1.                      Introduction

The development and application of chemistry transport models has a long tradition in and outside Europe. RIVM and TNO have independently developed models to calculate the dispersion and chemical transformation of air pollutants in the lower troposphere over Europe. The two models are the TNO model LOTOS (Builtjes, 1992; Schaap et al., 2004a) and the RIVM model EUROS (de Leeuw and van Rheineck Leyssius, 1990; van Loon, 1994, 1995; Matthijsen et al., 2002). LOTOS and EUROS were originally developed and used as photo-oxidant models (Builtjes, 1992; Hass et al., 1997; Hammingh et al, 2001, Roemer, 2003). During the last years attention was given to simulate the inorganic secondary aerosols SO4, NH4 and NO3. (Schaap et al., 2004a; Erisman and Schaap, 2004; Matthijsen et al., 2002) and carbonaceous aerosols (Schaap et al., 2004b). The EUROS model also contains the possibility to perform simulations for persistent organic compounds (Jacobs and van Pul, 1996).

 

The two models have a similar structure and comparable application areas. Hence, based on strategic and practical reasoning, RIVM/MNP and TNO agreed to collaborate on the development of a single chemistry transport model: LOTOS-EUROS. During 2004 the two models were unified which resulted in a LOTOS-EUROS version 1.0 (Schaap et al., 2005). For 2005 a project was defined to:

 

  1. Document the model version
  2. Perform validation studies
  3. Include several model features such as data assimilation and zooming.

 

In this report we provide a documentation of the LOTOS-EUROS model. The validation study, new developments and inclusion of several model features will be described in a forthcoming report.

The model description in this report is that of version 1.1, the model version operational at October, 1, 2005. This report is not intended to describe a fixed and definite status, because a model such as LOTOS-EUROS is under constant development. Hence, the documentation of the model will be updated continuously and made available through the LOTOS-EUROS website.