My home river has a new feature today. After last night’s storm, its biggest meander has been cut off. Three weeks ago about 12 feet of the bank – both in length and depth – was eroded, leaving a wedge of bank 11 feet wide to separate the river going into the bend from the river coming out of the bend. Yesterday, those 11 feet were washed away by the tremendous mass of water coming down the river. Not only that, but the newly-formed “soon-to-be” ox-bow lake has its up-arm completely sealed off from the river by silt and gravel, and its down-arm is nearly sealed too. The bank has gone from about 24 feet across to nothing in two big storms. I wonder what will happen in tomorrow’s torrential rain (forecast)?
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I’d no idea that tree rings could be used for such important science. I’ve always thought of it as a good hobby and a bit of fun at environmental centres where you can look at a slice of tree and work out what history it had seen.
Seems rainfall, temperature, height above sea-level all affect the growth of trees, as well as their growing conditions – how close together they are, how much covered by the canopies of other trees, how rich the soil is to provide nutrients, how well-drained the soil is, how disturbed/damaged by storms and other weather events or human damage, and so on.
Scientists prefer to sample trees that are near the edge of their natural range rather than in the middle of it as this gives better climate information. They also consider what factor they are trying to obtain most information about – for example, if it is rainfall deficiency, they will look at a tree (s) growing in an arid area and on a dry site, where the ring series would be sensitive to lack of water. They also need to sample several trees on one site, perhaps more than one stem on a single tree too, and also trees from another nearby site, to help ensure that they are looking at the correct environmental factor and to reduce likelihood of other factors disguising the wanted information.
Once information has been gathered, it can be compared with – for example – the timbers in a building or a ship to match the ring growth – width and density – and thus date the building.
Ring growth can be used to provide climate information from long before climate records were first kept. This information can be used to predict and manage future climatic conditions and changes.
The thought of all those short waves zipping in and long waves zooming out is exciting. Reminds me of the amateur radio exam course many, many moons ago. Thanks for clarification, Chris Wilkinson, physics graduate!
Would it be right to say that climate sets the parameters within which weather operates?
Learned a lot of new words this week, while moocing. Albedo sounds lovely and reflective – hope my albedo will improve as the weeks go by. The CFC thing was fascinating – destroying the ozone layer in the stratosphere but also trapping radiated heat from the earth in the troposphere – a double whammy.