Some indicators of interannual rainfall variability in Patagonia (Argentine)

GONZÁLEZ, MARCELA HEBE

Climate Variability ‐ Regional and Thematic Patterns

intech

Año: 2013; p. 1 - 30

Some large scale atmospheric forcings are described and then their influence on seasonal Patagonia rainfall is investigated. The relation between winter, spring, autumn and summer rainfall and some patterns of sea surface temperature (El Niño-Southern Oscillation, the Indian Dipole and sea surface temperatures in the surrounding oceans) are detailed. The influence of circulation patterns (Rossby waves displacing over the Pacific Ocean, regional cyclonic anomalies and the Antarctic Oscillation) are also considered. Results show that the factors which affect precipitation highly depend on the season and the region. The main conclusion is that cyclonic anomalies over the surrounding Atlantic and Pacific Oceans and over the continent enhance precipitation all over the Patagonia in all seasons. Besides, the weakening of subtropical heights and sub-polar lows over the Pacific Ocean is associated with more than normal precipitation all over the whole Patagonia especially in transition seasons when there is an evident relation with AAO. Warm phase of ENSO enhances rainfall in the east of Patagonia in autumn and winter and in the west and south of Patagonia in spring. Warm water in the Pacific coasts tends to increase rainfall in central and east of Patagonia in autumn meanwhile cold Atlantic coast enhances precipitation in west and south Patagonia in spring.