Davis Instruments Vantage Pro2 Console Manual

48
Evapotranspiration (ET)
Evapotranspiration (ET) is a measurement of the amount of water vapor
returned to the air in a given area. It combines the amount of water vapor
returned through evaporation (from wet vegetation surfaces and the stoma
of leaves) with the amount of water vapor returned through transpiration
(exhaling of moisture through plant skin) to arrive at a total. Effectively,
ET is the opposite of rainfall, and it is expressed in the same units of mea-
sure (Inches, millimeters).
The Vantage Pro2 uses air temperature, relative humidity, average wind
speed, and solar radiation data to estimate ET, which is calculated once an
hour on the hour. ET requires the optional solar radiation sensor.
Leaf Wetness
Leaf wetness (see “Optional Sensors” on page 2) provides an indication of
whether the surface of foliage in the area is wet or dry by indicating how
wet the surface of the sensor is. The leaf wetness reading ranges from 0
(dry) to 15. Leaf wetness requires an optional Leaf & Soil Moisture/Tem-
perature Station and is only available for Wireless Vantage Pro2 Stations.
Soil Moisture
Soil Moisture, as the name suggests, is a measure of the moisture content
of the soil. Soil moisture is measured on a scale of 0 to 200 centibars, and
can help choose times to water crops. The soil moisture sensor measures
the vacuum created in the soil by the lack of moisture. A high soil moisture
reading indicates dryer soil; a lower soil moisture reading means wetter
soil. Soil Moisture requires an optional Leaf & Soil Moisture/Temperature
Station or Soil Moisture Station and is only available for Wireless Vantage
Pro2 Stations.
Time
A built-in clock and calendar track the time and date. The console automat-
ically adjusts for daylight savings time in North America, Europe and Aus-
tralia (and allows manual adjustment elsewhere) and for leap years.
TABLE A-3: UV INDEX
Index Values Exposure Category
0 - 2
Low
3 - 4 Moderate
5 - 6 High
7 - 9 Very High
10+ Extreme
07395.234 Manual VP2 console Book.book Page 48 Wednesday, November 17, 2004 3:57 PM

Davis Instruments Vantage Pro2 Specifications

General

Update Interval	2.5 seconds
Wind Direction Resolution	1°
Wind Direction Range	0 to 360°
Rain Collector	Self-emptying tipping bucket
UV Index Range	0 to 16
Solar Radiation Range	0 to 1800 W/m²
Console Display	LCD with backlight
Wireless Transmission Range	1000 feet (300 meters) line of sight
Temperature Range	-40 to 150 °F (-40 to 65 °C)
Humidity Range	1 to 100%
Barometric Pressure Range	16.00 to 32.50 inHg (540 to 1100 hPa)
Wind Speed Range	0 to 200 mph (0 to 322 km/h)
Rain Collector Size	0.01 inch (0.2 mm) resolution
Rain Measurement Accuracy	±4% at rates up to 2 in/hr (50 mm/hr)
Power Supply	Solar-powered with battery backup
Console Power Supply	AC adapter or 3 C batteries