The HadCM3 contribution to PlioMIP phase 2

We present the UK's input into the Pliocene Model Intercomparison Project phase 2 (PlioMIP2) using the Hadley Centre Climate Model version 3 (HadCM3). The 400 ppm CO 2 Pliocene experiment has a mean annual surface air temperature that is 2.9 ∘ C warmer than the pre-industrial and a polar amplif...

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Bibliographic Details
Published in:Climate of the Past
Main Authors: S. J. Hunter, A. M. Haywood, A. M. Dolan, J. C. Tindall
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2019
Subjects:
Environmental pollution
TD172-193.5
Environmental protection
TD169-171.8
Environmental sciences
GE1-350
Pacific
North Atlantic
Sea ice
Online Access:https://doi.org/10.5194/cp-15-1691-2019
https://doaj.org/article/055b82f0337a4ecb9745f0d3a61f7444
Description
Summary:We present the UK's input into the Pliocene Model Intercomparison Project phase 2 (PlioMIP2) using the Hadley Centre Climate Model version 3 (HadCM3). The 400 ppm CO 2 Pliocene experiment has a mean annual surface air temperature that is 2.9 ∘ C warmer than the pre-industrial and a polar amplification of between 1.7 and 2.2 times the global mean warming. The Pliocene Research Interpretation and Synoptic Mapping (PRISM4) enhanced Pliocene palaeogeography accounts for a warming of 1.4 ∘ C, whilst the CO 2 increase from 280 to 400 ppm leads to a further 1.5 ∘ C of warming. Climate sensitivity is 3.5 ∘ C for the pre-industrial and 2.9 ∘ C for the Pliocene. Precipitation change between the pre-industrial and Pliocene is complex, with geographic and land surface changes primarily modifying the geographical extent of mean annual precipitation. Sea ice fraction and areal extent are reduced during the Pliocene, particularly in the Southern Hemisphere, although they persist through summer in both hemispheres. The Pliocene palaeogeography drives a more intense Pacific and Atlantic meridional overturning circulation (AMOC). This intensification of AMOC is coincident with more widespread deep convection in the North Atlantic. We conclude by examining additional sensitivity experiments and confirm that the choice of total solar insolation (1361 vs. 1365 Wm −2 ) and orbital configuration (modern vs. 3.205 Ma) does not significantly influence the anomaly-type analysis in use by the Pliocene community.

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