We describe a shallow-water type atmospheric model which includes the transport of moisture as well as related precipitation and convection effects. The model combines hydrodynamic nonlinearity of the standard shallow-water model with the intrinsic nonlinearity due to the precipitation threshold. It allows for both theoretical treatment by the method of characteristics and efficient numerical resolution using shock-capturing finite-volume schemes. Linearized in the dynamical sector, the model adequately reproduces the propagation of the edge of precipitation regions ͑precipitation fronts͒ found in earlier studies. Results of numerical experiments on simple wave scattering upon a moisture front are in agreement with analytical results and highlight the role of dissipative reflector played by precipitating zones. We also analyze the evolution of a disturbance propagating in a uniformly saturated region and obtain criteria for precipitation front formation. Finally, we simulate wave breaking as an example of essentially nonlinear phenomenon and show how moist effects modify the classical shock formation scenario.

[1] Recent studies have revealed that strong sea surface temperature (SST) fronts, on the scale of a Western Boundary Current, significantly affect not just the Marine Boundary Layer but the entire troposphere. This has aroused renewed interest in air-sea interactions. The present study investigates the atmospheric response to fixed SST anomalies associated with mesoscale oceanic eddies and submesoscale filaments, using idealized simulations. Our main result is that in weak wind conditions, the vertical velocity in the planetary boundary layer (PBL) is linearly proportional to the SST Laplacian. This is established by a quantitative analysis in the spatial space as well as in the spectral space. Comparing the responses to two different SST fields shows that vertical velocities are much more intense when the submesoscales are more energetic. These results hold for different configurations of the atmospheric large-scale state and for different PBL parameterizations. Surface winds play the role of low-pass filter and reduce the response at the smaller scales. To our knowledge, this study is the first to clearly reveal the high impact of oceanic submesoscales on the atmospheric boundary layer at midlatitudes, as well as the direct link between the vertical velocity and the SST Laplacian.Citation: Lambaerts, J., G. Lapeyre, R. Plougonven, and P. Klein (2013), Atmospheric response to sea surface temperature mesoscale structures, J. Geophys. Res. Atmos., 118,[9611][9612][9613][9614][9615][9616][9617][9618][9619][9620][9621]