assessment of synoptical pattern of inversion in mashhad using factor

in order to identify different types of effective weather on patterns of inversion in mashhad, the researchers first prepared the inversion statistics, then, the sea level pressure and finally they prepared access to the zero meeting gmt cumulative 2.5 degrees in the range 20 to 47.5 degrees to 67.5 degrees north and 35 east center, university ncep angelia east of england norwich city. then for the classification of pressure data, factor analysis has been used. the significance of this method is that while the number of variables reduces, the amount of variance in the original data is preserved. then the classified clusters array ward is done and turned to the 7 main agents, and then the map of each group was composed. the results show two types of summer, three types of winter and two types of autumn pattern. the inversion of the cold seasons has strong stability and the continuity is more. checking the other map patterns, high-pressure patterns are seen more active and in the seven existing types, type five is the strongest. keyword: weather types, inversion, principle component analysis, clustering, classification of pressure patterns.