A new and improved Multivariate ENSO Index (MEI)
Klaus Wolter, NOAA/ERL/CDC, Boulder, CO; and M. Timlin
This paper addresses the need for an internationally acceptable ENSO index that allows for the global definition of ENSO events under operational, near-realtime conditions. We developed the Multivariate ENSO Index originally as the first Principal Component of six atmosphere-ocean (COADS) variables in the tropical Pacific basin. It provides for a more complete and flexible description of the ENSO phenomenon than single variable ENSO indices such as the SOI or Niņo 3.4 SST. Here we describe a new effort to expand the MEI concept to include both satellite (OLR) and subsurface data. Since these data sets are only available for the last three decades, this project includes historical analyses to intercompare the new MEI with the original and other hybrid versions that go back further in the record. The best new version of the MEI is determined by assessing its ability to explain the most global precipitation variance, compared to the original MEI and other ENSO indices.
Session 11B, Seasonal-interannual variability - I
Wednesday, 14 January 2009, 4:15 PM-5:30 PM, Room 129B
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