Contrasting the stronger polluted and more continental marked Northern Hemisphere (NH) with the more pristine and more maritime pronounced Southern Hemisphere (SH) provides a natural laboratory to investigate and to better understand the direct and indirect (via the modification of clouds) role of aerosols in the climate system. We are proposing a coordinated joint HALO-mission to obtain in-situ observations and remote sensing of aerosol and cloud microphysical properties in cold super-liquid and mixed-phase clouds, where the differences in ice nucleating particles (INP) show the largest effect on the freezing temperatures.
Hypothesis: Aerosol sources, transport, processing, and aerosol particle physical and chemical properties resulting from aerosol-cloud-interaction (ACI) differ in the NH and the SH, which results in differences in super-cooled and mixed phase cloud compositional, microphysical, dynamic and radiative properties.
HALO observations and leads:
· In-situ measured aerosol, CCN, BC abundance and properties (TROPOS)
· In-situ measured INP and CPR properties (TROPOS and Uni Frankfurt/KIT)
· In-situ measured liquid, mixed-phase and ice cloud microphysical properties (DLR and KIT)
· Cloud radiative properties and cloud top radiative cooling (LIM)
· Remote sensing (ground-based, HALO and satellite) of aerosol and cloud microphysical properties (DLR and TROPOS)
· In-situ measurements of water vapor and tracers (DLR)
The HALO-South mission will be synchronized with DACAPO-goSouth. Furthermore, it is planned to carry out accompanying atmospheric measurements in the marine environment with the German research vessel Sonne.
Platform: HALO aircraft
Location: New Zealand region in combination with NIWA and TROPOS ground-based remote sensing. Additional ship observations proposed.
Timing: October 2025
- Andreas Macke (macke<@>tropos.de)
- Mira Pöhlker (poehlker<@>tropos.de)