Airborne observations of Arctic air mass transformations during the HALO-(AC)3 campaign

The HALO-(AC)3 campaign was conducted in March and April 2022 to investigate warm air intrusions into the Arctic and marine cold air outbreaks. In coordinated flights over the Arctic, the High Altitude and Long Range Research Aircraft (HALO), equipped with a remote sensing payload and dropsondes, investigated these air mass transformations together with the research aircraft Polar 5 and Polar 6. In this report, we give an overview about the research flights and preliminary results from projects, which are carried out by employees of the Leipzig Institute for Meteorology (LIM).Die HALO-(AC)3 Kampagne wurde im März und April 2022 durchgeführt, umWarmlufteinbrüche in die Arktis und marine Kaltluftausbrüche zu untersuchen. Das 'High Altitude and Long Range Research Aircraft' (HALO), ausgestattet mit Instrumenten zur Fernerkundung und Standardmeteorologiesonden, untersuchte zusammen mit den Forschungsflugzeugen Polar 5 und Polar 6, in koordinierten Flügen über der Arktis, diese Veränderungen der Luftmassen. In diesem Bericht wird eine Übersicht über die durchgeführten Forschungsflüge gegeben und Forschungsprojekte werden vorgestellt, welche von Mitarbeitern des Leipziger Instituts für Meteorologie (LIM) durchgeführt werden

EUREC⁴A

The science guiding the EUREC⁴A campaign and its measurements is presented. EUREC⁴A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC⁴A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC⁴A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC⁴A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement

EUREC⁴A

The science guiding the EUREC⁴A campaign and its measurements is presented. EUREC⁴A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC⁴A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC⁴A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC⁴A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement

TRIBOLOGICAL PROPERTIES OF SILICON INFILTRATED SiC GRADES CONTAINING CARBON PARTICLES

Le matériau SiSiC est intéressant pour de nombreuses applications telles que les roulements, bagues d'étanchéité ou pièces de pompes du fait de ses excellentes propriétés tribologiques. Cependant le comportement du matériau n'est pas satisfaisant dans des conditions de fonctionnement purement à sec. Un matériel SiSiC modifié avec différentes teneurs en particules de carbone a été développé, il combine la grande résistance à l'usure du SiSiC et le faible coefficient de frottement du carbone. Le comportement tribologique de ces matériaux ainsi que les mécanismes d'usure ont été étudiés.SiSiC-ceramic is useful for many applications ie bearings, seal rings or pump parts because of its excellent tribological properties. Exceptionally under purely dry running conditions the material's behaviour is unsatisfying. Modified SiSiC with different content of carbon particles was developed which combine the high wear resistance of SiSiC and the low friction coefficient of carbon. For these materials the tribological behaviour and the wear mechanism was invetigated

Airborne observations of Arctic air mass transformations during the HALO-(AC)3 campaign

The HALO-(AC)3 campaign was conducted in March and April 2022 to investigate warm air intrusions into the Arctic and marine cold air outbreaks. In coordinated flights over the Arctic, the High Altitude and Long Range Research Aircraft (HALO), equipped with a remote sensing payload and dropsondes, investigated these air mass transformations together with the research aircraft Polar 5 and Polar 6. In this report, we give an overview about the research flights and preliminary results from projects, which are carried out by employees of the Leipzig Institute for Meteorology (LIM).Die HALO-(AC)3 Kampagne wurde im März und April 2022 durchgeführt, umWarmlufteinbrüche in die Arktis und marine Kaltluftausbrüche zu untersuchen. Das 'High Altitude and Long Range Research Aircraft' (HALO), ausgestattet mit Instrumenten zur Fernerkundung und Standardmeteorologiesonden, untersuchte zusammen mit den Forschungsflugzeugen Polar 5 und Polar 6, in koordinierten Flügen über der Arktis, diese Veränderungen der Luftmassen. In diesem Bericht wird eine Übersicht über die durchgeführten Forschungsflüge gegeben und Forschungsprojekte werden vorgestellt, welche von Mitarbeitern des Leipziger Instituts für Meteorologie (LIM) durchgeführt werden

Airborne observations of Arctic air mass transformations during the HALO-(AC)3 campaign

The HALO-(AC)3 campaign was conducted in March and April 2022 to investigate warm air intrusions into the Arctic and marine cold air outbreaks. In coordinated flights over the Arctic, the High Altitude and Long Range Research Aircraft (HALO), equipped with a remote sensing payload and dropsondes, investigated these air mass transformations together with the research aircraft Polar 5 and Polar 6. In this report, we give an overview about the research flights and preliminary results from projects, which are carried out by employees of the Leipzig Institute for Meteorology (LIM).Die HALO-(AC)3 Kampagne wurde im März und April 2022 durchgeführt, umWarmlufteinbrüche in die Arktis und marine Kaltluftausbrüche zu untersuchen. Das 'High Altitude and Long Range Research Aircraft' (HALO), ausgestattet mit Instrumenten zur Fernerkundung und Standardmeteorologiesonden, untersuchte zusammen mit den Forschungsflugzeugen Polar 5 und Polar 6, in koordinierten Flügen über der Arktis, diese Veränderungen der Luftmassen. In diesem Bericht wird eine Übersicht über die durchgeführten Forschungsflüge gegeben und Forschungsprojekte werden vorgestellt, welche von Mitarbeitern des Leipziger Instituts für Meteorologie (LIM) durchgeführt werden

EUREC4A

Abstract. The science guiding the EUREC4A campaign and its measurements are presented. EUREC4A comprised roughly five weeks of measurements in the downstream winter trades of the North Atlantic – eastward and south-eastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC4A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or, or the life-cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso (200 km) and larger (500 km) scales, roughly four hundred hours of flight time by four heavily instrumented research aircraft, four global-ocean class research vessels, an advanced ground-based cloud observatory, a flotilla of autonomous or tethered measurement devices operating in the upper ocean (nearly 10000 profiles), lower atmosphere (continuous profiling), and along the air-sea interface, a network of water stable isotopologue measurements, complemented by special programmes of satellite remote sensing and modeling with a new generation of weather/climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC4A explored – from Brazil Ring Current Eddies to turbulence induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview EUREC4A's outreach activities, environmental impact, and guidelines for scientific practice. </jats:p