Surface winds across eastern and midcontinental North America during the Last Glacial Maximum: A new data-model assessment

Research output: Contribution to journalReview article

Abstract

Last Glacial Maximum (LGM) proxy evidence of surface wind direction across eastern and midcontinental North America comes primarily from loess and dune deposits, and overwhelmingly suggests surface winds had a strong westerly component. However, the season of sediment deposition and the temporal scale of wind information preserved in these deposits remains uncertain. Furthermore, paleoclimate model simulations over the last several decades have indicated a predominance of easterly winds across this region, due to the presence of an anticyclone over the Laurentide Ice Sheet as well as katabatic winds flowing off the ice sheet and over the adjacent land surface. Here we reassess model-data near-surface wind direction agreement using nine general circulation models participating in the LGM experiment of the third Paleoclimate Model Intercomparison Project (PMIP3) and a compilation of previously published paleowind directions from loess and dune deposits dating to the LGM. We find the highest overall model-proxy data agreement in winter (December–February), indicating predominantly westerly winds across the region in the LGM model simulations. We also find high zonal and meridional wind direction agreement in spring (March–May) and fall (September–November) in many models. Winter, spring and fall also have faster mean daily near-surface wind speeds in the LGM simulations relative to pre-industrial control simulations. Thus, this model-data assessment suggests LGM aeolian deposition in the study region likely occurred dominantly in these three seasons, at times when local conditions favorable for aeolian deflation coincided with high wind speed events. Models that agree best with the proxy data have strengthened Aleutian and Icelandic Low pressure systems and a weakened Laurentide High pressure system, which constrains the spatial footprint of the Laurentide High to the ice sheet, reducing northeasterly winds near the ice sheet margin. A weaker Laurentide High in turn coincides with warmer surface temperatures over the ice sheet and the North Atlantic. The strength and location of semi-permanent pressure systems were thus key controls on surface wind direction across midcontinental and eastern North America during the LGM.

Original languageEnglish (US)
Pages (from-to)14-29
Number of pages16
JournalQuaternary Science Reviews
Volume220
DOIs
StatePublished - Sep 15 2019

Fingerprint

Last Glacial Maximum
surface wind
wind direction
ice
ice sheet
loess
dunes
wind speed
simulation models
simulation model
paleoclimate
westerly
simulation
dune
General Circulation Models
sediment deposition
wind erosion
winter
wind velocity
deflation

Keywords

  • Climate model
  • Last glacial maximum
  • Loess
  • North America
  • Wind

ASJC Scopus subject areas

  • Global and Planetary Change
  • Ecology, Evolution, Behavior and Systematics
  • Archaeology
  • Archaeology
  • Geology

Cite this

@article{5eac17a4fe354419b3b27c7a7e087317,
title = "Surface winds across eastern and midcontinental North America during the Last Glacial Maximum: A new data-model assessment",
abstract = "Last Glacial Maximum (LGM) proxy evidence of surface wind direction across eastern and midcontinental North America comes primarily from loess and dune deposits, and overwhelmingly suggests surface winds had a strong westerly component. However, the season of sediment deposition and the temporal scale of wind information preserved in these deposits remains uncertain. Furthermore, paleoclimate model simulations over the last several decades have indicated a predominance of easterly winds across this region, due to the presence of an anticyclone over the Laurentide Ice Sheet as well as katabatic winds flowing off the ice sheet and over the adjacent land surface. Here we reassess model-data near-surface wind direction agreement using nine general circulation models participating in the LGM experiment of the third Paleoclimate Model Intercomparison Project (PMIP3) and a compilation of previously published paleowind directions from loess and dune deposits dating to the LGM. We find the highest overall model-proxy data agreement in winter (December–February), indicating predominantly westerly winds across the region in the LGM model simulations. We also find high zonal and meridional wind direction agreement in spring (March–May) and fall (September–November) in many models. Winter, spring and fall also have faster mean daily near-surface wind speeds in the LGM simulations relative to pre-industrial control simulations. Thus, this model-data assessment suggests LGM aeolian deposition in the study region likely occurred dominantly in these three seasons, at times when local conditions favorable for aeolian deflation coincided with high wind speed events. Models that agree best with the proxy data have strengthened Aleutian and Icelandic Low pressure systems and a weakened Laurentide High pressure system, which constrains the spatial footprint of the Laurentide High to the ice sheet, reducing northeasterly winds near the ice sheet margin. A weaker Laurentide High in turn coincides with warmer surface temperatures over the ice sheet and the North Atlantic. The strength and location of semi-permanent pressure systems were thus key controls on surface wind direction across midcontinental and eastern North America during the LGM.",
keywords = "Climate model, Last glacial maximum, Loess, North America, Wind",
author = "Jessica Conroy and Christina Karamperidou and Grimley, {David Aaron} and William Guenthner",
year = "2019",
month = "9",
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doi = "10.1016/j.quascirev.2019.07.003",
language = "English (US)",
volume = "220",
pages = "14--29",
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TY - JOUR

T1 - Surface winds across eastern and midcontinental North America during the Last Glacial Maximum

T2 - A new data-model assessment

AU - Conroy, Jessica

AU - Karamperidou, Christina

AU - Grimley, David Aaron

AU - Guenthner, William

PY - 2019/9/15

Y1 - 2019/9/15

N2 - Last Glacial Maximum (LGM) proxy evidence of surface wind direction across eastern and midcontinental North America comes primarily from loess and dune deposits, and overwhelmingly suggests surface winds had a strong westerly component. However, the season of sediment deposition and the temporal scale of wind information preserved in these deposits remains uncertain. Furthermore, paleoclimate model simulations over the last several decades have indicated a predominance of easterly winds across this region, due to the presence of an anticyclone over the Laurentide Ice Sheet as well as katabatic winds flowing off the ice sheet and over the adjacent land surface. Here we reassess model-data near-surface wind direction agreement using nine general circulation models participating in the LGM experiment of the third Paleoclimate Model Intercomparison Project (PMIP3) and a compilation of previously published paleowind directions from loess and dune deposits dating to the LGM. We find the highest overall model-proxy data agreement in winter (December–February), indicating predominantly westerly winds across the region in the LGM model simulations. We also find high zonal and meridional wind direction agreement in spring (March–May) and fall (September–November) in many models. Winter, spring and fall also have faster mean daily near-surface wind speeds in the LGM simulations relative to pre-industrial control simulations. Thus, this model-data assessment suggests LGM aeolian deposition in the study region likely occurred dominantly in these three seasons, at times when local conditions favorable for aeolian deflation coincided with high wind speed events. Models that agree best with the proxy data have strengthened Aleutian and Icelandic Low pressure systems and a weakened Laurentide High pressure system, which constrains the spatial footprint of the Laurentide High to the ice sheet, reducing northeasterly winds near the ice sheet margin. A weaker Laurentide High in turn coincides with warmer surface temperatures over the ice sheet and the North Atlantic. The strength and location of semi-permanent pressure systems were thus key controls on surface wind direction across midcontinental and eastern North America during the LGM.

AB - Last Glacial Maximum (LGM) proxy evidence of surface wind direction across eastern and midcontinental North America comes primarily from loess and dune deposits, and overwhelmingly suggests surface winds had a strong westerly component. However, the season of sediment deposition and the temporal scale of wind information preserved in these deposits remains uncertain. Furthermore, paleoclimate model simulations over the last several decades have indicated a predominance of easterly winds across this region, due to the presence of an anticyclone over the Laurentide Ice Sheet as well as katabatic winds flowing off the ice sheet and over the adjacent land surface. Here we reassess model-data near-surface wind direction agreement using nine general circulation models participating in the LGM experiment of the third Paleoclimate Model Intercomparison Project (PMIP3) and a compilation of previously published paleowind directions from loess and dune deposits dating to the LGM. We find the highest overall model-proxy data agreement in winter (December–February), indicating predominantly westerly winds across the region in the LGM model simulations. We also find high zonal and meridional wind direction agreement in spring (March–May) and fall (September–November) in many models. Winter, spring and fall also have faster mean daily near-surface wind speeds in the LGM simulations relative to pre-industrial control simulations. Thus, this model-data assessment suggests LGM aeolian deposition in the study region likely occurred dominantly in these three seasons, at times when local conditions favorable for aeolian deflation coincided with high wind speed events. Models that agree best with the proxy data have strengthened Aleutian and Icelandic Low pressure systems and a weakened Laurentide High pressure system, which constrains the spatial footprint of the Laurentide High to the ice sheet, reducing northeasterly winds near the ice sheet margin. A weaker Laurentide High in turn coincides with warmer surface temperatures over the ice sheet and the North Atlantic. The strength and location of semi-permanent pressure systems were thus key controls on surface wind direction across midcontinental and eastern North America during the LGM.

KW - Climate model

KW - Last glacial maximum

KW - Loess

KW - North America

KW - Wind

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