I was reading over the Christmas holidays that there are records of the weather that go back as far as 13th Century BC. The records were found amongst the Anyang oracle bones, which give us an historical account of the Shang dynasty in China. But it’s the way in which nature responds to our weather that gives us the long record that we use for studying our climate beyond the more systematic observations we have over the last century or so – the sorts of information that comes from tree rings or trapped air in ice cores, and that is what we call paleoclimatology. It’s these observations together with our complex climate models that help us to understand and give context to how our climate is changing.
Our recent summers haven’t been great in the UK, most likely a response to the effects of a strong La Niña – a large pool of cold water of the south-American coast. This natural feature of the earth’s climate has masked the underlying warming of land temperatures to some extend. That being said the climate models are telling us that by all accounts 2009 is set to be a warm year globally, although the seasonal forecasts for the UK are showing that we will have a cold start – with colder than average temperatures in January and an average February.
Showing posts with label weather. Show all posts
Showing posts with label weather. Show all posts
Saturday, 3 January 2009
Sunday, 28 December 2008
Very Cold December
It’s been the coldest start to December since 1976. Very cold Decembers are not uncommon but a little unusual as our coldest months in the UK are usually January and February. I was talking about the cold weather to some friends over Christmas and we got on to talking about why we can feel hot or cold. I don’t mean that the heating isn’t on or there’s a freezing wind outside, I mean where the sensation of heat actually comes from.
Well, something feels hot to us because the atoms inside it are moving fast, and when it feels cold they are moving slowly. We interpret this movement through the feeling of something being hot or cold, and a thermometer interprets as a certain temperature, in for example degrees Centigrade of Fahrenheit.
Scientists often use Kelvin as a measure of temperature rather than deg C or deg F. The bottom of the Kelvin scale is 0 K or Absolute Zero. What got me thinking about this recently was my God Son who asked me what is Absolute Zero. I was able to give the temperature 0 K or -273.15°C, but not the definition. It’s one of those things that I am sure I did know and could make a reasonable guess of what I thought it was, but to be precise I looked it up for myself. And it is as you might guess a point at which no more heat exists.
What that means specifically in classical kinetic theory is that there should be no movement of individual molecules at Absolute Zero. In practice we don’t of course know this as we have never been able to observe anything at 0 K, but we have come close in the laboratory. The experimental evidence shows us that as we reduce temperatures close to 0 K molecules do slow right down, but there is still movement.
Well, something feels hot to us because the atoms inside it are moving fast, and when it feels cold they are moving slowly. We interpret this movement through the feeling of something being hot or cold, and a thermometer interprets as a certain temperature, in for example degrees Centigrade of Fahrenheit.
Scientists often use Kelvin as a measure of temperature rather than deg C or deg F. The bottom of the Kelvin scale is 0 K or Absolute Zero. What got me thinking about this recently was my God Son who asked me what is Absolute Zero. I was able to give the temperature 0 K or -273.15°C, but not the definition. It’s one of those things that I am sure I did know and could make a reasonable guess of what I thought it was, but to be precise I looked it up for myself. And it is as you might guess a point at which no more heat exists.
What that means specifically in classical kinetic theory is that there should be no movement of individual molecules at Absolute Zero. In practice we don’t of course know this as we have never been able to observe anything at 0 K, but we have come close in the laboratory. The experimental evidence shows us that as we reduce temperatures close to 0 K molecules do slow right down, but there is still movement.
Sunday, 12 October 2008
My New Meteorological Watch
With one thing and another it has been a while since I last put ‘finger-to-keyboard’ so to speak, but felt I should share a few thoughts about my new meteorological watch.
At my age it is not often I get excited about my birthday (perhaps that is just because I am a bit miserable, as my wife reminds me), but this year I had a very exciting present – no not a vintage Harley Davidson bike, an antique Les Paul guitar, or tickets to see Catherine Jenkins in concert (front row seats); it was a meteorological watch. Yes, you did read correctly a watch that makes observations of the weather. I have had much fun with this, making observations of temperature pressure and altitude. It reminded me of a few things apart from how hopeless I am at finding out how it all works.
The first was how careful you have to be when making observations, to understand what is being observed (like the temperature of the atmosphere, or my wrist), and that the observations are well calibrated. I am waiting to my next blue sky day at the coast to set my altitude and pressure calibrations.
The second was that what I am measuring is all inter-related. Pressure, temperature and humidity are all related. For example in the troposphere, a very small layer of the earths atmosphere relatively speaking that is closest to the surface of the earth and where we have all of our weather, pressure decreases with height in the atmosphere and so does temperature, by roughly 6oC per kilometre (if we make some assumptions about what we call a standard atmosphere). I wonder whether my watch really does measure temperature, pressure and altitude independently or whether, as I suspect, it uses some of our understanding of how these things are linked.
At my age it is not often I get excited about my birthday (perhaps that is just because I am a bit miserable, as my wife reminds me), but this year I had a very exciting present – no not a vintage Harley Davidson bike, an antique Les Paul guitar, or tickets to see Catherine Jenkins in concert (front row seats); it was a meteorological watch. Yes, you did read correctly a watch that makes observations of the weather. I have had much fun with this, making observations of temperature pressure and altitude. It reminded me of a few things apart from how hopeless I am at finding out how it all works.
The first was how careful you have to be when making observations, to understand what is being observed (like the temperature of the atmosphere, or my wrist), and that the observations are well calibrated. I am waiting to my next blue sky day at the coast to set my altitude and pressure calibrations.
The second was that what I am measuring is all inter-related. Pressure, temperature and humidity are all related. For example in the troposphere, a very small layer of the earths atmosphere relatively speaking that is closest to the surface of the earth and where we have all of our weather, pressure decreases with height in the atmosphere and so does temperature, by roughly 6oC per kilometre (if we make some assumptions about what we call a standard atmosphere). I wonder whether my watch really does measure temperature, pressure and altitude independently or whether, as I suspect, it uses some of our understanding of how these things are linked.
Thursday, 26 June 2008
It’s getting darker by the second
Watch a related video of Paul being interviewed on BBC Radio Berkshire
Well, we’ve had the longest day for 2008 and summer has officially begun, albeit a very windy start – the Yorkshire relatives had their plant pots blown away last week! On the radio slot this week we were talking about why we have seasons and of late it’s certainly felt like we’ve had all of these in a week or so (not quite as Crowded House sang about). It did remind me what interesting weather we have by virtue of being an island near a large ocean and continent in the mid-latitudes, and how lucky we are that we don’t have to battle the sort of severe weather that some parts of the world face this time of year.
Central Europe has been having some lively weather if the football coverage is anything to go by. But for a change, Glastonbury had a very sunny start. Tonight (Thursday) and Sunday might require the wellies to be unpacked, well at least the shower coat anyway. I noticed on Sunday that The Verve, Leonard Cohen, Neil Diamond and Gilbert O’Sullivan are playing – now there’s an eclectic music mix that sounds like the sort of thing you get when you put your iPod into Shuffle mode.
I’m a tennis fan so I’m hoping that we have some very seasonal summer weather for the next week of Wimbledon, but by all accounts it does look like we might be in for a shower or two on the middle Sunday and later in the second week. Let’s hope Andy Murray’s still out on the court braving the elements!
Well, we’ve had the longest day for 2008 and summer has officially begun, albeit a very windy start – the Yorkshire relatives had their plant pots blown away last week! On the radio slot this week we were talking about why we have seasons and of late it’s certainly felt like we’ve had all of these in a week or so (not quite as Crowded House sang about). It did remind me what interesting weather we have by virtue of being an island near a large ocean and continent in the mid-latitudes, and how lucky we are that we don’t have to battle the sort of severe weather that some parts of the world face this time of year.
Central Europe has been having some lively weather if the football coverage is anything to go by. But for a change, Glastonbury had a very sunny start. Tonight (Thursday) and Sunday might require the wellies to be unpacked, well at least the shower coat anyway. I noticed on Sunday that The Verve, Leonard Cohen, Neil Diamond and Gilbert O’Sullivan are playing – now there’s an eclectic music mix that sounds like the sort of thing you get when you put your iPod into Shuffle mode.
I’m a tennis fan so I’m hoping that we have some very seasonal summer weather for the next week of Wimbledon, but by all accounts it does look like we might be in for a shower or two on the middle Sunday and later in the second week. Let’s hope Andy Murray’s still out on the court braving the elements!
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