The Effect of Sand Grain Size in the Aeolian Transport Processes of Transgressives Dunefields of the Coast of the Santa Catarina State Brazil

The aeolian transport of sediment is a result of the relationship between wind energy and local sediment properties. The aim at this paper is analyze the effect of sand grains in the aeolian transport processes of the dunefields of the Santa Catarina coast plain. Along it's 538 kilometers the coast of Santa Catarina presents transgressive dunefields. An inversion in the migration direction can be verified in the central portion of the state, in an distance of approximately 50 kilometers between the cities of Florianópolis and Palhoça. The existing dunefields south of Palhoça migrate towards SW, whit the northern fields migrate towards NW. In an attempt to explain this divergence in the migration directions, 39 samples from 8 dunefields, between the latitudes 26°58'37"S and 29°18'18"S along in the coastal. Grain sized analysis was conducted and used to account the threshold velocity. The results show that the mean sand grain size increases from south to north as well as the fluid threshold shear stress (u*t), impact threshold wind velocity at 10 m u₍₁₀₎. The pattern shows that the role of grain size is an important factor in the analysis of eolian transport processes.