skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Roles of Convection Parameterization in the Formation of Double ITCZ Syndrome in the NCAR CESM: I. Atmospheric Processes

Journal Article · · Journal of Advances in Modeling Earth Systems
DOI:https://doi.org/10.1002/2017MS001191· OSTI ID:1429528
ORCiD logo [1]; ORCiD logo [1]
  1. Scripps Institution of Oceanography, University of California San Diego, La Jolla CA USA
+ Show Author Affiliations

Abstract Several improvements are implemented in the Zhang‐McFarlane (ZM) convection scheme to investigate the roles of convection parameterization in the formation of double intertropical convergence zone (ITCZ) bias in the NCAR CESM1.2.1. It is shown that the prominent double ITCZ biases of precipitation, sea surface temperature (SST), and wind stress in the standard CESM1.2.1 are largely eliminated in all seasons with the use of these improvements in convection scheme. This study for the first time demonstrates that the modifications of convection scheme can eliminate the double ITCZ biases in all seasons, including boreal winter and spring. Further analysis shows that the elimination of the double ITCZ bias is achieved not by improving other possible contributors, such as stratus cloud bias off the west coast of South America and cloud/radiation biases over the Southern Ocean, but by modifying the convection scheme itself. This study demonstrates that convection scheme is the primary contributor to the double ITCZ bias in the CESM1.2.1, and provides a possible solution to the long‐standing double ITCZ problem. The atmospheric model simulations forced by observed SST show that the original ZM convection scheme tends to produce double ITCZ bias in high SST scenario, while the modified convection scheme does not. The impact of changes in each core component of convection scheme on the double ITCZ bias in atmospheric model is identified and further investigated.

Research Organization:
Univ. of California, San Diego, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
Grant/Contract Number:
DE‐SC0016504; SC0016504
OSTI ID:
1429528
Alternate ID(s):
OSTI ID: 1429529; OSTI ID: 1511465
Journal Information:
Journal of Advances in Modeling Earth Systems, Journal Name: Journal of Advances in Modeling Earth Systems Vol. 10 Journal Issue: 3; ISSN 1942-2466
Publisher:
American Geophysical Union (AGU)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 30 works
Citation information provided by
Web of Science

References (41)

A Cumulus Parameterization with State-Dependent Entrainment Rate. Part I: Description and Sensitivity to Temperature and Humidity Profiles journal July 2010
The Community Climate System Model, Version 2 journal October 2004
Double ITCZs journal June 2001
An Investigation of the Initial Development of the Double-ITCZ Warm SST Biases in the CCSM journal January 2012
Double ITCZ in Coupled Ocean-Atmosphere Models: From CMIP3 to CMIP5: DOUBLE ITCZ IN CMIP3 AND CMIP5 AOGCMS journal October 2015
The Seasonal Cycle over the Tropical Pacific in Coupled Ocean–Atmosphere General Circulation Models journal September 1995
Global Precipitation: A 17-Year Monthly Analysis Based on Gauge Observations, Satellite Estimates, and Numerical Model Outputs journal November 1997
Relationships between Water Vapor Path and Precipitation over the Tropical Oceans journal April 2004
Spread of model climate sensitivity linked to double‐Intertropical Convergence Zone bias journal May 2015
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
Links between Annual Variations of Peruvian Stratocumulus Clouds and of SST in the Eastern Equatorial Pacific journal November 1999
Convection Parameterization, Tropical Pacific Double ITCZ, and Upper-Ocean Biases in the NCAR CCSM3. Part I: Climatology and Atmospheric Feedback journal August 2009
Evaluation of Trigger Functions for Convective Parameterization Schemes Using Observations journal October 2014
Convective quasi-equilibrium in midlatitude continental environment and its effect on convective parameterization journal January 2002
Estimation of entrainment rate in simple models of convective clouds journal January 2001
Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian climate centre general circulation model journal September 1995
Simulation of the Madden–Julian Oscillation in a Coupled General Circulation Model. Part I: Comparison with Observations and an Atmosphere-Only GCM journal February 2003
GFDL's CM2 Global Coupled Climate Models. Part III: Tropical Pacific Climate and ENSO journal March 2006
Link between the double-Intertropical Convergence Zone problem and cloud biases over the Southern Ocean journal March 2013
Angular Distribution Models for Top-of-Atmosphere Radiative Flux Estimation from the Clouds and the Earth’s Radiant Energy System Instrument on the Terra Satellite. Part I: Methodology journal April 2005
Toward mitigating the double ITCZ problem in NCAR CCSM3 journal January 2006
Estimating Changes in Global Temperature since the Preindustrial Period journal September 2017
Peruvian Stratus Clouds and the Tropical Pacific Circulation: A Coupled Ocean-Atmosphere GCM Study journal July 1996
The double ITCZ bias in CMIP5 models: interaction between SST, large-scale circulation and precipitation journal January 2015
Impacts of an improved low-level cloud scheme on the eastern Pacific ITCZ-cold tongue complex journal July 2005
Global Climate Impacts of Fixing the Southern Ocean Shortwave Radiation Bias in the Community Earth System Model (CESM) journal June 2016
THE CLOUDSAT MISSION AND THE A-TRAIN: A New Dimension of Space-Based Observations of Clouds and Precipitation journal December 2002
Convective Entrainment and Large-Scale Organization of Tropical Precipitation: Sensitivity of the CNRM-CM5 Hierarchy of Models journal May 2013
Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data journal January 2004
The Impact of Convection on ENSO: From a Delayed Oscillator to a Series of Events journal November 2008
Effects of Southeastern Pacific Sea Surface Temperature on the Double-ITCZ Bias in NCAR CESM1 journal October 2016
Impact of a modified convective scheme on the Madden-Julian Oscillation and El Niño-Southern Oscillation in a coupled climate model: MJO AND ENSO SIMULATED BY A COUPLED GCM journal August 2007
The Double-ITCZ Problem in IPCC AR4 Coupled GCMs: Ocean–Atmosphere Feedback Analysis journal September 2007
The Art and Science of Climate Model Tuning journal March 2017
The Role of Entrainment in the Diurnal Cycle of Continental Convection journal May 2010
Mechanisms for ENSO Phase Change in a Coupled GCM journal April 2003
Precipitation Reproducibility over Tropical Oceans and Its Relationship to the Double ITCZ Problem in CMIP3 and MIROC5 Climate Models journal September 2011
Some Bulk Properties of Cumulus Ensembles Simulated by a Cloud-Resolving Model. Part II: Entrainment Profiles journal November 1999
An Ocean Analysis System for Seasonal to Interannual Climate Studies journal February 1995
The impact of low-level cloud over the eastern subtropical Pacific on the “Double ITCZ” in LASG FGCM-0 journal May 2003
The Version-2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979–Present) journal December 2003

Similar Records

Culprit of the Eastern Pacific Double-ITCZ Bias in the NCAR CESM1.2
Journal Article · Tue Aug 27 00:00:00 EDT 2019 · Journal of Climate · OSTI ID:1429528
The double ITCZ syndrome in GCMs: A coupled feedback problem among convection, clouds, atmospheric and ocean circulations
Journal Article · Sat Jun 29 00:00:00 EDT 2019 · Atmospheric Research · OSTI ID:1429528
Role of Equatorial Cold Tongue in Central Pacific Double-ITCZ Bias in the NCAR CESM1.2
Journal Article · Mon Nov 09 00:00:00 EST 2020 · Journal of Climate · OSTI ID:1429528

Related Subjects

54 ENVIRONMENTAL SCIENCES
double ITCZ
convection parameterization
spectral cloud model
climate model