What is the meaning of deep winter mixing?
The winter mixing of stratified layers in lakes and seas due to temperature changes can vary in depth, so scientists sometimes say &quot;deeper winter mixing&quot; and &quot;deep winter mixing&quot;. Scientists measure the water arising from 300 or from 800 meters depending on the year, so the deeper winter mixing is a relative term. i.e.:
1992, associated with more stormy weather and higher precipitation than usual. This anomaly was the cause for the deeper winter mixing in the Cyprus Eddy (&gt;500 m) than the typical 350 to 400 m reported by Brenner et al. (1991). Exceptionally deep vertical mixing (&gt;850 m) was reported that winter also in the Gulf of Aqaba https://www.int-res.com/articles/meps/167/m167p047.pdf
Here is basic description of winter mixing:
https://teara.govt.nz/en/diagram/11817/water-circulation-in-a-lake

and here is a science paper:
https://www.jstor.org/stable/2259960?seq=1
A wiki page on lake stratification:
https://en.wikipedia.org/wiki/Lake_stratification