Atmospheric river changes shaped mid-latitude hydroclimate since the mid-Holocene

•Atmospheric river characteristics are sensitive to changes in orbital forcing.•Atmospheric rivers weakened and moved equatorward between 6 ka BP and preindustrial.•Hydroclimate signals in several paleo proxies are driven by atmospheric river changes. Paleoclimate proxies indicate that changes in in...

Full description

Saved in:
Bibliographic Details
Published in:Earth and planetary science letters 2020-07, Vol.541 (C), p.116293, Article 116293
Main Authors: Skinner, Christopher B., Lora, Juan M., Payne, Ashley E., Poulsen, Christopher J.
Format: Article
Language:English
Subjects:
atmospheric river
climate change
Holocene climate
precipitation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Atmospheric river characteristics are sensitive to changes in orbital forcing.•Atmospheric rivers weakened and moved equatorward between 6 ka BP and preindustrial.•Hydroclimate signals in several paleo proxies are driven by atmospheric river changes. Paleoclimate proxies indicate that changes in insolation since the mid-Holocene have driven widespread hydrologic changes across the midlatitudes. It is unclear how atmospheric rivers (ARs), which are fundamental to global moisture transport today, may have contributed to these Holocene hydroclimate changes. Here, we use a set of climate model simulations with the Community Earth System Model (CESM), and introduce an AR algorithm optimized to identify ARs within different climate states, to show that changes to the location and intensity of landfalling ARs explain the majority of the precipitation difference between the mid-Holocene and the preindustrial period in several midlatitude regions. During the mid-Holocene, enhanced seasonality increased summer season AR vapor content and displaced ARs poleward of their preindustrial period trajectories, especially in the Northern Hemisphere. Consequently, in high midlatitude coastal areas of western North America and East Asia, ARs account for greater than 10% more of total precipitation during the mid-Holocene, and nearly 100% of the simulated change in precipitation between the two climates. The simulated AR changes are consistent with moisture-sensitive proxy records and with present-day relationships between ARs and regional circulation, enhancing confidence that ARs served as the underlying synoptic mechanism responsible for mid-Holocene hydroclimate anomalies in several coastal mid-latitude areas. The results indicate that ARs are sensitive to background climate state, and suggest that changes in ARs may have contributed to hydroclimate changes throughout Earth's past.
ISSN:0012-821X
1385-013X
DOI:10.1016/j.epsl.2020.116293