A recent paper claims to have detected a global wave-4 pattern in subtropical SSTs. But have they really?
This are some quick notes on Global wave number-4 pattern in the southern subtropical sea surface temperature (Senapati, Dash, and Behera 2021). The article claims to discover a wave-4 pattern in the southern Sea Surface Temperature (SST). Their basic method is to perform Empirical Orthogonal Function (EOF) to SST between 55°S and 20°S. They discard the first EOF as uninteresting because it’s “ENSO-like” (unsurprising) and focus on the second EOF, whose spatial pattern is in Figure 1.