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Author (up) Wallcraft, A.J.; Kara, A.B.; Hurlburt, H.E.; Chassignet, E.P.; Halliwell, G.H.
Title Value of bulk heat flux parameterizations for ocean SST prediction Type $loc['typeJournal Article']
Year 2008 Publication Journal of Marine Systems Abbreviated Journal Journal of Marine Systems
Volume 74 Issue 1-2 Pages 241-258
Keywords Bulk heat fluxes; Ocean model SST; Exchange coefficients; Atmospheric forcing; Climate
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0924-7963 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 405
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Author (up) Wei, J.; Dirmeyer, P.A.; Guo, Z.; Zhang, L.; Misra, V.
Title How Much Do Different Land Models Matter for Climate Simulation? Part I: Climatology and Variability Type $loc['typeJournal Article']
Year 2010 Publication Journal of Climate Abbreviated Journal J. Climate
Volume 23 Issue 11 Pages 3120-3134
Keywords Land surface model; Climatology; Surface fluxes; Climate variability; Model comparison; Precipitation
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0894-8755 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 370
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Author (up) Winterbottom, H
Title The Development of a High-Resolution Coupled Atmosphere-Ocean Model and Applications Toward Understanding the Limiting Factors for Tropical Cyclone Intensity Prediction Type $loc['typeManuscript']
Year 2010 Publication Abbreviated Journal
Volume Issue Pages
Keywords Tropical cyclone vortex initialization, Coupled atmosphere-ocean model
Abstract The prediction of tropical cyclone (TC) motion has improved greatly in recent decades. However, similar trends remain absent with respect to TC intensity prediction. Several hypotheses have been proposed attempting to explain why dynamical NWP models struggle to predict TC intensity. The leading candidates are as follows: (1) the lack of an evolving ocean (i.e., sea-surface temperature) boundary condition which responds as a function of the atmosphere (e.g., TC) forcing, (2) inappropriate initial conditions for the TC vortex (e.g., lack of data assimilation methods), (3) NWP model grid-length resolutions which are unable to resolve the temporal and length scale for the features believed responsible for TC vortex intensity. modulations (i.e., eye-wall dynamics, momentum transport, vortex Rossby wave interactions, etc.), and (4) physical parametrization which do not adequately represent the air-sea interactions observed during TC passage. In this study, a coupling algorithm for two independent, high-resolution, and state-of-the-art atmosphere and ocean models is developed. The atmosphere model -- the Advanced Weather Research and Forecasting (WRF-ARW) model is coupled to the HYbrid Coordinate Ocean Model (HYCOM) using a (UNIX) platform independent and innovative coupling methodology. Further, within the WRF-ARW framework, a dynamic initialization algorithm is developed to specify the TC vortex initial condition while preserving the synoptic-scale environment. Each of the tools developed in this study is implemented for a selected case-study: TC Bertha (2008) and TC Gustav (2008) for the coupled-model and TC vortex initialization, respectively. The experiment results suggest that the successful prediction (with respect to the observations) for both the ocean response and the TC intensity cannot be achieved by simply incorporating (i.e., coupling) an ocean model and/or by improving the initial structure for the TC. Rather the physical parametrization governing the air-sea interactions is suggested as the one of the weaknesses for the NWP model. This hypothesis is (indirectly) supported through a diagnostic evaluation of the synoptic-scale features (e.g., sea-level pressure and the deep-layer mean wind beyond the influence of the TC) while the assimilated TC vortex is nudged toward the observed intensity value. It is found -- in the case of TC Gustav (2008) using WRF-ARW, that as the assimilated TC vortex intensity approaches that of the observed, the balance between the mass and momentum states for WRF-ARW is compromised leading to unrealistic features for the environmental sea-level pressure and deep-layer (800- to 200-hPa) mean wind surrounding the TC. Forcing WRF-ARW to assimilate a TC vortex of the observed maximum wind-speed intensity may ultimately compromise the prediction for the TC's motion and subsequently mitigate any gains for the corresponding intensity prediction.Suggestions for additions to the coupled atmosphere-ocean model include a wave-model (WAVEWATCH3), the assimilation of troposphere thermodynamic observations, and modifications to the existing atmospheric boundary-layer parametrization. The current suite of atmosphere model parametrizations do not accurately simulate the observed azimuthal and radial variations for the exchange coefficients (e.g., drag and enthalpy) that have been indicated as potentialpredictor variables for TC intensity modulation. However, these modifications should be implemented only after the limitations for the current coupled-model and TC vortex initialization methods are fully evaluated.
Address Department of Meteorology
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
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 572
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Author (up) Xue, W.; Xin, X.; Zhang, J.; Zhang, W.; Wu, H.; Huang, Z.; Zhang, T.; Li, H.; Ding, N.; Huang H.
Title Development and Testing of a Multi-model Ensemble Coupling Framework Type $loc['typeBook Chapter']
Year 2016 Publication Development and Evaluation of High Resolution Climate System Models Abbreviated Journal
Volume Issue Pages 163-208
Keywords Climate system model; Ensemble coupling platform; Atmospheric noise; Process layout
Abstract
Address
Corporate Author Thesis
Publisher Springer Place of Publication 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 91
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Author (up) Yu, P
Title Development of New Techniques for Assimilating Satellite Altimetry Data into Ocean Models Type $loc['typeManuscript']
Year 2006 Publication Abbreviated Journal
Volume Issue Pages
Keywords Data Assimilation, Reduced Space, First Baroclinic Mode, Ocean Models, Vertical Normal Mode Decomposition, Variational
Abstract State of the art fully three-dimensional ocean models are very computationally expensive and their adjoints are even more resource intensive. However, many features of interest are approximated by the first baroclinic mode over much of the ocean, especially in the lower and mid latitude regions. Based on this dynamical feature, a new type of data assimilation scheme to assimilate sea surface height (SSH) data, a reduced-space adjoint technique, is developed and implemented with a three-dimensional model using vertical normal mode decomposition. The technique is tested with the Navy Coastal Ocean Model (NCOM) configured to simulate the Gulf of Mexico. The assimilation procedure works by minimizing the cost function, which generalizes the misfit between the observations and their counterpart model variables. The “forward” model is integrated for the period during which the data are assimilated. Vertical normal mode decomposition retrieves the first baroclinic mode, and the data misfit between the model outputs and observations is calculated. Adjoint equations based on a one-active-layer reduced gravity model, which approximates the first baroclinic mode, are integrated backward in time to get the gradient of the cost function with respect to the control variables (velocity and SSH of the first baroclinic mode). The gradient is input to an optimization algorithm (the limited memory Broyden-Fletcher-Goldfarb-Shanno (BFGS) method is used for the cases presented here) to determine the new first baroclinic mode velocity and SSH fields, which are used to update the forward model variables at the initial time. Two main issues in the area of ocean data assimilation are addressed: 1. How can information provided only at the sea surface be transferred dynamically into deep layers? 2. How can information provided only locally, in limited oceanic regions, be horizontally transferred to ocean areas far away from the data-dense regions, but dynamically connected to it? The first problem is solved by the use of vertical normal mode decomposition, through which the vertical dependence of model variables is obtained. Analyses show that the first baroclinic mode SSH represents the full SSH field very closely in the model test domain, with a correlation of 93% in one of the experiments. One common way to solve the second issue is to lengthen the assimilation window in order to allow the dynamic model to propagate information to the data-sparse regions. However, this dramatically increases the computational cost, since many oceanic features move very slowly. An alternative solution to this is developed using a mapping method based on complex empirical orthogonal functions (EOF), which utilizes data from a much longer period than the assimilation cycle and deals with the information in space and time simultaneously. This method is applied to map satellite altimeter data from the ground track observation locations and times onto a regular spatial and temporal grid. Three different experiments are designed for testing the assimilation technique: two experiments assimilate SSH data produced from a model run to evaluate the method, and in the last experiment the technique is applied to TOPEX/Poseidon and Jason-1 altimeter data. The assimilation procedure converges in all experiments and reduces the error in the model fields. Since the adjoint, or “backward”, model is two-dimensional, the method is much more computationally efficient than if it were to use a fully three-dimensional backward model.
Address Department of Oceanography
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
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Funding NSF, ONR, NASA Approved $loc['no']
Call Number COAPS @ mfield @ Serial 589
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Author (up) Yu, P.; Morey, S.L.; O'Brien, J.J.
Title A reduced-dynamics variational approach for the assimilation of altimeter data into eddy-resolving ocean models Type $loc['typeJournal Article']
Year 2009 Publication Ocean Modelling Abbreviated Journal Ocean Modelling
Volume 27 Issue 3-4 Pages 215-229
Keywords Ocean modeling; Data assimilation; Variational adjoint methods
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-5003 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 400
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Author (up) Zavala-Hidalgo, J; Pares-Sierra, A; Ochoa, J
Title Seasonal variability of the temperature and heat fluxes in the Gulf of Mexico Type $loc['typeJournal Article']
Year 2002 Publication Atmosfera Abbreviated Journal
Volume 15 Issue 2 Pages 81-104
Keywords Gulf of Mexico; heat fluxes; numerical model; sea surface temperature; seasonal variability
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication 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 498
Permanent link to this record
 

 
Author (up) Zeng, H.; Chambers, J.Q.; Negron-Juarez, R.I.; Hurtt, G.C.; Baker, D.B.; Powell, M.D.
Title Impacts of tropical cyclones on U.S. forest tree mortality and carbon flux from 1851 to 2000 Type $loc['typeJournal Article']
Year 2009 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc Natl Acad Sci U S A
Volume 106 Issue 19 Pages 7888-7892
Keywords Biodiversity; Biomass; Carbon; *Cyclonic Storms; Ecosystem; Greenhouse Effect; Models, Statistical; Southeastern United States; *Trees; United States
Abstract Tropical cyclones cause extensive tree mortality and damage to forested ecosystems. A number of patterns in tropical cyclone frequency and intensity have been identified. There exist, however, few studies on the dynamic impacts of historical tropical cyclones at a continental scale. Here, we synthesized field measurements, satellite image analyses, and empirical models to evaluate forest and carbon cycle impacts for historical tropical cyclones from 1851 to 2000 over the continental U.S. Results demonstrated an average of 97 million trees affected each year over the entire United States, with a 53-Tg annual biomass loss, and an average carbon release of 25 Tg y(-1). Over the period 1980-1990, released CO(2) potentially offset the carbon sink in forest trees by 9-18% over the entire United States. U.S. forests also experienced twice the impact before 1900 than after 1900 because of more active tropical cyclones and a larger extent of forested areas. Forest impacts were primarily located in Gulf Coast areas, particularly southern Texas and Louisiana and south Florida, while significant impacts also occurred in eastern North Carolina. Results serve as an important baseline for evaluating how potential future changes in hurricane frequency and intensity will impact forest tree mortality and carbon balance.
Address Department of Ecology and Evolutionary Biology, Tulane University, 400 Boggs Center, New Orleans, LA 70118, USA. hzeng@tulane.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 0027-8424 ISBN Medium
Area Expedition Conference
Funding PMID:19416842; PMCID:PMC2683102 Approved $loc['no']
Call Number COAPS @ mfield @ Serial 658
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