Global lightning activity from the ENSO perspective

The recently reprocessed (1998-2006) OTD/LIS space-based lightning database is used to investigate the global lightning climatology in response to the ENSO cycle. Temporal correlation maps depicting lightning anomalies-NINO3.4 identify areas that generally follow patterns similar to the widely documented ENSO-related precipitation anomalies. However, areas having statistically significant lightning anomaly-NINO3.4 correlations accompanied by non-significant precipitation anomaly-NINO3.4 correlations are found over the mid-latitudes in both hemispheres. Analysis shows that these areas are related to upper level circulation anomalies (enhanced wind shear) induced by the corresponding ENSO phase. A special case is observed over the western Maritime continent where typical drought conditions during the warm ENSO phase are related to enhanced lightning activity. Further attention is given toward identifying areas over which consistent thunderstorm activity is observed during the two major warm and cold ENSO phases of the past decade. Their spatial distribution shows strong regional preference and in general agrees with the already established ENSO-related precipitation regimes.