Evaluating the large-scale hydrological cycle response within the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) ensemble

• DOI: 10.5194/cp-17-2537-2021
• Publication Date: 2021-12-08T14:26:34Z
• Authors: Zixuan Han; Qiong Zhang; Qiang Li; Ran Feng; Alan M. Haywood; Julia C. Tindall; Stephen J. Hunter; Bette L. Otto-Bli...; Esther C. Brady; Nan Rosenbloom; Zhongshi Zhang; Xiangyu Li; Chuncheng Guo; Kerim H. Nisancioglu; Christian Stepanek; Gerrit Lohmann; Linda E. Sohl; Mark A. Chandler; Ning Tan; Gilles Ramstein; Michiel L. J. Baa...; Anna S. von der H...; Deepak Chandan; W. Richard Peltier; Charles J. R. Wil...; Daniel J. Lunt; Jianbo Cheng; Qin Wen; Natalie J. Burls
• Keywords: Intertropical Convergence Zone; Hadley cell; Subtropical ridge; Atmospheric Circulation; Water cycle; Walker circulation; Convergence zone

Abstract. The mid-Pliocene (∼3 Ma) is one of the most recent warm periods with high CO2 concentrations in atmosphere and resulting temperatures, it often cited as an analog for near-term future climate change. Here, we apply a moisture budget analysis to investigate response large-scale hydrological cycle at low latitudes within 13-model ensemble from Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). results show that increased atmospheric content (due thermodynamic effect) wetter conditions over deep tropics, i.e., Pacific intertropical convergence zone (ITCZ) Maritime Continent, drier subtropics. Note dynamic effect plays more important role than regional precipitation minus evaporation (PmE) changes (i.e., northward ITCZ shift northern Indian Ocean). offset some extent by involving Hadley circulation dries tropics moistens subtropics Northern Hemisphere subtropical Pacific). From perspective Earth's energy budget, enhanced southward cross-equatorial transport (0.22 PW), induced hemispheric asymmetries energy, favors approximately 1∘ ITCZ. reorganizes circulation, favoring circulation. In addition, Walker consistently shifts westward PlioMIP2 models, leading Ocean. highlights imbalance interhemispheric during could have led effect, offsetting and, hence, altering hydroclimate.