A group of space agencies is providing - free and as quickly as possible - satellite images of any area affected by a natural or man-made disaster, according to our partner The Conversation.
By capturing the disaster seen from space, with very high resolution satellites, space quickly provides crucial information.
Since 2000, this procedure has been activated 760 times in more than 130 countries.
This analysis was conducted by Emilie Bronner, representative of the National Center for Space Studies (CNES) at the Executive Secretariat of the International Space and Major Disasters Charter.
During the earthquake in Haiti on August 14, 2021, the country's Civil Protection Department, noting the scale of the event, requested at 8:20 p.m. the activation of the international charter "Space and major disasters".
An operator, available 24 hours a day, every day of the year, receives the Haitian call, validates it and sends the request in less than an hour to an on-call engineer who is in charge of requesting the programming of the satellites the most appropriate.
In the hours following the disaster, the missioned satellites then went one after the other to focus on Haiti.
A specialist in spatial data processing oversees the monitoring of operations and the correct reception of satellite images produced by various data providers.
Thus, only a few hours after activation, the first satellite images arrive.
They can be immediately used by the rescue teams dispatched to the field, in native form or in the form of maps of the affected areas, landslide maps, population regrouping areas, etc.
Every year, millions of people all over the world are affected by natural disasters (cyclone/tornado/typhoon, earthquake, landslide, volcanic eruption, tsunami, flood, forest fire , etc.) or human (pollution by hydrocarbons, industrial explosion).
The intensity and frequency of these events are unfortunately intensifying with climate change, creating every day a little more disaster victims or precarious habitats.
Anatomy of a Disaster
Within the framework of the international charter "Space and Major Disasters", a disaster is defined as a large-scale, sudden, unique and uncontrolled event, resulting in the loss of human lives or damage to property and the environment and requiring urgent action to acquire and supply data.
This charter was created by the National Center for Space Studies and the European Space Agency in 1999, quickly joined by the Canadian Space Agency.
Today, 17 member space agencies are uniting to provide satellite images of the disaster area as quickly as possible.
Since 2000, the charter has been activated 760 times in more than 130 countries.
It has since been supplemented by similar initiatives (Copernicus Emergency or Sentinel Asia).
Nearly three-quarters of the charter's activations are due to hydrometeorological phenomena: storms, hurricanes and especially floods, which alone account for half of the activations.
In these unforeseen crisis situations, when the ground is damaged or flooded and the roads impassable, land resources do not always make it possible to analyze the extent of the disaster and to organize relief and humanitarian aid as well as possible.
By capturing the situation seen from space, with very high resolution satellites, space quickly provides crucial information.
In some cases, the chart cannot be activated.
Either because the object is outside the scope of the charter (wars and armed conflicts), or because the spatial imagery is sometimes not of great interest (heat waves, epidemics), or because the phenomena have a slow evolution (droughts) which is incompatible with the notion of urgency at the heart of the charter's mission.
Satellite data in response to crises around the world
As soon as a disaster occurs, the satellites are programmed to acquire images over the impacted areas in a very short time.
More than sixty satellites, optical or radar, can be mobilized at any time.
Depending on the type of disaster, different satellites will be mobilized, based on pre-established crisis scenarios – among them: TerraSAR-X/Tandem-X, QuickBird-2, Radarsat, Landsat-7/8, SPOT, Pléiades, Sentinel- 2 in particular.
Optical images are similar to photos seen from space, but radar images, for example, are more difficult to interpret by the uninitiated.
Thus, following the disaster, satellite information is reworked to make it intelligible and provide added value.
They are, for example, transformed into maps of impacts or changes for rescue workers, flood vigilance maps for populations, maps of burned or flooded areas with damage estimates for decision-makers.
Collaborative work between field users and satellite operators is essential.
Progress has been made thanks to innovations in Earth observation technologies (in particular the performance of optical resolutions – going from 50 to 20 meters and then to 30 centimeters currently) and 3D data processing software, but also thanks to the development digital tools that can combine satellite and in situ data.
In addition, the needs in the field have contributed to the evolution of the charter's intervention processes in terms of delivery time and quality of the products delivered.
Reconstruction after disasters
Emergency management is of course essential, but it is important for all affected countries to consider reconstruction and the future.
Indeed, in the “risk cycle”, after the disaster and the humanitarian emergency, the return to normal will open the time for reconstruction, resilience, prevention and alert.
We cannot predict disasters but we can better prepare for them, especially in countries where misfortune is recurrent, with for example anti-seismic construction, moving residential areas to a safe place, raising awareness of gestures of survival, the creation of safe gathering places, among others.
Our “CATASTROPHES” file
Several initiatives, called "Reconstruction Observatories", have been carried out after major disasters, for example in Haiti in 2021, or following the explosion in Beirut in 2019. The goal: to plan coordinated satellite image acquisitions to allow a detailed and dynamic assessment of the damage to the most affected areas (buildings, roads, agriculture, forests, etc.), to follow the planning of reconstructions, to reduce the risks and finally to carry out a follow-up of the changes on the horizon of 3- 4 years.
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This analysis was written by Emilie Bronner, representative of the National Center for Space Studies (CNES) at the Executive Secretariat of the International Space and Major Disasters Charter.
The original article was published on
The Conversation website
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