A new approach to construction of atmospheric circulation scenarios for making ecological predictions and planning is proposed. It is based on a combined use of hydrothermodynamic models and archived data on climate. The main feature required from the scenarios is that their information content in climatic aspect to be no less than that of climatic models of the general circulation of the atmosphere. In addition, the scenarios should reasonably accurate reconstruct any situation from the database used for its construction according to some preset criteria. Implementation of the approach is based on the factor analysis, measurement data assimilation, and optimal extrapolation on the informative basis. Depending on the aim of a study, multicomponent bases with a given time and spatial structure are constructed. Numerical models are used to fit and assimilate measurement data, to reconstruct missing data, to calculate the state functions, as well as the adjoint and sensitivity functions needed in forming the scenarios.