In contrast, zone B stations subject to a strong drainage wind regime (see the "Nocturnal drainage flows along valleys" sidebar ) tend to show the largest correlations in the nocturnal phase during the cold season, when these winds are stronger.
Interestingly, lessons learned in configuring the WRF Model for the drainage winds over the Atacama Desert aided subsequently the modeling of surface wind fields over Antarctica, where katabatic winds are common (Falvey and Rojo 2016).
The scientific use of these observational and modeling results has led to the documentation of strong drainage winds along valleys traversing the Atacama Desert (Munoz et al.
(2013) classified these winds as drainage winds and provided a more complete observational characterization of them.
The simulation shows that this line of precipitation was associated with a density current formed by the interaction between a cold air mass arriving at the sea as a result of a drainage wind and a warmer prevailing synoptic flow.
Consequently, this cooler and denser air begins to drain towards the coast by descending from mountain ranges and following rivers and dry streams until it forms a density current driven by drainage winds. A density current is the intrusion of a denser fluid beneath a lighter one, due mainly to the hydrostatic forces arising from gravity and the density differences .
First, it channels northern flows from the Massif Central in France and encourages drainage winds to follow the valleys and slopes of some mountains near the coast.
These areas of convergence are formed by the inland cold air mass driven by drainage winds interacting with the warmer maritime air mass driven by the prevailing easterly flow.
At 00:00 UTC on 6 September 2011, some precipitation cells are simulated offshore, driven by drainage winds. An offshore rainband with approximately 150 km length formed by several raincells is simulated at 03:00 and 08:00 UTC (Figures 10(c) and 10(d), resp.).