In the companion to the present paper, the soil model associated with CLASS (Canadian Land Surface Scheme) was outlined. In this paper, the accompanying vegetation model is described. This model includes physically based treatment of energy and moisture fluxes from the canopy as well as radiation and precipitation cascades through it, and incorporates explicit thermal separation of the vegetation from the underlying ground. Seasonal variations of canopy parameters are accounted for. The morphological characteristics of the 'composite canopy' associated with each grid square are calculated as weighted averages over the vegetation types present. Each grid square is divided into a maximum of four separate subareas: bare soil, snow-covered, vegetation-covered, and snow-and-vegetation covered.

Abstract. The Canadian Earth System Model version 5 (CanESM5) is a global model developed to simulate historical climate change and variability, to make centennial-scale projections of future climate, and to produce initialized seasonal and decadal predictions. This paper describes the model components and their coupling, as well as various aspects of model development, including tuning, optimization, and a reproducibility strategy. We also document the stability of the model using a long control simulation, quantify the model's ability to reproduce large-scale features of the historical climate, and evaluate the response of the model to external forcing. CanESM5 is comprised of three-dimensional atmosphere (T63 spectral resolution equivalent roughly to 2.8∘) and ocean (nominally 1∘) general circulation models, a sea-ice model, a land surface scheme, and explicit land and ocean carbon cycle models. The model features relatively coarse resolution and high throughput, which facilitates the production of large ensembles. CanESM5 has a notably higher equilibrium climate sensitivity (5.6 K) than its predecessor, CanESM2 (3.7 K), which we briefly discuss, along with simulated changes over the historical period. CanESM5 simulations contribute to the Coupled Model Intercomparison Project phase 6 (CMIP6) and will be employed for climate science and service applications in Canada.

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[1] Size-segregated sea-salt aerosols were included as dynamic constituents in the third generation of the Canadian general circulation model (GCMIII) using the Canadian Aerosol Module (CAM). A 12-bin sectional model was used to simulate wind-dependent sea-salt aerosol generation at the surface, diffusive, and advective transports, as well as wet and dry removals as a function of particle size. The dependence of model-predicted atmospheric sea-salt concentration on wind speed is weaker than the u 3.41 dependence of sea-salt emissions but nevertheless still significant. A comparison of GCMIII surface winds with European Centre for Medium-Range Weather Forecasting reanalyzed winds was used to identify a globally averaged bias of modeled surface marine winds of 18%. After taking this into account, two-year simulations were performed to study the atmospheric sea-salt cycle. Comparisons of seasonal mean model predictions with observed sea-salt mass concentrations at 24 marine observatories were in reasonable agreement (generally better than a factor of 2). The annual global sea-salt flux is estimated to be 1.01 Â 10 13 kg with $32% from the Northern Hemisphere and with 98% in supermicron particles. Although emissions to the atmosphere of submicron sea-salt particles larger than 0.2 mm radius make up only 2% of the total global emissions, they contribute significantly to the background aerosol mass and number concentrations in the marine atmosphere. Submicron sea-salt aerosols contribute substantially to the total optical depth of the atmosphere over the open oceans. They account for 5-15% of total sea-salt mass in air at the surface and 20% at 700 hPa. The global mass mean dry diameter of sea-salt aerosols over oceans is 2.8 mm at the surface and 1.9 mm in the midtroposphere. Concentrations are highest in the roaring forties of the Southern Hemisphere and over the northern oceans from October to March. Residence times of sea-salt aerosols were highly variable depending on size, vertical dispersion, and removal processes. The mean residence time for 7.7 mm and 0.4 mm particles in the marine boundary layer were in the range 0.3-10 hours and 80-360 hours, respectively. Citation: Gong, S. L., L. A. Barrie, and M. Lazare, Canadian Aerosol Module (CAM): A size-segregated simulation of atmospheric aerosol processes for climate and air quality models, 2, Global sea-salt aerosol and its budgets,

Abstract. The Canadian Centre for Climate Modelling and Analysis third generation atmospheric general circulation model (AGCM3) is described. The discussion summarizes the details of the complete physics package emphasizing the changes made relative to the second generation version of the model. AGCM3 is the underlying model for applications which include the IPCC fourth assessment, coupled atmosphere-ocean seasonal forecasting, the first generation of the CCCma earth system model (CanESM1), and middleatmosphere chemistry-climate modelling (CCM). Here we shall focus on issues related to an upwardly extended version of AGCM3, the Canadian Middle-Atmosphere Model (CMAM). The CCM version of CMAM participated in the 2006 WMO/UNEP Scientific Assessment of Ozone Depletion and issues concerning its climate such as the impact of gravity-wave drag, the modelling of a spontaneous QBO, and the seasonality of the breakdown of the Southern Hemisphere polar vortex are discussed here.