Whether the latitudinal dependence of ocean mixing is true or not

Gregg M (2003) proposed a possible relationship between the latitude and the ocean mixing based on microstructure data. However, the data sets he used seems cannot tell the visual relationship between them are real, since the high diffusive region appearing in the mid-latitude are associated with rough topography and the low diffusive region in the low-latitude appear with smooth topography. The decreasing mixing toward low-latitude is thus due to either the changing latitude or the changing topography. More data set are needed to examine the possible relationship.