Weather Conditions Measured/Calculated
Vantage Pro Manual
Page 53
It is important to realize that relative humidity changes with temperature, pres-
sure, and water vapor content. A parcel of air with a capacity for 10 g of water
vapor which contains 4 g of water vapor, the relative humidity would be 40%.
Adding 2 g more water vapor (for a total of 6 g) would change the humidity to
60%. If that same parcel of air is then warmed so that it has a capacity for 20 g
of water vapor, the relative humidity drops to 30% even though water vapor
content does not change.
Relative humidity is an important factor in determining the amount of evapo-
ration from plants and wet surfaces since warm air with low humidity has a
large capacity for extra water vapor.
Dew-Point
Dew-point is the temperature to which air must be cooled for saturation (100%
relative humidity) to occur, providing there is no change in water content. The
dew-point is an important measurement used to predict the formation of dew,
frost, and fog. If dew-point and temperature are close together in the late after-
noon when the air begins to turn colder, fog is likely during the night. Dew-
point is also a good indicator of the air’s actual water vapor content, unlike rel-
ative humidity, which takes the air’s temperature into account. High dew-
point indicates high vapor content; low dew-point indicates low vapor content.
In addition a high dew-point indicates a better chance of rain and severe thun-
derstorms. You can even use dew-point to predict the minimum overnight tem-
perature. Provided no new fronts are expected overnight and the afternoon
Relative Humidity
≥
50%, the afternoon’s dew-point gives you an idea of what
minimum temperature to expect overnight, since the air is not likely to get
colder than the dew-point anytime during the night.
Rainfall
Vantage Pro provides four separate registers for tracking rainfall totals: “rain
storm”, “daily rain”, “monthly rain”, and “yearly rain”. The Vantage Pro also
calculates the rate of rainfall by measuring the interval of time between each
.01 in or 0.254 mm rainfall increment. Vantage Pro physically measures incre-
ments of 0.01 in. If you display in mm, the console converts from inches to mm.
If you display millimeters, you may occasionally see the counter skip a reading
due to rounding.
Summary of Contents for and Vantage Pro
Page 6: ...Page 6 Vantage Pro Console Manual ...
Page 10: ...Welcome to Vantage Pro Page 10 Vantage Pro Console Manual ...
Page 16: ...Console Installation Page 16 Vantage Pro Manual ...
Page 18: ...Console Installation Page 18 Vantage Pro Manual ...
Page 44: ...Using the Console Page 44 Vantage Pro Console Manual ...
Page 63: ...Vantage Pro Manual Page 63 ...