MAESTRO : étudier les nuages convectifs et leur relation avec le réchauffement climatique

Safire's ATR42 was in Cape Verde (Sal Island) to carry out scientific flights between August 10 and September 10, 2024.

The aircraft flies either solo or in coordination with the German HALO aircraft and/or the Earthcare or Sentinel 1 (SAR) satellites.

As of August 19, 8 of these flights have already been carried out for a cumulative duration of 30 hours, allowing a great harvest of data while waiting for the occurrence of a deep convection episode in the investigation area.

A summary of MAESTRO

The goal of the MAESTRO project - part of the international ORCESTRA initiative - is to understand the mesoscale organization of tropical organization over the ocean. To do this, we must characterize the physical processes by which clouds interact with each other, with their environment and with the boundary layer. From these processes, scientists will seek to explain what controls the diversity of convective clouds encountered (more or less deep, precipitating or not, etc.), the spacing and spatial organization of clouds (formation of regular patterns, transition between shallow and deep convection), and the greater or lesser tendency of clouds to self-aggregate into lines / clusters / etc.

To do this, it is necessary to characterize 3 environments:

1. the organization of the boundary layer under the clouds (heterogeneities of water vapor, temperature, turbulence, wind, aerosols, coherent structures of the thermal type or cold pockets),
2. the spectrum of convective clouds, in particular: the size distribution of the cloud base + microphysical and turbulent properties inside the clouds + cloud geometry (vertical extension, cloud cover) + occurrence of precipitation / drizzle + rising and falling mass fluxes,
3. the properties of the clear air between the clouds (distribution of humidity, presence of mesoscale circulations, radiative fluxes, aerosols). It is therefore necessary to fly under the clouds, at the base of the clouds and in the middle troposphere. The flights do not consist of "chasing clouds" but of characterizing the cloud field statistically. 

These scientific objectives are also accompanied by cal/val exercises of the EarthCare satellite, coinciding with the satellite's passages near the Cape Verde Islands.

The instruments used on board the SAFIRE ATR42

• RALI (RASTA+LNG) in vertical view
• BASTA in horizontal view
• aWALI: airborne version of the Raman lidar WALI (measures water vapor, temperature, aerosols and clouds) in horizontal view
• Sensors for rapid measurement of wind (turbulence), air temperature and water vapor flux
• PMA for aerosols, liquid water clouds and ice clouds (at least: UHSAS, CDP-2, 2D-S, FCDP, FSSP300, Nevzorov
• Basic Safire instruments including WVSSII, pygeometers (CGR4), pyranometers (CMP21 with red filter, CMP22)
• CLIMAT radiometer
• GSMA Fastwave fast hygrometer - first use in aircraft version

Une page spécifique du site de projet MAESTRO décrit en détail l'instrumentation.

Scientific managers

• Sandrine Bony, LMD
• Julien Delanoë, LATMOS

Participants from the laboratories involved

• LMD - Nicolas Rochetin, Jean-Louis Dufresne, Basile Poujol, Nicolas Maury, McKim Brett, Emilie Fons, Enora le Gall, Clarisse Dufaux
• LATMOS - Sophie Bounissou, Kevin Huet, Emmeline François
• LSCE - Patrick Chazette, Jeremy Lagarrigue, Laurent Forges, Frédéric Laly, Valentin Guillet
• LAMP - Pierer Coutris, Thierry Latchimy, Antoine Baudoux, Alfons Schwarzenboeck, Guy Febvre
• LAERO - Marie Lothon, Hélène Cassan, Louis Jaffeux
• AERIS - Vincent Douet, Jérémie Trules
• LEGOS - Thomas Fiolleau, Louis Netz, Laurent Gouttesoulard
• CNRM - Fleur Couvreux, Emma Chauvin, Philippe Peyrillé, Florent Beucher
• ICTP - Giovanni Biagoli
• IGN - Touchent Pierre

Funding

• ERC (European Research Council) Advanced Grant
• CNES/ESA (CalVal EarthCare)

Photo gallery