Spatial distribution of global annual average SST variance

Under the background of global warming, in order to study the variation of Sea Surface Temperature (SST) in different waters, we have already analyzed the spatial distribution of variance that of global average SST over one century by referring to 155 year's global SST data-ERSST V2, and the 155 year's data from 1854 to 2008 showed that there are several regions with big variance all over the world. Overall, these regions primarily distribute in the tropical and mid-latitude ocean. Furthermore, in the Northern Hemisphere the regions generally have larger area and bigger maximum variance value than in the Southern Hemisphere. Comparing with the previous study, we find that the regions marked by big variance are the regions having abundant modes of SST variability. For a further study, we split the period into three parts (1854-1909, 1910-1969, 1970-2008), plotting the spatial distribution of variance for every parts. As global warming, the gridded variance becomes bigger in general, especially in the eastern tropical Pacific (Nino regions). It suggests that the strength of ENSO will increase as global warming. On the other hand, global warming has great effect on the ENSO event.