Tuesday, October 16, 2007

Late post for the Environment

Just caught up with something Tillerman posted on - that yesterday was Blog Action Day for the environment.

We have only one planet and it needs a bit of TLC. The environment is increasingly under pressure as greenhouse gases change the atmosphere and loss of bio diversity due to habitat destruction.

But we can fix it and live our modern lifestyle without giving up the modern world - buy electricity from renewable sources, use high efficiency light bulbs, offsetting flights or use trains, and so on.

Not going to go into this in too much detail - just say there are great resources at the BBC and New Scientist that keep up to date with the latest findings.

So instead will do a quick overview of the four types of fog mentioned under the earlier post on season of mellow mists based upon the summaries from "The Complete Sailing Manual":

Radiation Fog

Radiation fog is formed at night during clear conditions, when rapidly cooling land cools the air above and makes water vapour condense into droplets. The fog forms first as mist in low valleys, and spreads and thickens as the air continues to cool.

Advection Fog

When warm, moisture-laden air passes over cold water, it cools down to its dew point, the water vapour in the air condense, and advection fog forms. Also known as sea fog, advection fog can be persistent, requiring a dry wind to disperse it.

Frontal Fog

Frontal fog develops when warm, moist air at the front of a depression rises over cold air. This causes the temperature of the warm air to fall below its dew point. Frontal fog causes most problems for sailors when it obscures landmarks.

Sea Smoke

Cold air flowing over warm sea absorbs and immediately condenses any water evaporating off the sea, forming fog. The water warms the air, raising the dew point, and dispersing the fog. Higher up, the air cools again and the fog reforms.

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