Mixing with latitude

摘要

Measurements over a range of latitudes support a theory relating ocean turbulence to internal waves. The upshot should be easier mapping of ocean mixing, and eventually better climate models. Anyone who looks at the sky can see that clouds have a big effect on weather and climate. But global computer models cannot deal explicitly with individual clouds, let alone the water droplets in them. Phenomena that mix the ocean are likewise important but too small to be resolved in models of ocean circulation. These 'subgrid-scale' processes need to be mapped, in both the atmosphere and the ocean. They also need to be understood so that their effects can be 'parametrized' ― that is, represented in terms of larger-scale features that are dealt with explicitly in the models. Only in this way can we correctly allow for changes in such processes and their effects in a changing world. As they describe on page 513, Gregg and colleagues have produced an exciting advance in ideas about how both mapping and parametrization in the ocean might be accomplished.