Two types of yardangs in Loulan (Lop Nur), eastern Tarim Basin: contrasting formation mechanisms

UAV imagery was processed in Pix4Dmapper (v4.5.6)—a fully automated rapid image processing software—to generate digital surface models (DSMs) with a spatial resolution below 5 cm. Morphological parameters—including length, width, and long-axis orientation—were measured exclusively on isolated yardangs to minimize adjacency effects.

Length was defined as the maximum linear dimension parallel to the yardang's primary elongation axis, while width was measured perpendicularly at the maximum width position. A total of 133 teardrop (TD) and 228 mesa-like (ML) yardangs across three study sites were sampled to ensure that both morphotypes coexisted at each location.