Impact of Mountains on Tropical Circulation in Two Earth System Models
Author
Naiman, ZacharyGoodman, Paul J.
Krasting, John P.
Malyshev, Sergey L.
Russell, Joellen L.
Stouffer, Ronald J.
Wittenberg, Andrew T.
Affiliation
Univ Arizona, Dept GeosciIssue Date
2017-06
Metadata
Show full item recordPublisher
AMER METEOROLOGICAL SOCCitation
Impact of Mountains on Tropical Circulation in Two Earth System Models 2017, 30 (11):4149 Journal of ClimateJournal
Journal of ClimateRights
© 2017 American Meteorological Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Two state-of-the-art Earth systemmodels (ESMs) were used in an idealized experiment to explore the role of mountains in shaping Earth's climate system. Similar to previous studies, removing mountains from both ESMs results in the winds becoming more zonal and weaker Indian and Asian monsoon circulations. However, there are also broad changes to the Walker circulation and El Nino-Southern Oscillation (ENSO). Without orography, convection moves across the entire equatorial Indo-Pacific basin on interannual time scales. ENSO has a stronger amplitude, lower frequency, and increased regularity. A wider equatorial wind zone and changes to equatorial wind stress curl result in a colder cold tongue and a steeper equatorial thermocline across the Pacific basin during La Nina years. Anomalies associated with ENSO warm events are larger without mountains and have greater impact on the mean tropical climate than when mountains are present. Without mountains, the centennial-mean PacificWalker circulation weakens in both models by approximately 45%, but the strength of the mean Hadley circulation changes by less than 2%. Changes in the Walker circulation in these experiments can be explained by the large spatial excursions of atmospheric deep convection on interannual time scales. These results suggest that mountains are an important control on the large-scale tropical circulation, impacting ENSO dynamics and the Walker circulation, but have little impact on the strength of the Hadley circulation.Note
6 month embargo; Published Online: 8 May 2017ISSN
0894-87551520-0442
Version
Final published versionSponsors
National Science Foundation (NSF) Frontiers in Earth System Dynamics and NSF [EAR-1338553]Additional Links
http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0512.1ae974a485f413a2113503eed53cd6c53
10.1175/JCLI-D-16-0512.1