Abstract ID: 455

REGIONAL PRECIPITATION VARIABILITY OVER THE EASTERN AMAZON IN THE CONTEXT OF TROPICAL CLIMATE DYNAMICS

The intrinsic characteristic of the Amazonian climate is the existence of a complex and high temporal and spatial variability of the tropical convective activity and precipitation, which are the most important climate variables of the region. A statistical-dynamic approach (using percentiles, empirical orthogonal functions, composites and correlations) is conducted in the present work in order to investigate the seasonal pluviometric variability over the eastern Amazon during rainy season (December to May). These analyses are based on RPCH* precipitation which is a new integrated database containing in situ measurements extracted from 150 rain-gauge stations scattered over the eastern Amazon, during the last 30 years (1978-2007). The climatological precipitation features over the eastern Amazon as depicted by percentiles considering five categories (very wet, wet, normal, dry and very dry) revealed a high spatial variability of rainfall on a regional scale. The correlation maps between equatorial Pacific and tropical Atlantic SST indices and precipitation demonstrated the existence of preferential regions with significant impacts on Amazonian rainfall, which is relevant on regional climate monitoring and forecasting tasks. EOF analyses and the composites results for large-scale climate scenarios observed in Pacific (El Niño and La Niña phases) and Atlantic (meridional SST gradient) indicated that regional pluviometric variability, considering the five precipitation categories, in the context of tropical climate dynamics, is explained by the large-scale atmospheric circulation patterns associated with the ZCAS and ZCIT. * The project RPCH is funded by FINEP/MCT.

Session:  Feedbacks to Climate - Land cover, surface hydrology, and atmospheric feedbacks.

Presentation Type:  Poster