Tangent linear superparameterization of convection in a 10 layer global atmosphere with calibrated climatology

Journal Article · Mon Apr 24 00:00:00 EDT 2017 · Journal of Advances in Modeling Earth Systems

DOI:https://doi.org/10.1002/2016MS000871· OSTI ID:1352938

Kelly, Patrick ^[1]; Mapes, Brian  ^[2]; Hu, I-Kuan ^[2]; Song, Siwon ^[2]; Kuang, Zhiming  ^[3]

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1. Pacific Northwest National Laboratory, Richland Washington USA
2. Department of Atmospheric Sciences, University of Miami, Miami Florida USA
3. Department of Earth and Planetary Sciences, Harvard University, Cambridge Massachusetts USA

This study describes a new intermediate global atmosphere model in which synoptic and planetary dynamics including the advection of water vapor are explicit, the time mean flow is centered near a realistic state through the calibration of time-independent 3D forcings, and temporal anomalies of convective tendencies of heat and moisture in each column are represented as a linear matrix acting on the anomalous temperature and moisture profiles in the GCM. This matrix was devised from Kuang’s [2010] linear response function (LRF) of a cooled cyclic convection-permitting model (CCPM) with 256 km periodic domain and 1km mesh, measured around an equilibrium state with a mean rainrate of 3.5 mm/d. The goal of this effort was to cleanly test the role of convection’s free-tropospheric moisture sensitivity in tropical waves, without incurring large changes of mean climate that confuse the interpretation of experiments with entrainment rates in the convection schemes of full-physics GCMs. As the sensitivity to free tropospheric moisture (columns 12-20 of the matrix, representing sensitivity to humidity above 900 hPa altitude) is multiplied by a factor ranging from 0 to 2, the model’s variability ranges from: (1) moderately strong convectively coupled waves with speeds near 20 m s^-1; to (0) weak waves, but still slowed by convective coupling; to (2) wave variability that is greater in amplitude as the water vapor field plays an increasingly important role. Longitudinal structure in the model’s time-mean tropical flow is not fully realistic, and does change significantly with matrix edits, disappointing initial hopes that the Madden-Julian oscillation would be well simulated in the control and could be convincingly decomposed, but further work could improve this class of models.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1352938
• Alternate ID(s): OSTI ID: 1352939; OSTI ID: 1358482
• Report Number(s): PNNL-SA-122511
• Journal Information: Journal of Advances in Modeling Earth Systems, Journal Name: Journal of Advances in Modeling Earth Systems; ISSN 1942-2466
• Publisher: American Geophysical Union (AGU)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
super-parameterization
convection
calibrated climatology
coupling