COVARIABILITY AND CLIMATIC CHANGES OF THE LOWER-TROPOSPHERE TEMPERATURES OVER THE NORTHERN-HEMISPHERE

The covariability and the long-term fluctuation of the lower-troposphe re temperatures is studied, applying factor analysis on grid point (10 00 divided by 500) hPa thickness data for the Northern Hemisphere. Abo ut 30 factors were retained and rotated for each season and year, but only about half of them were found to be significant. The grouping of the grid points according to the factor loadings has been mainly influ enced by the land and sea distribution. Three teleconnections were fou nd only, one in winter and two in summer. The winter one is a see-saw phenomenon between West Asia and North-West Scandinavia. In summer, th e British Isles were found to covary with East Canada and the same is the case for almost all the subtropical deserts. The study of the fact or scores revealed that the recent warming of the Earth's surface in t he lower troposphere appears over the continents only.