Appendix A _________________________________________________________________ Glossary
VAISALA _______________________________________________________________________ 191
The temperature at which the air, if cooled, would reach saturation,
and at which dew would therefore begin to condense out on a solid
surface. The TD is calculated using the following formula:
15
.
273
b
2
a
c
b
c
TD
−
+
×
×
=
where
a
=
RH
100
ln
b
=
2711.5
TA
2.1
a
15.0
+
×
−
×
c
=
TA + 273.15
TA =
Actual air temperature [°C] measured by MAWS
Dew point
(temperature)
RH =
Actual relative humidity [%] measured by MAWS
DSI485A
Serial RS-485 communication module for MAWS.
DSU232
Serial RS-232 communication module for MAWS.
Global radiation
The total of direct solar radiation and diffuse sky radiation received
by a horizontal surface. Global radiation is measured by
pyranometers.
Gust
The peak momentary wind velocity within a given interval of time,
for example, 10 minutes. (V
max
-V
min
)/V
mean
.
Hexadecimal
Numbering system using the base number 16 and including the ten
decimal digits (0 to 9) along with six alpha digits (A to F).
Humidity
The water vapor content of the air. Weather station sensors
commonly measure relative humidity. Relative humidity is the ratio
of water vapor pressure present in a gas (P
w
) to the maximum
pressure of water vapor that could be present in the gas in that
temperature [P
ws
(t)].
%RH = 100 x P
w
/ P
ws
(t)
LED
Light Emitting Diode
Logger
The processing unit of the MAWS weather station. The electronics
of the logger take care of measuring, storing, and processing of the
measured quantities.
Logging
The process of storing the measured and calculated values in the
logger's memory.
