Davis Instruments DWW6351 Manuale Utente
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.
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.
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.
Humidity
that 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.
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.
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.
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.
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.
from plants 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
Severe Gale
54 - 63 mph; (86.9 - 101.4 kph)
10
Storm
63 - 73 mph; (101.4 - 117.5 kph)
11
Violent Storm
73 mph or above; (117.5 kph)
12
Hurricane