A single‐column model intercomparison on the stratocumulus representation in present‐day and future climate

Abstract

Six Single-Column Model (SCM) versions of climate models are evaluated on the basis of their representation of the dependence of the stratocumulus-topped boundary layer regime on the free tropospheric thermodynamic conditions. The study includes two idealized experiments corresponding to the present-day and future climate conditions in order to estimate the low-cloud feedback. Large-Eddy Simulation (LES) results are used as a benchmark and GCM outputs are included to assess whether the SCM results are representative of their 3-D counterparts. The SCMs present a variety of dependencies of the cloud regime on the free tropospheric conditions but, at the same time, several common biases. For all the SCMs the stratocumulus-topped boundary layer is too shallow, too cool, and too moist as compared to the LES results. Moreover, they present a lack of clouds and liquid water and an excess of precipitation. The disagreement among SCMs is even more distinct for the response to a climate perturbation. Even though the overall feedback is positive for all the models, in line with the LES results, the SCMs show a rather noisy behavior, which depends irregularly on the free tropospheric conditions. Finally, the comparison with the host GCM outputs demonstrates that the considered approach is promising but needs to be further generalized for the SCMs to fully capture the behavior of their 3-D counterparts.

Large-Eddy Simulations of EUCLIPSE–GASS Lagrangian Stratocumulus-to-Cumulus Transitions: Mean State, Turbulence, and Decoupling

“…The LES results point to a reduction of the amount of subtropical marine low clouds in a warmer climate (Blossey et al 2013; Van der Dussen et al 2015;Bretherton 2015). The study by Zhang et al (2013), and follow-up studies by Dal Gesso et al (2014) andDal Gesso et al (2015) report a wide scatter in the change of the steady-state subtropical low-cloud amount in the SCM results. These results actually give rise to the question of how large-scale forcing conditions like the sea surface temperature, free-tropospheric temperature and humidity, and the large-scale subsidence determine control the SCT.…”

“…The presence of such modes may be indicative of a local hydrological cycle that is distinctively different among the models. The finding that the degree of decoupling has an important consequence for the LWP suggests that the decoupling parameters can be a helpful quantity in evaluating parameterization schemes for cloud-topped boundary layers (Dal Gesso et al 2014). The 3D instantaneous LES (thermo-) dynamic fields may be further used to evaluate parameterizations used in global models.…”

Assessing the sensitivity of the hydroxyl radical to model biases in composition and temperature using a single-column photochemical model for Lauder, New Zealand

“…To illustrate this, we repeat the above simulation but now using European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis (hereafter ERAI) H 2 O (Dee et al, 2011). Irrespectively of the large differences and the opposite signs in H 2 O biases between Lauder radiosonde and ERAI data, the OH response to biases in H 2 O shows approximately the same linear relationship in both cases (Fig.…”

“…However, their analyses only pertain to polluted environments not representative of much of the global atmosphere and only take in episodic and surface measurements. Single-column models have been applied to modelling the atmospheric boundary layer (Mihailovic et al, 2005;Cuxart et al, 2006), diabatic processes (Randall et al, 2003;Bergman and Sardeshmukh, 2004), clouds and aerosols (Kylling et al, 2005;Lebassi-Habtezion and Caldwell, 2015;Dal Gesso et al, 2015), the impacts of GHGs on climate change (Vupputuri et al, 1995), and the chemistry of halogen compounds (Piot and von Glasow, 2008;Joyce et al, 2014). Tropospheric OH chemistry of the remote atmosphere has not been assessed in a single-column model framework before.…”

Recent progress toward reducing the uncertainty in tropical low cloud feedback and climate sensitivity: a review

“…In the CFMIP framework together with related research projects, a variety of approaches have been conducted: multi-model ensemble Open Access *Correspondence: kamae.yoichi.fw@u.tsukuba.ac.jp 1 Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8506, Japan Full list of author information is available at the end of the article using climate models developed by different modeling centers independently (e.g., Andrews et al 2012a;Zelinka et al 2013;Vial et al 2013), perturbed physics ensemble (PPE; detailed in a later section) focusing on the sensitivity of model physics (e.g., cumulus convection, cloud microphysics, and turbulence) on parameter settings (e.g., Collins et al 2011;Klocke et al 2011;Shiogama et al 2012), climate models which have physics schemes swapped (Gettelman et al 2012;Watanabe et al 2012b) or turned off (Webb et al 2015), simplified aqua planet simulations (e.g., Wang et al 2012;Stevens and Bony 2013;Medeiros et al 2014), single column models simulating one-dimensional atmospheric column (e.g., Zhang et al 2013;Dal Gesso et al 2015), high-resolution models resolving the cloud-convection system (Wyant et al 2009;Sato et al 2014;, or large eddy simulations (LES; e.g., Blossey et al 2013;Bretherton et al 2013;Bretherton and Blossey 2014). Satellite observations have been applied to assess the performance of climate model simulations and evaluate cloud feedback in a warming climate by using satellite simulators implemented in climate models (e.g., Klein and Jakob 1999;Webb et al 2001;Bodas-Salcedo et al 2011;Pincus et al 2012).…”