Single-column surface-atmosphere climate modelling

The interconnections between the land including water surfaces and the Earth’s climate system involve numerous non-linear processes. Tridimensional weather and climate models use quantitative methods to simulate the interactions of the important drivers, including atmosphere, oceans and lakes, land surface, biosphere and ice. They require a huge amount of computing resources, however. The use of a single-column model (SCM) provides an alternative, practical and economical framework for assessing nonlinearities of the surface types to current and perturbed climatic conditions. A coupled atmosphere-surface SCM, nicknamed FIZC, has been developed to investigate numerically the nonlinear interactions occurring in the lower atmosphere. It includes the contributions to the evolution of large-scale circulation dynamics in combination with diabatic contributions as parameterized in tridimensional weather and climate models, thus allowing for a realistic time evolution of the prognostic atmospheric temperature, moisture and winds. Recently, FIZC has been used to explore some of the non-linear interactions in the vertical dimension between the lower atmosphere and the deep-Lake Geneva in Switzerland.

coupling process taking place at the air-water interface

Schematic diagram showing the coupling process taking place at the air-water interface in the lowest atmospheric model layer and the upper lake model layer; Rs,sfc represent the incoming and reflected solar radiation fluxes, RL,sfc the atmospheric and the surface longwave radiation fluxes, QH and QE, the sensible and latent heat fluxes, QN,sfc the surface energy budget, [u, v]anem  the anemometer wind speed components, tsfc the surface wind stress, Tsfc the surface water temperature, αw the water surface albedo, CD, the drag coefficient, and k-ε represents the lake model used in this study (source Goyette and Perroud, 2012).

REFERENCES

Goyette, S., 2016 : Numerical investigation with a coupled single-column lake-atmosphere model. Using the Alpert-Stein Factor Separation Methodology to assess the sensitivity of surface interactions. Climate Dynamics, 48, 2359-2373. DOI 10.1007/s00382-016-3209-1

Perroud, M., and S. Goyette, 2012 : Interfacing a one-dimensional lake model with a single-column atmospheric model II. Thermal response of the deep Swiss Lake Geneva under a 2 x CO2 global climate change. Water Resour. Res., 48, W06522, doi:10.1029/2011WR011222.

Goyette, S. and M. Perroud, 2012 : Interfacing a one-dimensional lake model with a single-column atmospheric model: Application to the deep Lake Geneva, Switzerland. Water Resour. Res., 48, W04507, doi:10.1029/2011WR011223.