University of Florida Thesis Or Dissertation Formatting

Total Page:16

File Type:pdf, Size:1020Kb

University of Florida Thesis Or Dissertation Formatting VERIFICATION AND VALIDATION OF ATMOSPHERIC TRANSPORT MODELS USING THE UNIVERSITY OF FLORIDA TRAINING REACTOR By GABRIEL ALFREDO SANDLER A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2019 1 © 2019 Gabriel A. Sandler 2 To my partner, family, and friends 3 ACKNOWLEDGMENTS To begin, I want to thank my adviser Dr. James Baciak for guiding me for the past four and a half years. As a graduate student under Dr. Baciak, I truly learned how to work independently at a high level. I would also like to thank Dr. Andreas Enqvist who was my first research adviser as an undergraduate student and has been an amazing source of help throughout my time as a graduate student. I would also like to thank Brian Shea, Dan Cronin, and Matt Berglund from the University of Florida Training Reactor for helping me accomplish tasks essential for my research. I have also furthered my knowledge and abilities outside the University of Florida. I would like to thank Dr. Scott Kiff from Sandia National Laboratory and Dr. Micah Lowenthal from the National Academies of Science for helping me develop new skillsets which I will carry on as I continue my career. Additionally, I would like to thank the National Nuclear Security Administration for providing funding throughout my graduate career as part of the Consortium for Verification Technology. My educational path would not have been the same without my mom, dad, and brother. Their support and love throughout the entirety of my life has allowed me to follow my passions and become the person I am today. Also, I would like to thank all the friends I have made in high school, undergrad, and graduate school. My time as a student would not have been the same without you all. Lastly, I would like to thank my partner Hannah Kaufman for providing constant support and pushing me to always be the best version of myself. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES ........................................................................................................ 11 LIST OF ABBREVIATIONS ........................................................................................... 14 ABSTRACT ................................................................................................................... 16 CHAPTER 1 INTRODUCTION AND MOTIVATION..................................................................... 18 Introduction to Atmospheric Transport Models ....................................................... 18 Impact of Atmospheric Transport Models in the Nuclear Field ................................ 21 Utilizing the University of Florida Training Reactor ................................................. 26 Objective of Research............................................................................................. 30 2 THEORY ................................................................................................................. 32 Atmospheric Dispersion Theory .............................................................................. 32 Atmospheric Transport Models ............................................................................... 34 The Gaussian Dispersion Model ...................................................................... 37 The Lagrangian Model ..................................................................................... 40 The Puff Model ................................................................................................. 41 The Eulerian Model .......................................................................................... 42 Computational Fluid Dynamics Modeling ......................................................... 43 Comparison of Models ..................................................................................... 43 Radiation Detection ................................................................................................ 45 Gas-filled Detectors .......................................................................................... 46 Scintillators ....................................................................................................... 47 Semiconductors ................................................................................................ 48 Selection of Detector for Measurements .......................................................... 49 3 VERIFICATION AND VALIDATION PROCESS ..................................................... 51 Experimental Measurements .................................................................................. 51 Instrumentation ................................................................................................. 51 Measurement Setups ....................................................................................... 53 Proving the Detectability of the 41Ar Plume ............................................................. 58 Coupling ATMs with MCNP .................................................................................... 59 UF Developed MATLAB Gaussian Model ........................................................ 62 AERMOD .......................................................................................................... 64 5 FLEXPART ....................................................................................................... 68 Summary of Weather Data Sources ................................................................. 71 4 HIGH VELOCITY PLUME STACK .......................................................................... 73 Measurement Results for May 2018 and March 2019 Trials ................................... 73 Simulation Results for May 2018 and March 2019 Trials ........................................ 84 Discussion and Analysis of Results ........................................................................ 94 5 LOW VELOCITY PLUME STACK ......................................................................... 100 Measurement Results for November 2018 and January 2019 Trials .................... 100 Simulation Results for November 2018 and January 2019 Trials ......................... 111 Discussion and Analysis of Results ...................................................................... 125 6 SENSITIVITY ANALYSIS OF COUPLED MODELS ............................................. 130 Overview of Proposed Sensitivity Analyses .......................................................... 130 One-factor-at-a-time Sensitivity Analysis .............................................................. 131 Wind Speed .................................................................................................... 132 Wind Orientation ............................................................................................. 136 Atmospheric Stability ...................................................................................... 141 Plume Length and Resolution ........................................................................ 141 7 CONCLUSION AND FUTURE WORK .................................................................. 145 APPENDIX: 10 MINUTE AVERAGED MEASUREMENT AND SIMULATION DATA .. 150 LIST OF REFERENCES ............................................................................................. 185 BIOGRAPHICAL SKETCH .......................................................................................... 193 6 LIST OF TABLES Table page 1-1 August 2017 measurement and low velocity plume stack info ........................... 28 1-2 Air sampling information #1 ................................................................................ 28 1-3 Air sampling information #2. ............................................................................... 29 2-1 Stability classifications for Gaussian model based on wind speed and solar irradiation. ........................................................................................................... 39 2-2 Stability classifications for Gaussian model based on atmospheric lapse rate ... 39 2-3 Summary of ATM code selection for various applications and dispersion distances. ........................................................................................................... 45 3-1 Proposed detectors surrounding UFTR .............................................................. 54 3-2 Detector location coordinates. ............................................................................ 54 3-3 Elevations of selected locations. ......................................................................... 56 3-4 Modified Pasquill stability scheme in the daytime ............................................... 63 3-5 Parameters used to solve vertical dispersion coefficient (σz). ............................ 64 3-6 Parameters used to solve horizontal dispersion coefficient (σy). ........................ 64 4-1 May 8th, 2018 measurement 41Ar count rates and count rate ratios. .................. 80 4-2 March 20th, 2019 measurement 41Ar count rates and count rate ratios. ............. 81 4-3 March 22nd, 2019 measurement 41Ar count rates and count rate ratios. ............. 82 4-4 May 8th, 2018 wind information (averaged hourly) .............................................
Recommended publications
  • The Lagrangian Chemistry and Transport Model ATLAS: Validation of Advective Transport and Mixing
    Geosci. Model Dev., 2, 153–173, 2009 www.geosci-model-dev.net/2/153/2009/ Geoscientific © Author(s) 2009. This work is distributed under Model Development the Creative Commons Attribution 3.0 License. The Lagrangian chemistry and transport model ATLAS: validation of advective transport and mixing I. Wohltmann and M. Rex Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany Received: 25 June 2009 – Published in Geosci. Model Dev. Discuss.: 3 July 2009 Revised: 15 September 2009 – Accepted: 2 October 2009 – Published: 2 November 2009 Abstract. We present a new global Chemical Transport In the context of this paper, numerical diffusion is defined Model (CTM) with full stratospheric chemistry and La- as any process that is triggered by the model calculations grangian transport and mixing called ATLAS (Alfred We- and behaves like a diffusive process acting on the chemical gener InsTitute LAgrangian Chemistry/Transport System). species in the model. Typically, numerical diffusion will be Lagrangian (trajectory-based) models have several important spurious and unrealistic, e.g. present in every grid cell with advantages over conventional Eulerian (grid-based) models, the same magnitude. We do not consider processes as nu- including the absence of spurious numerical diffusion, ef- merical diffusion here which are deliberately introduced into ficient code parallelization and no limitation of the largest the model, e.g. to mimic the observed diffusion. Eulerian ap- time step by the Courant-Friedrichs-Lewy criterion. The ba- proaches suffer from numerical diffusion because they con- sic concept of transport and mixing is similar to the approach tain an advection step that transfers information between dif- in the commonly used CLaMS model.
    [Show full text]
  • ESM-Tools Version 4.0: a Modular Infrastructure for Stand-Alone
    ESM-Tools Version 4.0: A modular infrastructure for stand-alone and coupled Earth System Modelling (ESM) Dirk Barbi1, Nadine Wieters1, Paul Gierz1, Fatemeh Chegini1, 3, Sara Khosravi2, and Luisa Cristini1 1Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany 2Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany 3Max Planck Institute for Meteorology, Hamburg, Germany Correspondence: Luisa Cristini ([email protected]) Abstract. Earth system and climate modelling involves the simulation of processes on a wide range of scales and within and across various compartments of the Earth system. In practice, component models are often developed independently by different research groups, adapted by others to their special interests, and then combined using a dedicated coupling software. This 5 procedure not only leads to a strongly growing number of available versions of model components and coupled setups, but also to model- and HPC-system dependent ways of obtaining, configuring, building, and operating them. Therefore, implementing these Earth System Models (ESMs) can be challenging and extremely time consuming, especially for less experienced mod- ellers, or scientists aiming to use different ESMs as in the case of inter-comparison projects. To assist researchers and modellers by reducing avoidable complexity, we developed the ESM-Tools software, which provides 10 a standard way for downloading, configuring, compiling, running and monitoring different models on a variety of High Perfor- mance Computing (HPC) systems. It should be noted that the ESM-Tools are equally applicable and helpful for stand-alone as for coupled models. In fact, the ESM-Tools are used as standard compile and runtime infrastructure for FESOM2, and currently also applied for ECHAM and ICON standalone simulations.
    [Show full text]
  • Winter Meeting & Expo
    Winter Meeting & Expo 2017 Official Program Generations in Collaboration: Building for Tomorrow October 29-November 2, 2017 Washington, D.C. Marriott Wardman Park Winter Meeting & Expo Our most sincere thanks to our sponsors for their support of the 2017 Winter Meeting & Expo. GOLD SPONSORSHIP BRONZE SPONSORSHIP COPPER SPONSORSHIP OTHER SPONSORSHIP Table of Contents GENERAL MEETING INFORMATION Organizing Committee ................................................................................ 2 Daily Schedule .......................................................................................... 3-6 General Information .................................................................................. 7-10 PLENARY, SPECIAL SESSIONS & EVENTS Young Professionals Congress Sessions . ...................................................... 11 ANS President’s Opening Reception ........................................................... 11 Opening Plenary Session ........................................................................... 11 ANS President’s Special Session ................................................................ 11 Operations & Power Division Dinner ............................................................ 11 Student Poster Session ............................................................................. 12 General Chair’s Special Session ................................................................. 12 Speakers Bureau Workshop ........................................................................ 12 Focus
    [Show full text]
  • Validation of Climate Models
    Validation of Climate Models Simon Tett 19/6/06 with thanks to: Keith Williams, Mark Webb, Mark Rodwell, Roy Kershaw, Sean Milton, Gill Martin, Tim Johns, Jonathan Gregory, Peter Thorne, Philip Brohan & © Crown copyright John Caesar Page 1 Approaches Parameterisation & Forecast error Climatology's Climate Variability Climate Change. © Crown copyright Page 2 Methodology for improving parametrizations CRMs Observations Forcing Evaluation Evaluation g Fo Analysis Development in rc rc on in Fo ati g alu Ev NWP Forecast SCMs Development Forcing Evaluation (consistent errors?) © Crown copyright Page 3 Tropical Systematic Biases in NWP Moisture balance from Thermodynamic (RH) Profile Errors Idealised Aquaplanet – suggest Vs ARM Manus Sondes JAS 2003– convection largest contributor to Errors in convection? humidity biases Convection too shallow? 20 hPa Unrealistic 77 Moistening and drying 192 in forecasts 367 576 777 Moister at cloud base & Freezing level 922 © Crown copyright Page 4 S.Milton & M.Willett NWP Tropical T, RH, and Wind Errors vs Sondes Summer 2005 – Impact of new Physics A package of physics improvements introduced in March 2006 Improved Thermodynamic Profiles • Adaptive detrainment (conv) –> improve detrainment of moisture. • Changes to marine BL –> reduce LH fluxes Old • Non-gradient momentum stress. -> Improve low level winds Model New Physics ΔRH Day 5 Circulation Errors In Equatorial Winds Reduced ΔT Day 5 S. Derbyshire, A. Maidens, A. Brown, J.Edwards, M.Willett & S.Milton © Crown copyright Page 5 Spinup Tendencies Used to assess the contribution of individual physical parametrisations and dynamics to systematic errors. Run a ~60-member ensemble of 1 to 5 day integrations started from operational NWP analyses scattered evenly over a period e.g.
    [Show full text]
  • Assimila Blank
    NERC NERC Strategy for Earth System Modelling: Technical Support Audit Report Version 1.1 December 2009 Contact Details Dr Zofia Stott Assimila Ltd 1 Earley Gate The University of Reading Reading, RG6 6AT Tel: +44 (0)118 966 0554 Mobile: +44 (0)7932 565822 email: [email protected] NERC STRATEGY FOR ESM – AUDIT REPORT VERSION1.1, DECEMBER 2009 Contents 1. BACKGROUND ....................................................................................................................... 4 1.1 Introduction .............................................................................................................. 4 1.2 Context .................................................................................................................... 4 1.3 Scope of the ESM audit ............................................................................................ 4 1.4 Methodology ............................................................................................................ 5 2. Scene setting ........................................................................................................................... 7 2.1 NERC Strategy......................................................................................................... 7 2.2 Definition of Earth system modelling ........................................................................ 8 2.3 Broad categories of activities supported by NERC ................................................. 10 2.4 Structure of the report ...........................................................................................
    [Show full text]
  • ESM-Tools Version 4.0: a Modular Infrastructure for Stand-Alone and Coupled Earth System Modelling
    https://doi.org/10.5194/gmd-2020-100 Preprint. Discussion started: 11 August 2020 c Author(s) 2020. CC BY 4.0 License. ESM-Tools Version 4.0: A modular infrastructure for stand-alone and coupled Earth System Modelling (ESM) Dirk Barbi1, Nadine Wieters1, Paul Gierz1, Fatemeh Chegini1, 3, Sara Khosravi2, and Luisa Cristini1 1Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany 2Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany 3Max Planck Institute for Meteorology, Hamburg, Germany Correspondence: Luisa Cristini ([email protected]) Abstract. Earth system and climate modelling involves the simulation of processes on a wide range of scales and within and across var- ious components of the Earth system. In practice, component models are often developed independently by different research groups and then combined using a dedicated coupling software. This procedure not only leads to a strongly growing number of 5 available versions of model components and coupled setups, but also to model- and system-dependent ways of obtaining and operating them. Therefore, implementing these Earth System Models (ESMs) can be challenging and extremely time consum- ing, especially for less experienced modellers, or scientists aiming to use different ESMs as in the case of inter-comparison projects. To assist researchers and modellers by reducing avoidable complexity, we developed the ESM-Tools software, which pro- 10 vides a standard way for downloading, configuring, compiling, running and monitoring different models - coupled ESMs and stand-alone models alike - on a variety of High Performance Computing (HPC) systems.1 With the ESM-Tools, the user is only required to provide a short script consisting of only the experiment specific definitions, while the software executes all the phases of a simulation in the correct order.
    [Show full text]
  • Part I: Signatures Attesting to Integrity (Applicable to All Institutions)
    University of Florida Fifth-Year Interim Report Southern Association of Colleges and Schools Commission on Colleges March 2010 University of Florida Fifth-Year Interim Report Southern Association of Colleges and Schools Commission on Colleges March 2010 The Commission on Colleges Southern Association of Colleges and Schools THE FIFTH-YEAR INTERIM REPORT (Revised February 2009—Formerly incorrectly stated as 2008) Name of Institution: University of Florida Address of the Institution: Office of the Provost PO Box 113175, 235 Tigert Hall Gainesville, FL 32611-1375 Name, title, contact numbers of person(s) preparing the report: Dr. Joseph Glover, Provost and Senior Vice President for Academic Affairs Phone: (352) 392-2404 The Fifth-Year Interim Report is divided into five parts: Part I: Signatures Attesting to Integrity (applicable to all institutions). Requests that the chief executive officer and accreditation liaison attest to the accuracy of institutional assessment and documentation supporting that assessment. Part II: Abbreviated Institutional Summary Form Prepared for Commission Reviews (applicable to all institutions). Requests that the institution complete the abbreviated “Institutional Summary Form Prepared for Commission Reviews.” Part III: Abbreviated Compliance Certification (applicable to all institutions). Monitors continued compliance with identified Core Requirements and Comprehensive Standards at the decennial interval. Part IV: Additional Report (applicable to select institutions). Addresses issues identified in an action letter following a recent review of the institution. If applicable, issues are identified in an attached letter. Part V: Impact Report of the Quality Enhancement Plan (applicable to all institutions reaffirmed since 2004 using the Principles of Accreditation). An institution may also be requested to host an off-site committee charged to review new, but unvisited, off-campus sites initiated since the institution’s previous reaffirmation.
    [Show full text]
  • Landscape Implications of Plant-Fungal Interactions for Tree Migration in Alaska
    Landscape Ecol (2016) 31:895–911 DOI 10.1007/s10980-015-0306-1 RESEARCH ARTICLE Getting to the root of the matter: landscape implications of plant-fungal interactions for tree migration in Alaska Rebecca E. Hewitt . Alec P. Bennett . Amy L. Breen . Teresa N. Hollingsworth . D. Lee Taylor . F. Stuart Chapin III . T. Scott Rupp Received: 8 May 2015 / Accepted: 29 October 2015 / Published online: 14 November 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract whether EMF inoculum potential influences patterns Context Forecasting the expansion of forest into of tundra afforestation and associated flammability. Alaska tundra is critical to predicting regional ecosys- Methods Using two downscaled CMIP3 general tem services, including climate feedbacks such as circulation models (ECHAM5 and CCCMA) and a carbon storage. Controls over seedling establishment mid-range emissions scenario (A1B) at a 1 km2 govern forest development and migration potential. resolution, we compared simulated tundra afforesta- Ectomycorrhizal fungi (EMF), obligate symbionts of tion rates and flammability from four parameteriza- all Alaskan tree species, are particularly important to tions of EMF effects on seedling establishment and seedling establishment, yet their significance to land- growth from 2000 to 2100. scape vegetation change is largely unknown. Results Modeling predicted an 8.8–18.2 % increase Objective We used ALFRESCO, a landscape model in forest cover from 2000 to 2100. Simulations that of wildfire and vegetation dynamics, to explore explicitly represented landscape variability in EMF inoculum potential showed a reduced percent change afforestation of up to a 2.8 % due to low inoculum potential limiting seedling growth. This reduction limited fuel availability and thus, cumulative area & R.
    [Show full text]
  • Climate Research 60:103
    Vol. 60: 103–117, 2014 CLIMATE RESEARCH Published online June 17 doi: 10.3354/cr01222 Clim Res Ranking of global climate models for India using multicriterion analysis K. Srinivasa Raju1, D. Nagesh Kumar2,3,* 1Department of Civil Engineering, Birla Institute of Technology and Science-Pilani, Hyderabad campus, India 2Center for Earth Sciences, Indian Institute of Science, 560012 Bangalore, India 3Present address: Department of Civil Engineering, Indian Institute of Science, 560012 Bangalore, India ABSTRACT: Eleven GCMs (BCCR-BCCM2.0, INGV-ECHAM4, GFDL2.0, GFDL2.1, GISS, IPSL- CM4, MIROC3, MRI-CGCM2, NCAR-PCMI, UKMO-HADCM3 and UKMO-HADGEM1) were evaluated for India (covering 73 grid points of 2.5° × 2.5°) for the climate variable ‘precipitation rate’ using 5 performance indicators. Performance indicators used were the correlation coefficient, normalised root mean square error, absolute normalised mean bias error, average absolute rela- tive error and skill score. We used a nested bias correction methodology to remove the systematic biases in GCM simulations. The Entropy method was employed to obtain weights of these 5 indi- cators. Ranks of the 11 GCMs were obtained through a multicriterion decision-making outranking method, PROMETHEE-2 (Preference Ranking Organisation Method of Enrichment Evaluation). An equal weight scenario (assigning 0.2 weight for each indicator) was also used to rank the GCMs. An effort was also made to rank GCMs for 4 river basins (Godavari, Krishna, Mahanadi and Cauvery) in peninsular India. The upper Malaprabha catchment in Karnataka, India, was chosen to demonstrate the Entropy and PROMETHEE-2 methods. The Spearman rank correlation coefficient was employed to assess the association between the ranking patterns.
    [Show full text]
  • (Hadgem1). Part I: Model Description and Global Climatology
    1274 JOURNAL OF CLIMATE VOLUME 19 The Physical Properties of the Atmosphere in the New Hadley Centre Global Environmental Model (HadGEM1). Part I: Model Description and Global Climatology G. M. MARTIN,M.A.RINGER,V.D.POPE,A.JONES,C.DEARDEN, AND T. J. HINTON Hadley Centre for Climate Prediction and Research, Met Office, Exeter, United Kingdom (Manuscript received 28 April 2005, in final form 28 July 2005) ABSTRACT The atmospheric component of the new Hadley Centre Global Environmental Model (HadGEM1) is described and an assessment of its mean climatology presented. HadGEM1 includes substantially improved representations of physical processes, increased functionality, and higher resolution than its predecessor, the Third Hadley Centre Coupled Ocean–Atmosphere General Circulation Model (HadCM3). Major devel- opments are the use of semi-Lagrangian instead of Eulerian advection for both dynamical and tracer fields; new boundary layer, gravity wave drag, microphysics, and sea ice schemes; and major changes to the convection, land surface (including tiled surface characteristics), and cloud schemes. There is better cou- pling between the atmosphere, land, ocean, and sea ice subcomponents and the model includes an inter- active aerosol scheme, representing both the first and second indirect effects. Particular focus has been placed on improving the processes (such as clouds and aerosol) that are most uncertain in projections of climate change. These developments lead to a significantly more realistic simulation of the processes represented, the most notable improvements being in the hydrological cycle, cloud radiative properties, the boundary layer, the tropopause structure, and the representation of tracers. 1. Introduction Lagrangian dynamical core, which has recently been implemented in the Met Office’s operational forecast Advances in our understanding of the climate sys- models.
    [Show full text]
  • Measured and Modelled Air Quality Trends in Italy Over the Period 2003
    https://doi.org/10.5194/acp-2020-1058 Preprint. Discussion started: 4 January 2021 c Author(s) 2021. CC BY 4.0 License. Measured and modelled air quality trends in Italy over the period 2003-2010 Ilaria D’Elia, Gino Briganti, Lina Vitali, Antonio Piersanti, Gaia Righini, Massimo D’Isidoro, Andrea Cappelletti, Mihaela Mircea, Mario Adani, Gabriele Zanini, Luisella Ciancarella 5 Laboratory of Atmospheric Pollution - Italian National Agency for New Technologies, Energy and Sustainable Economic Development - ENEA, Rome, 00123, Italy Correspondence to: Ilaria D’Elia ([email protected]) Abstract. Air pollution harms human health and the environment. Several regulatory efforts and different actions have been taken in 10 the last decades by authorities. Air quality trend analysis represents a valid tool in assessing the impact of these actions taken both at national and local levels. This paper presents for the first time the capability of the Italian national chemical transport model, AMS-MINNI, in capturing the observed concentration trends of three air pollutants, NO2, inhalable particles having diameter less than 10 micrometres (PM10) and O3, in Italy over the period 2003-2010. We firstly analyse the model performance finding it in line with the state of the art of regional models applications. The modelled trends result in a general 15 significant downward trend for the three pollutants and, in comparison with observations, the values of the simulated slopes -3 -1 show the same magnitude for NO2 (in the range -3.0 ÷ -0.5 g m yr ), while a smaller variability is detected for PM10 (-1.5 -3 -1 -3 -1 ÷ -0.5 g m yr ) and O3-maximum daily 8-hour average concentration (-2.0 ÷ -0.5 g m yr ).
    [Show full text]
  • Single-Precision Arithmetic in ECHAM Radiation Reduces Runtime and Energy Consumption
    Geosci. Model Dev., 13, 2783–2804, 2020 https://doi.org/10.5194/gmd-13-2783-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Single-precision arithmetic in ECHAM radiation reduces runtime and energy consumption Alessandro Cotronei and Thomas Slawig Kiel Marine Science (KMS) – Centre for Interdisciplinary Marine Science, Dep. of Computer Science, Kiel University, 24098 Kiel, Germany Correspondence: Thomas Slawig ([email protected]) Received: 3 January 2020 – Discussion started: 17 January 2020 Revised: 23 April 2020 – Accepted: 14 May 2020 – Published: 24 June 2020 Abstract. We converted the radiation part of the atmospheric refer to the home page of the institute (https://mpimet.mpg. model ECHAM to a single-precision arithmetic. We ana- de, last access: 22 April 2020). Version 5 of the model was lyzed different conversion strategies and finally used a step- used in the 4th Assessment Report of the Intergovernmental by-step change in all modules, subroutines and functions. Panel on Climate Change (IPCC, 2007) and version 6 in the We found out that a small code portion still requires higher- Coupled Model Intercomparison Project CMIP (World Cli- precision arithmetic. We generated code that can be easily mate Research Programme, 2019a). changed from double to single precision and vice versa, ba- The motivation for our work was the use of ECHAM for sically using a simple switch in one module. We compared long-time paleo-climate simulations in the German national the output of the single-precision version in the coarse reso- climate modeling initiative “PalMod: From the Last Inter- lution with observational data and with the original double- glacial to the Anthropocene – Modeling a Complete Glacial precision code.
    [Show full text]