World Meteorological Day – A look back at Hurricane Freddy

Meteorological Day

On the occasion of World Meteorological Day, Data Terra reiterates its support to the victims of Cyclone Freddy, especially in Malawi, Mozambique and Madagascar. As a reminder, this cyclone – which hit the South West Indian Ocean in February-March 2023 – broke several records according to the World Meteorological Organization:

– It will have lasted more than 30 days, the longest ever recorded for a cyclone (typhoon or hurricane),

– It is one of the longest trajectories (in km): 8000 km, with a very atypical path “in loop” between Madagascar and Malawi,

– The winds generated were of a rare violence: gusts of more than 60 m/s at some moments of the phenomenon and average winds of 209 to 252 km/h.

– The storm killed more than 463 people in Southern Africa, including 360 in Malawi, and caused considerable damage where heavy rains led to flooding and landslides.

Data Terra provides seamless and continuous access to the multi-source, multi-domain and multi-agency data set of the Earth system. The data are deployed and supported by its own Data and Service Centers (DSCs) on national and regional infrastructures. One of the major challenges of IR is to enable and facilitate the implementation of cross-cutting use cases, involving computer resources and heterogeneous data.

The accessible data are, on the one hand, satellite data acquired by international space centers and multi-source observation data from in situ devices, remote sensing, experiments, or inventories acquired within the Observatories. On the other hand, higher level data (spatially and/or temporally averaged, aggregated,…) and derived products come from the processing of regular production services. For the data acquired through observation IRs, Data Terra ensures the curation and dissemination as well as the processing for the production of derived products.

The cyclone seen by geostationary satellites

DATA TERRA’s Atmosphere cluster, AERIS, federates at the national level data management activities and scientific expertise in the atmosphere. Atmospheric research data are intended to be stored, distributed and combined, whether they are data from long-term observation sites, results of large field or airborne campaigns, satellite measurements, or results of laboratory experiments. These data allow us to record the causes and signs of climate change, to better understand the chemistry and physics of our atmosphere, and to probe the interactions with other compartments of the Earth system.

Cyclone Freddy was thus observed from geostationary satellite images, and an animation produced by the ICARE/AERIS data and services center shows the cyclone’s exceptional trajectory over 35 days. We can see the famous “loop” trajectory of the cyclone.

  • This animation shows the trajectory of Hurricane Freddy using geostationary satellite images. It has been realized by our data and services center ICARE/AERIS.

Cyclone progression and intensity in the Indian Ocean

Cyclones draw their energy from the heat of the ocean, like a fire needs oxygen to fuel combustion. The energy content of the ocean, i.e. the amount of heat contained in a layer of water higher than 26°, allows quantifying the energy available to fuel a cyclone.

DATA TERRA’s Ocean Data and Services Center, ODATIS, operates and manages many of the data that helped illustrate the exceptional size of Hurricane Freddy. It is possible to find these data in the ODATIS catalog, from the work of Shom, CERSAT and AVISO.

Track of Cyclone Freddy (small circles, wind scale in m/s) in the Mozambique Channel, superimposed on sea level anomalies measured by altimeters (measured in m) on March 7, 2023. (SLA data: Copernicus Marine Service, track: Regional and Mesoscale Meteorology Branch (RAMMB) Noaa/Nesdis; AVISO+ figure)

Sur le site web d’AVISO, il est possible de voir la progression et l’intensité du cyclone via plusieurs paramètres physiques tels que la hauteur significative des vagues, la direction de la houle et la vitesse du vent. On y découvre que les vitesses des vents semblent se renforcer dans les zones ou des anomalies de hauteur de mer sont plus élevées.

Le cyclone Freddy, qui se caractérise par une longévité exceptionnelle, a causé des dégâts considérables. Le travail des scientifiques permet de démontrer que le réchauffement climatique tend à rendre les cyclones plus intenses. Nous profitons de cette Journée Mondiale de la météorologie pour sensibiliser à l’importance d’étudier ces phénomènes avec des approches plus transverses et intégrées. Celles-ci aideront sans doute à agir plus durablement face à des risques naturels et climatiques de plus en plus aléatoires et qui impactent grandement les populations et la biodiversité.