ENSO impact on dry sequences during different phenological periods in the East-Northeast of Argentina

PENALBA OC, PÁNTANO V C., SPESCHA L B.; MURPHY G M

Conferencia; III International Conference on ENSO: Bridging the gaps between Global ENSO Science and regional processes, extremes and impacts; 2014

The magnitude of rainfall during El Niño (EN) or La Niña (LN) events is recognized to cause different impact over the yields of crops in the east-northeast of Argentina. However, there is lack of understanding on how often these rainfalls occur. In order to better understand the impact of scarce of rainfall over agriculture activity; this paper analyzes dry sequences in different phenological periods for ENSO phases during 1970-2010. For this purpose, consecutive days with rainfall below 5mm were quantified using daily observed rainfall in 30 stations. In general, during austral autumn, EN and LN dry sequences show an opposite signal. For example, long dry sequences (more than 15 days) in south Buenos Aires province are characterized by slightly more (less) frequency during LN (EN) events, limiting the water recharge of the soil for the development of the crops. During austral winter, long dry sequences are more frequent under both events, mainly in the centre of the region. This analysis is better understood when the water storage in the soil is incorporated, assessing the impact of long dry sequences.