Davis Instruments Vantage Pro2 User Manual

46
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 surfaces) with the amount of water vapor returned through transpiration
(exhaling of moisture through plant stomata) to arrive at a total. Effectively, ET is the
opposite of rainfall, and it is expressed in the same units of measure (inches, millime-
ters).
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 & Transmitting Stations” 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/Temperature 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 mois-
ture reading means wetter soil. Soil Moisture requires an optional Leaf & Soil Mois-
ture/Temperature Station or Soil Moisture Station and is only available for Wireless
Vantage Pro2 Stations.
Time
The console has a built-in clock and calendar track the time and date. It automatically
adjusts for daylight saving time in most of North America and Europe (and allows
manual adjustment elsewhere) and for leap years, providing you have entered the cor-
rect year, latitude and longitude, and daylight saving settings in the Setup Mode.
T
ABLE A-3: UV INDEX
Index Values Exposure Category
0 - 2 Low
3 - 4 Moderate
5 - 6 High
7 - 9 Very High
10+ Extreme

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