P4.4
PNA and NAO patterns/indices versus midwestern temperature anomalies during El Niņo, La Niņa, and transition periods
Samuel John O'Connor, Purdue University, West Lafayette, IN
This presentation complements and extends a presentation given in another conference at this AMS annual meeting (Vincent et al., Symposium on Global Change and Climate Variations, 2003). In that paper, a possible statistical relationship between either the PNA or the NAO Index and temperature anomalies in the Midwest during ENSO winters, including transition periods, was explored. In general, the relationships were not very good, despite the fact that 11 different winter seasons were examined (4 El Niņo, 3 La Niņa and 4 Transition periods). Nevertheless, some interesting case studies were identified for further investigation, especially when the results were partitioned into a two-month (Nov-Dec) and three-month (Jan-Mar) period. One such example, the 1984-85 La Niņa event, is shown in the Vincent et al. paper. This study focuses on two additional cases, the 1982-83 El Niņo and the transition period, 1985-86, between the aforementioned 1984-85 La Niņa and the 1988-87 El Niņo. Results will be shown in a variety of formats, including time series of three-day averages (histograms) of PNA and NAO indices from 1 Nov- 31 Mar, as well as midwestern-averaged (10 stations) surface temperature anomalies. Scatter diagrams of either PNA or NAO values and Midwest temperature anomalies will also be utilized. Finally, a selection of daily 500 mb height and 850 mb temperature anomalies will be exhibited
Poster Session 4, Climate
Sunday, 9 February 2003, 5:30 PM-7:30 PM
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