Airmar PB100 Technical Information PDF herunterladen (Seite 54)

About the Air Temperature Sensor

The WeatherStation includes a built-in negative temperature coefﬁcient thermistor

that measures the ambient air temperature. This NTC thermistor is located in a

thermally isolated region of the WeatherStation housing that is open to the

outside air.

About the Relative Humidity Sensor

The WeatherStation contains a capacitive cell humidity sensor that measures the

relative humidity of the air. Humidity refers to the amount of water vapor in the air.

Relative humidity is the percentage of saturation of the water vapor in the air. It is

the ratio of the moisture content of the air to the saturated moisture level at the

same temperature and pressure.

About Dew Point

Dew point is the temperature at which the water vapor in the air begins to

condense into a liquid. If the air were gradually cooled while maintaining constant

moisture content, the relative humidity would rise until it reaches 100%. The air

temperature at this point of saturation is called the dew point.

If the air is dry enough, it is possible to have a dew point that is below freezing.

The dew point is then sometimes referred to as the frost point.

The WeatherStation calculates dew point from the measured air temperature and

relative humidity sensor readings.

About Wind Chill Temperature

Wind Chill is a term that describes the heat loss on the human body resulting from

the combined effects of low temperature and wind. As wind speed increases, heat

is carried away from the body at a faster rate, causing a reduction in skin

temperature. Because the face is the part of the human body that is most likely to

be exposed, the wind chill index is adjusted for the average adult face.

The concept of wind chill does not apply to inanimate objects, such as a boat. The

only effect that wind chill has in this case is to shorten the time it takes the object

to cool to the actual air temperature––wind chill does not cause an object to cool

below that temperature. For example, fresh water freezes at 0°C (32°F)

regardless of what the wind chill is.

The WeatherStation calculates two values for wind chill temperature: one using

the apparent wind speed, and one using the true wind speed. The

apparent

wind

chill temperature is relevant to what an observer is currently experiencing on the

vessel. The

true

wind chill temperature indicates what the wind chill would be if the

vessel were not moving.

Wind chill temperature is only deﬁned for temperatures at or below 10°C (50°F)

and wind speeds above 2.6 knots (3MPH).

By default, transmission of wind chill data is disabled by the WeatherStation.

When used with WeatherCaster, the wind chill data will be automatically enabled.

1 2 ... 49 50 51 52 53 54 55 56 57 58 59 60

Kommentare zu diesen Handbüchern

Keine Kommentare

Airmar PB100 Technical Information Seite 54

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Wetterstationen Airmar PB100