humidity. An open pine cone means dry

forestsaintregisΠετρελαϊκά και Εξόρυξη

8 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Weather Forecasting


The Traditional Approach


Pine cones open and close according to air
humidity. An open pine cone means dry
weather.


Ash leaf before oak, then we shall have a summer
soak


Red sky at night, shepherd’s delight.






60 seconds

How many of these data collection methods
can you remember?

Data Collection and Analysis


Over 10,000
surface stations

collect data
²

these
include weather ships and automatic buoys at sea and
manned and automated stations on land.



Radiosondes and aircraft collect data in the upper
air
.
Wind profilers and radar monitor changes lower down.



In
space,

polar satellites (NOAA), geostationary
satellites (meteosat) and operational environmental
satellites (GOES) measure and track weather systems.









Instruments used on the
surface include barometers,
anemometers and rain
gauges as well as visual
observations.

33 stations with observations
made every 3 hours.

400 voluntary vessels and 30
offshore drilling platforms.
This is part of international
monitoring. There are
drifting and moored buoys.









Balloon
-
borne radiosondes
provide information about
pressure, temp and humidity
of the atmosphere. Released
twice a day all over the world.

Weather radar can show rainfall
patterns. Often shown on TV
forecasts and used for river
management and flood warnings.









POLAR ORIBITING
SATELLITES pass around the
earth from pole to pole at a
height of 670km. 1 orbit
takes 1 hour and 42 minutes.

GEOSTATIONARY
SATELLITES remain over the
equator and are stationary
with respect to earth. At a
height of 36,000 km one
orbit takes exactly 24 hours.

Forecasting the Weather



1.
SYNOPTIC WEATHER FORECASTING uses surface
and upper air data to predict system movement.

2.
NUMERICAL AND STATISTICAL FORECASTING
uses analogue methods to compare current trends
with past records.

3.
ENSEMBLE FORECASTING uses computer models
with the input of different starting to conditions to
predict a certain type of weather (e.g. Snow)


The Forecast Preparation Process

Why is weather prediction a challenge?



If forecasters get it wrong then there can be many
consequences.


In technologically advanced societies many activities
depend on accurate predictions.


The impact of extreme events is costly to insurers and
governments. It is easier to respond if emergency
services are on standby.


One challenge is to assist countries less able to afford
sophisticated prediction.

When it all goes wrong…………………..