Holocene hydrological cycle changes in the Southern Hemisphere documented in East Antarctic deuterium excess records

Four Holocene-long East Antarctic deuterium excess records are used to stud y past changes of the hydrological cycle in the Southern Hemisphere. We com bine simple and complex isotopic models to quantify the relationships betwe en Antarctic deuterium excess fluctuations and the sea surface temperature (SST) integrated over the moisture source areas for Antarctic snow. The com mon deuterium excess increasing trend during the first half of the Holocene is therefore interpreted in terms of a warming of the average ocean moistu re source regions over this time. Available Southern Hemisphere SST records exhibit opposite trends at low latitudes (warming) and at high latitudes ( cooling) during the Holocene. The agreement between the Antarctic deuterium excess and low-latitude SST trends supports the idea that the tropics domi nate in providing moisture for Antarctic precipitation. The opposite trends in SSTs at low and high latitudes can potentially be explained by the decr easing obliquity during the Holocene inducing opposite trends in the local mean annual insolation between low and high latitudes. It also implies an i ncreased latitudinal insolation gradient that in turn can maintain a strong er atmospheric circulation transporting more tropical moisture to Antarctic a. This mechanism is supported by results from a mid-Holocene climate simul ation performed using a coupled ocean-atmosphere model.