Nocturnal equilibria of the atmospheric boundary layer at Dome C, Antarctica

Samenvatting

We aim to investigate the dynamical behavior of the nocturnal boundary layer as observed at Dome C, Antarctica. Understanding of this is currently limited as it results from a complex interplay of turbulent dynamics, atmospheric radiation, the surface and subsidence.

Recent observations show that the Antarctic stable boundary layer exhibits two distinct regimes: a continuously turbulent regime (high wind speeds) in which the air temperature remains relatively mixed, and a (very) weak turbulent regime (low wind speeds) in which air at the surface can be 25 K colder than the temperature at 10 meters! Small changes in wind speeds may lead to rapid transitions between these regimes giving an 'S'-shaped curve.
Both conceptual and global circulation models indicate that radiative energy transfer and coupling to the underlying surface are of critical importance to obtain this observed behaviour. These aforementioned models, however, do not give detailed information about the dynamics, the structure of turbulence, and rely on parametrizations of turbulence itself. As such, specific research questions remain unanswered, for example:
How does the quasi-equilibrium depend on external parameters such as the driving pressure gradient, and radiative transfer?

We aim to answer these research questions by use of detailed turbulence resolving simulations. Novel in our project is that we combine a Direct Numerical Simulation (DNS) with atmospheric radiative energy transport, and (later) a thermodynamic coupling to an underlying surface. To our knowledge, such a configuration has not been employed before in studies of the nocturnal stable boundary layer.

Kenmerken

Projectnummer

16703

Hoofdaanvrager

Ir. S.J.A. van der Linden

Verbonden aan

Technische Universiteit Delft, Faculteit Civiele Techniek en Geowetenschappen, Afdeling Geoscience & Engineering

Looptijd

17/01/2018 tot 31/12/2018