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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 (exhal-
ing 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 measure (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/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 vac-
uum 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 automati-
cally adjusts for daylight savings time in North America, Europe and Australia
(and allows manual adjustment elsewhere) and for leap years.
T
ABLE
A-3: UV I
NDEX
Index Values
Exposure Category
0 - 2
Low
3 - 4
Moderate
5 - 6
High
7 - 9
Very High
10+
Extreme
