Davis Instruments 6152C manual Evapotranspiration ET, Leaf Wetness, Soil Moisture

TABLE A-3: UV INDEX

Index Values	Exposure Category
0 - 2	Low
3 - 4	Moderate
5 - 6	High
7 - 9	Very High
10+	Extreme

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.

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