 | | | | | PROGRAMME INFO | | | |
| | | Richard Daniel chairs the interactive environmental programme in which he and his guests deal with listener's questions and concerns.
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Home Planet, PO Box 3096, Brighton BN1 1PL | | | | | LISTEN AGAIN 30 min | | | |
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| | PRESENTER | | | |
|  | | | | "Home Planet is the environmental programme for which you set the agenda. We tackle your questions and concerns and try and make some sense out of the conflicting opinions which make up the environmental debate."
Richard Daniel | | | | |
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Panel
Professor Graham Underwood
University of Essex
Dr Nick Riley
British Geological Survey
Professor Philip Stott
Bio-geographer, University of London
TOPICS
Can we use disused North Sea oil wells to store our waste?
North Sea oil info
Strategic environmental assessment
IEA Greenhouse Gas ProgrammeCO2 capture and storage info
What is the impact of acid rain on seas?
Acid rain info
BBC Science: acid oceans
The Royal Society
New Scientist story
University of Southampton research
How heavy are clouds?
The panel discussed the mass of clouds and not their weight. Here are Professor Stott's calculations:
Mass = volume x density.
Thus we need to know the volume of a cloud (near a sphere) and its density.
The density is primarily governed by its water content, which can vary from 0.1g to a whopping 15g per m3, as follows:
small cumulus cloud: 0.2-0.5 g /m3
large cumulus cloud: 0.5-1.0 g/m3
stratus cloud: 0.1-0.5 g/m3
cumulonimbus cloud: 5-15 g/m3
Thus a very large cumulus cloud forming an approximate sphere of 1km radius would contain 4 billion m3 at c.1 g/m3, which gives a "weight" of 4 billion g or 4 million kg.
How much ozone is there in the ozone layer?
Here are Professor Stotts' calculations: -
We should note that we are measuring stratospheric ozone, not ozone in the troposphere near to ground-level. Only about eight percent of atmospheric ozone occurs in the troposphere;
- Ozone is measured in Dobson Units (DU) with each DU = 2.7 x 1016 ozone molecules per cm2. At standard temperature and pressure (STP), one Dobson Unit is defined as corresponding to 0.001cm thickness. An undepleted ozone layer is usually c.300DUs, which gives a thickness, at STP, of c.3mm. In a depleted ozone layer, the DUs can fall to as little as 117DUs, ie 117 x 0.01~1mm;
- Now for the weight calculation. For a cm2 of the Earth's surface at STP:
The molecular weight of ozone is 47.9982 atomic mass units (amu);
One atomic mass unit (amu) = 1.660538 x 10-27 kg;
One Dobson Unit contains 2.7 x 1016 molecules per cm2;
There are, in an undepleted ozone layer, 300 DUs;
Thus: the weight of ozone per cm2 at STP is:
(1.660538 x (10-27)) x 47.9982 x (2.7 x (1016)) x 300
Which equals: 6.45592964 x 10-07 kg per cm2.
If we take the area of the surface of the Earth to be 5.112 x 1018 cm2, then the final figure for the weight of ozone in the stratosphere (at STP) is:
3.300 x 1012kg.
Jellyfish
British Marine Life Study Society: jellyfish info
Marine Conservation Society: jellyfish info
Looking after our soil
Soil Erosion Website
National Soil Resources InstituteBritish Society of Soil Science
DEFRA Soil Action Plan
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Environment Agency
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