The Canadian Fourth Generation Atmospheric Global Climate Model (CanAM4). Part I: Representation of Physical Processes

Abstract

The Canadian Centre for Climate Modelling and Analysis (CCCma) has developed the fourth generation of the Canadian Atmospheric Global Climate Model (CanAM4). The new model includes substantially modified physical parameterizations compared to its predecessor. In particular, the treatment of clouds, cloud radiative effects, and precipitation has been modified. Aerosol direct and indirect effects are calculated based on a bulk aerosol scheme. Simulation results for present-day global climate are analyzed, with a focus on cloud radiative effects and precipitation. Good overall agreement is found between climatological mean short-and longwave cloud radiative effects and observations from the Clouds and Earth's Radiant Energy System (CERES) experiment. An analysis of the responses of cloud radiative effects to variations in climate will be presented in a companion paper.RÉSUMÉ [Traduit par la rédaction] Le Centre canadien de la modélisation et de l'analyse climatique (CCmaC) a mis au point la quatrième génération du modèle canadien de circulation générale de l'atmosphère (CanAM4). Le nouveau modèle comprend des paramétrisations physiques passablement modifiées comparativement à son prédé-cesseur. En particulier, le traitement des nuages, des effets radiatifs des nuages et des précipitations a été modifié. Les effets directs et indirects des aérosols sont calculés à l'aide d'un schéma d'aérosols en bloc. Nous analysons des résultats de simulation pour le climat général du jour présent en mettant l'accent sur les effets radiatifs des nuages et les précipitations. Nous trouvons un bon accord général entre la moyenne climatologique des effets radiatifs des nuages pour les courtes et les grandes longueurs d'onde et les observations de l'expérience CERES (Clouds and Earth's Radiant Energy System). Une analyse de la réponse des effets radiatifs des nuages aux variations du climat sera présentée dans un article connexe.

Evaluation of extreme rainfall and temperature over North America in CanRCM4 and CRCM5

“…Both models share the same dynamical core (Zadra et al 2008), with further descriptions of configurations for CRCM5 in Martynov et al (2013) and Šeparović et al (2013), while CanRCM4 is described in Scinocca et al (2015), von Salzen et al (2013) and Diaconescu et al (2014).…”

“…Microphysics: Lohmann and Roeckner (1996), Rotstayn (1997) and Khairoutdinov and Kogan (2000) 5. Planetary boundary layer: Abdella andMcFarlane (1997) See Scinocca et al (2015) for description of CanRCM4 or von Salzen et al (2013) for further details on physics schemes that are shared with CanAM4 1. Convection: Kain and Fritsch (1990), a transient version of Kuo (1965) scheme (Bélair et al 2005) 2.…”

Rain-on-snow events over North America based on two Canadian regional climate models

“…The physical parameterizations in CRCM5 are similar to those in GEM, except for the land surface and the radiation schemes. CanRCM4 uses the same parameterizations as in the forth-generation Canadian Atmospheric global climate model, CanAM4 (von Salzen et al 2013). The main characteristics and physical parameterizations (e.g., radiation scheme, boundary layer scheme, orographic gravity wave drag, aerosol scheme, grid-scale microphysics, convection schemes, land-surface scheme, land use, soil initialization and so on) of the two RCMs have been compared in detail by Whan and Zwiers (2016), but a brief description is given here.…”

Internal variability in simulated and observed tropical tropospheric temperature trends

“…For simulations, we use historical and RCP4.5 runs from 44 different GCMs from the CMIP5 archive [Taylor et al, 2012;Bi et al, 2013;Xin et al, 2013;Ji et al, 2014;von Salzen et al, 2013;Meehl et al, 2012;Hurrell et al, 2012;Scoccimarro et al, 2011;Voldoire et al, 2013;Rotstayn et al, 2010;Hazeleger et al, 2010;Li et al, 2013;Delworth et al, 2006;Donner et al, 2011;Schmidt et al, 2014;Smith et al, 2010;Collins et al, 2011;Jones et al, 2011;Volodin et al, 2010;Dufresne et al, 2013;Hourdin et al, 2013;Sakamoto et al, 2012;Watanabe et al, 2010Watanabe et al, , 2011Giorgetta et al, 2013;Yukimoto et al, 2012;Bentsen et al, 2013], and from the 100 realization single-model large ensemble of the MPI-ESM [Giorgetta et al, 2013]. The large ensemble uses the model version MPI-ESM1.1 in low resolution (LR) configuration, with resolution T63 and 47 vertical levels in the atmosphere and 1.5 ∘ resolution and 40 vertical levels in the ocean.…”