For analyzing the health effects of particulate matter, it is necessary to consider not only the mass of particles, but also their sizes and composition. A simple measure for the former is the number concentration of particles. We present particle number concentrations in five major European cities, namely Helsinki, Oslo, London, Rotterdam, and Athens, in 2008, based mainly on modelling. The concentrations of PN were mostly influenced by the emissions from local vehicular traffic.

This study evaluates the performances of the new version (v.5.1) of 3D-CMCC Forest Ecosystem Model in simulating gross primary productivity (GPP), against eddy covariance GPP data for 10 FLUXNET forest sites across Europe. The model consistently reproduces both in timing and in magnitude daily and monthly GPP variability across all sites, with the exception of the two Mediterranean sites. Inclusion of forest structure within simulation ameliorate in some cases the model output.

In this study, we describe and evaluate a new four-mode version of the Modal Aerosol Module (MAM4) in the Community Atmosphere Model version 5 (CAM5). Compared to the current three-mode version of MAM in CAM5, MAM4 significantly improves the simulation of seasonal variation of BC concentrations in the polar regions, by increasing the BC concentrations in all seasons and particularly in cold seasons.

Thawing of permafrost is governed by a complex interplay of different processes, of which only conductive heat transfer is taken into account in most model studies. We present a new land-surface scheme designed for permafrost applications, CryoGrid 3, which constitutes a flexible platform to explore new parameterizations for a range of permafrost processes.

An experimental study was conducted to quantify the anthropic energy flux of traffic impact on RST in the winter season. It indicated an RST increase by 1 °C to 3 °C with respect to the absence of traffic. Additional work was undertaken so as to evaluate to which extent an accurate description of traffic might improve the TEB numerical model when dedicated to RST simulations. Two approaches to traffic integration in this model were detailed and tested.

LIMA, a new quasi two-moment, mixed-phase microphysical scheme, is introduced. LIMA relies on the prognostic evolution of a multimodal aerosol population and the careful description of their nucleating properties that enable cloud droplets and pristine ice to form. This paper describes LIMA and illustrates its ability to represent aerosol-cloud interactions for 2-D idealized simulations of a squall line and orographic cold clouds.

We have developed a mechanistic model of leaf utilization of nitrogen for assimilation (LUNA V1.0) to predict the photosynthetic capacities at the global scale based on the optimization of key leaf-level metabolic processes. LUNA model predicts that future climatic changes would mostly affect plant photosynthetic capabilities in high-latitude regions and that Earth system models using fixed photosynthetic capabilities are likely to substantially overestimate future global photosynthesis.

A sub-grid treatment based on Weibull distribution is introduced to CAM5 to take into account the impact of unresolved variability of surface wind speed on sea salt and dust emissions. Simulations show that sub-grid wind variability has relatively small impacts on the global mean sea salt emissions, but considerable influence on dust emissions. Dry convective eddies and mesoscale flows associated with complex topography are the major causes of dust emission enhancement.

This article describes the extension of the ESCIMO.spread spreadsheet-based point energy balance snow model by (i) an advanced approach for precipitation phase detection, (ii) a concept for cold and liquid water storage consideration and (iii) a canopy sub-model that allows one to quantify the effect of a forest canopy on the meteorological conditions inside the forest as well as the simulation of snow accumulation and ablation inside a forest stand.

This paper presents the first results of a new isotope-enabled GCM set-up, based on the ECHAM5/MPI-OM fully coupled atmosphere-ocean model. Results of two equilibrium simulations under pre-industrial and Last Glacial Maximum conditions reveal a good to very good agreement with many delta O-18 and delta D observational records, and a remarkable improvement for the modelling of the deuterium excess signal in Antarctic ice cores.

The Weather Research and Forecasting model with Chemistry (WRF/Chem) v3.6.1 is evaluated for its first decadal application during 2001 to 2010 using the Representative Concentration Pathway 8.5 emissions. The model evaluation shows acceptable performance for long-term climatological simulations of most meteorological variables and chemical concentrations. Larger biases exist for aerosol-cloud-radiation variables, which future model improvement should focus on.

A new model for gas–particles compressible turbulent dynamics is developed. It is implemented in a fluid dynamic code based on the OpenFOAM libraries. The solver is tested against well known benchmarks, in particular: single and multiphase isotropic turbulence, plume turbulent dynamics and shock tube experiments. These comparisons validate the capability of the solver to capture the desired physics. A volcanic plume is analyzed, focusing on non-equilibrium ash dynamics and mean plume properties.

In this paper, we show that different compiling setups can achieve exactly the same (bitwise identical) results in Earth system modeling, and a set of bitwise identical compiling setups of a model can be used across different compiler versions and different compiler flags. Moreover, we shows that new test cases can be generated based on differences of bitwise identical compiling setups between different models, which can help detect software bugs and finally improve the reliability.

In the aerosol-climate model ECHAM6-HAM2, dust source activation (DSA) observations from MSG satellite are used to replace the current Saharan source map. The new setup provides more realistically distributed, up to 20 % higher annual Saharan emissions. Modeled dust AOT is partly improved in the Sahara-Sahel region, as is the spatial variability. As a comparison to sub-daily MSG DSAs and a regional model shows, the representation of meteorological drivers of dust uplift remains a critical issue.

This paper highlights the sensitivity of simulated tropical cyclone climatology to the choice of ocean coupling grid in high-resolution climate simulations. When computations of atmosphere–ocean interactions are carried out on the coarser grid in the system, key quantities such as surface wind drag and heat fluxes are incorrectly calculated. In the case of a coarser ocean grid, significantly stronger cyclone winds result, due to misaligned frictional vectors in the atmospheric dynamical core.

In the atmospheric sciences and air quality studies, there is a widespread use of models which follows the trajectory of air particles. This paper provides the description and validation of the algorithm which parameterizes the vertical transport of air particles due to convective storms in the trajectory component of the model IL-GLOBO, which combines a trajectory model with a meteorological global-scale model, maintaining the consistency between the assumptions made by the two components.

The ECCOH (pronounced "echo") chemistry module interactively simulates the photochemistry of the CH₄–CO–OH system within a chemistry climate model, carbon cycle model, or Earth system model. The computational efficiency of the module allows many multi-decadal sensitivity simulations of the CH₄–CO–OH system. This capability is important for capturing nonlinear feedbacks of the CH₄–CO–OH system and understanding the perturbations to methane, CO, and OH and the concomitant climate impacts.

This paper presents a new Python-language software library, called CellLab-CTS, that enables rapid creation of continuous-time stochastic (CTS) cellular automata models. These models are quite useful for simulating the behavior of natural systems, but can be time-consuming to program. CellLab-CTS allows users to set up models with a minimum of effort, and thereby focus on the science rather than the software.

We present a simple conceptual model of soil carbon decomposition (PRIM) able to reproduce priming experiments. Parameters were optimized using a Bayesian framework and evaluated against another set of soil incubation. PRIM better fit data than the original, CENTURY-type soil decomposition model. We then compared both models incorporated into the global land biosphere model ORCHIDEE. Both versions reproduced observed decay litter rates, but only ORCHIDEE-PRIM could simulate the observed priming.

The response of crops to changing climate and atmospheric CO₂ could have large effects on food production, terrestrial carbon, water, energy fluxes and the climate feedbacks. We developed a new process-oriented terrestrial biogeochemical model named ORCHIDEE-CROP (v0), which integrates a generic crop phenology and harvest module into the land surface model ORCHIDEE. Our model has good ability to capture the spatial gradients of crop phenology, carbon and energy-related variables across Europe.

Satellite measurements of pollutants and greenhouse gases are useful to test and improve atmospheric models. But this requires that modellers account for the spatial and temporal representativeness and the vertical sensitivity of the satellite measurements. This paper provides guidelines on how to carry out a faithful model-satellite comparison for species such as nitrogen dioxide, sulfur dioxide, and formaldehyde that play a key role in air pollution studies.

In this paper we describe the development and application of a new web-based and open-source facility, UManSysProp (http://umansysprop .seaes.manchester.ac.uk), for automating predictions of molecular and atmospheric aerosol properties. Current facilities include pure component vapour pressures, critical properties, and sub-cooled densities of organic molecules; activity coefficient predictions for mixed inorganic-organic liquid systems; hygroscopic growth factors and CCN activation potential.

This study presents the hotspot parameterization, a novel approach to upscaling methane emissions in a boreal peatland from the micro-topographic scale to the landscape scale. We based this new parameterization on the analysis of water table patterns generated by the Hummock–Hollow (HH) model. We show how the hotspot parameterization successfully upscales the micro-topographic controls on methane emissions for both present-day conditions and for the next century under three different scenarios.