Detection equipment

ROMUALD

The weather station's main tool is the radar known as ROMUALD (the French acronym for Radar d’Observation Météorologique d’Utilisation Aisée Localement et à Distance or Easy to Use Local and Remote Meteorological Observation Radar). The result of a partnership with Météo-France, it is installed at the Grand Leblond site on the Montagne des Pères where CSG is responsible for its maintenance. Romuald operates 24 hours a day and all its data are disseminated in real time to Météo-France Rochambeau. Its predecessor, Rodin, which is enjoying a well-deserved retirement thanks to Romauld, is nevertheless still the backup radar, and is installed on the tower of the weather building.  This device is truly the meteorological 'key stone'.  Just like bats, radars detect obstacles (such as aircraft, rockets, swarms of insects, clouds, etc) by emitting waves and listening to their return signal.  The radar performs searches in all directions and in this way can locate any large clouds within a radius of more than 200 km. It also enables cloud activity to be estimated, including in terms of precipitation. Thanks to Romuald, meteorologists can calculate the movement of cloud masses – extremely useful when a cumulonimbus is approaching the ELAs.  The radar can also scan the atmosphere in a vertical plane, meaning that it can estimate the thickness of clouds: key data for determining the risk of lightning.  Although Rodin was already performing similar functions, Romuald's techniques are much more up-to-date, providing better images and ultimate performance, and enabling the speed and direction of cloud movement to be obtained using algorithms derived from signal processing.  These systems were developed in Germany, whereas the actual radar is American.  These data are essential for validating or invalidating the status of the C1, C2 and C3 weather criteria for the launch countdown.

THOR

Another basic weather forecasting tool used at CSG is THOR (THunderstorm OccuRrence), which determines the risk of lightning in real time. The weather station was recently equipped with this Finnish system, which consists of three masts, installed on the Montagne des Pères, the Salvation Islands and at the Diane station. The four antennas at the top of each mast and the electronic processing units which act as relays are constantly on the lookout for radio waves emitted by storm activity.   Thor is unique in that it is capable of detecting all kinds of lightning and of discriminating between them under certain conditions: those remaining in or between the clouds and those likely to strike the ground.  This information, which complements that of the radar, indicates the precise position and movement of the clouds, thus enabling us to determine whether a particular cloud formation is likely to constitute a risk of lightning. 

MAC

Lastly, the system is completed by the French MAC (Moulins à Champ) field generator. With four measurement points placed around the ELAs and three levels of alert which can be given at very short notice, MAC measures the ambient electric field at ground level, in kV/m and monitors electrical activity in nearby cloud cells.