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GroWeather System Overview
Page 6 GroWeather Manual
W
EATHER
C
ONDITIONS
M
EASURED
/C
ALCULATED
This section outlines each of the weather conditions measured/calculated by
the GroWeather. Each section includes a brief discussion of the weather condi-
tion and a listing of the various ways in which the unit displays or stores that
condition. Be aware that some of the weather conditions require an optional
sensor in order to measure/calculate a value (see “Optional Sensors” on
page 2).
Values which are described as “Daily” readings will provide true daily read-
ings only if they are cleared each day. You may clear these values yourself or
use AutoClear (see “AutoClear” on page 13) to clear them for you. If you do
not clear the values every day, you may use the “daily” readings to represent
any interval you desire: two days, one week, one month, etc. See “Period” on
page 12 for information on readings which are described as being for the
“period.”
The notation “(AutoClear)” next to a weather condition indicates that the
GroWeather’s AutoClear function may clear the weather condition at a set time
every day. For information on AutoClear, see “AutoClear” on page 13.
The notation “(Alarm:)” next to a weather condition indicates that an alarm
exists for the weather condition. The type of alarms are noted after the colon.
For information on Alarms, see “Alarms” on page 14.
EvapoTranspiration (ETo)
EvapoTranspiration (ETo) 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 for the area. Effectively,
ETo is the opposite of rainfall, and it is expressed in the same units of measure
(Inches, millimeters).
The GroWeather uses air temperature, relative humidity, wind run, and solar
radiation data to estimate ETo, the reference evapotranspiration based on a
standard turf model. The actual ETo calculations are performed by the
GroWeatherLink ET/Data Logger. (ETo is calculated once an hour on the hour.)
To calculate and display crop-specific ETc, you will need the GroWeatherLink
Software as well. See “Optional Accessories” on page 2 for more details.
• “Daily” ETo Sum (AutoClear) (Alarm: High)
• Total ETo for the period (Alarm: High)
• Average ETo per day over the period