electrical Winch

Parts for winch

Courtesy: Aluma Tower Company


3. Tri-pod Tower Quick setup Guy wiring and secure footing Mobile

Gila River has a 10 meter tripod on roof of school library. Couldn’t secure footing on roof.

Courtesy: NovaLynx


Data Loggers ESC

AC source, use in temperature control environment

Voltage Input Card Met Card

Tipping bucket, Sensor power source Campbell

DC source, use in outside ambient temperatures

Good for solar panels Retrieve data

Download data on laptop computer w/ RS-232 cable. Phone line w/ modem, Wireless, Satellite


Sine wave 0 – 1 Volt etc. Pulse wave Resistance Voltage

0 – 1 Volt etc.


Calibration equipment Vane Torque Gauge

Checks for wear on wind direction sensor bearing

Propeller Torque Disc Checks for wear on speed

sensor bearings Also used for Cup assay

sensors


Calibration equipment Anemometer Drive

Wind-speed calibrator (RPM) Used for propeller and cup assay

sensor Annual calibration traceable to

NIST (National institute of Standard and Technology)

Vane Angle Stand Set points of degree angles Airfoil vane requires another

angle bench


Calibration /verification of Sensors (manufacturer recommends annual or 6 months) Wind-speed sensor

7-point checks Wind-direction sensor

5-point checks


Temperature Sensor Wet Bath 3 point check

Ambient Temperature Hot water Temperature Cold water TemperatureBe aware combination RH/Temp sensor can not be submerge in water

Relative Humidity Sensor Micro-Bath /Dry Cal Salt solutions

Chamber (very expensive)


Precipitation gauge Verification equipment

Measured container or burette with Stand and nozzle squeeze container. Distill water (tap water causes residue)

In Clean rain bucket and screen(s) several times a year

Dirt, Leaves & Insects


Barometric Pressure Sensor Digital Pressure device

1 point ambient pressure reading

Precipitation Rain Bucket Check level of bucket Measured amount of distill water

Graduated cylinder Burette w/ stand & nozzle squeezable bottle

Solar Radiation Sensor Clean sensor of debris Cover and Uncover sensor


For cold climates sensor have internal heaters Maintenance

Clean sensors: direction vane, speed propeller or 3 cups assembly and temperature shield housing

Replace bearings and worn parts Lubricate rubber rings

Tighten connectors to sensors to prevent moisture damage

Check for crack lines Check guy wires and tighten bolts Tighten connectors to cross-arm shields and sensors


Documentation Site log book Personal log book Site check list Calibration & audit forms Repair forms Purchase-order forms Ship for certification and/or repairs Shipping receipts Disposition forms etc…


Recommendation Have some experience in Excel, Word, carpentry, electronics

and electricity Vendors to calibrate equipment and/or repair Purchase equipment similar to surrounding agencies

and tribal air programs For troubleshooting tips Audits

Items to have: Basis set of tools Digital multi-meter & 16 -14 gauge wiring Computer Conversion software Ty-wrap to secure cables Tap in monitor or sampler to collect certain data Solder

Pictures courtesy of: ESC, Met One, RMYoung, Cambell, Climatronics and SRMPIC.


Purchase calibration equipment to calibrate sensors

Have spare sensors and parts ready

Review operational and service manuals

If you have questions call tribes, state, county TAMS

for technical help

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