Modulation of station rainfall over the western Pacific by the Madden-Julian oscillation

Rainfall data from 140 stations in the PACRAIN network in the tropical western Pacific are analysed to assess the signal due to the Madden-Julian Oscillation (MJO). During northern winter, the station rainfall difference between the wet and dry phases of the MJO is up to 6 mm day-1, compared to the climatological mean value of 12 mm day-1. The anomalies have a strong spatial coherence, with over 80% of the individual point station anomalies having the same sign as the large-scale rainfall anomaly, as determined by the mainly satellite-derived CMAP rainfall product