The terminator "toy" chemistry test: a simple tool to assess errors in transport schemes
Summary: This test extends the evaluation of transport schemes from prescribed advection of inert scalars to reactive species. It consists of transporting two reacting chlorine-like species in an idealized flow field. The sources/sinks are given by a simple but non-linear toy chemistry that mimics photolysis-driven processes near the solar terminator. As a result, strong gradients in the spatial distribution of the species develop near the edge of the terminator.
Geosci. Model Dev., 8, 1299-1313, doi:10.5194/gmd-8-1299-2015, 2015
A generic approach to explicit simulation of uncertainty in the NEMO ocean model
Summary: In this paper, a simple and generic implementation approach is presented, with the aim of transforming a deterministic ocean model (like NEMO) into a probabilistic model. With this approach, several kinds of stochastic parameterizations are implemented to simulate the non-deterministic effect of unresolved processes, unresolved scales, and unresolved diversity. The method is illustrated with three applications, showing that uncertainties can produce a major effect in the model simulations.
Geosci. Model Dev., 8, 1285-1297, doi:10.5194/gmd-8-1285-2015, 2015
A stabilized finite element method for calculating balance velocities in ice sheets
Summary: We present a novel numerical method for computing velocity fields in ice sheets using the principle of mass conservation, and show that, for suitable smoothing of flow directions, the velocity converges to a unique solution under grid refinement. We use this method as the forward model in a constrained optimization problem, and use these so-called balance velocities to seamlessly fill in gaps between satellite-based velocity observations.
Geosci. Model Dev., 8, 1275-1283, doi:10.5194/gmd-8-1275-2015, 2015
A sparse reconstruction method for the estimation of multi-resolution emission fields via atmospheric inversion
Summary: The paper presents a statistical method (shrinkage) that can be used to estimate rough emission fields, e.g., fossil fuel CO2 emissions, from measurements of concentrations. This method is demonstrated in a test case where the emissions are modeled using wavelets. We find that the method can eliminate unnecessary complexity from the wavelet model, ensures non-negativity of the emissions, is computationally efficient and is, by construction, insensitive to prior guesses of the total emission.
Geosci. Model Dev., 8, 1259-1273, doi:10.5194/gmd-8-1259-2015, 2015
NEMOTAM: tangent and adjoint models for the ocean modelling platform NEMO
Summary: This paper presents the tangent and adjoint models for the NEMO ocean modelling framework. They are useful tools for sensitivity and stability analysis. The implementation choices and the validation of the code is presented as well as a selection of applications.
Geosci. Model Dev., 8, 1245-1257, doi:10.5194/gmd-8-1245-2015, 2015
Reduction of predictive uncertainty in estimating irrigation water requirement through multi-model ensembles and ensemble averaging
Summary: Irrigation agriculture is required to sustain yields that allow feeding the world population. A robust assessment of irrigation requirement (IRR) relies on a sound quantification of evapotranspiration (ET). We prepared a multi-model ensemble considering several ET methods and investigate uncertainties in simulating IRR. More generally, we provide an example of the value of investigating the uncertainty in models that may be used to inform policy-making and to elaborate best management practices.
Geosci. Model Dev., 8, 1233-1244, doi:10.5194/gmd-8-1233-2015, 2015
The software architecture of climate models: a graphical comparison of CMIP5 and EMICAR5 configurations
Summary: This paper describes an analysis of the software architecture of global climate models. The analysis provides a visualization of the structure of these models, and reveals interesting differences between the models developed at different research labs.
Geosci. Model Dev., 8, 1221-1232, doi:10.5194/gmd-8-1221-2015, 2015
Albany/FELIX: a parallel, scalable and robust, finite element, first-order Stokes approximation ice sheet solver built for advanced analysis
Summary: In this manuscript, we discuss the development and validation of a new momentum balance solver for modeling the flow of glaciers and ice sheets based on the 1st-order Stokes equations. We demonstrate the numerical convergence of our solver (with respect to computational mesh spacing), its flexibility (with respect to both the choice of mesh and finite element type), and its computational performance (robustness and scalability when applied to both idealized and realistic ice sheet simulations).
Geosci. Model Dev., 8, 1197-1220, doi:10.5194/gmd-8-1197-2015, 2015
Normal-mode function representation of global 3-D data sets: open-access software for the atmospheric research community
Summary: The article presents MODES, a new software for the analysis of properties of balanced and inertio-gravity circulations across many scales in (re)analyses, weather forecasts and climate models. The software and real-time results based on ECMWF model can be found at http://meteo.fmf.uni-lj.si/MODES. Evaluation of models' ability to reproduce the unbalanced tropical circulation is expected to provide new insights on model performance that is helpful to diagnose deficiencies and define improvements.
Geosci. Model Dev., 8, 1169-1195, doi:10.5194/gmd-8-1169-2015, 2015
IGCM4: a fast, parallel and flexible intermediate climate model
Geosci. Model Dev., 8, 1157-1167, doi:10.5194/gmd-8-1157-2015, 2015
JULES-crop: a parametrisation of crops in the Joint UK Land Environment Simulator
Geosci. Model Dev., 8, 1139-1155, doi:10.5194/gmd-8-1139-2015, 2015
The Secondary Organic Aerosol Processor (SOAP v1.0) model: a unified model with different ranges of complexity based on the molecular surrogate approach
Geosci. Model Dev., 8, 1111-1138, doi:10.5194/gmd-8-1111-2015, 2015
Modelling climate change responses in tropical forests: similar productivity estimates across five models, but different mechanisms and responses
Summary: This study evaluates the capability of five vegetation models to simulate the response of forest productivity to changes in temperature and drought, using data collected from an Amazonian forest. This study concludes that model consistencies in the responses of net canopy carbon production to temperature and precipitation change were the result of inconsistently modelled leaf-scale process responses and substantial variation in modelled leaf area responses.
Geosci. Model Dev., 8, 1097-1110, doi:10.5194/gmd-8-1097-2015, 2015
Technical challenges and solutions in representing lakes when using WRF in downscaling applications
Summary: Because global climate models (GCMs) are typically run at coarse spatial resolution, lakes are often poorly resolved in their global fields. When downscaling such GCMs using the Weather Research & Forecasting (WRF) model, use of WRF’s default interpolation methods can result in unrealistic lake temperatures and ice cover, which can impact simulated air temperatures and precipitation. Here, alternative methods for setting lake variables in WRF downscaling applications are presented and compared.
Geosci. Model Dev., 8, 1085-1096, doi:10.5194/gmd-8-1085-2015, 2015
Crop physiology calibration in the CLM
Summary: Farming is using more of the land surface terrestrial ground and this expansion exerts an increasing impact on the terrestrial carbon cycle. In order to understand the impact of such processes, we calibrate the parametric models within CLM-Crop (part of the Community Land Model (CLM)). The agreement between AmeriFlux observations and model projections is greatly improved for soybean, which is the focus of this study.
Geosci. Model Dev., 8, 1071-1083, doi:10.5194/gmd-8-1071-2015, 2015
Dynamic model evaluation for secondary inorganic aerosol and its precursors over Europe between 1990 and 2009
Geosci. Model Dev., 8, 1047-1070, doi:10.5194/gmd-8-1047-2015, 2015
An approach to enhance pnetCDF performance in environmental modeling applications
Geosci. Model Dev., 8, 1033-1046, doi:10.5194/gmd-8-1033-2015, 2015
libmpdata++ 1.0: a library of parallel MPDATA solvers for systems of generalised transport equations
Summary: This paper accompanies the first release of libmpdata++, a C++ library implementing the multidimensional positive-definite advection transport algorithm (MPDATA) on a regular structured grid. The library offers basic numerical solvers for systems of generalised transport equations. All solvers offer parallelisation through domain decomposition using shared-memory parallelisation. The paper describes the library programming interface, and serves as a user guide.
Geosci. Model Dev., 8, 1005-1032, doi:10.5194/gmd-8-1005-2015, 2015
Tropospheric chemistry in the Integrated Forecasting System of ECMWF
Summary: We describe modules for atmospheric chemistry, wet and dry deposition and lightning NO production, which have been newly introduced in ECMWF's weather forecasting model. With that model, we want to forecast global air pollution as part of the European Copernicus Atmosphere Monitoring Service. We show that the new model results compare as well or better with in situ and satellite observations of ozone, CO, NO2, SO2 and formaldehyde as the previous model.
Geosci. Model Dev., 8, 975-1003, doi:10.5194/gmd-8-975-2015, 2015
Twelve-month, 12 km resolution North American WRF-Chem v3.4 air quality simulation: performance evaluation
Summary: We evaluate the predictive performance of a 12-month, 12km horizontal resolution WRF-Chem air quality model simulation for the contiguous United States. Model performance is comparable to other contemporary models used for regulatory and health-effects analysis, with 12% bias for daytime ozone and -1% bias for fine particulate matter (PM2.5). Performance for PM2.5 is worse in winter and in the western U.S. than in other seasons and regions, suggesting opportunities for future model development.
Geosci. Model Dev., 8, 957-973, doi:10.5194/gmd-8-957-2015, 2015