The DPS is nothing more than a measure of how strongly the wind speed depends on the time of day.  It can't say anything about why the wind speed does that. 

In the Antarctic winter, the DPS should be zero because there's nothing about the time of day that could influence the wind speed.  On the Hawaiian coast, the DPS is probably quite high because the wind is driven by the sea breeze-land breeze cycle caused by solar heating of the land.  But the DPS is also very high at the hut at the base of the icefield where I spent last weekend, and it's nothing like the Hawaiian coast.  The (ferocious) wind there is driven by orography and the katabatic/anabatic cycle.