ENSO and PDO-related variability in South Pacific circulation patterns and seasonal range prediction for Bolivia in South America
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Seasonal range prediction over North America has been based on intraseasonal and interannual variability related to the Pacific North America (PNA) pattern and El Niño and Southern Oscillation (ENSO), respectively. These events have an impact on the occurrence of atmospheric blocking and the long-term conditions for North America. Similar studies may determine seasonal range prediction valid for South America, specifically for the Bolivian Altiplano region. Previous studies have examined ENSO-related variability of the South Pacific Jetstream as well as atmospheric blocking. Using the National Centers for Environmental Prediction / National Center for Atmospheric Research (NCEP/NCAR) reanalysis tool, the character of the monthly circulations was studied over the South Pacific / South America sector from 1969–2017. Initial results show significant pattern development in the upper air circulation over the East Pacific and downstream of South America during winter for ENSO. Also, the interannual variability in the jet-stream pattern for the region as related to ENSO shows a 180 degrees phase difference for the current, negative Pacific Decadal Oscillation (PDO), while having a slightly more zonal pattern during the latter part of the 20th century (Positive PDO). Finally, it can be shown that the circulation pattern for 1999–2017 is different from that of the Positive PDO as indicated by a recent turnaround of the interdecadal variability of atmospheric blocking over the South Pacific Region. Further pattern recognition will be completed in conjunction with surface observation.