The effect of two types of El Ni???±o on the southerly low?￠????level jets in North America

摘要

Low?￠????level jets (LLJs) are frequent weather phenomena in many regions of North America and have profound impacts on precipitation and wind energy. We used a 31?￠????year (1979?￠????2010) three?￠????hourly reanalysis data set to examine the teleconnection between southerly LLJ activity in North America and the two dominant patterns of the equatorial Pacific Ocean sea surface temperature anomalies characterized by El Ni???±o and El Ni???±o Modoki. We show that El Ni???±o and El Ni???±o Modoki exert different effects on the jet activities, and the results vary by region and by season. Overall, El Ni???±o Modoki affects jet activity all year round, but El Ni???±o's influence is limited mostly to the cold season (October?￠????March). El Ni???±o Modoki induces larger changes in jet frequency, but El Ni???±o's influence extends to larger regions. A better understanding of this teleconnection can be used to improve seasonal predictions of precipitation and wind energy resources in regions of North America.