Like here in the Aude, the episodes in the mediterranean are likely to increase in frequency and intensity.
Against the backdrop of deadly floods in the Aude, in the night of 14 to 15 October, and global warming turned out, the question of the accuracy of the prediction of meteorological phenomena intense is more fraught than ever. Fortunately, the technology continues to evolve…
The stages of a weather forecast by David Pagès on Scribd
Radar X-band : “to Know in advance precisely where an episode of the mediterranean will hit”
“A true technological breakthrough.” It is as well as Philippe Meyrand, vice-president of the company Novimet, describes the software and hardware solutions that offers his company in the field of rainfall at high resolution in real-time. In the clear, a tool, the platform Rainpol, which means “one to two hours in advance that an episode of the mediterranean is about to hit, with what intensity and for how long”.
This platform is based on a set consisting of a detection radar hydrology (the water contained in the clouds) type X-band (it is also used in some cases by Meteo France), an algorithm of prediction and a web interface. This device efficient and less expensive than the system Météo France (500 000 € per installation) not a substitute”, as pointed out by Philippe Meyrand. To get to “prevent floods and flash floods”, the company based in the Ile-de-France relies on a technology substantially different, in terms of its approach from that of Météo France, “without substituting for his service-general forecast or to the accompaniment of communities managed by its subsidiary, Predict”.
To demonstrate the effectiveness of Rainpol, Philippe Meyrand take for example the floods of Antibes (Alpes-Maritimes), from October 2015. The department had been placed in vigilance orange by Météo France. At the same time, the instruments of Novimet left “point to a marked worsening”, according to the vice-president. “We have seen that the situation is changing to black. Fortunately, the civil Security has taken us seriously and has upped the people in the story. We avoided the worst.” Finally, Novimet and Météo France have the same goal : to save lives, but with approaches and different means.
A radar band X.
Supercomputer : in order to better calculate the intensity
Météo France will soon be equipped with a supercomputer, additional that it can better predict the intensity of inclement weather, announced Tuesday, October 16, the minister of Justice in the aftermath of the deadly floods in the Aude.
Several million euros
“In the light of what happened, the State has taken the decision to fund a supercomputer for Weather France, which will be available within a year and a half,” said the keeper of the Seals Nicole Belloubet, about this tool “, which will mobilise several million euros”. The latter explained that this supercomputer will “enable better calculate the intensity of the rains so infradépartementale”.
In the Aude, an early controversy born on Monday, some residents complaining of having been ill-informed of the intensity of upcoming storms. Météo France had triggered the red alert at 6 p.m., But the Prime minister Édouard Philippe, who visited the site Monday afternoon, was of the view that this episode’s weather was “by itself unpredictable.”
The spokesman of the ministry of the Interior, Frédéric de Lanouvelle, has, him, referred to the “fragility” in the system of vigilance Météo France, “the level of vigilance orange, which is very often used, and when there is a real problem, people do not take into account”.
Meteo France already has supercomputers. In one of them, the national Centre of Météo France in Toulouse, are inflows of satellite images and other data to render a state of the atmosphere at a given time. This supercomputer uses an algorithm that is updated every six months, and simulation models built in.
Predict : “to Act before, during and after”
Prevention is better than cure, the saying goes ; especially when it is grappling with the devastating effects of hurricanes Leslie and Michael, “the two monsters weather that are at the origin of what happened in the Aude in the night from 14 to 15 October,” says Alix Roumagnac, president of the company héraultaise Predict. A structure specialized in the prevention of natural risks and in the accompaniment of communities.
On the bridge since the tragic and deadly flooding audoises, the issue of the work of Predict is “to make the right decisions and act before, during and after risk events to minimize the impact of these weather phenomena intense on people and property”.
To make good choices and give good recommendations to communities, businesses and individuals, which are likely to suffer the deleterious effects of a weather control, Predict (a subsidiary of Météo France) works directly on the data provided by its parent company thanks to its “means of calculating huge”.
From these data, the team Predict “works upstream weather events intense, with the forecasters of Météo France”, and then analyzes “the data provided by the different models of forecasting “, which, according to the confession of Alix Roumagnac, “do not say not necessarily quite the same thing.” The difficulty comes from “the uncertainty of the forecast models weather, it is necessary to draw recommendations and advice to be reliable in terms of the evolution of events,” said the president irritated, the word is weak, by the controversy emerging on the inefficiency alleged alerts and preventive actions to be implemented in the Aude.
“We have assisted more than 600 common between the Aude and the Hérault, and sent more than 250 000 SMS alert to the elect and to the persons listed in our files,” says the entrepreneur, who cites the example of Raissac-d’aude where “the totality of the population was secured by the city council following the recommendations of Predict”.
Alix Roumagnac in front of the wall of screens renders in real time the weather situation.
The widespread use and the democratization of smartphones is a real asset in the field of prevention of natural risks ; weather or other. Either on Apple store or Google Play, they are many and varied.
Among these, the applications developed by Météo France and the company Predict (myPredict) are able to disseminate weather alerts location-based and tips to have good reflexes in the face of risk. The only weak point of this type of alert system is that to receive, it is necessary to have the network. Different networks can be undermined by the weather.
The alert system weather, currently in force, has been put in place following the major storms of December 1999. It consists of four levels of alert. They will color green (no vigilance to be observed) to red for which absolute vigilance is required. Between the two, the yellow for which it is recommended to “be careful” and the orange level alert on the “hazards expected”.
Satellite weather are indispensable tools for the forecasters. They are complementary to the land-based radars and other measurement systems in the field. Tiros 1, the first of them was launched at the beginning of years 60 by the Americans. They can be classified into two categories : geostationary and scrollable. The first are located at 36 000 km from the Earth at the base of a fixed point.
The latter are in low orbit around the Earth and flying over the same area twice in 24 hours. Able to make many observations on the clouds, the oceans, and the atmosphere they provide, according to Météo France, “between 75 and 95 % of the observational data that feed the numerical models of weather prediction”.