Megadroughts and late Holocene dune activation at the eastern margin of the Great Plains, north-central Kansas, USA

Hanson, Paul R.; Arbogast, Alan F.; Johnson, William C.; Joeckel, R.M.; Young, Aaron R.

doi:10.1016/j.aeolia.2009.10.002

Cited by 40 publications

(41 citation statements)

References 31 publications

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“…The geologic record provides evidence for widespread and recurrent dune mobilization events during the MCA (Forman et al 2001;Hanson et al 2010;Miao et al 2007), with the most recent events likely occurring during the fourteenth and fifteenth centuries. These events were driven primarily by megadrought-induced vegetation mortality and reductions in vegetation cover.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…For our MCA runs, we prescribed our dune mobilization region (Fig. 1b) over the central plains (328-448N, 1058-958W), based qualitatively on maps and evidence from geomorphological analyses (Forman et al 2001;Hanson et al 2010;Miao et al 2007). For the model, we translated this to 1) a 50% reduction in vegetation cover (simulating the vegetation mortality) and 2) a new dust aerosol emission source coincident with the region of reduced vegetation cover and added to the default source map of Ginoux et al (2001).…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…These droughts had significant ecological and societal consequences, causing major disruptions in regional civilizations (e.g., Benson et al 2007a,b;Douglass 1929) and leading to widespread vegetation mortality and dune mobilization (Forman et al 2001;Hanson et al 2010;Miao et al 2007). These so-called megadroughts are not only unprecedented in the instrumental record but are also largely absent in climate reconstructions of the last 500 years.…”

Section: Introductionmentioning

confidence: 99%

“…With less energy available to drive vertical movement of the atmosphere, convection, and precipitation were subsequently reduced. These feedbacks may be especially important to consider for the MCA megadroughts that occurred over the central plains, given the large-scale vegetation mortality, wind erosion, and dust aerosol transport that occurred during this interval, as inferred from records of paleo dunes (Forman et al 2001;Hanson et al 2010;Miao et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

et al. 2013

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Tree-ring-based reconstructions of the Palmer drought severity index (PDSI) indicate that, during the Medieval Climate Anomaly (MCA), the central plains of North America experienced recurrent periods of drought spanning decades or longer. These megadroughts had exceptional persistence compared to more recent events, but the causes remain uncertain. The authors conducted a suite of general circulation model experiments to test the impact of sea surface temperature (SST) and land surface forcing on the MCA megadroughts over the central plains. The land surface forcing is represented as a set of dune mobilization boundary conditions, derived from available geomorphological evidence and modeled as increased bare soil area and a dust aerosol source (328-448N, 1058-958W). In the experiments, cold tropical Pacific SST forcing suppresses precipitation over the central plains but cannot reproduce the overall drying or persistence seen in the PDSI reconstruction. Droughts in the scenario with dust aerosols, however, are amplified and have significantly longer persistence than in other model experiments, more closely matching the reconstructed PDSI. This additional drying occurs because the dust increases the shortwave planetary albedo, reducing energy inputs to the surface and boundary layer. The energy deficit increases atmospheric stability, inhibiting convection and reducing cloud cover and precipitation over the central plains. Results from this study provide the first model-based evidence that dust aerosol forcing and land surface changes could have contributed to the intensity and persistence of the central plains megadroughts, although uncertainties remain in the formulation of the boundary conditions and the future importance of these feedbacks.

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Section: Boundary Conditionsmentioning

confidence: 99%

Section: Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

et al. 2013

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“…It is assumed that under extremely high wind stress, vegetation is destroyed and dunes are reactivated. Furthermore, it has been shown that long droughts or mega-droughts lead to a reduction in vegetation cover and dune reactivation (Schmeisser et al 2009, Hanson et al 2010.…”

Section: Introductionmentioning

confidence: 99%

Evidence of coastal dune mobility increases over the last half century in response to historical human intervention

et al. 2016

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Summary:Given the risk of two roads being buried by the sand of two highly mobile coastal dunes (Valdevaqueros and Bolonia, SW Spain), several measures have been taken over the last half century in order to stabilize them or at least slow their progress: installation of several rows of 1-m-high concrete structures, planting of species such as Pinus pinea, Retama monosperma and Ammophila arenaria, wicker and wooden fencing, and sand mining (only performed on the Valdevaqueros dunefield). The evolution of the two dunes was investigated through the interpretation of intensive topographical monitoring and aerial photography. Average migration rates of approximately 10 m yr -1 were detected and the burial of anthropic structures has eventually occurred. This process has caused a serious regional problem, making dune management of these areas a difficult challenge. The comparison of the evolution of these two dunes has been of great importance in assessing the effect of historical human intervention and has provided a new perspective for future dune management strategies. The results obtained show that management measures based on sand removal have been proven to be unsustainable. Moreover, the monitoring methodology presented herein has proven very useful in predicting dune advance rates. For instance, the Bolonia dune could reach the nearest road in approximately 12 years.Keywords: coastal dunes, dune mobility; aeolian transport rate; topographic monitoring; aerial photography; dune management; dune evolution.Evidencias del incremento en la movilidad de dunas costeras en el último medio siglo como respuesta a la intervención humana Resumen: Se han tomado diferentes medidas a lo largo del último medio siglo tratando de estabilizar o al menos ralentizar el progreso de dos dunas costeras de alta movilidad (Valdevaqueros y Bolonia, SW España) dado el riesgo de enterramiento de sendas carreteras: Entre las medidas tomadas cabe destacar la instalación de filas de estructuras de hormigón de 1 m de altura, la plantación de diferentes especies (como el Pinus pinea, la Retama monosperma o la Ammophila arenaria), vallas de madera y brezo, y la extracción de arena (sólo en la duna de Valdevaqueros). La evolución de ambas dunas se ha investigado a través de la comparación de levantamientos topográficos y fotografías aéreas. Se han detectado tasas medias de avance de aproximadamente 10 m/año hasta que, finalmente, se han enterrado estructuras antrópicas. Este proceso ha causado graves problemas convirtiendo en un difícil reto la gestión de dunas de estas áreas. La comparación de la evolución de estas dos dunas ha resultado de gran importancia a la hora de evaluar el efecto de la intervención humana, y ha proporcionado una nueva perspectiva para las futuras estrategias de gestión. Entre los resultados obtenidos, debería destacarse el que la gestión basada en la retirada de arena ha resultado insostenible. Además, la metodología de seguimiento aquí presentada ha probado ser de gran utilidad al predecir las tasas de avance de las du...

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Parabolic dune distribution, morphology and activity during the last 20 000 years: A global overview

Vimpere

2023

Earth Surf Processes Landf

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Parabolic dunes form and migrate in almost every climate and geographic zones of the world, ranging from the tropical coastlines to the arid continental deserts. Despite their extensive distribution and their importance within the aeolian sediment landscape, the understanding of their morphological development, activity and link with climates remains somewhat limited to local or regional scales. A good understanding of the present climate conditions under which parabolic dunes are formed and/or reactivated would be significantly helpful to constrain past climate models. Similarly, an improved knowledge of parabolic dunes behaviour during past climatic episodes would provide some valuable long‐term data to better predict their future activity. This review first aims at providing a non‐exhaustive global database on parabolic dune morphology and the present wind regimes with which they are associated. To do so, the morphology of 750 dunes distributed worldwide was first analysed using a high‐resolution global digital elevation model, suggesting an intrinsic relationship between the different measured morphoparameters. The analysis of the associated local wind regimes shows that parabolic dunes develop under strong unidirectional winds, which are more conspicuous in coastal than continental environments. Dunes of different ages are globally aligned with present prevailing winds, which suggests a prevalent control of long‐term global atmospheric circulation on dune orientations. Finally, this study explores the link between parabolic dune activity and climates over the past 20 000 years by reviewing ages from the literature and combining them with the ones compiled in the INQUA Dunes Atlas Chronologic Database. Overall, it appears that changes towards drier conditions have triggered dunes migration during both warm and cold periods of the Last Glacial Maximum, Holocene Climate Optimum, Roman Climate Optimum, Medieval Climate Optimum and Little Ice Age. The present day aeolian activity is predominantly linked with deteriorating environmental conditions caused by human disturbances.

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Megadroughts and late Holocene dune activation at the eastern margin of the Great Plains, north-central Kansas, USA

Cited by 40 publications

References 31 publications

Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing*

Evidence of coastal dune mobility increases over the last half century in response to historical human intervention

Parabolic dune distribution, morphology and activity during the last 20 000 years: A global overview

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