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Author Guimond, S
Title Tropical Cyclone Inner-Core Dynamics: A Latent Heat Retrieval and Its Effects on Intensity and Structure Change; and the Impacts of Effective Diffusion on the Axisymmetrization Process Type $loc['typeManuscript']
Year 2010 Publication Abbreviated Journal
Volume Issue Pages
Keywords Hurricanes, Doppler Radar, Latent Heat, Axisymmetrization, Diffusion, Numerical Modeling
Abstract Despite the fact that latent heating in cloud systems drives many atmospheric circulations, including tropical cyclones, little is known of its magnitude and structure due in large part to inadequate observations. In this work, a reasonably high-resolution (2 km), four-dimensional airborne Doppler radar retrieval of the latent heat of condensation is presented for rapidly intensifying Hurricane Guillermo (1997). Several advancements in the retrieval algorithm are shown including: (1) analyzing the scheme within the dynamically consistent framework of a numerical model, (2) identifying algorithm sensitivities through the use of ancillary data sources and (3) developing a precipitation budget storage term parameterization. The determination of the saturation state is shown to be an important part of the algorithm for updrafts of ~ 5 m s-1 or less. The uncertainties in the magnitude of the retrieved heating are dominated by errors in the vertical velocity. Using a combination of error propagation and Monte Carlo uncertainty techniques, biases were found to be small, and randomly distributed errors in the heating magnitude were ~16 % for updrafts greater than 5 m s-1 and ~156 % for updrafts of 1 m s- 1. The impact of the retrievals is assessed by inserting the heating into realistic numerical simulations at 2 km resolution and comparing the generated wind structure to the Doppler radar observations of Guillermo. Results show that using the latent heat retrievals outperforms a simulation that relies on a state-of-the-art microphysics scheme (Reisner and Jeffery 2009), in terms of wind speed root-mean-square errors, explained variance and eye/eyewall structure. The incorrect transport of water vapor (a function of the sub-grid model and the numerical approximations to advection) and the restrictions on the magnitude of heat release that ensure the present model's stability are suggested as sources of error in the simulation without the retrievals. Motivated by the latent heat retrievals, the dynamics of vortex axisymmetrization from the perspective of thermal anomalies is investigated using an idealized, non-linear atmospheric model (HIGRAD). Attempts at reproducing the results of previous work (Nolan and Grasso 2003; NG03) revealed a discrepancy with the impacts of purely asymmetric forcing. While NG03 found that purely asymmetric heating led to a negligible, largely negative impact on the vortex intensification, in the present study the impacts of asymmetries are found to have an important, largely positive role. Absolute angular momentum budgets revealed that the essential difference between the present work and that of NG03 was the existence of a significant, axisymmetric secondary circulation in the basic-state vortex used in the HIGRAD simulations. This secondary circulation was larger than that present in NG03's simulations. The spin-up of the vortex caused by the asymmetric thermal anomalies was dominated by the axisymmetric fluxes of angular momentum at all times, indicating fundamentally different evolution of asymmetries in the presence of radial flow. Radial momentum budgets were performed to elucidate the mechanisms responsible for the formation of the physically significant secondary circulation. Results show that explicit (sub-grid) diffusion in the model was producing a gradient wind imbalance, which drives a radial inflow and associated secondary circulation in an attempt to re-gain balance. In addition, the production of vorticity anomalies from the asymmetric heating was found to be sensitive to the eddy diffusivity, with large differences between HIGRAD and the widely used WRF model for the exact same value of this uncertain parameter.
Address Department of Earth, Ocean and Atmospheric Science
Corporate Author Thesis $loc['Ph.D. thesis']
Publisher Florida State University
Place of Publication Tallahassee, FL
Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @
Serial 573
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Author Gouillon, F
Title Internal Wave Propagation and Numerically Induced Diapycnal Mixing in Oceanic General Circulation Models Type $loc['typeManuscript']
Year 2010 Publication Abbreviated Journal
Volume Issue Pages
Keywords spurious mixing, numerical modeling, internal wave, tide
Abstract Numerical ocean models have become powerful tools for providing a realistic view of the ocean state and for describing ocean processes that are difficult to observe. Recent improvements in model performance focus on simulating realistic ocean interior mixing rates, as ocean mixing is the main physical process that creates water masses and maintains their properties. Below the mixed layer, diapycnal mixing primarily arises from the breaking of internal waves, whose energy is largely supplied by winds and tides. This is particularly true in abyssal regions, where the barotropic tide interacts with rough topography and where high levels of diapycnal mixing have been recorded (e.g., the Hawaiian Archipelago). Many studies have discussed the representation of internal wave generation, propagation, and evolution in ocean numerical models. Expanding on these studies, this work seeks to better understand the representation of internal wave dynamics, energetics, and their associated mixing in several different classes of widely used ocean models (e.g., the HYbrid Coordinate Ocean Model, HYCOM; the Regional Ocean Modeling System, ROMS; and the MIT general circulation model, MITgcm). First, a multi-model study investigates the representation of internal waves for a wide spectrum of numerical choices, such as the horizontal and vertical resolution, the vertical coordinate, and the choice of the numerical advection scheme. Idealized configurations are compared to their corresponding analytical solutions. Some preliminary results of realistic baroclinic tidal simulations are shown for the Gulf of Mexico. Second, the spurious diapycnal mixing that exists in models with fixed vertical coordinates (i.e., geopotential and terrain following) is documented and quantified. This purely numerical error arises because, in fixed-coordinate models, the numerical framework cannot properly maintain the adiabatic properties of an advected water parcel. This unrealistic mixing of water masses can be a source of major error in both regional and global ocean models. We use the tracer flux method to compute the spurious diapycnal diffusivities for both a lockexchange scenario and a propagating internal wave field using all three models. Results for the lock exchange experiments are compared to the results of a recent study. Our results, obtained by using three different model classes, provide a comprehensive analysis of the impact of model resolution choice and numerical framework on the magnitude of the spurious diapycnal mixing and the representation of internal waves.
Address Department of Oceanography
Corporate Author Thesis $loc['Ph.D. thesis']
Publisher Florida State University
Place of Publication Tallahassee, FL
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @
Serial 571
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Author Glazer, R. H.
Title The Influence of Mesoscale Sea Surface Temperature Gradients on Tropical Cyclones Type $loc['typeManuscript']
Year 2014 Publication Abbreviated Journal
Volume Issue Pages
Keywords Air-Sea Interaction ; Numerical Modeling ; Sea Surface Temperature ; Tropical Cyclones ; Tropical Meteorology
Abstract
Address Department of Earth, Ocean, and Atmospheric Science
Corporate Author Thesis $loc['Master's thesis']
Publisher Florida State University
Place of Publication Tallahassee, FL
Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @
Serial 161
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Author Conlon, K.C. ; Kintziger, K.W. ; Jagger, M. ; Stefanova, L. ; Uejio, C.K. ; Konrad, C.
Title Working with Climate Projections to Estimate Disease Burden: Perspectives from Public Health Type $loc['typeJournal Article']
Year 2016 Publication International Journal of Environmental Research and Public Health Abbreviated Journal Int J Environ Res Public Health
Volume 13
Issue 8
Pages
Keywords *Climate Change/statistics & numerical data ; Florida ; Forecasting ; Humans ; Models, Theoretical ; Public Health/*trends ; United States ; adaptation ; attributable fraction ; climate modeling ; project disease burden ; public health
Abstract There is interest among agencies and public health practitioners in the United States (USA) to estimate the future burden of climate-related health outcomes. Calculating disease burden projections can be especially daunting, given the complexities of climate modeling and the multiple pathways by which climate influences public health. Interdisciplinary coordination between public health practitioners and climate scientists is necessary for scientifically derived estimates. We describe a unique partnership of state and regional climate scientists and public health practitioners assembled by the Florida Building Resilience Against Climate Effects (BRACE) program. We provide a background on climate modeling and projections that has been developed specifically for public health practitioners, describe methodologies for combining climate and health data to project disease burden, and demonstrate three examples of this process used in Florida.
Address Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3220, USA. konrad@unc.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English
Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1660-4601
ISBN Medium
Area Expedition Conference
Funding PMID:27517942; PMCID:PMC4997490
Approved $loc['no']
Call Number COAPS @ mfield @
Serial 73
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Author Glazer, R. H. ; Misra, V.
Title Ice versus liquid water saturation in simulations of the Indian summer monsoon Type $loc['typeJournal Article']
Year 2018 Publication Climate Dynamics Abbreviated Journal
Volume Issue Pages
Keywords Indian monsoon ; Regional modeling ; Saturation vapor pressure ; Cloud microphysics scheme
Abstract
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Funding Approved $loc['no']
Call Number COAPS @ mfield @
Serial 943
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Author Morrison, T. ; Dukhovskoy, D. S. ; McClean, J. ; Gille, S. T. ; Chassignet, E.
Title Causes of the anomalous heat flux onto the Greenland continental shelf Type $loc['typeAbstract']
Year 2018 Publication American Geophysical Union Abbreviated Journal AGU
Volume Fall Meeting
Issue Pages
Keywords 0726 Ice sheets, CRYOSPHEREDE: 4207 Arctic and Antarctic oceanography, OCEANOGRAPHY: GENERALDE: 4215 Climate and interannual variability, OCEANOGRAPHY: GENERALDE: 4255 Numerical modeling, OCEANOGRAPHY: GENERAL
Abstract On the continental shelf around Greenland, warm-salty Atlantic water at depth fills the deep narrow fjords where Greenland's tidewater glaciers terminate. Changes in the quantity or properties of this water mass starting in the mid 1990s is thought to be largely responsible for increased ocean-driven melting of the Greenland Ice Sheet. Using high-resolution (nominal 0.1-degree) ocean circulation models we cannot accurately resolve small-scale processes on the shelf or within fjords. However, we can assess changes in the flux of heat via Atlantic water onto the continental shelf. To understand the causes of the anomalous heat that has reached the shelf we examine heat content of subtropical gyre water and shifts in the North Atlantic and Atlantic Multidecadal Oscillations.
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Funding Approved $loc['no']
Call Number COAPS @ user @
Serial 1009
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Author Armstrong, E. M. ; Bourassa, M. A. ; Cram, T. ; Elya, J. L. ; Greguska, F. R., III ; Huang, T. ; Jacob, J. C. ; Ji, Z. ; Jiang, Y. ; Li, Y. ; McGibbney, L. J. ; Quach, N. ; Smith, S. R. ; Tsontos, V. M. ; Wilson, B. D. ; Worley, S. J. ; Yang, C. P.
Title An information technology foundation for fostering interdisciplinary oceanographic research and analysis Type $loc['typeAbstract']
Year 2018 Publication American Geophysical Union Abbreviated Journal AGU
Volume Fall Meeting
Issue Pages
Keywords 1914 Data mining, INFORMATICSDE: 4805 Biogeochemical cycles, processes, and modeling, OCEANOGRAPHY: BIOLOGICAL AND CHEMICALDE: 4273 Physical and biogeochemical interactions, OCEANOGRAPHY: GENERALDE: 4504 Air/sea interactions, OCEANOGRAPHY: PHYSICAL
Abstract Before complex analysis of oceanographic or any earth science data can occur, it must be placed in the proper domain of computing and software resources. In the past this was nearly always the scientist's personal computer or institutional computer servers. The problem with this approach is that it is necessary to bring the data products directly to these compute resources leading to large data transfers and storage requirements especially for high volume satellite or model datasets. In this presentation we will present a new technological solution under development and implementation at the NASA Jet Propulsion Laboratory for conducting oceanographic and related research based on satellite data and other sources. Fundamentally, our approach for satellite resources is to tile (partition) the data inputs into cloud-optimized and computation friendly databases that allow distributed computing resources to perform on demand and server-side computation and data analytics. This technology, known as NEXUS, has already been implemented in several existing NASA data portals to support oceanographic, sea-level, and gravity data time series analysis with capabilities to output time-average maps, correlation maps, Hovmöller plots, climatological averages and more. A further extension of this technology will integrate ocean in situ observations, event-based data discovery (e.g., natural disasters), data quality screening and additional capabilities. This particular activity is an open source project known as the Apache Science Data Analytics Platform (SDAP) (https://sdap.apache.org), and colloquially as OceanWorks, and is funded by the NASA AIST program. It harmonizes data, tools and computational resources for the researcher allowing them to focus on research results and hypothesis testing, and not be concerned with security, data preparation and management. We will present a few oceanographic and interdisciplinary use cases demonstrating the capabilities for characterizing regional sea-level rise, sea surface temperature anomalies, and ocean hurricane responses.
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Language Summary Language Original Title
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Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @
Serial 1004
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Author Le Sommer, Julien ; Chassignet, E.P. ; Wallcraft, A. J.
Title Ocean Circulation Modeling for Operational Oceanography: Current Status and Future Challenges Type $loc['typeBook Chapter']
Year 2018 Publication New Frontiers in Operational Oceanography Abbreviated Journal
Volume Issue Pages 289-305
Keywords OCEAN MODELING ; OCEAN CIRCULATION ; PARAMETERIZATIONS
Abstract This chapter focuses on ocean circulation models used in operational oceanography, physical oceanography and climate science. Ocean circulation models area particular branch of ocean numerical modeling that focuses on the representation of ocean physical properties over spatial scales ranging from the global scale to less than a kilometer and time scales ranging from hours to decades. As such, they are an essential build-ing block for operational oceanography systems and their design receives a lot of attention from operational and research centers.
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Publisher GODAE OceanView
Place of Publication Tallahassee, FL
Editor Chassignet, E. P., A. Pascual, J. Tintoré, and J. Verron
Language Summary Language Original Title
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Series Volume Series Issue Edition
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Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @
Serial 948
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