One Hundred Fifty Kilometers, One Hundred Years, Four Kilometers discussed on The Naked Scientists


The easiest way to describe what happened in the modern meteorologists office would be the most of us will be looking at the output from the mathematical models of the atmosphere and using raw data coming in to represent a starting position you can then use the equations of the atmosphere have the the moves arrows exchanges energy exchanges temperature moisture and so on those parameters can be represented with the cohesions in the model and it will predict what those numbers look like in a short time step ahead and if you keep leapfrogging those far enough into the future you can i get an idea of what say the temperature field display would look like in six hours time twelve hours and models now i used to work as a programmer in the metaphysics bracknell years ago on the civil computer and this is in the seventies before we all had computers at home and the models would split the atmosphere all over the globe up into a bit lucky imagine and onion with several different layers and on that onion their lines that cross like latitude longitude lines and each of those grid points represents a data value and in those days the computing power was so limited that the data points were one hundred fifty kilometers apart and there were ten onion skins in this model that represented the real virtual well so what happened is that as computers go quicker and more able we now have models that have data points four kilometers apart used regularly to drive your tv graphics for example and a lot of aviation meteorology in some specialised cases they're one kilometer apart they don't have ten onion skins if you like they have ninety so they're much better able to rep present the real physics of the atmosphere so forecasts are become much better and you can move them farther ahead in time and still get a good result so when you say there is a model basically people like yourself have written computer programs that know what the atmosphere does and they put some energy in and how it's going to move how the masses are going to move and how the energy is going to change the behavior of that patch of the earth surface and so we know from experience but also for modeling how it's likely to play out and how that's going to move around and never what is going to do to whether patterns systems around the world is that is that what you sensually it and the interesting follow on from that actually which is probably firm or significant important is that when you've tuned your models to be successful in the short term you know pretty well at the physics is working reasonably well they're still not powerful enough to represent individual show clouds accurately but they can get them in a in a sort of parameters way but nonetheless interesting point is that once you know the work what's to stop you running it not for next week or the week after but running it for next year the raft of that and the year after that and so on so you run these models for a model world's worth of thirty years data and see if the average temperatures that you cokie late match the average temperatures that we have in our current climate so you've calibrated the model to represent what we have now and then you can play golden do all the things that climate change people are interested in which is you can chop down the amazon rainforest you can irrigate the desert you can melt the polar ice caps and you can run the model to gain and see how those values change now you won't be able to represent it exactly but you give the scale of direction of where it will go and it's the refining of those models that gives people the various answers about what comet change might look like in one hundred years time until it's certainly true that the quality and the parent accuracy whether we're causing does appear to have improved dramatically in recent years now talking about the weather we've got this question few jane which adam has sentence why does the.

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