Detectability of Decadal Anthropogenic Hydroclimate Changes over North America

Detectability of Decadal Anthropogenic Hydroclimate Changes over North America AbstractRegional hydroclimate changes on decadal time scales contain substantial natural variability. This presents a challenge for the detection of anthropogenically forced hydroclimate changes on these spatiotemporal scales, because the “signal” of anthropogenic changes is modest compared to the “noise” of natural variability. However, previous studies have shown that this “signal to noise” ratio can be greatly improved in a large model ensemble where each member contains the same “signal” but different “noise”. Here using multiple state-of-the-art large ensembles from two climate models, we quantitatively assess the detectability of anthropogenically caused decadal shifts in precipitation-minus-evaporation (PmE) mean state against natural variability, focusing on North America during 2000-2050.Anthropogenic forcing is projected to cause detectable (“signal” larger than “noise”) shifts in PmE mean state relative to the 1950-1999 climatology over 50-70% of North America by 2050. The earliest detectable signals include, during November-April, a moistening over northeastern North America and a drying over southwestern North America and, during May- October, a drying over central North America. Different processes are responsible for these signals. Changes in submonthly transient eddy moisture fluxes account for the northeastern moistening and central drying while monthly atmospheric circulation changes explain the southwestern drying. Our model findings suggest that, despite the dominant role of natural internal variability on decadal time scales, anthropogenic shifts in PmE mean state can be detected over most of North America before the middle of the current century. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Climate American Meteorological Society

Detectability of Decadal Anthropogenic Hydroclimate Changes over North America

Loading next page...
 
/lp/ams/detectability-of-decadal-anthropogenic-hydroclimate-changes-over-north-ekKPmOydvG
Publisher
American Meteorological Society
Copyright
Copyright © American Meteorological Society
ISSN
1520-0442
D.O.I.
10.1175/JCLI-D-17-0366.1
Publisher site
See Article on Publisher Site

Abstract

AbstractRegional hydroclimate changes on decadal time scales contain substantial natural variability. This presents a challenge for the detection of anthropogenically forced hydroclimate changes on these spatiotemporal scales, because the “signal” of anthropogenic changes is modest compared to the “noise” of natural variability. However, previous studies have shown that this “signal to noise” ratio can be greatly improved in a large model ensemble where each member contains the same “signal” but different “noise”. Here using multiple state-of-the-art large ensembles from two climate models, we quantitatively assess the detectability of anthropogenically caused decadal shifts in precipitation-minus-evaporation (PmE) mean state against natural variability, focusing on North America during 2000-2050.Anthropogenic forcing is projected to cause detectable (“signal” larger than “noise”) shifts in PmE mean state relative to the 1950-1999 climatology over 50-70% of North America by 2050. The earliest detectable signals include, during November-April, a moistening over northeastern North America and a drying over southwestern North America and, during May- October, a drying over central North America. Different processes are responsible for these signals. Changes in submonthly transient eddy moisture fluxes account for the northeastern moistening and central drying while monthly atmospheric circulation changes explain the southwestern drying. Our model findings suggest that, despite the dominant role of natural internal variability on decadal time scales, anthropogenic shifts in PmE mean state can be detected over most of North America before the middle of the current century.

Journal

Journal of ClimateAmerican Meteorological Society

Published: Jan 10, 2018

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches

$49/month

Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial