Home page of L95-GRS


	Lorenz95-GRS coupled model (L95-GRS) L95-GRS mimics meteorology with continental and transcontinental transport and photochemistry of ozone. It is mainly meant to test advanced data assimilation methods.

Model description

The L95-GRS model is a low order coupled chemistry meteorology model. On the one hand, there is the chaotic Lorenz-95 (L95) one-dimensional model which simulates winds along a mid-latitude circle. It has 40 variables that are considered to be magnitude and direction of winds at 40 locations. On the other hand, there is a reduced photochemistry module, the Generic Reaction Set (GRS). GRS consists of 7 chemical species supposed to represent the tropospheric chemistry of ozone formation from VOC and NO_x emissions.

In the L95-GRS, the wind variables from the L95 advect the chemical species from GRS, thus creating a coupled chemistry meteorology model. This coupling aims at creating a simplified model, of low order, capable to render the usual variability of ozone chemistry on a regional to transcontinental scale.
It serves as a playground for testing advanced data assimilation schemes in the context of atmospheric chemistry. More specifically, it has been tested with the iterative ensemble Kalman smoother (IEnKS).
For more details on the model, its equations and its parametrisation, please refer to the reference below.

Another model, the L95-T model, is also available for download. It was introduced in Bocquet, M., & Sakov, P. (2013).
Similarly, it consists of the L95 wind field advecting a simple tracer field.
Download

L95-GRS (v1.0)
L95-T
Reference

Haussaire, J.-M. & Bocquet, M. (2016). A low-order coupled chemistry meteorology model for testing online and offline data assimilation schemes: L95-GRS (v1.0).
Geosci. Model Dev., 9, 393-412, doi:10.5194/gmd-9-393-2016

Bocquet, M., & Sakov, P. (2013). Joint state and parameter estimation with an iterative ensemble Kalman smoother.
Nonlinear Processes in Geophysics, 20(5), 803-818. doi:10.5194/npg-19-383-2012
Contact

If you have further questions, please contact: Jean-Matthieu Haussaire (Jean-Matthieu.Haussaire@enpc.fr)