La Crosse Technology WS-2510 manual Technical data, Explanation of terms

9.	Technical data
Measuring interval:		approx.3 min
Transmission frequency:		433.92 MHz
Free field range:		max.100 m
Indoor temperature range:		-30.0ºC to +70ºC
External temperature range:		-30.0ºC to +70ºC
Resolution:		0.1ºC
Accuracy:		.±1ºC
Measuring range relative humidity:		20%- 95%
Resolution:		1%
Accuracy:		8%
Air pressure measuring range:		800 to 1100 hPa
Resolution:		1 hPa
Accuracy:		±1 hPa
Rainfall indicator:		0 to 3,999 mm
Resolution:		<0.5 mm
Accuracy:		2 % ±1 mm
Brightness display:		0 to 200000 lux

Resolution: up to 1 klux:1 lux;up to 10 klux:10 lux;up to/above 100 klux: 0.1/1 klux;

Accuracy:		±10% ±4Digit
Sunshine duration:		0 to 9999 h
Resolution:	up to 100 h:1 min;up to 999 h:1/10 h;above 1000 h:1 h
Wind speed:		0 -200 km/h
Resolution:		0.1 km/h
Accuracy:		3 %±1km/h
Wind direction:	graphical resolution 22.5º,numerical resolution 5 degrees
Voltage supply:		4 “C” cell alkaline batteries
..................................................................		Plug-in power supply 7.5 V/500 mA
Dimensions (W x H x D):		Housing: 10.1” x 8.3” x 1.4” (257 x 211 x 36 mm)

10.Explanation of terms

WWVB -WWVB is a time signal sensor, operating on the long wave with a range of approx. 2000 miles. It is located at Ft. Collins, Co. The sensor transmits a time signal that is provided by the NIST atomic clock located in Boulder, CO, which has a time deviation of less than 1 second in 1 million years. Astronomical related time corrections, leap years and date changes are automatically implemented by time transmissions.

Perceived temperature -see Wind chill

Dewpoint -Temperature point that is dependent on the conjunction of a specific air pressure, a specific temperature and a specific humidity. At this temperature, the humidity in the air begins to condense, the so-called dew point, the humidity in the air condenses and precipitates as a liquid (fog, steam and even spots of mildew on walls). If the dew point for water vapor is less than 32ºF, the condensation occurs as snow or frost.

Air pressure tendency -Calculated from recent developments in air pressure values.

Absolute/relative air pressure -The air in the Earth ’s atmosphere has a specific gravity, which is defined in grams per liter. The boundary of the Earth’s atmosphere is of a (relatively) constant size. In contrast to this, the surface of the earth including the oceans varies between the lowest sea level and the highest mountain peaks.

As a result of this, a different “weight” of air acts on every area depending upon the mean height above sea level and the height of the column of air above the measuring point. The air pressure at sea level is therefore considerably higher than that in the Himalayan peaks.

In order to provide a reference quantity, in most cases, weather reports either give the absolute air pressure referred to mean sea level (general information, say for a country) or, in the case of more accurate reports, the graduated air pressure represented by means of isobars (the air pressure lines on more accurate weather maps).

In the latter case, one can easily recognize the trend of the air pressure fronts and can find out more about the path of the fronts.

However, as the weather station always measures the absolute air pressure at its location, a correction factor must be defined, which makes it possible to display the difference between absolute and relative air pressure. This is achieved (with this weather station) by entering the accurately known local air pressure (either as notified by the local

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