It’s a new term so a fresh set of science presentations from Reading’s Café Scientifique at Monroe’s Rock Cafe. I enjoy these forays into learning although only partly for the education as it is rare for there to be a subject covered that isn’t already well-referenced on Wikipedia. Mainly it’s for the beer (although the venue is currently pretty poor in this regard) and chances to look clever asking probing questions.
Tonight the subject was The Science of Weather Forecasting, presented by Professor Alan Thorpe who works just down the road as Director General at the European Centre for Medium-Range Weather Forecasting. Here’s a picture of Alan (left) introducing Slovenia as the 20th member state last month.
Alan gave a very professional presentation in the slightly out-of–the-ordinary environs of Monroe’s, not helped by the frequent interruption by staff carrying food past the stage for science-loving diners.
Things I learned (mainly numbers):
- The ECMWF predicted the arrival of ex-hurricane Sandy at New York eight days in advance of its landfall, generating a lot of Twitter traffic and (putting the nose of their American rivals out of joint). Luckily the prediction came true as Twitter and weather predictions have a chequered past.
- The super computer used for modelling the weather generates 50 predictions using slightly modified sets of the same data to allow for chaos. So if you see “40% chance of rain that means 20 predictions resulted in precipitation and 30 didn’t.
- The atmosphere is divided into square slabs, 16 km on each side and 100m or more thick (high). The thickness increases with altitude and there are 91 slabs in each 80km high column. The super computer calculates the weather for each slab and, being 16 km across, means it can’t be as specific as, say, “the weather for Reading”. This will change as computing power, data collection and the understanding of the physics behind weather improves. There is a lot of the Earth that has minimal information on weather being generated, especially at sea, and a global picture is required for better accuracy so good data is key.
- The centre has around 250 staff, one half of whom are scientists and the other half keep the supercomputer running.
- Weather satellites last around 4-5 years before they become pretty sparkles in the sky. This is a “good thing” as it allows newer technology to be regularly deployed on replacement satellites and helps support an important industry sector.
- Alan introduced me to the term “anthropocene” (in response to a question from the audience) which means a period of time where human activity has a significant impact on the world.