Many studies examining the MJO's impacts utilize the Real-Time Multivariate MJO index which utilizes a combination of outgoing longwave radiation (OLR) and upper- and lower-level zonal winds. OLR is only available since 1974, and consequently, these studies only have 40 years of data with which to work. However, recently, Oliver and Thompson (2012) have developed an extended MJO dataset that goes back to 1905 using surface pressure reconstructions.
A preliminary analysis of this dataset shows similar robust relationships between TC activity and MJO phase extending back to 1905. In addition, given the 100+ years of data available with this new dataset, relationships between MJO phase-TC activity and longer-period indices such as the Atlantic Multidecadal Oscillation and El Niño-Southern Oscillation can also be investigated. These results will be discussed in detail in this presentation.