UK: March was dominated by high pressure, but by Tuesday last, low pressure near Iceland swept weather fronts and more unsettled, breezy, but mild weather over Britain.
Ascension: A few rain showers early Thursday & again early Monday, otherwise dry and sunny.
The Smell of Rain:
I never meant to cause you any sorrow Smell the rain, Smell the rain
Smell the rain, Smell the rain Smell the rain, Smell the rain
“There’s just something about the smell of rain on a hot sidewalk. It sort of sizzles and steams up into a big, hot, intoxicating whiff”.
You may have noticed the smell of rain, - or rather the various smells that occur just after rain falls. (There may also be a slight smelliness just before it rains). You'll find it in a lot of poetry and on lists of things to be happy about. But what causes it?
During dry weather plants release nitrates and volatile oils; fungi and bacteria, spores. These aromatic chemicals collect on plants, rocks and other surfaces and in the surface layers of soil.
When the humidity in the air increases, it changes the vapour pressure of the atmosphere. The increase in humidity allows these chemicals to become airborne, this may happen to some extent just before rain, but mainly during and just after rain. The warmer the temperature, and the longer the spell of dry weather, the more these chemicals will have accumulated. So the first shower is usually the “smelliest”.
One of the more pleasant rain smells, the one often noticed in the woods, is often caused by bacteria. The bacterial spores have a distinctive, earthy sweet, smell. Another smell is caused by acidity. As it falls rain tends to become slightly acidic. When the rain comes in contact with organic debris or chemicals on the ground, it can cause some particularly aromatic reactions. It releases minerals and reacts with other chemicals, giving a stronger smell. Some of these reactions may produce more unpleasant odours, which is why the “after-the-rain” smell isn't “always” pleasant.
Compiled by Chill
Crown Copyright 2011 Met Office