El Nino impacts on seasonal U.S. atmospheric circulation, temperature, and precipitation anomalies: the OLR-event perspective.

摘要

This study shows that, since 1979 when outgoing longwave radiation (OLR) observations became reliably available, most of the useful U.S. seasonal weather impact of El Nino events is associated with the few events identified by the behavior of outgoing longwave radiation (OLR) over the eastern equatorial Pacific ("OLR-El Nino events"). These events produce composite seasonal regional weather anomalies that are 95% statistically significant and robust (associated with almost all events). Results also show that there are very few statistically significant seasonal weather anomalies, even at the 80% level, associated with the non-OLR-El Nino events. A major enhancement of statistical seasonal forecasting skill over the contiguous United States appears possible by incorporating these results. It is essential to respect that not all events commonly labeled as El Nino events lead to statistically useful U.S. seasonal forecast skill.