Correlations between El Niño and Climate
In order to see what relationships exist between SOI and climate variables in the three regions under study, I performed a correlation analysis with the climate variables chosen and SOI. Below in table 2 results of this analysis are displayed. From table 2 we can see that SOI has a positive and significant relationship with precipitation in Borneo but not in Malaysia or the Philippines. The correlation results in Borneo were expected as low SOI values mean presence of El Niño event which is known to result in drought in Southeast Asia. There is a negative significant relationship between SOI and temperatures in all three regions. This means that at lower SOI values, or during El Niño, the temperatres rise for all three regions. This corresponds to the correlation of El Niño and drought in the region.
Table 2: Spearman's correlation coefficients (rho) between SOI and climate variables
Graph 7 shows moving correlations between monthly climate variables and SOI for the three regions. Graph 8 shows the climate normals for the three regions from 1950-2002. We can see that in the Philippines there is one dry season from January to May. The coldest month appears to be January when both minimum and maximum temperatures are the lowest. The temperatures peak by the end of the dry season. Cloud cover and humidity are lowest during the dry season. In Malaysia and Borneo there are two dry seasons: one in December, January, February and the other one in June, July, August. Temperature, humidity and cloud cover appear to be lower during the dry seasons. However the trends are not as pronounced as in the Philippines data.
From graph 7, we can see that the highest positive correlation between SOI and precipitation takes place in the dry months for the regions. For the Philippines, the highest correlation between SOI and precipitation is in February, March and April. For Borneo ad Malaysia, the highest correlations are during February, June, July and August. Temperatures follow the opposite trends for all the regions. The highest negative correlation between SOI and temperatures is during the dry seasons. Cloud cover and Humidity have weak correlations with SOI in all the regions.
From graph 7, we can see that the highest positive correlation between SOI and precipitation takes place in the dry months for the regions. For the Philippines, the highest correlation between SOI and precipitation is in February, March and April. For Borneo ad Malaysia, the highest correlations are during February, June, July and August. Temperatures follow the opposite trends for all the regions. The highest negative correlation between SOI and temperatures is during the dry seasons. Cloud cover and Humidity have weak correlations with SOI in all the regions.
Graph 7: Correlation coefficients (rho)
Graph 8: Climate Normals for Borneo, Malaysia, the Philippines 1950-2002
