Integrating peatlands into the coupled Canadian Land Surface Scheme (CLASS) v3.6 and the Canadian Terrestrial Ecosystem Model (CTEM) v2.0
Summary: About 20% of the carbon stored in global soils occurs in peatlands. Warmer and drier conditions will both tend to stimulate the decomposition of peat and increase CO2 and methane emissions, thus potentially enhancing the warming trend. It is important that this feedback mechanism be captured in climate models. This work integrated peatlands into the Canadian Earth System Model (CanESM) for global climate predictions and represent a valuable enhancement to the family of Earth System Models.
Geosci. Model Dev. Discuss., 8, 10089-10143, doi:10.5194/gmdd-8-10089-2015, 2015
Background error covariance with balance constraints for aerosol species and applications in data assimilation
Summary: The aerosol data assimilation and forecasts can be improved by adopting balance constraints that spread observation information across variables thus produces balanced initial distributions. Surface and aircraft aerosol observations were assimilated to demonstrate the impact of the balance constraints. The results showed that the forecasting experiment with balance constraints is more skillful and durable than the experiment without balance constraints.
Geosci. Model Dev. Discuss., 8, 10053-10088, doi:10.5194/gmdd-8-10053-2015, 2015
pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling
Summary: We often capture knowledge about the subsurface in the form of structural geological models, as a basis for subsurface usage or resource extraction. Here, we provide a modeling code to construct such models on the basis of significant deformational events in geological history, encapsulated in kinematic equations. Our methods simplify complex dynamic processes, but enable us to evaluate how events interact, and finally how certain we are about predictions of structures in the subsurface.
Geosci. Model Dev. Discuss., 8, 10011-10051, doi:10.5194/gmdd-8-10011-2015, 2015
Impacts of air–sea interactions on regional air quality predictions using WRF/Chem v3.6.1 coupled with ROMS v3.7: southeastern US example
Summary: WRF/Chem simulations are performed to understand the impacts of cumulus parameterizations and air-sea interactions on coastal air quality. The use of different cumulus parameterizations gives different vertical mixing and wet scavenging. The use of different air-sea interaction treatments also gives different predictions of O3 and PM2.5 by up to 17.3 ppb and 7.9 μg m-3, respectively. WRF/Chem-ROMS improves model predictions, illustrating the benefits and needs of using coupled atmospheric-ocean
Geosci. Model Dev. Discuss., 8, 9965-10009, doi:10.5194/gmdd-8-9965-2015, 2015
Large ensemble modeling of last deglacial retreat of the West Antarctic Ice Sheet: comparison of simple and advanced statistical techniques
Summary: Computer modeling of variations of the Antarctic Ice Sheet help to understand the ice sheet's sensitivity to climate change. We apply a numerical model to its retreat over the last 20,000 years, from its maximum glacial extent to modern. An ensemble of 625 simulations is performed with systematic combinations of uncertain model parameter values. Results are analyzed using (1) simple averaging, and (2) advanced statistical techniques, and reasonable agreement is found between the two.
Geosci. Model Dev. Discuss., 8, 9925-9963, doi:10.5194/gmdd-8-9925-2015, 2015
Experimental design for three interrelated Marine Ice-Sheet and Ocean Model Intercomparison Projects
Summary: Coupled ice sheet-ocean models capable of simulating moving grounding lines are just becoming available. Such models have a broad range of potential applications in studying the dynamics of ice sheets and glaciers, including assessing their contributions to sea level change. Here we describe the idealized experiments that make up three interrelated Model Intercomparison Projects (MIPs) for marine ice sheet models and regional ocean circulation models incorporating ice shelf cavities.
Geosci. Model Dev. Discuss., 8, 9859-9924, doi:10.5194/gmdd-8-9859-2015, 2015
Bitwise identical compiling setup: prospective for reproducibility and reliability of earth system modeling
Geosci. Model Dev. Discuss., 8, 9817-9857, doi:10.5194/gmdd-8-9817-2015, 2015
ISSM-SESAW v1.0: mesh-based computation of gravitationally consistent sea level and geodetic signatures caused by cryosphere and climate driven mass change
Summary: We present a numerically accurate, computationally efficient, (km-scale) high resolution model for gravitationally consistent relative sea-level that, unlike contemporary pseudo-spectral models, operates efficiently on a flexible finite-element mesh system. The model is useful for earth system modeling and space geodesy. A straightforward and computationally less burdensome coupling to a dynamical ice model, for example, allows a refined and realistic simulation of fast-flowing outlet glaciers.
Geosci. Model Dev. Discuss., 8, 9769-9816, doi:10.5194/gmdd-8-9769-2015, 2015
The Marine Virtual Laboratory: enabling efficient ocean model configuration
Summary: The Marine Virtual Laboratory (MARVL) is designed to help ocean modellers hit the ground running. Usually, setting up an ocean model involves a hand full of technical steps that take time and effort. MARVL provides a user-friendly interface that allows a user to choose what options they want for their model; including the region, time-period, and input data sets. The user then hits "go" and MARVL does the rest - delivering a "take-away bundle" that contains all the files needed to run the model.
Geosci. Model Dev. Discuss., 8, 9741-9768, doi:10.5194/gmdd-8-9741-2015, 2015
The location of the thermodynamic atmosphere–ice interface in fully-coupled models
Summary: This study compares two methods of coupling a sea ice model to an atmospheric model in a series of idealised one-dimensional experiments. The 'JULES' method calculates surface variables in the atmosphere; the 'CICE' method calculates surface variables in the sea ice. It is found that simulations of all variables are more accurate in the 'JULES' method, likely because of the shorter timestep of the atmosphere.
Geosci. Model Dev. Discuss., 8, 9707-9739, doi:10.5194/gmdd-8-9707-2015, 2015
UManSysProp: an online facility for molecular property prediction and atmospheric aerosol calculations
Summary: n this paper we describe the development and application of a new web based 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.
Geosci. Model Dev. Discuss., 8, 9669-9706, doi:10.5194/gmdd-8-9669-2015, 2015
TerrSysMP-PDAF (version 1.0): a modular high-performance data assimilation framework for an integrated land surface–subsurface model
Geosci. Model Dev. Discuss., 8, 9617-9668, doi:10.5194/gmdd-8-9617-2015, 2015
Sensitivity of chemical transport model simulations to the duration of chemical and transport operators: a case study with GEOS-Chem v10-01
Summary: We assessed the sensitivity of simulation accuracy to the duration of chemical and transport operators in a chemical transport model. Longer transport timesteps increase concentrations of emitted species. Longer chemical timesteps increase HOx and chemical feedbacks. Chemical timesteps twice that of the transport timestep offer more simulation accuracy per unit computation. The simulation error from coarser spatial resolution generally exceeds that from longer timesteps.
Geosci. Model Dev. Discuss., 8, 9589-9616, doi:10.5194/gmdd-8-9589-2015, 2015
Global scale modeling of melting and isotopic evolution of Earth's mantle
Geosci. Model Dev. Discuss., 8, 9553-9587, doi:10.5194/gmdd-8-9553-2015, 2015
CellLab-CTS 2015: a Python library for continuous-time stochastic cellular automaton modeling using Landlab
Summary: 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.
Geosci. Model Dev. Discuss., 8, 9507-9552, doi:10.5194/gmdd-8-9507-2015, 2015
The description and validation of a computationally-Efficient CH4-CO-OH (ECCOHv1.01) chemistry module for 3-D model applications
Geosci. Model Dev. Discuss., 8, 9451-9505, doi:10.5194/gmdd-8-9451-2015, 2015
mizuRoute version 1: a river network routing tool for a continental domain water resources applications
Summary: mizuRoute version-1 is a stand-alone runoff routing tool that post-processes runoff outputs from any distributed hydrologic models to produce streamflow estimates in large scale river network. mizuRoute is flexible to river network representation and includes two different river routing schemes. This paper demonstrates mizuRoute's capability of multi-decadal streamflow estimations in the river networks over the entire contiguous Unites States, which contains over 54000 river segments.
Geosci. Model Dev. Discuss., 8, 9415-9449, doi:10.5194/gmdd-8-9415-2015, 2015
Air Quality Modeling with WRF-Chem v3.5 in East and South Asia: sensitivity to emissions and evaluation of simulated air quality
Geosci. Model Dev. Discuss., 8, 9373-9413, doi:10.5194/gmdd-8-9373-2015, 2015
Modeling the diurnal cycle of conserved and reactive species in the convective boundary layer
Geosci. Model Dev. Discuss., 8, 9323-9372, doi:10.5194/gmdd-8-9323-2015, 2015
InMAP: a new model for air pollution interventions
Summary: We develop InMAP (Intervention Model for Air Pollution), an Eulerian model which estimates changes in primary and secondary fine particle (PM2.5) concentrations attributable to annual changes in precursor emissions. InMAP uses a variable resolution grid to focus on human exposures by employing higher spatial resolution in urban areas and lower spatial resolution in rural and remote locations and in the upper atmosphere; and by directly calculating steady-state, annual average concentrations.
Geosci. Model Dev. Discuss., 8, 9281-9321, doi:10.5194/gmdd-8-9281-2015, 2015
Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling
Summary: Oligomerization is one of the most important identified processes of secondary organic aerosol evolution. We have simulated the formation of oligomers from biogenic precursors, using two different parameterizations implemented in the air quality model Chimere. This study shows that oligomer concentration fields are quite sensitive to the way the competition between local formation, evaporation and transport is restituted. The benefits and disadvantages of each approach are discussed in details.
Geosci. Model Dev. Discuss., 8, 9229-9279, doi:10.5194/gmdd-8-9229-2015, 2015
Towards a representation of priming on soil carbon decomposition in the global land biosphere model ORCHIDEE (version 184.108.40.206)
Summary: 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.
Geosci. Model Dev. Discuss., 8, 9193-9227, doi:10.5194/gmdd-8-9193-2015, 2015
A flexible importance sampling method for integrating subgrid processes
Summary: Numerical models of weather and climate can estimate grid-box-averaged rates of physical processes such as microphysics using Monte Carlo integration. Monte Carlo integration is simple and general but requires many evaluations of the physical process rate. To reduce the number of function evaluations, this paper describes a new, flexible method of importance sampling. It divides the domain into categories, and allows the modeler to prescribe the sampling density in each category.
Geosci. Model Dev. Discuss., 8, 9147-9191, doi:10.5194/gmdd-8-9147-2015, 2015
Inverse transport modeling of volcanic sulfur dioxide emissions using large-scale ensemble simulations
Summary: A new inverse modeling and simulation system is developed to enable efficient and reliable transport simulations of volcanic SO2 at large scale The complex time- and altitude-dependent volcanic emission pattern of the Nabro eruption is identified by our inversion algorithm The simulation results show good agreements with the AIRS satellite observations in terms of SO2 horizontal distributions, and help to further reveal the complex transport processes through the Asian monsoon circulation
Geosci. Model Dev. Discuss., 8, 9103-9146, doi:10.5194/gmdd-8-9103-2015, 2015
Transient climate simulations of the deglaciation 21–9 thousand years before present; PMIP4 Core experiment design and boundary conditions
Summary: This manuscript presents the experiment design for the PMIP4 Last Deglaciation Core experiment; a transient simulation of the last deglaciation, 21-9ka. Specified model boundary conditions include time-varying orbital parameters, greenhouse gases, ice sheets and other geographical changes. However, prescribed ice meltwater is zero. The context of the experiment and the choices for the boundary conditions are explained, along with the future direction of the working group.
Geosci. Model Dev. Discuss., 8, 9045-9102, doi:10.5194/gmdd-8-9045-2015, 2015
3-D radiative transfer in large-eddy simulations – experiences coupling the TenStream solver to the UCLA–LES
Summary: Radiative heating or cooling plays a vital role in the evolution and lifecycle of clouds. Due to the immense computational cost of 3D radiative transfer, today's atmospheric models usually employ crude 1D approximations which neglect any horizontal energy transport whatsoever and may introduce non-negligible errors. This paper documents the implementation and runtime characteristics of the new TenStream solver that enables us to study 3D effects on large domains and extended periods of time.
Geosci. Model Dev. Discuss., 8, 9021-9043, doi:10.5194/gmdd-8-9021-2015, 2015
Improving data transfer for model coupling
Geosci. Model Dev. Discuss., 8, 8981-9020, doi:10.5194/gmdd-8-8981-2015, 2015
ASHEE: a compressible, Equilibrium–Eulerian model for volcanic ash plumes
Summary: 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
Geosci. Model Dev. Discuss., 8, 8895-8979, doi:10.5194/gmdd-8-8895-2015, 2015
Glacial–interglacial changes of H218O, HDO and deuterium excess – results from the fully coupled Earth System Model ECHAM5/MPI-OM
Summary: This paper presents first results of a new isotope-enabled GCM setup, based on the fully coupled atmosphere-ocean model ECHAM5/MPI-OM. 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.
Geosci. Model Dev. Discuss., 8, 8835-8894, doi:10.5194/gmdd-8-8835-2015, 2015
The Arctic Predictability and Prediction on Seasonal-to-Interannual TimEscales (APPOSITE) data set
Summary: Recent decades have seen significant developments in seasonal-to-interannual timescale climate prediction. However, until recently the potential of such systems to predict Arctic climate had not been assessed. This paper describes a multi-model predictability experiment which was run as part of the Arctic Predictability and Prediction On Seasonal to Inter-annual Timescales (APPOSITE) project. The main goal of APPOSITE was to quantify the timescales on which Arctic climate is predictable.
Geosci. Model Dev. Discuss., 8, 8809-8833, doi:10.5194/gmdd-8-8809-2015, 2015
Inconsistent strategies to spin up models in CMIP5: implications for ocean biogeochemical model performance assessment
Summary: This paper explores how the large diversity in spin-up protocols used for ocean biogeochemistry in CMIP5 models contributed to inter-model differences in modeled fields. We show that a link between spin-up duration and skillscore metrics emerges from both individual IPSL-CM5A-LR's results and an ensemble of CMIP5 models. Our study suggests that differences in spin-up protocols constitute a source of inter-model uncertainty which would require more attention in future intercomparison exercices.
Geosci. Model Dev. Discuss., 8, 8751-8808, doi:10.5194/gmdd-8-8751-2015, 2015
Earth System Chemistry Integrated Modelling (ESCiMo) with the Modular Earth Submodel System (MESSy, version 2.51)
Geosci. Model Dev. Discuss., 8, 8635-8750, doi:10.5194/gmdd-8-8635-2015, 2015
The infrastructure MESSy submodels GRID (v1.0) and IMPORT (v1.0)
Geosci. Model Dev. Discuss., 8, 8607-8633, doi:10.5194/gmdd-8-8607-2015, 2015
Determining lake surface water temperatures (LSWTs) worldwide using a tuned 1-dimensional lake model (FLake, v1)
Summary: With the availability of Lake Surface Water Temperature (LSWT) satellite data for 246 globally distributed large lakes, I tune a lake model, FLake, by varying 3 basic lake properties, shown to have the most influence over the modelled LSWTs. Tuning reduces the mean absolute difference (between model and satellite LSWTs) from an average of 3.38ºC per day (untuned model) to 0.85ºC per day (tuned model). The effect of several LSWT drivers, such as wind speed and lake depth are also demonstrated.
Geosci. Model Dev. Discuss., 8, 8547-8606, doi:10.5194/gmdd-8-8547-2015, 2015
Upscaling methane emission hotspots in boreal peatlands
Geosci. Model Dev. Discuss., 8, 8519-8546, doi:10.5194/gmdd-8-8519-2015, 2015
PRACTISE – Photo Rectification And ClassificaTIon SoftwarE (V.2.0)
Summary: This paper describes a new method to produce spatially and temporally calibrated NDSI-based satellite snow cover maps utilising simultaneously captured photographs as in-situ information. First results confirm a high quality of the produced satellite snow cover maps and underline the need for calibration to ensure a high accuracy and reproduciblity. The software "PRACTISE - Photo Rectification And ClassificaTIon SoftwarE (V.2.0)" was developed to process the photographs and satellite images.
Geosci. Model Dev. Discuss., 8, 8481-8518, doi:10.5194/gmdd-8-8481-2015, 2015
OMI NO2 column densities over North American urban cities: the effect of satellite footprint resolution
Summary: Fair comparison between satellite- and modeled urban NO2 column densities is important in emission inventory evaluation and regulation policy making. This study focuses on the impact of satellite footprint resolution geometry. Since OMI NO2 pixels are too coarse to resolve fine-scale urban plumes, it may cause 20-30% bias over major cities. We introduce approaches to adjust spatial and vertical structure (downscaling & averaging kernel), and demonstrate improved agreement between sat. and model.
Geosci. Model Dev. Discuss., 8, 8451-8479, doi:10.5194/gmdd-8-8451-2015, 2015
Validation of the ALARO-0 model within the EURO-CORDEX framework
Geosci. Model Dev. Discuss., 8, 8387-8409, doi:10.5194/gmdd-8-8387-2015, 2015
Evaluation of improved land use and canopy representation in BEIS v3.61 with biogenic VOC measurements in California
Geosci. Model Dev. Discuss., 8, 8117-8154, doi:10.5194/gmdd-8-8117-2015, 2015
The carbon cycle in the Australian Community Climate and Earth System Simulator (ACCESS-ESM1) – Part 1: Model description and pre-industrial simulation
Summary: The paper describes a version of the Australian Community Climate and Earth System Simulator that has been enabled to simulate the carbon cycle, which is designated ACCESS-ESM1. The model performance for pre-industrial conditions is assessed and land and ocean carbon fluxes are found to be simulated realistically.
Geosci. Model Dev. Discuss., 8, 8063-8116, doi:10.5194/gmdd-8-8063-2015, 2015
FPLUME-1.0: An integrated volcanic plume model accounting for ash aggregation
Geosci. Model Dev. Discuss., 8, 8009-8062, doi:10.5194/gmdd-8-8009-2015, 2015
Impact of ocean coupling strategy on extremes in high-resolution atmospheric simulations
Summary: 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 poorly represented. In the case of a coarser ocean grid, significantly stronger cyclone winds result, due to misaligned frictional vectors in the atmospheric dynamical core.
Geosci. Model Dev. Discuss., 8, 7983-8007, doi:10.5194/gmdd-8-7983-2015, 2015
VISIR-I: small vessels, least-time nautical routes using wave forecasts
Summary: The operational availability of high spatial and temporal resolution forecasts of environmental fields opens the way to services close to end-user needs. We have developed VISIR, a new numerical model for the computation of optimal ship routes out of sea-state forecasts. Motorboats with lengths of up to a few tens of meters and a displacement hull are considered. Route diversions result from the safety constraints and the temporal evolution and spatial variability of the environmental fields.
Geosci. Model Dev. Discuss., 8, 7911-7981, doi:10.5194/gmdd-8-7911-2015, 2015
ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth System Models in CMIP
Summary: A community diagnostics and performance metrics tool for the evaluation of Earth System Models (ESMs) in CMIP has been developed that allows for routine comparison of single or multiple models, either against predecessor versions or against observations.
Geosci. Model Dev. Discuss., 8, 7541-7661, doi:10.5194/gmdd-8-7541-2015, 2015
Tracking influential haze source areas in North China using an adjoint model, GRAPES–CUACE
Summary: The adjoint of the aerosol module in the the atmospheric chemical modeling system GRAPES-CUACE was developed, tested for its correctness and used in a receptor-source sensitivity test. The results showed that controlling critical emission-sources during critical time intervals on the basis of adjoint sensitivity analysis is much more efficient than controlling administrative specified regions during an experiential time period.
Geosci. Model Dev. Discuss., 8, 7313-7345, doi:10.5194/gmdd-8-7313-2015, 2015
Development and evaluation of CNRM Earth-System model – CNRM-ESM1
Summary: This paper presents the first IPCC-class Earth system model developed at Centre National de Recherches Météorologiques (CNRM-ESM1). We detail how the various carbon reservoirs were initialized and analyze the behavior of the carbon cycle and its prominent physical drivers, comparing model results to the most up-to-date climate and carbon cycle dataset over the latest decades.
Geosci. Model Dev. Discuss., 8, 5671-5739, doi:10.5194/gmdd-8-5671-2015, 2015
Modelling spatial and temporal vegetation variability with the Climate Constrained Vegetation Index: evidence of CO2 fertilisation and of water stress in continental interiors
Summary: A model was developed to simulate spatio-temporal variations in vegetation in response to temperature, precipitation and atmospheric CO2 levels. The model reproduced variations in vegetation well; it showed a greater response to drought stress in N Hemisphere continents than previous implementations and showed a decline in vegetation during the US dust bowl (1930s and 1950s) and the drought of the century in the Sahel (1984). Vegetation greenness increased in response to atmospheric CO2 levels.
Geosci. Model Dev. Discuss., 8, 4781-4821, doi:10.5194/gmdd-8-4781-2015, 2015