Oklahoma Mesonet Stations

Oklahoma Mesonet sites collect observations of soil and atmospheric variables at intervals between 5 and 30 minutes. For more information about the Oklahoma Mesonet station instruments and measurements, please click here.

OKCnet Traffic Signal Stations

The standard variables collected at OKCnet traffic signal stations include:

  • air temperature measured at approximately 9 meters above the ground,
  • relative humidity measured at approximately 9 meters above the ground,
  • wind speed and direction measured at approximately 9 meters above the ground,
  • barometric pressure, and
  • rainfall

Air temperature, relative humidity, pressure, and rainfall are sampled every 3 seconds while the wind measurements are sampled four times per second. All samples are averaged over a 1-minute interval and sent from the site to the Central Operations Facility in Norman.

Sensor Overview

The Oklahoma City Micronet utilizes the Vaisala WXT510 multi-parameter weather transmitter as its source for meteorological measurements. The sensor package is compact and light weight, has no moving parts, and uses very little power, while still providing research quality data. Each WXT510 consists of three main parts:

  • a PTU module for measuring temperature, humidity, and pressure,
  • a WindCap sensor for measuring wind speed and direction, and
  • a RainCap sensor for measuring precipitation.

Instruments

Instrument Categories:

Temperature, Humidity, and Pressure Measurements

TAIR

The 1-minute average air temperature.

Units Range Resolution Manufacturer Accuracy Expected Field Accuracy
Degrees Celsius -52°C to 60°C 0.1°C ±0.3°C up to ±1°C in light winds and strong radiation

RELH

The 1-minute average relative humidity. Because of the sorption sensor's inherent inaccuracy at saturation, the Oklahoma City Micronet restricts all readings above 100% to 100%.

Units Range Resolution Manufacturer Accuracy Expected Field Accuracy
Percent 0 to 100% 0.1% ±3% (for 0 to 90%)
±5% (for 90 to 100%)		 ±3% (for 0 to 90%)
±5% (for 90 to 100%)

PRES

The average station pressure during the last 1-minute interval.

Units Range Resolution Manufacturer Accuracy Expected Field Accuracy
Millibars 600 to 1100 mb 0.1 mb (at -52 to 60°C)

±0.5 mb (for 0°C to 30°C)

±1.0mb (for -52°C to 0°C and 30°C to 60°C)

±0.5 mb (for 0°C to 30°C)

±1.0mb (for -52°C to 0°C and 30°C to 60°C)

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Wind Measurements

WSPD

The 1-minute average wind speed using 4 Hz sonic data.
  • The average wind speed is independent of the wind direction.
  • When WSPD is zero, all other wind variables are set to zero.
Units Range Resolution Manufacturer Accuracy Expected Field Accuracy
Meters per second 0 to 60 m/s 0.1 m/s

±0.3 m/s or ±3% (whichever is greater)
for 0 to 35 m/s

±5% for 36 to 60 m/s

±0.3 m/s or ±3% (whichever is greater)
for 0 to 35 m/s

±5% for 36 to 60 m/s

WVEC

The average wind velocity (speed and direction are accounted for).
  • Note that this is a vector average (i.e., the wind direction is considered). If the wind is out of the north at 10 m/s for 30 seconds and then out of the south at 10 m/s for 30 seconds, the average vector wind velocity will be zero during that 1-minute period.

WDIR

The vector average wind direction. Note: wind direction always describes the direction from which the wind is blowing.
  • When WSPD is zero, all other wind variables are set to zero.
Units Range Resolution Manufacturer Accuracy Expected Field Accuracy
Degrees 0° to 360° 1° ±3° ±3°

WDSD

The standard deviation of the wind direction.
  • This variable is a measure of the steadiness of wind direction. A small standard deviation indicates the wind is blowing from the same direction; a large standard deviation indicates significant changes in wind direction during the 1-minute interval. The standard deviation may be large for either inclement weather or relatively light winds.

WSSD

The standard deviation of the wind speed.
  • This variable is a measure of the steadiness of wind speed. A small standard deviation indicates the wind generally blowing at the same speed; a large standard deviation indicates significant changes in wind speed during the 1-minute interval. The standard deviation may be large for inclement weather.

WMAX

The maximum (or peak) - second wind speed observed during a 1-minute interval. It is the largest value observed during the 1-minute averaging interval.
  • WMAX is independent of wind direction.
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Precipitation Measurements

RTOT

The total amount of rainfall measured since 0000 UTC at instrument height.

Units Range Resolution Manufacturer Accuracy Expected Field Accuracy
Millimeters NA 0.01mm within 5% ±5 mm

RINT

The rainfall intensity calculated from the last 60 seconds worth of rainfall measurements. The units are millimeters per hour.

HINT

The hail fall intensity calculated from the last 60 seconds worth of hail fall measurements. The units are hits per centimeter squared per hour.

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Site Variables

Data collected every 1 minute from the Oklahoma City Micronet contains the following values.

Label Parameter Sensor
TAIR Air Temperature (°C) PTU
RELH Relative Humidity (%) PTU
PRES Barometric Pressure (mb) PTU
WSPD Avg. Wind Speed (m/s) WindCap
WVEC Wind Vector (m/s) WindCap
WDIR Avg. Wind Direction (°) WindCap
WDSD Wind Direction Std. Deviation (°) WindCap
WSSD Wind Speed Std. Deviation (m/s) WindCap
WMAX Max. Wind Speed (m/s) WindCap
RTOT Rain Accumulation since 00 UTC (mm) RainCap
RINT Rain Intensity (mm/hr) RainCap
HINT Hail Intensity (hits/(cm^2 hr)) RainCap

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