The UN organization UNOSAT provides the international community with geographic information and access to satellite imagery to cope with natural disasters and post-conflict situations. UNOSAT has been based at CERN since 2002 in order to benefit from CERN's IT infrastructure and network connectivity. During the recent international crisis following the Asian tsunami, UNOSAT's website proved vital for ensuring that relief organizations had the necessary information to plan actions in the field.
When news of the earthquake and resulting tsunami reached UNOSAT on 26 December, the first major decision was whether to activate the international charter Space and Major Disasters, which allows satellites belonging to several major space organizations to be directed at specific sites. The UNOSAT team decided to wait until it had pieced together enough of the information arriving from various sources before choosing the most critical areas at which to point the satellites. This cautious approach proved wise, because the extent of the destruction became clear only gradually.
By the evening of 27 December key areas had been selected, and UNOSAT activated the charter. This ensured that 13 different satellites collected essential data in the ensuing days. In parallel with this, UNOSAT was busy making available on its website many maps based on archival data. These maps provided detailed measurements of the topography of affected coastal regions, enabling relief organizations to assess the most probable areas of damage and plan their interventions accordingly.
The unprecedented demand for images put the Central Web Services at CERN under considerable strain because downloads of maps required large files to be loaded into server memory for relatively long periods. This resulted in problems with memory capacity, which threatened to block access to websites supported by CERN; however, a way of avoiding such data jams was quickly found by CERN's Internet Services Group. As a result, and because CERN's computer centre is manned around the clock, the UNOSAT data remained available continuously despite the growing number of requests. This was not the case for some of the computing centres in the affected countries, where servers were not sufficiently robust and key data became inaccessible at times.
To give a sense of the scale of the challenge, 200,000 maps were downloaded from the UNOSAT website during the whole of 2004, whereas this year this number was exceeded during the month of January alone. Moreover, UNOSAT, with a team of only 12 people, is already having to respond to new crises, such as the earthquake in Iran in February, while providing further analysis of the post-tsunami devastation. For example, UNOSAT recently prepared a detailed study of roads and bridges damaged by the tsunami, which is already being used by many organizations involved in rebuilding the affected regions.
Alain Retière, the head of UNOSAT, is confident that collaborating with CERN on advanced IT solutions can help facilitate the job of humanitarian organizations in responding to future natural disasters and complex crisis situations. Grid computing, which is being pioneered by the particle physics community, could prove particularly useful in handling the large amounts of data and significant data processing that UNOSAT's work involves.
The total amount of data UNOSAT is storing at CERN is relatively small at present - about 850 gigabytes (Gb) - but growing fast. NASA, the European Space Agency, the Centre National d'Etudes Spatiales and the Indian Space Research Organisation among others are giving UNOSAT access to archives containing terabytes of satellite images, and these need to be processed. Plans by some commercial companies to develop surveillance drones carrying arrays of digital cameras could one day result in the routine production of petabytes of image data from disaster zones, rivalling even the production of data at the Large Hadron Collider.
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Compiled by Hannelore Hämmerle and Nicole Crémel