Using field observations to inform thermal hydrology models of permafrost dynamics with ATS (v0.83)
Summary: Development and calibration of a process-rich model representation of thaw-depth dynamics in Arctic tundra is presented. Improved understanding of polygonal tundra thermal hydrology processes, of thermal conduction, surface and subsurface saturation and snowpack dynamics is gained by using measured field data to calibrate and refine model structure. The refined model is then used identify future data needs and observational studies.
Geosci. Model Dev. Discuss., 8, 3235-3292, doi:10.5194/gmdd-8-3235-2015, 2015
Evaluation of modeled surface ozone biases as a function of cloud cover fraction
Summary: This study focuses on the evaluation of regional air quality model's performance based on the cloud information from satellite. While cloud information is crucial in photochemistry model, the definition of cloud fraction from model and satellite are not physically consistent. We demonstrate that improper model of cloud fraction is correlated with surface ozone bias, and also show that current model cloud field might be too bright, causing an overestimation of surface ozone-level.
Geosci. Model Dev. Discuss., 8, 3219-3233, doi:10.5194/gmdd-8-3219-2015, 2015
Representation of vegetation effects on the snow-covered albedo in the Noah land surface model with multiple physics options
Summary: Snow albedo varies with snow grain size, snow cover thickness, etc. It also depends on the spatial characteristics of land cover and on the canopy density and structure. The Noah-MP model shows a bias error of albedo in winter due to no proper reflection of the vegetation effect. We developed new parameters, called leaf index and stem index, which reflect the vegetation effect on winter albedo. The Noah-MP's performance in albedo has prominently improved with about 73% decrease in the RMS error.
Geosci. Model Dev. Discuss., 8, 3197-3218, doi:10.5194/gmdd-8-3197-2015, 2015
The Yale Interactive terrestrial Biosphere model: description, evaluation and implementation into NASA GISS ModelE2
Summary: The Yale Interactive Terrestrial Biosphere Model (YIBs) predicts land carbon fluxes and tree growth based on mature schemes but with special updates in phenology, ozone vegetation damage, and photosynthetic-dependent biogenic volatile organic compound. Evaluations with data from 145 flux tower sites and multiple satellite products show that the model predicts reasonable magnitude, seasonality, and spatial distribution of land carbon fluxes.
Geosci. Model Dev. Discuss., 8, 3147-3196, doi:10.5194/gmdd-8-3147-2015, 2015
Revision of the convective transport module CVTRANS 2.4 in the EMAC atmospheric chemistry–climate model
Geosci. Model Dev. Discuss., 8, 3117-3145, doi:10.5194/gmdd-8-3117-2015, 2015
OESbathy version 1.0: a method for reconstructing ocean bathymetry with realistic continental shelf-slope-rise structures
Summary: A methodology is presented for reconstructing past global ocean bathymetry using a plate cooling model for the oceanic lithosphere, the age distribution of the oceanic crust, global oceanic sediment thicknesses, plus shelf-slope-rise structures calibrated at modern active and passive continental margins. The final product is a globally complete ocean bathymetry at arbitrary resolution with an isostatically adjusted, multicomponent sediment layer.
Geosci. Model Dev. Discuss., 8, 3079-3115, doi:10.5194/gmdd-8-3079-2015, 2015
A new sub-grid surface mass balance and flux model for continental-scale ice sheet modelling: validation and last glacial cycle
Summary: A long-term challenge for any model of complex large-scale processes is accounting for the impact of unresolved sub-grid (SG) processes. We quantify the impact of SG mass-balance and ice fluxes on glacial cycle ensemble results for North America. We find no easy solutions to accurately capture these impacts. We show that SG process representation and associated parametric uncertainties can have significant impact on coarse resolution model results for glacial cycle ice sheet evolution.
Geosci. Model Dev. Discuss., 8, 3037-3077, doi:10.5194/gmdd-8-3037-2015, 2015
Improving the global applicability of the RUSLE model – adjustment of the topographical and rainfall erosivity factors
Summary: We adjusted the topographical and rainfall erosivity factors that are the triggers of erosion in the Revised Universal Soil Loss Equation model (RUSLE) to make the model better applicable on a coarse resolution on a global scale. The adjusted RUSLE model compares much better to current high resolution estimates of soil erosion in the USA and Europe. It therefore provides a basis for estimating past and future global impacts of soil erosion on climate with the use of Earth system Models.
Geosci. Model Dev. Discuss., 8, 2991-3035, doi:10.5194/gmdd-8-2991-2015, 2015
High resolution numerical modeling of mesoscale island wakes and sensitivity to static topographic relief data
Geosci. Model Dev. Discuss., 8, 2973-2990, doi:10.5194/gmdd-8-2973-2015, 2015
Increasing vertical mixing to reduce Southern Ocean deep convection in NEMO
Summary: Most ocean models, including NEMO, have unrealistic Southern Ocean deep convection. That is, through extensive areas of the Southern Ocean, they exhibit convection from the surface of the ocean to the sea floor. We find this convection to be an issue as it impacts the whole ocean circulation, notably strengthening the Antarctic Circumpolar Current. Using sensitivity experiments, we show that counter-intuitively the vertical mixing needs to be enhanced to reduce this spurious convection.
Geosci. Model Dev. Discuss., 8, 2949-2972, doi:10.5194/gmdd-8-2949-2015, 2015
Construction of an Eulerian atmospheric dispersion model based on the advection algorithm of M. Galperin: dynamic cores v.4 and 5 of SILAM v.5.5
Summary: The paper presents a transport mechanism of dispersion model SILAM based on the algorithm of Michael Galperin. We describe the original scheme and its updates needed for applications to long-living species, complex atmospheric flows, dynamics of aerosol spectra, etc. The scheme is connected with vertical diffusion, chemical transformation and deposition algorithms. The scheme performance in numerous tests was close to the best of the state-of-art schemes, at much lower computational costs.
Geosci. Model Dev. Discuss., 8, 2905-2947, doi:10.5194/gmdd-8-2905-2015, 2015
Improving the representation of fire disturbance in dynamic vegetation models by assimilating satellite data
Summary: Despite its importance, land surface models poorly simulate fire disturbance and its dynamic effects. Here we present a novel and model-independent methodology of implementing a realistic fire size distribution in a Dynamic Vegetation Model by assimilating satellite data and employing blob detection. While focusing in the Arctic, we verify our results against field data and showcase the improved fire representation in the model.
Geosci. Model Dev. Discuss., 8, 2875-2904, doi:10.5194/gmdd-8-2875-2015, 2015
An analytical verification test for numerically simulated convective flow above a thermally heterogeneous surface
Geosci. Model Dev. Discuss., 8, 2847-2873, doi:10.5194/gmdd-8-2847-2015, 2015
Assessment of the uncertainty of snowpack simulations based on variance decomposition
Geosci. Model Dev. Discuss., 8, 2807-2845, doi:10.5194/gmdd-8-2807-2015, 2015
A regional air quality forecasting system over Europe: the MACC-II daily ensemble production
Summary: This paper describes the current status of the air quality forecasting system over Europe put in place in the Monitoring Atmospheric Composition and Climate projects. It provides daily 4-days forecasts and analyses for the previous day for six major gas and particulate pollutants and their main precursors. These products are based on a multi-model approach using seven state-of-the-art models developed in Europe. This system is evaluated daily and evolves with time to fit user’s requirements.
Geosci. Model Dev. Discuss., 8, 2739-2806, doi:10.5194/gmdd-8-2739-2015, 2015
Methods for automatized detection of rapid changes in lateral boundary condition fields for NWP limited area models
Geosci. Model Dev. Discuss., 8, 2691-2737, doi:10.5194/gmdd-8-2691-2015, 2015
Matching soil grid unit resolutions with polygon unit scales for DNDC modelling of regional SOC pool
Summary: Matching soil grid unit resolution with polygon unit map scale is important to minimize uncertainty of regional soil organic carbon (SOC) pool simulation by DeNitrification–DeComposition (DNDC) process-based model as their strong influences on the uncertainty. A series of soil grid units at varying cell sizes were derived from soil polygon units. Both format soil units were used for regional SOC pool simulation with DNDC model, to determine an optimal raster resolution of grid simulation units.
Geosci. Model Dev. Discuss., 8, 2653-2689, doi:10.5194/gmdd-8-2653-2015, 2015
MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering
Summary: The measurement of snow properties on global scale relies on microwave remote sensing data. The interpretation of this data is, however, challenging. Here we introduce MEMLS3&a, an extension of the snow emission model MEMLS to include a backscatter model for active microwave remote sensing. In MEMLS3&a, snow input parameters can be derived by objective measurement methods which avoids fitting the scattering efficiency of snow. The model is validated with combined active and passive measurements.
Geosci. Model Dev. Discuss., 8, 2605-2652, doi:10.5194/gmdd-8-2605-2015, 2015
A non-equilibrium model for soil heating and moisture transport during extreme surface heating
Geosci. Model Dev. Discuss., 8, 2555-2603, doi:10.5194/gmdd-8-2555-2015, 2015
Development of Global Sea Ice 6.0 CICE configuration for the Met Office Global Coupled Model
Summary: The paper presents a new sea ice configuration, GSI6.0, in the Met Office coupled atmosphere-ocean-ice model. Differences in the sea ice from a previous configuration (GSI4.0) are explained in the context of a previously-published sensitivity study. In summer, Arctic sea ice is thicker and more extensive than in GSI4.0, bringing it closer to the observationally-derived datasets. In winter, the Arctic ice is thiker but less extensive than in GSI4.0.
Geosci. Model Dev. Discuss., 8, 2529-2554, doi:10.5194/gmdd-8-2529-2015, 2015
PyXRD v0.6.2: a FOSS program to quantify disordered, layered minerals using multi-specimen X-ray diffraction profile fitting
Summary: This paper presents a FOSS model called PyXRD used to improve the quantification of complex mixed-layer phyllosilicate assemblages using X-ray diffraction. The novelty of this model is the ab initio incorporation of the multi-specimen method, making it possible to share phases and (a selection of) their parameters across multiple specimens. Using PyXRD we checked if the increased number of observations lead to an improved automatic parameter refinement, which does not always seem to be the case.
Geosci. Model Dev. Discuss., 8, 2497-2528, doi:10.5194/gmdd-8-2497-2015, 2015
Validating a 1-D SVAT model in a range of USA and Australian ecosystems: evidence towards its use as a tool to study Earth's system interactions
Summary: The performance of the SimSphere SVAT model was comprehensively validated against in situ measurements from selected USA and Australian sites belonging to the FLUXNET monitoring network for 2011. Results obtained confirmed the correspondence of the model structure to real conditions for which it had been parameterised, evidencing its ability to reproduce outputs akin to the in situ reference data.To our knowledge this is the first comprehensive validation of SimSphere for Australia and USA.
Geosci. Model Dev. Discuss., 8, 2437-2495, doi:10.5194/gmdd-8-2437-2015, 2015
Enhancement for bitwise identical reproducibility of Earth system modeling on the C-Coupler platform
Geosci. Model Dev. Discuss., 8, 2403-2435, doi:10.5194/gmdd-8-2403-2015, 2015
A parallelization scheme to simulate reactive transport in the subsurface environment with OGS#IPhreeqc
Summary: This technical paper presents a new tool to simulate reactive transport processes in subsurface systems, which couples the open source software packages OpenGeoSys and IPhreeqc. A flexible parallelization scheme was developed and implemented to enable an optimized allocation of computer resources. The performance tests of the coupling interface and parallelization scheme illustrate the promising efficiency of this generally valid approach to simulate reactive transport problems.
Geosci. Model Dev. Discuss., 8, 2369-2402, doi:10.5194/gmdd-8-2369-2015, 2015
Impact of climate, vegetation, soil and crop management variables on multi-year ISBA-A-gs simulations of evapotranspiration over a Mediterranean crop site
Summary: This paper investigates the impacts of errors in climate, vegetation, soil and irrigation drivers on the simulation of evapotranspiration (ET) from the ISBA-A-gs land surface model over a 12-year Mediterranean crop succession. Vegetation dynamic and irrigation have the greatest impact on simulated evapotranspiration. Differences in climate datasets slightly influence simulated ET. Errors in the forcing variables generate smaller impact on simulated ET than errors in the soil parameters.
Geosci. Model Dev. Discuss., 8, 2053-2100, doi:10.5194/gmdd-8-2053-2015, 2015
MOPS-1.0: modelling the regulation of the global oceanic nitrogen budget by marine biogeochemical processes
Geosci. Model Dev. Discuss., 8, 1945-2010, doi:10.5194/gmdd-8-1945-2015, 2015
DYNAMICO, an icosahedral hydrostatic dynamical core designed for consistency and versatility
Summary: The design of the icosahedral atmospheric dynamical core DYNAMICO is presented. The key contribution is to combine a strict separatation of kinematics from dynamics to a Hamiltonian formulation of the equations of motion in a non-Eulerian vertical coordinate to achieve energetic consistency. This approach allows a unified treatment of various equations of motion, here multi-layer shallow-water equations and hydrostatic primitive equations.
Geosci. Model Dev. Discuss., 8, 1749-1800, doi:10.5194/gmdd-8-1749-2015, 2015
The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives
Summary: The paper gives a detailed description of the PArallelized Large-eddy simulation Model (PALM) version 4.0 for the simulation of turbulent atmospheric and oceanic boundary layer flows. The model is optimized for use on massively parallel computer architectures and has been applied for various boundary-layer research studies over the last 15 years by various work groups all over the world. Beside the model description we outline past PALM applications and also discuss future perspectives.
Geosci. Model Dev. Discuss., 8, 1539-1637, doi:10.5194/gmdd-8-1539-2015, 2015
EwE-F 1.0: an implementation of Ecopath with Ecosim in Fortran 95/2003 for coupling
Summary: Marine ecosystem-based management requires integrating multiple models in one unified scheme. Being the most widely used food web model, Ecopath with Ecosim (EwE) is potentially a crucial component of such schemes. Written in Visual Basic for the .NET framework, integration of EwE with physical and/or biogeochemical oceanographic models, which are mostly in Fortran, is complicated. We release a re-coding of EwE in Fortran (EwE-F) so as to facilitate integrating EwE in coupled modelling schemes.
Geosci. Model Dev. Discuss., 8, 1511-1537, doi:10.5194/gmdd-8-1511-2015, 2015
PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies
Geosci. Model Dev. Discuss., 8, 1375-1509, doi:10.5194/gmdd-8-1375-2015, 2015
On the use of Schwarz–Christoffel conformal mappings to the grid generation for global ocean models
Summary: This article applies Schwarz-Christoffel (SC) conformal mappings, especially those for multiple-connected regions, to the grid generation for oceanic general circulation models. The generated grids could achieve: (1) removal of landmass & easier computational load balancing, (2) potentially better spatial resolution on continental boundaries, and alignment of these boundaries to grid lines. These grids could readily be utilized in current Bryan-Cox-Semtner type OGCMs.
Geosci. Model Dev. Discuss., 8, 1337-1373, doi:10.5194/gmdd-8-1337-2015, 2015
Experiences with distributed computing for meteorological applications: Grid computing and Cloud computing
Summary: Three practical meteorological applications with different characteristics highlight the core computer science aspects and applicability of distributed computing to meteorology. Presenting Cloud and Grid computing this paper shows use case scenarios fitting a wide range of meteorological applications from operational to research studies. The paper concludes that distributed computing complements and extends existing high performance computing concepts.
Geosci. Model Dev. Discuss., 8, 1171-1199, doi:10.5194/gmdd-8-1171-2015, 2015
Evaluation of the high resolution WRF-Chem air quality forecast and its comparison with statistical ozone predictions
Geosci. Model Dev. Discuss., 8, 1029-1075, doi:10.5194/gmdd-8-1029-2015, 2015
Analysis of the impact of inhomogeneous emissions in a semi-parameterized street canyon model
Summary: Semi-parameterized street canyon models are popular due to their speed and low input requirements. One often used assumption is that emissions are homogeneously distributed in the entire length and width of the street. It is thus the aim of the present study to analyse the impact of this assumption by implementing an inhomogeneous emission geometry scheme and validating it. The results show an improved performance, however confounded by challenges estimating the emissions accurately.
Geosci. Model Dev. Discuss., 8, 935-977, doi:10.5194/gmdd-8-935-2015, 2015
S2P3-R (v1.0): a framework for efficient regional modelling of physical and biological structures and processes in shelf seas
Summary: Our relatively shallow shelf seas are warmed at the surface in spring and summer, while strong tidal currents act to mix away the surface warmth. These competing effects strongly influence the conditions for seasonal growth of the phytoplankton that support marine food webs. We have developed a versatile framework for fast computer modelling of shelf seas, to explore seasonal and year-to-year variations of warming and plankton productivity, tested against observations in different regions.
Geosci. Model Dev. Discuss., 8, 673-713, doi:10.5194/gmdd-8-673-2015, 2015
Development of PM2.5 source impact spatial fields using a hybrid source apportionment air quality model
Summary: An integral part of air quality management is knowledge of the impact of pollutant sources on ambient concentrations of particulate matter (PM). This work presents a novel spatiotemporal source apportionment method that generates source impacts for the continental U.S. Key sources presented include fossil fuel combustion, biomass burning, dust, sea salt, as well as agricultural activities, biogenics, and aircraft.
Geosci. Model Dev. Discuss., 8, 645-671, doi:10.5194/gmdd-8-645-2015, 2015
Plant functional type classification for Earth System Models: results from the European Space Agency's Land Cover Climate Change Initiative
Summary: Land cover is an essential variable in earth system models and determines conditions driving biogeochemical, energy, and water exchange between ecosystems and the atmosphere. A methodology is presented for mapping plant functional types used in global vegetation models from a updated land cover classification system and open-source conversion tool, resulting from a consultative process among map producers and modelers engaged in the European Space Agency’s Land Cover Climate Change Initiative.
Geosci. Model Dev. Discuss., 8, 429-462, doi:10.5194/gmdd-8-429-2015, 2015
ESP v2.0: enhanced method for exploring emission impacts of future scenarios in the United States – addressing spatial allocation
Summary: We present and demonstrate Version 2.0 of the Emission Scenario Projection (ESP) method. This method produces multi-decadal air pollutant emission projections suitable for air quality modeling. The method focuses on energy-related emissions, including those from the electric sector, buildings, industry and transportation. ESP v2.0 enhances ESP v1.0 by taking into population growth and migration and land use change into consideration.
Geosci. Model Dev. Discuss., 8, 263-300, doi:10.5194/gmdd-8-263-2015, 2015
CH4 parameter estimation in CLM4.5bgc using surrogate global optimization
Summary: We tune the CH4-related parameters of the Community Land Model (CLM) using surrogate global optimization in order to reduce the discrepancies between the CLM predictions and observed CH4 emissions. This is the first application of a surrogate optimization method to calibrate a global climate model. We found that the observation data drives the model to predict more CH4 emissions in the northern latitudes and less in the tropics.
Geosci. Model Dev. Discuss., 8, 141-207, doi:10.5194/gmdd-8-141-2015, 2015
Development of efficient GPU parallelization of WRF Yonsei University planetary boundary layer scheme
Summary: To expedite weather research and prediction, we have put tremendous effort into developing an accelerated implementation of the entire WRF model using GPU massive parallel computing architecture. This paper presents our efficient GPU-based design on WRF YSU PBL scheme. Using one NVIDIA Tesla K40 GPU, the GPU-based YSU PBL scheme achieves a speedup of 193x with respect to its runtime on one CPU core. We can even boost the speedup to 360x with respect to one CPU core as two K40 GPUs are applied.
Geosci. Model Dev. Discuss., 7, 8031-8077, doi:10.5194/gmdd-7-8031-2014, 2014
gpuPOM: a GPU-based Princeton Ocean Model
Summary: This paper provides a full GPU accelerated solution of mpiPOM. We design and implement several optimizing methods: (i) computation optimization in a single GPU (ii) communication optimization among multiple GPUs (iii) I/O optimization between a hybrid GPU and CPU. Our experimental results indicate that the performance of the gpuPOM on a workstation containing 4 GPUs is comparable to a powerful cluster with 408 CPU cores and it reduces the energy consumption by 6.8 times.
Geosci. Model Dev. Discuss., 7, 7651-7691, doi:10.5194/gmdd-7-7651-2014, 2014
Thermo-hydro-mechanical processes in fractured rock formations during glacial advance
Summary: The paper examines the coupled thermo-hydro-mechanical (THM) processes that develop in a fractured rock region within a fluid-saturated rock mass due to loads imposed by an advancing glacier. This scenario needs to be examined in order to assess the suitability of potential sites for the location of deep geologic repositories for the storage of high-level nuclear waste. The THM processes are examined using a computational multiphysics approach.
Geosci. Model Dev. Discuss., 7, 7351-7394, doi:10.5194/gmdd-7-7351-2014, 2014
Mapping of satellite Earth observations using moving window block kriging
Geosci. Model Dev. Discuss., 7, 5381-5405, doi:10.5194/gmdd-7-5381-2014, 2014