Interdecadal Change In The Relationship Of Indochina Peninsula May Precipitation To Enso

The present study detected an obvious interdecadal change in the relationship of Indochina Peninsula (ICP) May precipitation to El Nino-Southern Oscillation (ENSO). During the 1950s through the late-1970s, more (less) ICP precipitation tends to occur in May of La Nina (El Nino) developing years, whereas after the late-1990s, more (less) ICP precipitation tends to appear in May of La Nina (El Nino) decaying years. During the late-1970s through the late-1990s, more (less) ICP precipitation occurs in May of La Nina (El Nino) persisting years. The interdecadal change in the ICP May precipitation-ENSO relationship is related to two factors. One factor is the developing time of ENSO events. During the 1950s through the late-1970s, ENSO events develop earlier with larger equatorial central-eastern Pacific sea surface temperature (SST) anomalies in May. SST-induced lower-level wind anomalies extend northwestward from the equatorial central Pacific to the ICP. After the late-1990s, ENSO events develop later with smaller equatorial central-eastern Pacific SST anomalies in May. SST-induced lower-level wind anomalies are confined to the Pacific region. The other factor is the tropical Indo-Pacific SST anomaly pattern. During the ENSO decaying years after the late-1990s, opposite SST anomalies in the North Indian Ocean and central North Pacific work together to induce stronger wind anomalies over the ICP in May. In contrast, during the ENSO decaying years during the 1950s through the late-1970s, wind anomalies are weaker over the ICP in May under the sole influence of the North Indian Ocean SST anomalies.