2. Plot graphs of the variations in temperature, rainfall, pressure
and compare with other schools in your group. Describe
and explain the graphs.
3. Draw a map of wind speeds and/or pressure
recorded in different parts of the UK and Europe and comment on the
results.
4. Draw graphs to compare latitude or altitude with
temperature or rainfall readings for all of the schools
in your group.
5. Investigate the influence of continentality (distance
inland) on temperature range or rainfall.
6. Write a personal account of a severe weather event that you
have experienced eg a gale or flood. The best accounts will be
published on the MetNet Europe web site.
7. Write a forecast of the weather for your own school over
the next 24 hours or Email a prediction to another school in your
group.
From: Ross Reynolds
Department of Meteorology
University of Reading
Reading RG6 6AU
http://www.met.reading.ac.uk
Subject: Clouds are heavy
Date: Fri, 5 Feb 1999 14:42:58 -0000
Dear MetLink participants
Here in the semi-arid (!) South-East of England we've had a run of
six rain-free days at the University of Reading - and more widely in
this region. This has provided some respite to what has been an
anomalously wet winter.
There is a risk of snow over a good deal of Britain this next Monday
though the likelihood has decreased since yesterday's forecast
run.
Apart from these few comments, have you ever wondered how heavy
clouds are ?
To work it out can involve the practical use of formulas for the
volume of different shapes and the use of the concepts of mass and
density.
So, here goes - assume that a fair-weather cumulus cloud is
hemispheric. You'll need to estimate the typical dimension, say a
radius of 200 metres (or something else that's reasonable).
With this, you can find the volume of the cloud ie 2/3 pie r
cubed.
Next you need to know the 'liquid water content' of such a cloud -
this will vary from about 0.4 g/m cubed to 0.5 g/m cubed. So you can
very quickly estimate the mass of water in such a small cloud.
If you wanted to, you could in fact do it differently by knowing
(i) the number of droplets in such a cloud - around 200 million per
cubic metre (!) for 'continental' types and
(ii) the volume of each droplet - typical radius is about 5
micro-meters, assuming each is spherical - 4/3 pie r cubed
(iii) that you then convert the total volume of water in the cloud to
a mass by using 1000kg/m cubed density value !!!
You can do the same exercise for a cumulonimbus cloud, given that the
liquid water content is something like 2g/m cubed - and that you can
take the cloud to be cylindrical.
You'll find that these clouds weigh a lot !
Happy calculating !
Ross Reynolds
