Universität Hamburg - der Forschung, der Lehre, der Bildung, zur Homepage
CLICCS
Cluster of ExcellenceClimate, Climatic Change,
and Society (CLICCS)

Photo: J.Marotzke/ M.Böttinger

Theme A

A3 - Canopies in the Earth System

Chairs: Felix Ament (UHH), Jörn Behrens (UHH), Bernd Leitl (UHH)

CLICCS-funded Scientists: Kristin Ludewig (UHH), Harihar Jaishree Subrahmaniam (UHH), Lizeth Vásconez Navas (UHH),  Arim Yoon (MPI-M)

Team: Michael Bänsch (UHH), Friederike Bär (UHH), Annette Eschenbach (UHH), David Grawe (UHH), Frankziska Hanf (UHH), Frank Harms (UHH), Cathy Hohenegger (MPI-M), Kai Jensen (UHH), Johanna Metzger (UHH)

On land the lowest part of the atmosphere features a canopy, a zone where obstacles intersect the air and that acts as the interface between large-scale climate and social systems.

Prominent examples of canopies are cities and forests, which modulate the local climate considerably in a complex way, for example by reducing the mean wind speed and by enhancing turbulence intensity and gustiness. Canopy effects need to be accounted for to link global climate evolutions with the local perception of climate near the surface, where the link is most relevant for humans and the biosphere. The project contributes to the overarching CLICCS question through an improved physical understanding of weather and climate in forests and cities needed by Theme C.

Obstacles in the lower 100 m of the atmosphere distort the flow forming canopy layers. Vertically distributed sinks and sources result in a local modification of climate conditions.

The project will detail globally possible and plausible climate futures to the local scale and explain climate variability in canopies, a key component of the Earth system. It will extend the parameterizations of the ICON-ESM to represent effects of all canopy types explicitly on the model grid for envisaged resolution of a few kilometers. We will advance the knowledge on one of the fundamental questions in climate modeling as to what extent and how canopies modulate the climate in the lowest 100 m of the atmosphere.

The focus will be on transport processes within the canopy on different scales and the relevance of considering the three-dimensional structure of the flow. Since canopies interact with the surrounding atmosphere and pedosphere, this includes the reverse forcing exerted by the canopy layer on these climate system components.