Soil Temperature Hours; Temperature/Humidity Hours; Air Density; Equilibrium Moisture Content (Emc) - DAVIS WeatherLink Software User's Manual

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Weather Data Calculations

Soil Temperature Hours

Soil temperature hours may be used to monitor the relative portion of time that
soil temperature is above freezing (or some other threshold) in order to select a
time to plant. For more information, contact your local agricultural agent or uni-
versity agricultural extension.

Temperature/Humidity Hours

Certain pests (in particular, some molds) develop most aggressively under spe-
cific combinations of temperature and humidity. Each pest can be expected to
emerge when a specific number of temperature/humidity hours has accumu-
lated. Temperature/Humidity hours, therefore, can be used to select the optimum
time for application of preventative measures. The use of pesticides can be mini-
mized and, when needed, used more efficiently and effectively. For more informa-
tion, contact your local agricultural agent or university agricultural extension.

Air Density

Air Density (the weight of 1 cubic foot of air) is an extremely valuable tool for rac-
ing enthusiasts, because it helps determine the optimal jetting under current
weather conditions.

Equilibrium Moisture Content (EMC)

Moisture content in wood affects both the size and strength of lumber. If one
knows the EMC of the storage or manufacturing area (which is derived using
temperature and humidity readings), one can also determine the moisture content
of the wood stored there.

Bad Data

Should a sensor get disconnected or malfunction, the software displays any "bad
data" recorded by that sensor as dashes (--). When you create a plot, the software
ignores "bad data," and skips that point on the plot. You may enter dashes (--)
into the database using the database record editor (see "Edit a Record" on
page 61) to mark bad data points as well.
Note: A dashed wind direction reading does not indicate bad data. See "Wind Direction" on page 95
for an explanation.
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