Bramwell Brown Barometric Weather Clock, Инструкция по эксплуатации и руководство пользователя

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10
Forecasting the Weather with a
Barometer
The traditional barometers of old required a certain degree
of familiarity and regular observation to be used accurately.
This is because it is not the absolute value of the air
pressure at any given moment that matters, but the amount
and direction in which it changes.
Your own Weather Clock contains a nifty electrical
barometer that calculates the rate of change in atmospheric
pressure. It therefore does more than a traditional
barometer, monitoring the changes and their rapidity for
you – translating these into forecasts. This means that what
you see in the mechanically animated sky should, more
often than not, be what you get when you step outside in
the following few hours.
Large, swift changes in pressure usually lead to significant
changes in the weather. Fast drops in atmospheric pressure
often result in unsettled weather and rapid rises are
associated with improving conditions and clearing skies.
Whilst there is nothing else at all that affects the clock’s
weather scenery movements apart from changing air
pressure, other variables such as temperature and humidity
do also have an important part to play in modern weather
forecasting. Barometers (and air pressure), therefore, have
always been more often used as a simple and convenient
guide to changing conditions. For example, the air pressure
in the clock’s location could drop, leading it to change
its display to ‘Rain’. The rain may not, though, arrive at
that moment or in the subsequent hours or days if other
meteorological factors are at play such as temperature and