Davis Instruments Vantage Vue Wireless Weather Station DAV-6250EU Data Sheet
Product codes
DAV-6250EU
44
Temperature
Beaufort Scale
The Beaufort Scale is an empirical measure for describing wind speed which ranks wind
speeds in classes. The Beaufort Scale classification for the current wind condition is listed in
the Weather Center when WIND is pressed and WxCEN is pressed several times. See “Wind
Speed and Direction” on page 17 for more information.
speeds in classes. The Beaufort Scale classification for the current wind condition is listed in
the Weather Center when WIND is pressed and WxCEN is pressed several times. See “Wind
Speed and Direction” on page 17 for more information.
Temperature
The ISS houses the outside temperature sensor in a vented and shielded enclosure that
minimizes solar radiation-induced temperature error. The console houses the inside
temperature sensor.
minimizes solar radiation-induced temperature error. The console houses the inside
temperature sensor.
Humidity
Humidity itself simply refers to the amount of water vapor in the air. However, the total
amount of water vapor that the air can contain varies with air temperature and pressure.
Relative humidity takes into account these factors and offers a humidity reading which reflects
the amount of water vapor in the air as a percentage of the amount the air is capable of
holding. Relative humidity, therefore, is not actually a measure of the amount of water vapor
in the air, but a ratio of the air’s water vapor content to its capacity. When we use the term
humidity in the manual and on the screen, we mean relative humidity.
amount of water vapor that the air can contain varies with air temperature and pressure.
Relative humidity takes into account these factors and offers a humidity reading which reflects
the amount of water vapor in the air as a percentage of the amount the air is capable of
holding. Relative humidity, therefore, is not actually a measure of the amount of water vapor
in the air, but a ratio of the air’s water vapor content to its capacity. When we use the term
humidity in the manual and on the screen, we mean relative humidity.
It is important to realize that relative humidity changes with temperature, pressure, and water
vapor content. If a parcel of air with a capacity for 10 g of water vapor 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.
vapor content. If a parcel of air with a capacity for 10 g of water vapor 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 evaporation from plants
and wet surfaces since warm air with low humidity has a large capacity to absorb extra water
vapor.
and wet surfaces since warm air with low humidity has a large capacity to absorb extra water
vapor.
Wind Speed
Beaufort
Number
Description
0 -1 mph; (0 -1.6 kph)
0
Calm
1-3 mph; (1.6 - 4.8 kph)
1
Light Air
3 - 7 mph; (4.8 - 11.3 kph)
2
Light Breeze
7 -12 mph; (11.3 - 19.3 kph)
3
Gentle Breeze
12 - 18 mph; (19.3 - 29.0 kph)
4
Moderate Breeze
18 - 24 mph; (29.0 - 38.6 kph)
5
Fresh Breeze
24 - 31 mph; (38.6 - 49.9 kph)
6
Strong Breeze
31 - 38 mph; (49.9 - 61.2 kph)
7
Near Gale
38 - 46 mph; (61.2 -74.1 kph)
8
Gale
46 - 54 mph; (74.1 - 86.9 kph)
9
Strong Gale
55 - 63 mph; (88.5 - 101.4 kph)
10
Storm
64 - 73 mph; (103.0 - 117.5 kph)
11
Violent Storm
74 mph or above; (119.1 kph)
12
Hurricane