Significance of the normalized seasonality of wind field and its rationality for characterizing the monsoon

The significance of the normalized seasonality of wind field is theoretical ly studied and the intrinsic relationship between its critical value and th e definition of the monsoon region is revealed. As a result, the rationalit y which the monsoon region is characterized by the significant normalized s easonality is proved. Based on this, by use of the NECP/NCAR reanalysis dat a during 1958-1997, the spatial structure of the significant normalized sea sonality of wind field is investigated, and the significant baroclinity of the seasonal variation of the atmospheric general circulation in the vertic al direction is verified. Moreover, in the tropics there exists an anti-sym metric distribution between the significant seasonality in the eastern hemi sphere and that in the western hemisphere, and the monsoon is linked closel y to some important systems such as the subtropical highs, the night jet an d the west wind channels.