Tapio Schneider
California Institute of Technology, USA
Turbulent Water Vapor Transport in the Atmosphere: Phenomenology and Stochastic Models
Abstract: Fluxes effected by macroturbulent eddies (>1,000 km scale) dominate the poleward water vapor transport from lower into higher latitudes in Earth's atmosphere. Particle displacements in macroturbulent eddies are approximately confined to two-dimensional isentropic surfaces, suggesting that understanding this approximately two-dimensional transport of water vapor is a starting point for understanding the hydrological cycle of the atmosphere.As a particle is displaced poleward along an isentropic surface, it cools adiabatically, leading to condensation of water vapor, precipitation, and an irreversible poleward water vapor flux. The kinematics of this process is captured in advection-condensation models, in which a turbulent (possibly wavy) flow advects water vapor as a passive scalar with a strongly nonlinear sink that prevents the water vapor concentration from exceeding a spatially dependent saturation value.
I will discuss the kinematics of such two-dimensional advection-condensation models with homogeneous turbulent velocity fields, as well as one-dimensional stochastic models with Gaussian velocity fields, which capture the kinematics of the two-dimensional turbulent models well. Analysis of the stochastic models in limiting cases and solution of certain first-passage time problems provides insight into processes controlling the distribution of atmospheric water vapor.
This talk is based on joint work with Paul O'Gorman, Karen Smith, and Chris Walker.
| Zeit: | Freitag, 16. Juni, 2006, 14.15 (Kaffee/Tee um 15.30) |
| Ort: | FU Berlin, Arnimallee 2-6, Raum 032 im EG |