Davis Vantage Pro2+ Instruments

About the ASRC Weather Station's sensor suite



The radiometer measures the "sunburn " portion of the EM spectrum (290 to 390nm). The spectral response is closely matched to the Erythema Action Spectrum, defined by McKinlay and Diffey (1987) and internationally recognized as the radiation that is most responsible for causing redness of the human skin.
The radiometer is useful for quantifying the amount of harmful radation. Data gathered from this sensor allows for occupants of an area to adequately use sun protection for sunny days. A radiometer is especially useful for monitoring UV radiation in regions where the ozone layer is not as effective, such as the Southern regions of South America.

Pyranometer Spec Sheet

Operating Temperature
Storage Temperature
Spectral Response
Supplied Cable Length
Cable Type
I/O Specs
Green wire
Black & Red wires
Yellow wire
Housing Material
Dimensions (length x width x height)

-40° to +150° F (-40° to +65° C)
-50° to +158°F (-45° to +70°C)
Semiconductor photodiode
280 to 360 nm (Erythema Action Spectrum)
±4% FS (0° to 90° zenith angle)
2' (0.6 m)
4-conductor, 26 AWG
Modular RJ-11
Output (0 to 2.5VDC); 150 mV per UV Index, 364 mV per MED/hour
+3V ±10%, 2.4 mA
UV-resistant ABS plastic
2” x 2.75” x 2.25” (51 mm x 70 mm x 57 mm)
0.5 lbs. (226 g)

Ultra Violet (UV) Radiation Dose
Resolution and Units
Update Interval
Ultra Violet (UV) Radiation Index
Resolution and Units
Cosine Response

0.1 MEDs to 19.9 MEDs; 1 MED above 19.9 MEDS
0 to 199 MEDs
±5% of daily total
up to ±2% per year
50 seconds to 1 minute (5 minutes when dark)

0.1 Index
0 to 16 Index
±5% of full scale (Reference: Yankee UVB-1 at UV Index of 10 [extremely high]) plus 0.5 UV Index per 100' (30 m) of additional cable
±4% FS (0° to 90° zenith angle)

UV Sensor


The pyranometer detects solar radiation at wavelengths of 400nm to 1100nm. It is a type of actinometer which measures solar irridiance, the solar radiation flux density (W/m^2) using a silicon photodiode trasnducer.
Pyranometer originates from Greek language, meaning "Fire from above ". It is used to quantify solar radiation and can be useful for comparing vegetation growth to amount of avaiable sun light, area heating due to radiation absorption, etc.

Radiation Sensor Spec Sheet

Operating Temperature
Spectral Response (10% points)
Cosine Response Percent of Reading
Percent of Full Scale
Temperature Coefficient
Reference temperature
Correction per degree above reference temp
Correction per degree below reference temp
Housing Material
Dimensions (Length x Width x Height)

-40° to +150° F (-40° to +65° C)
Silicon photodiode
400 to 1100 nanometers
±3% (0° to ±70° incident angle); ±10% (±70° to ±85° incident angle)
±2% (0° to ±90°)
+0.067% per °F (+ 0.12% per °C)
77°F (25°C)
-0.067% of reading per °F (-0.12% per °C)
+0.067% of reading per °F (+0.12% per °C)
UV-resistant PVC plastic
2.00” x 2.75” x 2.25” (51 mm x 70 mm x 57 mm)
0.5 lbs. (226 g)

Resolution and Units
Update Interval

1 W/m2
0 to 1800 W/m2
±5% of full scale (Reference: Eppley PSP at 1000 W/m2) plus 45 W/m2 per 100' (30 m) of additional cable
up to ±2% per year
50 seconds to 1 minute

UAnemometer and Wind Vane

Anemometer and Wind Vane

Wind Vane and anemometer The wind vane and anemometer are paired together as one unit. Mounted above the integrated sensor suite (ISS). The wind vane indicates the direction which the wind blows. The anemometer measures wind speed. The combination of these two sensors allow for rose plots of wind direction and speed, plots of transient wind speed as well as visualizing wind gusts during a storm.

Anemometer and Wind Vane Spec Sheet

Operating Temperature
Wind Speed
Wind Direction
Display Resolution
Percent of Full Scale
Wind Vane Accuracy
Resolution & Units
Anemometer Accuracy

-40° to +149° F (-40° to +65° C)
Solid state magnetic sensor
Wind vane and potentiometer
16 points (22.5°) on compass rose, 1° in numeric display
±3°Wind Speed
Measured in 1 mph. Other units are converted from mph and rounded to nearest 1 km/h, 0.1 m/s, or 1 knot
1 to 200 mph, 1 to 173 knots, 0.5 to 89 m/s, 1 to 322 km/h
±2 mph (2 kts, 3 km/h, 1 m/s) or ±5%, whichever is greater

Temperature and Humidity Sensor

Temperature and Humidity Sensor

The temperature and humidity sensor of the Vantage Pro+ 2 comes in one unit. The termperature sensor is a platinum wire thermistor and humidity sensor uses a film capacitor element. A thermistor experiences a change in electrical resistance during temperature change. This change in resistance can be detected and converted to temperature. The humidity sensor uses a thin strip of metal oxide between two electrodes, the metal oxide experiences a change in electrical resitance as moisture levels increase. The measurement is relative and linear and will go from 0% to 100%.

Temperature and Humidity Spec Sheet

Relative Humidity
Housing Material

Platinum wire thermistor
Film capacitor element
White ABS with UV Inhibitor added
3.5" wide x 3.25 " long x 1.5" high (89 mm x 83 mm x 38 mm)
15 oz. (425 g)

Temperature Range
Relative Humidity
Dew Point
Temperature Accuracy
Relative Humidity Accuracy
Dew point Accuracy
Temperature Resolution
Relative Humidity Accuracy
Dew Point Accuracy
Temperature Update Interval
Relative Humidity Update Interval

-50° to 140° F (-45° to 60° C)
-99° to 140° F (-73° to 60° C)
±1°F (±0.5°C)
±3%, from 0 to 90% RH, ±4% from 90% to 100% RH
±4°F (±2°C)
1.0° or 0.1°, selectable, F or C
1°F (1°C)
16 seconds (max)
16 seconds (max)

Tipping  Bucket

Rain Collector

The rain collector unit measures rainfall using a tipping bucket. For the use of the ASRC weather station, the tipping bucket used is the metric version as it has greater precision due to its smaller container size increased frequency of measurement.

Rain Collector Spec Sheet

Sensor Type

Tipping bucket with magnetic switch
For rain rates up to 4"/hr (100 mm/hr): ±4% of total or ± 1 tip of the bucket (0.01"/0.2 mm), whichever is greater