The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
Go to topicThank you for liking
You have already liked this page, you can only like it once!
Strike probability map for Typhoon Matsa, starting from the ECMWF analysis of 4 August 2005 00UTC and incorporating C-band ERS-2 scatterometer data.
ECMWF operates a so-called 'Ensemble Plotting System' (EPS) in which, in addition to the operational high-resolution forecast (OPER), 51 other alternatives forecasts are made at a lower resolution. One of these forecasts, the control (CTRL) is run from the same starting point but at lower resolution; the other 50 members of EPS are each run from slightly perturbed starting points with perturbed physics models - between them representing uncertainty in the initial state and errors built in to ECMWF's non-perfect physics models. Both contribute to incorrect forecasts and so are incorporated into the probability forecast.
The idea is that all these members together provide an error bar for the OPER run - the larger the spread, the less certain the result.
The probabilities range from 0.05 (one out of 20) to 1 (one out of one), so the numbers in the legend should be divided by ten or 100.