Influence of Pacific decadal oscillation and El Ni?o Southern oscillation on the summer monsoon precipitation in Myanmar

摘要

In the present study, we have examined the influence of two major teleconnections, namely, El Ni?o Southern oscillation (ENSO) and Pacific decadal oscillation (PDO) on the summer monsoon precipitation of Myanmar. We used 52 years (1951-2002) of monthly precipitation data from a high-resolution gridded dataset developed by Climate Research Unit (CRU). The analysis was conducted at the regional scale consisting of five homogenous precipitation regions, and at the national level. The results of our study indicated an overall negative relationship between ENSO and precipitation patterns across Myanmar, with substantial regional level variations in the strength of the relationship. The role of ENSO on the resulting precipitation patterns, during El Ni?o years was stronger during the cold phase of PDO, whereas the reverse occurred during La Ni?a years. On the other hand, the role of PDO on the prevailing precipitation patterns was mostly positive during both its cold and warm phases. Furthermore, the difference between precipitations during the different phases of ENSO superimposed with the warm and cold periods of PDO, and showed overall higher average annual precipitation during cold PDO episodes.