Fran Beckerleg speaks to the Met Office's Simon Cardy
Part of the show Forecasting Weather and Climate
Fran - I'm up on the roof of the Met Office's London Weather Centre. This is one of many hundreds of weather centres across the UK where information is collected to provide short and long term forecasts. I've got Simon Cardy from the London Weather Centre with me. Simon, there's a lovely view from here. We're quite high up. I understand this square we're standing on is quite special at Christmas.
Simon - Yes, on Christmas day we're out here looking for any snowflake that might fall on the London Weather Centre roof and let the bookies know that there's a day of snow here in London.
Fran - That must be a bit of a chilly job.
Simon - It sure is.
Fran - So what kind of data is collected up here?
Simon - Well temperatures are the main thing. We've got several thermometers which tell us the maximum temperature and the minimum temperature. And also that helps us to work out the humidity of the air as well. It's tell us how wet or how dry the air is.
Fran - Perhaps you could tell me a bit about some of the instruments that you use here. What's this green bowl - like thing here?
Simon - Well this is going to collect the rain that falls or the snow or the hail. The rain fall through this green bowl here and every 0.2 millimetres that falls, we get a little click on the machine downstairs, and that's how it works out the intensity of the rainfall. Now the rain gauge next to it, we collect rain in here too. This is measured at 9 o'clock in the morning and 9 o'clock in the evening and we get 12 hour totals of rainfall.
Fran - Perhaps you can tell me a bit about this white thing over here that looks a bit like a beehive. What goes on in here?
Simon - Well this is a Stevenson screen. It's made of wood and it's painted white so it reflects some of the sunshine away. We like to know what the temperature is in the shade, because when the sun gets on the thermometers it can adversely affect the temperature reading. So I'm just opening the door here now. We can see that we've got several thermometers inside. One of them is reading the maximum temperature of the day and we'll read that at 9 o'clock this evening. The other thermometer reads the minimum temperature of the night time.
Fran - So what's the temperature now? Can you tell me?
Simon - Yeah at the moment that temperature's not doing to bad. We've got 13 degrees Celsius, which is 55 Fahrenheit.
Fran - Is that a usual type of temperature for this time of year?
Simon - We've had lots of sunshine up until now and the temperatures have risen quite well and responded well to the sunshine. In fact, that's about average for this time of year.
Fran - Fantastic. What happens to the data once it's all been collected?
Simon - All the data from hundreds and thousands of weather stations across the UK and across the world get input into a massive computer model. It works out the forecast for the next few days and in fact the next few weeks or even seasons ahead.
Fran - Now all this equipment looks quite basic. Are there any new technologies being developed to make forecasting more accurate?
Simon - Well we use satellite pictures very regularly now. We get pictures in every half and hour and that's a great help to the forecast. We also have radar rainfall and we can see what type of rain is falling, whether it's really heavy or light rain or drizzle. Taking the observations that we've just talked about and using the laws of physics, we can then work out the forecast for the next few days ahead.
Fran - Thanks very much Simon. Back to you in the studio Chris.