Mapping the World’s Inland Sand Dunes – A Progress Report

Lancaster, Nicholas; Hesse, Paul; Telfer, Matt W.

doi:10.1130/abs/2017am-303254

Cited by 2 publications

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“…The magnitude of the diurnal near-surface temperature cycle is represented by the daily 2-m temperature range (δT 2 ), while the daily maximal 10-m wind speed (u 10,max ) is our proxy for formative near-surface winds for sand transport that day. Dune-field size is represented by area (A), mapped from satellite data (28). As expected, we see that dune fields correspond to regions of the planet having the largest diurnal temperature ranges (Fig.…”

Section: Global Resultssupporting

confidence: 77%

Circadian rhythm of dune-field activity

Gunn¹,

Wanker²,

Lancaster³

et al. 2018

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Wind-blown sand dunes are both a consequence and a driver of climate dynamics; they arise under persistently dry and windy conditions, and are a principle source for airborne dust. Dune fields experience extreme daily changes in temperature, yet the role of atmospheric stability in driving sand transport and dust emission has not been established. Here we report on an unprecedented multi-scale field experiment at the White Sands Dune Field (New Mexico, USA), where we demonstrate that a daily rhythm of sand and dust transport arises from nonequilibrium atmospheric boundary layer convection. A global analysis of 28 dune fields confirms the connection between surface wind speed and diurnal temperature cycles, revealing an unrecognized climate feedback that may contribute to the growth of deserts on Earth and other planets.Wind-blown sediments define the regional climate and topography of large swaths of Earth and other planets (1-4). Sand saltates across deserts creating forms like dunes and ripples (5), while dust lofted high into the atmosphere serves as a catalyst for other Earth-system processes (6) like cloud nucleation (7) and phytoplankton growth (8). Appropriately representing these dynamics in global climate models is an important challenge, especially considering predictions of increased aridity in Earths future (9). Current models used to estimate dust and sand fluxes (5, 10) rely on parameterizations to estimate the surface-friction velocities that must be achieved to initiate sediment motion. These are informed by field and laboratory experiments that neglect the role of atmospheric stability, a transient property of the boundary layer important for momentum transfer (10-13). One reason for this discrepancy is that typical instantaneous and localized measurements of surface transport conditions (14-16) are disembodied from formative synoptic-scale weather (17). Virtually all reported methods for determining surface-wind stresses (10-16) neglect transient effects, and therefore cannot predict the atmospheric conditions that lead to transport.

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Section: Global Resultssupporting

confidence: 77%