Precipitation variation in the Indochina Penisula

What is it about?

The time-lagged correlations of monthly precipitation in Myanmar and the Indochina Peninsula (ICP) with several climate indices were investigated by using the Global Precipitation Climatology Centre dataset after checking its quality with rain-gauge data. The results showed significant time-lagged correlations of several climate indices related to El Niño-Southern Oscillation and El Niño Modoki with precipitation anomalies in southern Myanmar during pre-monsoon (April) and post-monsoon (October) months. The analyses showed a good association between precipitation in southern Myanmar and a large-scale precipitation structure that affects the southern Myanmar and ICP simultaneously during these two months. An analysis of moisture flux over a wide area of ICP, including the surrounding seas, showed that the regressed variability of its convergence with the first principal component (PC1) of EOF analysis on precipitation over the whole ICP is statistically significant over the wide area from the Bay of Bengal to southern ICP and South China Sea for the two months. The significant time-lagged correlations were confirmed by regressing sea surface temperature (SST) in the Pacific and Indian Oceans and 850-hPa zonal wind (U850) upon the PC1. We propose an area-averaged SST, U850, or the combination of these variables at each corresponding best location in the equatorial region to the highest correlation searched in this study as a good predictor for operational long-range statistical prediction of monthly precipitation in the southern part of ICP, particularly for the pre-monsoon month. Using a linear model and the proposed predictors, we demonstrate a successful hindcast in predicting the pre-monsoon and post-monsoon precipitation in the southern part of ICP (south of 20°N) up to six and three months ahead, respectively.

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Why is it important?

Long time-lagged relationship up to 12 month ahead between climate indices related to ENSO and precipitation in the Indochina Peninsula during pre-monsoon and post-monsoon season is investigated. The significant time-lagged correlations were confirmed by regressing sea surface temperature (SST) in the Pacific and Indian Oceans and 850-hPa zonal wind (U850) upon the PC1. We propose an area-averaged SST, U850, or the combination of these variables at each corresponding best location in the equatorial region to the highest correlation searched in this study as a good predictor for operational long-range statistical prediction of monthly precipitation in the southern part of ICP.

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