<P> Different meteorological factors affect the Argentine climate . Some of these factors are local while others come from other countries . </P> <P> The most important geographical factors that influence the climate of Argentina are latitude, elevation, and distance from the sea . With Argentina extending from 22 S to 55 S, there are differences in the amount of incoming solar radiation and the amount of daylight received in each season, which affects temperature . Thus, temperatures decrease from north to south due to the differences in latitudes . </P> <P> Although the centre and the eastern parts of the country are mostly flat, the west is mountainous . Both the Andes and Sierras Pampeanas affect the climate of Argentina, leading to differences in temperature, pressure, and spatial distribution of precipitation depending on the topography and altitude . Here, the Andes exert an important influence on the climate . Owing to the higher altitudes of the Andes north of 40 S, they completely block the normal westerly flow, preventing low pressure systems containing moisture from the Pacific Ocean from coming in . Thus, much of Argentina north of 40 S is dominated by wind circulation patterns from the South Atlantic High . South of 40 S, the Andes are lower in altitude, allowing much of Patagonia to be dominated by westerly winds and air masses from the Pacific Ocean . However, the north--south orientation of the Andes creates a barrier for humid air masses originating from the Pacific Ocean . This is because they force these air masses upwards, cooling adiabactically . Most of the moisture is dropped on the Chilean side, causing abundant precipitation and cloudiness while on the Argentine side, the air warms adiabatically, causing it to become drier as it descends . Thus, an extensive rain--shadow is present in much of Patagonia, causing it to receive very little precipitation . The Sierras Pampeanas influences the climate on a much smaller scale than the Andes . </P> <P> Distance from the sea is another important geographic factor . Owing to the shape of the country, the close proximity to the ocean means that most of the country, excluding the north is moderated by the surrounding oceans, leading to lower thermal amplitudes than comparable latitudes in the northern hemisphere . The two main currents that impact the climate of Argentina are the Brazil Current from the north and the Malvinas Current from the south (a branch of the Antarctic Circumpolar Current). The Brazil Current transports warm subtropical waters southwards while the Malvinas Current transports cold, subantarctic waters northwards . The Malvinas Current cools the coastal areas, particularly during winter when the current is more stronger . Thus, coastal areas of the Pampas have cooler summers and a longer frost period owing to the cold Malvinas Current . As well, it is the main factor in making Tierra del Fuego colder than at comparable latitudes in the northern hemisphere in Europe since it is influenced by the cold Malvinas Current rather than the warm North Atlantic Current . </P>

Where does the warm moist air mass over the andes mountains in argentina come from