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Reduction of Pacific Double‐ITCZ Bias by Convection Parameterization in NCAR CESM2.2

Journal Article · · Journal of Advances in Modeling Earth Systems
DOI:https://doi.org/10.1029/2024MS004309· OSTI ID:2498417
 [1];  [1]
  1. Scripps Institution of Oceanography La Jolla CA USA
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Abstract

The impact of convective closure on the double‐ITCZ bias in the NCAR CESM2.2 is investigated in this study. The standard CESM2.2 simulates a remarkable double‐ITCZ bias in the central and eastern Pacific, especially in boreal winter and spring. Modifications to the closure in convection parameterization scheme greatly reduce the double‐ITCZ bias in all seasons, demonstrating that convection parameterization can substantially influence the double‐ITCZ bias in CESM2.2. Further analyses suggest that convection parameterization can modulate the tropical atmosphere‐ocean feedback processes, through which it influences the SST in the southern ITCZ region and hence the double‐ITCZ bias. The changes in the upper ocean temperature advection induced by modified convective closure plays important roles in reducing the warm SST bias and double‐ITCZ precipitation bias in the southern ITCZ region. The modified convective closure improves the low‐level cloud and shortwave cloud radiative forcing in the southeastern Pacific. However, surface heat flux plays only a limited role in reducing warm SST bias and double ITCZ bias because the impacts of shortwave radiation changes are largely canceled by changes in longwave radiation and latent heat flux.

Sponsoring Organization:
USDOE
Grant/Contract Number:
SC0022064; SC0023069
OSTI ID:
2498417
Journal Information:
Journal of Advances in Modeling Earth Systems, Journal Name: Journal of Advances in Modeling Earth Systems Journal Issue: 1 Vol. 17; ISSN 1942-2466
Publisher:
American Geophysical Union (AGU)Copyright Statement
Country of Publication:
United States
Language:
English

References (27)

Double ITCZ in Coupled Ocean-Atmosphere Models: From CMIP3 to CMIP5: DOUBLE ITCZ IN CMIP3 AND CMIP5 AOGCMS journal October 2015
Can reducing the incoming energy flux over the Southern Ocean in a CGCM improve its simulation of tropical climate?: Southern Ocean-Tropics Link in a CGCM journal October 2016
Predicting the severity of spurious “double ITCZ” problem in CMIP5 coupled models from AMIP simulations journal February 2017
The Roles of Convection Parameterization in the Formation of Double ITCZ Syndrome in the NCAR CESM: I. Atmospheric Processes journal March 2018
Intermodel spread of the double-ITCZ bias in coupled GCMs tied to land surface temperature in AMIP GCMs: Double-ITCZ and Land journal August 2017
Relationship between shortwave radiation bias over the Southern Ocean and the double‐intertropical convergence zone problem in MRI‐ESM2 journal July 2021
The double‐ITCZ problem in CMIP6 and the influences of deep convection and model resolution journal January 2023
The ERA5 global reanalysis journal June 2020
Convective quasi-equilibrium in midlatitude continental environment and its effect on convective parameterization journal January 2002
Double ITCZs journal June 2001
Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century journal January 2003
Toward mitigating the double ITCZ problem in NCAR CCSM3 journal January 2006
The GCM-Oriented CALIPSO Cloud Product (CALIPSO-GOCCP) journal January 2010
Evolution of the Double‐ITCZ Bias Through CESM2 Development journal July 2019
Improved Diurnal Cycle of Precipitation in E3SM With a Revised Convective Triggering Function journal July 2019
The Community Earth System Model Version 2 (CESM2) journal February 2020
The Double‐ITCZ Bias in CMIP3, CMIP5, and CMIP6 Models Based on Annual Mean Precipitation journal April 2020
Impact of Grids and Dynamical Cores in CESM2.2 on the Surface Mass Balance of the Greenland Ice Sheet journal October 2022
Link between the double-Intertropical Convergence Zone problem and cloud biases over the Southern Ocean journal March 2013
Subtropical clouds key to Southern Ocean teleconnections to the tropical Pacific journal August 2022
Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian climate centre general circulation model journal September 1995
The Impact of Convection on ENSO: From a Delayed Oscillator to a Series of Events journal November 2008
Convection Parameterization, Tropical Pacific Double ITCZ, and Upper-Ocean Biases in the NCAR CCSM3. Part I: Climatology and Atmospheric Feedback journal August 2009
Convection Parameterization, Tropical Pacific Double ITCZ, and Upper-Ocean Biases in the NCAR CCSM3. Part II: Coupled Feedback and the Role of Ocean Heat Transport journal February 2010
An Investigation of the Initial Development of the Double-ITCZ Warm SST Biases in the CCSM journal January 2012
The Double-ITCZ Problem in IPCC AR4 Coupled GCMs: Ocean–Atmosphere Feedback Analysis journal September 2007
Reduction of Pacific double-ITCZ bias by convection parameterization in NCAR CESM2.2 dataset January 2024

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