MET3A METEOROLOGICAL SYSTEM

NEW SOLAR RADIATION TEST REPORT in Temperature Section

• Pressure Accuracy ±0.08 hPa from 620 to 1100 hPa 
• Temperature Accuracy ±0.1 deg C from -50 to +60 deg C
• Relative Humidity Accuracy ±2 Percent from 0 to 100 %RH at 25 deg C. 
• Rapid Humidity Recovery Time after Saturation.

• Weatherproof Enclosure
• Fan Aspirated Probe System
• High Performance Pressure Port
• RS-232 Bi-Directional Interface
• NEW Instrument Status LED Indicators (Power, Transmit, Receive)
• 3 Year Warranty on Barometer Stability
• NIST Traceable - ISO 9001:2000 Quality System
  CE Certified

• GPS Meteorology
• Environmental Monitoring
• Laboratory and Field Portable Calibrators
• Automated Surface Observation Systems
• Ground Based Altimeter Setting Indicators

The MET3A is a Fan-Aspirated Meteorological Measurement System that provides high accuracy data from barometric pressure, temperature, and relative humidity sensors. Pressure resolution is better than 1 microbar with a total accuracy of 0.08 hPa over the extended barometric range of 620 to 1100 hPa. Temperature resolution is 0.01 degree C with a total accuracy of 0.1 degree C over the full temperature range of –50 to +60 degrees C. Relative humidity performance is better than 2% at 25 degrees C and the recovery time after 100% RH saturation is less than 2 minutes.   

Atmospheric pressure is measured with a Paroscientific Digiquartz^® Barometer that features better than 1 microbar resolution and an accuracy of 0.08 hPa over the extended barometric range of 620 to 1100 hPa. The barometers are fully thermally compensated with an internal quartz crystal temperature sensor over the calibrated temperature range of –50 to +60 degrees C. 

A high-performance, tuned, dual-pressure-port arrangement minimizes dynamic pressure errors due to wind.  Click here for NEW TEST REPORT. The static pressure port is engineered to provide barometric accuracy of better than 0.08 hPa in strong winds (up to 40 knots), all wind directions, rain, and freezing conditions.

Pressure hysteresis has been measured to be less than 8 parts per million of full scale (0.008 hPa). To review the Barometer Hysteresis Report, click here.   

Ambient temperature is measured with an external, 1000 ohm, precision thin-film platinum Resistance Temperature Detector (RTD). The Fan-Aspirated MET3A draws outside air past the RTD and the electronics linearize and output the temperature signals on the RS-232 interface. Temperature resolution is better than 0.01 degree C and temperature accuracy is better than +/-0.1 degree C over the full range from –50 to +60 degrees C.

The fan-aspirated MET3A offers 5 to 7 times better accuracy than non-aspirated systems.

Considerations of aspirated systems and solar radiation effects are discussed in the report "Design and performance of MET3A Fan-Aspirated Temperature Probe System".  Click here for NEW TEST REPORT.

Temperature testing of the three MET3A qualification units showed that all points were within +/- 0.05 degree C of the reference standard for three cycles from –50 to +60 degrees C. The MET3A temperature sensor is mounted in an isothermal mass that maintains thermal equilibrium with the reference standard during calibration and conformance testing. Traceable accuracy of the reference standard is +/-0.016 degree C. Results are shown below. 

Relative Humidity (RH) is measured with a monolithic IC capacitance humidity sensor. The Fan-Aspirated MET3A draws outside air past the RH Sensor and the electronics linearize, temperature compensate, and output the percent RH signals on the RS-232 interface. The accuracy of the RH Sensor at 25 degrees C is better than +/-2%. The aspirated system ensures rapid response times, even after prolonged periods at 100% saturation. As shown below, the response time for a step change in relative humidity of approximately 70% was less than 2 minutes.

To review the full MET3A RH Response Time Test Report, click here.

• Click here for MET3A data sheet
• Resonant Quartz Barometers
• GPS Meteorology ~ Measurement of Precipitable Water Vapor Using the MET3 Meteorological Measurement System and Global Positioning System Radio Signals
• Broadband Meteorological Sensors Co-located with GPS Receivers for Geophysical and Atmospheric Measurements (Click here for a slide presentation)
• Integrating Digiquartz® MET3 and MET3A Broadband Meteorological System with a GPS Receiver 
• Barometer Intercomparison Report
• Pressure Hysteresis Report
• Barometer Stability Report
• Design and performance of MET3A Fan-Aspirated Temperature Probe System
• MET3A RH Response Time Report
• Calculating Dew Point Using the MET3A
• Met3A to Met3 Feature Comparison Table
• Click Here to See Real-Time MET3A Weather Information at Paroscientific
• High Performance Pressure Port

©2007 Paroscientific, Inc.