Water vapor and circulation: spatial and annual variations over Argentina

Subtropical Argentinean areas are characterized by strong spatial and annual variation of precipitation. These variations are linked to the annual distribution of water vapor associated with the annual variation of atmospheric circulation over southern South America The main goal of the present paper is to study the annual variation of water vapor and atmospheric circulation characteristics over Southern South America. Specific humidity, precipitable water, winds dominant and water vapor transport are analyzed using the 1958 - 82 data records from the Argentinean upper air network. The results show maximum water vapor in lower levels during summer in subtropical areas of Argentina. Maximum standard deviation of specific humidity appears in 850 hPa level during autumn and summer in the same region. Precipitable water decrease towards west during winter and transition months. Otherwise variation is North South direction during summer. Frequency wind directions analysis over Salta and Resistencia during summer show a penetration of the monsoon associated to the movement of Atlantic subtropical anticyclone. Regarding meridional transports, a convergence zone around 34° S over central-east region is observed during summer. In winter, transport towards north is prevailing and variation of transport towards south is enhanced over the east subtropics. The results shows eastwards zonal transports all around the year in the analyzed region.