Precipitation predictions from the European Centre for Medium Range Weather (ECMWF) seasonal forecast system (System 4) are combined with observed precipitation data to generate forecasts of the standardized precipitation index (SPI) for Latin America, and their skill is evaluated over the hincast period 1981–2010. The value-added utility in using the ensemble S4 forecast to predict the SPI is identified by comparing the skill of its forecasts with a baseline skill based solely on the climatological characteristics of the SPI itself. As expected, skill of the S4-generated SPI forecasts depends on the month, location, and specific index considered (the 3- and 6-month SPI were evaluated). Added skill from the S4 for lead times equaling the SPI accumulation periods is primarily in regions with high intra-annual precipitation variability, and is found mostly for themonths at the end of the dry seasons for 3-month SPI, and half-yearly periods for 6-month SPI. Thu s, in the near term, the largest advances in the prediction of meteorological drought for Latin America are obtainable from improvements in near-real-time precipitation observations for the region. In the longer term, improvements in precipitation forecast skill from dynamical models will be essential in this effort.

SAIOTE CARRAO Hugo Miguel;  NAUMANN Gustavo;  MARINHO FERREIRA BARBOSA Paulo; 

2016-12-19

Publications Office of the European Union

JRC104401

978-92-79-64024-7 (print),    978-92-79-64025-4,   

1018-5593 (print),    1831-9424 (online),   

EUR 28260 EN,    OP LB-NA-28260-EN-C (print),    OP LB-NA-28260-EN-N (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC104401,   

10.2788/928 (print),    10.2788/826147 (online),