Seasonal and latitudinal features of the greenhouse effect in Russia

The annual cycle of air temperature trends is analyzed in comparison with total cloud amount trends. It is shown that during the last 30 years the cloud amount changes were associated with air temperature trends with positive and negative correlation in cold and warm half-year, respectively, which is in perfect agreement with the well-known facts of the influence of clouds on radiation balance and of the latter on temperature regime of the atmosphere. In all cases, the greenhouse effect increases when the radiation budget is nearly zero due to physical-geographic features; the small contribution of the greenhouse effect to the budget change manifests itself in climate changes. A conclusion is drawn on the presence of a greenhouse component of CO₂ in the phenomena described; however, in the high latitudes, this effect is exceeded by long-term changes in cloud amount.