  Three dimensional models that account for chemistry are useful tools to
predict the chemical composition of (exo)planet and brown dwarf atmospheres and
interpret observations of future telescopes. Recent Juno observations of the
NH3 tropospheric distribution in Jupiter also indicate that 3D chemical
modelling may be necessary to constrain the deep composition of the giant
planets of the Solar System. However, due to the high computational cost of
chemistry calculations, 3D chemical modelling has so far been limited. A
solution to include chemical kinetics in a 3D model is to use a reduced
chemical scheme. In this view, we have developed a reduced scheme containing 30
species and 181 reversible reactions, from the full chemical scheme of Venot et
al. 2012. This scheme reproduces accurately the vertical profiles of the
observable species (H2O, CH4, CO, CO2, NH3, and HCN) and has a large range of
validity. It can be used to study all kind of warm atmospheres, except hot
C-rich ones, which contains a high amount of C2H2. It can be used in 1D models,
for fast computations, but also in 3D models for hot giant (exo)planet and
brown dwarf atmospheres.
