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Author (up) LaCasce, J.H.; Escartin, J.; Chassignet, E.P.; Xu, X.
Title Jet instability over smooth, corrugated and realistic bathymetry Type $loc['typeJournal Article']
Year 2018 Publication Journal of Physical Oceanography Abbreviated Journal J. Phys. Oceanogr.
Volume Issue Pages
Keywords
Abstract The stability of a horizontally- and vertically-sheared surface jet is examined, with a focus on the vertical structure of the resultant eddies. Over a flat bottom, the instability is mixed baroclinic/barotropic, producing strong eddies at depth which are characteristically shifted downstream relative to the surface eddies. Baroclinic instability is suppressed over a large slope for retrograde jets (with a flow anti-parallel to topographic wave propagation), and to a lesser extent for prograde jets (with flow parallel to topographic wave propagation), as seen previously. In such cases, barotropic (lateral) instability dominates if the jet is sufficiently narrow. This yields surface eddies whose size is independent of the slope but proportional to the jet width. Deep eddies still form, forced by interfacial motion associated with the surface eddies, but they are weaker than under baroclinic instability and are vertically aligned with the surface eddies. A sinusoidal ridge acts similarly, suppressing baroclinic instability and favoring lateral instability in the upper layer.

A ridge with a 1 km wavelength and an amplitude of roughly 10 m is sufficient to suppress baroclinic instability. Surveys of bottom roughness from bathymetry acquired with shipboard multibeam echosounding reveal that such heights are common, beneath the Kuroshio, the Antarctic Circumpolar Current and, to a lesser extent, the Gulf Stream. Consistent with this, vorticity and velocity cross sections from a 1/50° HYCOM simulation suggest that Gulf Stream eddies are vertically aligned, as in the linear stability calculations with strong topography. Thus lateral instability may be more common than previously thought, due to topography hindering vertical energy transfer.
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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 0022-3670 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @ Serial 998
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Author (up) Laurencin, C.; Misra, V.
Title Characterizing the Variations of the motion of the North Atlantic tropical cyclones Type $loc['typeJournal Article']
Year 2018 Publication Meteorology and Atmospheric Physics Abbreviated Journal Meteorol Atmos Phys
Volume 130 Issue 303 Pages 1-12
Keywords climatology; interannual scales; environment
Abstract In this study, we examine the seasonal and interannual variability of the North Atlantic (NATL) tropical cyclone (TC) motion from the historical Hurricane Database (HURDAT2) over the period 1988-2014. We characterize these motions based on their position, lifecycle, and seasonal cycle. The main findings of this study include: (1) of the 11,469 NATL TC fixes examined between 1988 and 2014, 81% of them had a translation speed of < 20 mph; (2) TCs in the deep tropics of the NATL are invariably slow-moving in comparison with TCs in higher latitudes. Although fast-moving TCs (> 40 mph) are exclusively found north of 30 N, the slow-moving TCs have a wide range of latitude. This is largely a consequence of the background steering flow being weaker (stronger) in the tropical (higher) latitudes with a minimum around the subtropical latitudes of NATL; (3) there is an overall decrease in the frequency of all categories of translation speed of TCs in warm relative to cold El Niño Southern Oscillation (ENSO) years. However, in terms of the percentage change, TCs with a translation speed in the range of 10-20 mph display the most change (42%) in warm relative to cold ENSO years; and (4) there is an overall decrease in frequency across all categories of TC translation speed in small relative to large Atlantic Warm Pool years, but in terms of percentage change in the frequency of TCs, there is a significant and comparable change in the frequency over a wider range of translation speeds than the ENSO composites. This last finding suggests that Atlantic Warm Pool variations have a more profound impact on the translation speed of Atlantic TCs than ENSO.
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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 @ rl18 @ Serial 991
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Author (up) 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.
Address
Corporate Author Thesis
Publisher GODAE OceanView Place of Publication Tallahassee, FL Editor Chassignet, E. P., A. Pascual, J. Tintoré, and J. Verron
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 @ user @ Serial 948
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Author (up) Liu, M.; Lin, J.; Wang, Y.; Sun, Y.; Zheng, B.; Shao, J.; Chen, L.; Zheng, Y.; Chen, J.; Fu, T.-M.; Yan, Y.; Zhang, Q.; Wu, Z.
Title Spatiotemporal variability of NO2 and PM2.5 over Eastern China: observational and model analyses with a novel statistical method Type $loc['typeJournal Article']
Year 2018 Publication Atmospheric Chemistry and Physics Abbreviated Journal Atmos. Chem. Phys.
Volume 18 Issue 17 Pages 12933-12952
Keywords TROPOSPHERIC NITROGEN-DIOXIDE; PROVINCIAL CAPITAL CITIES; CRITERIA AIR-POLLUTANTS; BOUNDARY-LAYER; NORTH CHINA; HILBERT SPECTRUM; UNITED-STATES; TIME-SERIES; OZONE; EMISSIONS
Abstract Eastern China (27-41 degrees N, 110-123 degrees E) is heavily polluted by nitrogen dioxide (NO2), particulate matter with aerodynamic diameter below 2.5 mu m (PM2.5), and other air pollutants. These pollutants vary on a variety of temporal and spatial scales, with many temporal scales that are nonperiodic and nonstationary, challenging proper quantitative characterization and visualization. This study uses a newly compiled EOF-EEMD analysis visualization package to evaluate the spatiotemporal variability of ground-level NO2, PM2.5, and their associations with meteorological processes over Eastern China in fall-winter 2013. Applying the package to observed hourly pollutant data reveals a primary spatial pattern representing Eastern China synchronous variation in time, which is dominated by diurnal variability with a much weaker day-to-day signal. A secondary spatial mode, representing north-south opposing changes in time with no constant period, is characterized by wind-related dilution or a buildup of pollutants from one day to another.

We further evaluate simulations of nested GEOS-Chem v9-02 and WRF/CMAQ v5.0.1 in capturing the spatiotemporal variability of pollutants. GEOS-Chem underestimates NO2 by about 17 mu g m(-3) and PM2.5 by 35 mu g m(-3 )on average over fall-winter 2013. It reproduces the diurnal variability for both pollutants. For the day-to-day variation, GEOS-Chem reproduces the observed north-south contrasting mode for both pollutants but not the Eastern China synchronous mode (especially for NO2). The model errors are due to a first model layer too thick (about 130 m) to capture the near-surface vertical gradient, deficiencies in the nighttime nitrogen chemistry in the first layer, and missing secondary organic aerosols and anthropogenic dust. CMAQ overestimates the diurnal cycle of pollutants due to too-weak boundary layer mixing, especially in the nighttime, and overestimates NO2 by about 30 mu g m(-3) and PM2.5 by 60 mu g m(-3). For the day-to-day variability, CMAQ reproduces the observed Eastern China synchronous mode but not the north-south opposing mode of NO2. Both models capture the day-to-day variability of PM2.5 better than that of NO2. These results shed light on model improvement. The EOF-EEMD package is freely available for noncommercial uses.
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 1680-7324 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @ Serial 946
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Author (up) Maksimova, E.V.
Title A conceptual view on inertial internal waves in relation to the subinertial flow on the central west Florida shelf Type $loc['typeJournal Article']
Year 2018 Publication Abbreviated Journal Sci Rep
Volume 8 Issue 1 Pages 15952
Keywords GRAVITY-WAVES; HARMONIC-ANALYSIS; OCEAN; GENERATION; PATHWAYS; SPECTRUM
Abstract The study reported here focuses on inertial internal wave currents on the west Florida midshelf in 50 m depth. In situ observations showed that the seasonal shifts in stratification change both the frequency range of inertial internal waves and their modulation time scales. According to the analysis, the subinertial flow evolution time scales also undergo compatible seasonal variations, and the inertial internal wave currents appear to be temporally and spatially related to the subinertial flow. Specifically, the subinertial flow evolving on frontal-/quasi-geostrophic time scales appears to be accompanied by the near-inertial oscillations/inertia-gravity waves in corresponding small/finite Burger number regimes, respectively. The quasi-geostrophic subinertial currents on the west Florida shelf are probably associated with the synoptic wind-forced flow, whereas the frontal-geostrophic currents are related to the evolution of density fronts. Further details of this conceptual view should, however, be elucidated in the future.
Address Center for Ocean-Atmospheric Prediction Studies, Florida State University, Tallahassee, Florida, 32306, USA. evm07c@my.fsu.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 2045-2322 ISBN Medium
Area Expedition Conference
Funding 0374060PMC6206015 Approved $loc['no']
Call Number COAPS @ rl18 @ Serial 982
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Author (up) Misra, V.; Bhardwaj, A.; Mishra, A.
Title Local onset and demise of the Indian summer monsoon Type $loc['typeJournal Article']
Year 2018 Publication Climate Dynamics Abbreviated Journal
Volume 51 Issue 5-6 Pages 1609-1622
Keywords Indian monsoon; ENSO; Onset of monsoon
Abstract This paper introduces an objective definition of local onset and demise of the Indian summer monsoon (ISM) at the native grid of the Indian Meteorological Department's rainfall analysis based on more than 100 years of rain gauge observations. The variability of the local onset/demise of the ISM is shown to be closely associated with the All India averaged rainfall onset/demise. This association is consistent with the corresponding evolution of the slow large-scale reversals of upper air and ocean variables that raise the hope of predictability of local onset and demise of the ISM. The local onset/demise of the ISM also show robust internannual variations associated with El Nino and the Southern Oscillation and Indian Ocean dipole mode. It is also shown that the early monsoon rains over northeast India has a predictive potential for the following seasonal anomalies of rainfall and seasonal length of the monsoon over rest of India.
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 360
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Author (up) Misra, V.; Mishra, A.; Bhardwaj, A.
Title Simulation of the Intraseasonal Variations of the Indian Summer Monsoon in a Regional Coupled Ocean-Atmosphere Model Type $loc['typeJournal Article']
Year 2018 Publication Journal of Climate Abbreviated Journal J. Climate
Volume 31 Issue 8 Pages 3167-3185
Keywords Asia; Indian Ocean; Mixed layer; Monsoons; Atmosphere-ocean interaction; Regional models
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 557
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Author (up) Misra, V.; Mishra, A.; Bhardwaj, A.; Viswanthan, K.; Schmutz, D.
Title The potential role of land cover on secular changes of the hydroclimate of Peninsular Florida Type $loc['typeJournal Article']
Year 2018 Publication Climate and Atmospheric Science Abbreviated Journal Clim Atmos Sci
Volume 1 Issue 1 Pages
Keywords
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 2397-3722 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 833
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Author (up) Misra, V; Bhardwaj, A; Mishra, A
Title Characterizing the rainy season of Peninsular Florida Type $loc['typeJournal Article']
Year 2018 Publication Climate Dynamics Abbreviated Journal
Volume 51 Issue 5-6 Pages 2157-2167
Keywords
Abstract Peninsular Florida (PF) has a very distinct wet season that can be objectively defined with onset and demise dates based on daily rainfall. The dramatic onset of rains and its retreat coincides with the seasonal cycle of the regional scale atmospheric and upper ocean circulations and upper ocean heat content of the immediate surrounding ocean. The gradual warming of the Intra-Americas Seas (IAS; includes Gulf of Mexico, Caribbean Sea and parts of northwestern subtropical Atlantic Ocean) with the seasonal evolution of the Loop Current and increased atmospheric heat flux in to the ocean eventually enhance the moisture flux into terrestrial PF around the time of the onset of the Rainy Season of PF (RSPF). Similarly, the RSPF retreats with the cooling of the IAS that coincides with the weakening of the Loop Current and reduction of the upper ocean heat content of the IAS. It is also shown that anomalous onset and demise dates of the RSPF have implications on its seasonal rainfall anomalies.
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 556
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Author (up) Morey, S. L.; Wienders, N.; Dukhovskoy, D. S.; Bourassa, M. A.
Title Impact of Stokes Drift on Measurements of Surface Currents from Drifters and HF Radar Type $loc['typeAbstract']
Year 2018 Publication American Geophysical Union Abbreviated Journal AGU
Volume Fall Meeting Issue Pages
Keywords 3307 Boundary layer processes, ATMOSPHERIC PROCESSESDE: 4504 Air/sea interactions, OCEANOGRAPHY: PHYSICALDE: 4560 Surface waves and tides, OCEANOGRAPHY: PHYSICALDE: 4572 Upper ocean and mixed layer processes, OCEANOGRAPHY: PHYSICAL
Abstract Concurrent measurements by surface drifters of different configurations and HF radar reveal substantial differences in estimates of the near-surface seawater velocity. On average, speeds of small ultra-thin (5 cm) drifters are significantly greater than co-located drifters with a traditional shallow drogue design, while velocity measurements from the drogued drifters closely match HF radar velocity estimates. Analysis of directional wave spectra measurements from a nearby buoy reveals that Stokes drift accounts for much of the difference between the velocity measurements from the drogued drifters and the ultra-thin drifters, except during times of wave breaking. Under wave breaking conditions, the difference between the ultra-thin drifter velocity and the drogued drifter velocity is much less than the computed Stokes drift. The results suggest that surface currents measured by more common approaches or simulated in models may underrepresent the velocity at the very surface of the ocean that is important for determining momentum and enthalpy fluxes between the ocean and atmosphere and for estimating transport of material at the ocean surface. However, simply adding an estimate of Stokes drift may also not be an appropriate method for estimating the true surface velocity from models or measurements from drogued drifters or HF radar under all sea conditions.
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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 @ user @ Serial 1008
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