Spatial-temporal evolution of aeolian blowout dunes at cape cod

摘要: Abstract This paper explores historical evolution of blowouts at Cape Cod National Seashore (CCNS), USA — a site that hosts one the world's highest densities active and stabilized blowouts. The Spatial–Temporal Analysis Moving Polygons (STAMP) method is applied to multi-decadal dataset aerial photography LiDAR extract patterns two-dimensional movement morphometric changes in erosional deflation basins depositional lobes. Blowout development CCNS characterized by several geometric (overlap) (proximity) responses, including: i) generation disappearance, ii) extension contraction, iii) union or division, iv) clustering v) divergence stabilization. Other possible events include migration, amalgamation proximal stabilization, but they were not observed this study. Generation more frequent than disappearance events; former between 1985 1994, while latter 2000 2005. High rates areal change occurred 1998 (+ 3932 m2 a−1), lowest rate (+ 333 m2 a−1) 2005 2009, maximum (+ 4589 m2 a−1) 2009 2011. Union mostly recent years (2000–2012), only division was earlier (1985–1994). Net lobes showed gradual growth from period contraction (− 1119 m2 a−1) rapid (+ 2030 m2 a−1) 2010, which roughly concurrent with 2009. Blowouts extended radially multi-modal wind regime and, despite odd shapes initially, became simpler form (more circular) larger over time. toward ESE (109°) SSE (147°). Lobes aligned strongest (winter) sand drift vector although their magnitude 33% basins. These differences responses likely result complex evolving flow-form interactions inside Historical photographs documents suggest blowout may be influenced land-use changes, such as revegetation campaigns followed high generation. regional storm (e.g., hurricanes) also play role. analytical framework presented provides systematic means for geomorphic detection pattern analysis can other landscapes.