Every so often, meteorologists world-wide engage in a flurry of activity intended to reduce the proverbial inexactitude of their profession. And when such a notion takes them, before all else they must devise an acronym which pithily describes the task proposed, making sure it ends with EX to denote the experimental nature of the exercise.
Thus ALPEX, some years ago, concerned the weather in the Alps. GEWEX stands for the Global Energy and Water Cycle Experiment, and concerns hydrology. And readers of Weather Eye will know of FASTEX, the Fronts and Atlantic Storms Experiment, which was masterminded from a little room at Shannon Airport just a year ago. The latest EX-rated activity to be put in train is INDOEX, and is an attempt to gain a better understanding of the complex meteorology of the Indian Ocean.
An essential requirement for any such investigation nowadays is a steady supply of satellite pictures of the region, and on this occasion the need has been met in quite a novel way. EUMETSAT, the European Meteorological Satellite Organisation, has for many years operated the Meteosat series of geostationary weather satellites. Geostationary satellites are positioned directly over the equator, and have their speed in orbit matched exactly to that of the rotating Earth; thus they appear to be fixed in space - or as their name implies, stationary - when viewed by someone on the ground below.
EUMETSAT's customary equatorial patch is on the Greenwich meridian, with the Meteosats sitting semi-permanently over a spot just south of Ghana; from there, to the north, they have a commanding view of Europe. But EUMETSAT, fortuitously, is very well equipped at present. In addition to Meteosats 6 and 7 - the operational satellite and spare respectively - the oldest living member of the family, Meteosat 5, is still in working order. It has therefore been agreed that Meteosat 5 will be "lent" to INDOEX, and repositioned 8,000 miles further to the east, over the middle of the Indian Ocean.
It only needed a short "kick" from the satellite's motor on January 14th to lower its altitude, increase its orbital velocity in relation to the Earth, and cause Meteosat 5 to drift eastwards along the Equator on its lengthy journey. The controlled drift is at a walking pace, to conserve precious fuel so that the satellite can be manoeuvred whenever necessary during its sojourn in the Orient. Today the satellite is just north of the Seychelles, and by May 20th it will have reached its new position at 63E, from where it will provide valuable information to INDOEX and, it is hoped, help significantly to improve the art of weather forecasting.