http://worldcat.org/entity/work/id/9437147

Relationships between El Nino-southern oscillation and the Arctic oscillation a climate-weather link

"Time series representing two of the climate systems' most leading variability in northern hemisphere, namely the El Nino-Southern Oscillation (ENSO) and the Arctic Oscillation (AO), together with 50 years of observed daily mean surface air temperature, precipitation over the conterminous United States, as well as circulation fields from NCEP/NCAR CDAS/Reanalysis are used to investigate the climate impact of ENSO and AO and their combined effects. Composites of ENSO only (El Nino, neutral, La Nina) phase, AO only (high, neutral, low) phase, and their nine combinations are constructed for US temperature, precipitation and the circulation fields for each 12 running season. The results show that both ENSO and AO have profound impact on US temperature and precipitation in winter. In general, the low index phase of AO resembles that of La Nina and high index phase of AO resembles El Nino. Therefore, during (C, AO- ) and (W, AO+), enhanced impact on temperature and precipitation anomalous field is expected. For example, while it is normally warmer and drier in the northern states, cooler and wetter in the southern states during El Nino years, the high index phase of AO provides much warmer winter for large areas of US from northern border to central and northeast than the low index phase of AO in the same phase of ENSO. The AO impact on precipitation is less well organized but the impact exists through out the year in the south and east coastal area, as well as the Tennessee and Ohio valley. These composites provide useful tools to support the 6-10 day, monthly and seasonal forecasts in the Climate Prediction Center."

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