Effects of wind patterns and changing wind velocities on aeolian drift potential along the Lake Michigan shore

Abstract

Climate influences the amount of wind energy available to transport sand in coastal dune complexes. Wind data from meteorological stations were used to calculate aeolian sand drift potential along the Lake Michigan shore and surrounding region. Data from 11 nearshore stations were used to identify 83 potential aeolian transport events during 2015. All events were associated with the passage of cyclones and anticyclones with the strongest pressure gradients occurring when the lake was between high- and low-pressure centers. There are statistically significant correlations between the positions of cyclones and anticyclones and the orientation of the shores with onshore drift potential. There is enough variability in cyclone and anticyclone tracks to drive aeolian activity on the north, east and south coasts, not all of which can be explained by the regional “prevailing” winds. Wind data from seven airports were used to examine changes in regional drift potential since 1948. Total drift potential decreased over this time, including a decrease of approximately 40% over the period 1961–2019. Trends in directional drift potential are less clear and appear to indicate a decrease in the proportion of onshore drift potential for the east and north shores and an increase for the south shore. This decrease in the ability of winds along Lake Michigan shores to transport sand should contribute to a stabilization of the coastal dunes. Shifts in the tracks of cyclones and anticyclones associated with climate change are anticipated to shift the relative amounts of aeolian activity associated with shores of different orientations.