# INFORMATION & MODELS______________________________________________________

## Lakemip II participants :

## Lakemip II models :

## Lakemip II other data :

## links :

## 1) FLake official web page : Fresh water lake model

FLake is an integral (bulk) fresh-water lake model. It is based on a two-layer parametric representation of the evolving temperature profile and on the integral budget of energy for the layers in question. The structure of the stratified layer between the upper mixed layer and the basin bottom, the lake thermocline, is described using the concept of self-similarity (assumed shape) of the temperature-depth curve. The same concept is used to describe the temperature structure of the thermally active upper layer of bottom sediments and of the ice and snow cover. An entrainment equation is used to compute the depth of a convectively-mixed layer. A relaxation-type equation is used to compute the wind-mixed layer depth in stable and neutral stratification, where a multi-limit formulation for the equilibrium mixed-layer depth accounts for the effects of the earth's rotation, of the surface buoyancy flux, and of the static stability in the thermocline. Both mixing regimes are treated with due regard for the volumetric character of solar radiation heating. Simple thermodynamic arguments are invoked to develop the evolution equations for the ice and snow depths. In this way, the problem of solving partial differential equations (in depth and time) for the temperature and turbulence quantities is reduced to solving ordinary differential equations for the time-dependent parameters that specify the evolving temperature profile.

### Reference

Mironov, D., Heise, E., Kourzeneva, E., Ritter, B., Schneider, N. and Terzhevik, A. 2010: Implementation of the lake parameterisation scheme FLake into the numerical weather prediction model COSMO. Boreal Env. Res. 15: 218–230.

Mironov, D. V., 2008: *Parameterization of lakes in numerical weather prediction. Description of a lake model*. COSMO Technical Report, No. 11, Deutscher Wetterdienst, Offenbach am Main, Germany, 41 pp.

--> pdf : Flake Tech. Rep.

## 2) LAKE model official web page : Lake Model

The one-dimensional "k-epsilon" model, taking into account ice, snow formation, heat and moisture transport in bottom sediments and soil.

## 3) DYRESM official web page : DYRESM

DYRESM is a one-dimensional hydrodynamics model for predicting the vertical distribution of temperature, salinity and density in lakes and reservoirs. It is assumed that the water bodies comply with the one-dimensional approximation in that the destabilising forcing variables (wind, surface cooling, and plunging inflows) do not act over prolonged periods of time. DYRESM has been used for simulation periods extending from weeks to decades. Thus the model provides a means of predicting seasonal and inter-annual variation in lakes and reservoirs, as well as sensitivity testing to long term changes in environmental factors or watershed properties.

DYRESM can be run either in isolation, for hydrodynamic studies, or coupled to CAEDYM for investigations involving biological and chemical processes. The computational demands of DYRESM are quite modest and multi-year simulations can be performed on PC platforms under Windows operating systems. The code is written in modular fashion to support future updates and improvements.

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