The paper presents a transport mechanism of SILAM CTM based on an algorithm of M. Galperin. We describe the original scheme and its updates needed for applications to long-living species, complex atmospheric flows, etc. The scheme is connected to vertical diffusion, chemical transformation and deposition algorithms. Quality of the advection routine is evaluated with a large set of tests, which showed performance fully comparable with state-of-the-art algorithms at much lower computational costs.

The MACC project is preparing the operational atmosphere service of the European Copernicus Programme, and uses data assimilation to combine atmospheric models with available observations. Our paper provides an overview of the aerosol and trace gas validation activity of MACC. Topics are the validation requirements, the measurement data, the assimilation systems, the upgrade procedure, operational aspects and the scoring methods. A summary is provided of recent results, including special events.

This study presents the inclusion of 10 Mediterranean agricultural plants in an agro-ecosystem model (LPJmL): nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. With this development presented, LPJmL is now able to simulate in good detail and mechanistically the functioning of Mediterranean agriculture.

Dynamic vegetation models (DVMs) often have high computational expenses, which the presented dynamic two-layer classification concept (D2C) aims to reduce. When implementing D2C into a DVM, a new layer for the dynamic grouping of grid-cells with similar climate and species compositions is introduced. The grouping of cells reduces the number of required calculations. With TreeMig-2L, I present how D2C can be implemented in a DVM and demonstrate that D2C can strongly reduce computational expenses.

A “three-step” methodology is proposed to effectively obtain the optimum combination of some key parameters in cloud and convective parameterizations according to a comprehensive objective evaluation metrics. The optimal results improve the metrics performance by 9%. A software framework can automatically execute any part of the “three-step” calibration strategy. The proposed methodology and framework can easily be applied to other GCMs to speed up the model development process.

Predicting the distribution of vegetation under novel climates is important, both to understand how climate change will impact ecosystem services, but also to understand how vegetation changes might affect the carbon, energy and water cycles. Historically, predictions have been heavily dependent upon observations of existing vegetation boundaries. In this paper, we attempt to predict ecosystem boundaries from the ``bottom up'', and illustrate the complexities and promise of this approach.

We describe the creation of boundary conditions related to the presence of ice sheets, including ice-sheet extent and height, ice-shelf extent, and the distribution and altitude of ice-free land, at the Last Glacial Maximum (LGM), for use in LGM experiments conducted as part of the Coupled Modelling Intercomparison Project (CMIP5) and Palaeoclimate Modelling Intercomparison Project (PMIP3). The difference in the ice sheet boundary conditions as well as the climate response to them are discussed.

The non-stationary links between sea surface temperature and global atmospheric circulation have served to create the S⁴CAST model. Here we describe the model, based on a statistical tool to be focused on the study of teleconnections and predictability of any climate-related variable that keeps a link with sea surface temperature. Due to its intuitive operation and free availability of the code, the model can be used both to supplement general circulation models and in a purely academic context.

We present a workflow to convert geological models into the open-source VTU format for usage in numerical simulation models. Tackling relevant scientific questions or engineering tasks often involves multidisciplinary approaches. Conversion workflows are needed between the diverse tools of the various disciplines. Our approach offers an open-source, platform-independent, robust, and comprehensible method that is potentially useful for a multitude of similar environmental studies.

Flux footprint models describe the surface area of influence of a flux measurement. They are used for designing flux tower sites, and for interpretation of flux measurements. The two-dimensional footprint parameterisation (FFP) presented here is suitable for processing large data sets, and, unlike other fast footprint models, FFP is applicable to daytime or night-time measurements, fluxes from short masts over grassland to tall towers over mature forests, and even to airborne flux measurements.

We introduce the Explicit Wake Parametrisation (EWP) for wind farms in mesoscale models that accounts for the wake expansion within a turbine-containing cell. In the EWP approach, turbulence kinetic energy (TKE) production results from changes in vertical shear. The velocity recovery compares well to mast data downstream of the offshore wind farm Horns Rev I. The vertical structure of the TKE and the velocity profile are qualitatively similar to that simulated with large eddy simulations.

This study investigate the representation of hemispheric transport in a regional chemical transport model (CTM) in terms of lateral boundary conditions (LBCs). We evaluate the LBCs both directly with satellite retrievals and indirectly by forcing a regional CTM with LBCs and compare to in-domain observations. We believe that our work makes an important contribution to the methodology of validating LBCs for regional modelling.

Volatile organic compounds released from forests into the atmosphere play a key role in governing atmospheric concentrations of trace gases and aerosol particles. We describe the development of a 1-D model that simulates the processes occurring within and above the forest canopy that regulate the transfer of these compounds and their products. We evaluate model performance by comparison of modelled concentrations against measurements from a field campaign at a northern Michigan forest site.

A perennial crop model CLM-Palm is developed, including multilayer structure, phenology, and carbon and nitrogen allocation functions, for modeling an important oil palm agricultural system in the tropical regions. Simulated LAI, yield and NPP were calibrated and validated with multiple sites in Sumatra, Indonesia. The new model allows exploring the effects of tropical land use change, from natural ecosystems to monoculture plantations on carbon, water and energy cycles and regional climate.