Title: Impact of Physics Parameterization Ordering in a Global Atmosphere Model

Abstract

Abstract Because weather and climate models must capture a wide variety of spatial and temporal scales, they rely heavily on parameterizations of subgrid‐scale processes. The goal of this study is to demonstrate that the assumptions used to couple these parameterizations have an important effect on the climate of version 0 of the Energy Exascale Earth System Model (E3SM) General Circulation Model (GCM), a close relative of version 1 of the Community Earth System Model (CESM1). Like most GCMs, parameterizations in E3SM are sequentially split in the sense that parameterizations are called one after another with each subsequent process feeling the effect of the preceding processes. This coupling strategy is noncommutative in the sense that the order in which processes are called impacts the solution. By examining a suite of 24 simulations with deep convection, shallow convection, macrophysics/microphysics, and radiation parameterizations reordered, process order is shown to have a big impact on predicted climate. In particular, reordering of processes induces differences in net climate feedback that are as big as the intermodel spread in phase 5 of the Coupled Model Intercomparison Project. One reason why process ordering has such a large impact is that the effect of each process is influencedmore » by the processes preceding it. Where output is written is therefore an important control on apparent model behavior. Application of k ‐means clustering demonstrates that the positioning of macro/microphysics and shallow convection plays a critical role on the model solution.« less

Authors:

Donahue, Aaron S.  ^[1];

• Search DOE PAGES for author "Donahue, Aaron S."
• Search DOE PAGES for ORCID "0000-0002-4710-753X"

Caldwell, Peter M.  ^[1]

• Search DOE PAGES for author "Caldwell, Peter M."
• Search DOE PAGES for ORCID "0000-0001-8604-0844"

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+ Show Author Affiliations

1. Lawrence Livermore National Laboratory Livermore CA USA

Publication Date:

Fri Feb 23 00:00:00 EST 2018

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1422431

Alternate Identifier(s):

OSTI ID: 1425706; OSTI ID: 1432960

Report Number(s):

LLNL-JRNL-730895
Journal ID: ISSN 1942-2466

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Published Article

Journal Name:

Journal of Advances in Modeling Earth Systems

Additional Journal Information:

Journal Name: Journal of Advances in Modeling Earth Systems Journal Volume: 10 Journal Issue: 2; Journal ID: ISSN 1942-2466

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; 97 MATHEMATICS AND COMPUTING