scholarly journals Wind and Gulf Stream influences on along-shelf transport and off-shelf export at Cape Hatteras, North Carolina

2001 ◽  
Vol 106 (C6) ◽  
pp. 11505-11527 ◽  
Author(s):  
Dana K. Savidge ◽  
John M. Bane
Keyword(s):  
North Carolina ◽  
Gulf Stream ◽  
Cape Hatteras

Characterization of Patches Along Transects Using High-Resolution 70-kHz Integrated Acoustic Data

1989 ◽  
Vol 46 (12) ◽  
pp. 2056-2064 ◽  
Author(s):  
R. W. Nero ◽  
J. J. Magnuson
Keyword(s):  
North Carolina ◽  
High Resolution ◽  
Gulf Stream ◽  
Window Size ◽  
Recognition Algorithm ◽  
Pass Filter ◽  
Acoustic Data ◽  
Cape Hatteras ◽  
High Pass

A patch recognition algorithm was applied to high-resolution (1 m vertical and 25 m horizontal) daytime sonar date collected from a 20-km-length transect to a depth of 200 m. The transect was oriented perpendicular to the Gulf Stream frontal zone, 105 km east–northeast ENE of Cape Hatteras, North Carolina, on August 8 1985. An adaptive high-pass filter was used to identify patches of high-intensity echo strengths. For a broad based averaging "window size" of 13 m deep by 1.4 km long and an echo strength threshold of 1.4 × integrated echo units patches resemble fine-scale features of the original echogram. A discrimination of patches using sonar statistics from within the patches gave good separation of slope water patches from patches belonging to four other water masses Slope water patches were characteristically small and of low mean scattering. Large but infrequent targets were present In the Gulf Stream, by contrast, patches contained more uniformly distributed targets with a higher mean scattering The observed correlation between echo patches, biological structures, and oceanographic features suggests that the measurement of echo statistics and our patch recognition techniques produce biologically meaningful parameters.

The Combined Effects of Gulf Stream–Induced Baroclinicity and Upper-Level Vorticity on U.S. East Coast Extratropical Cyclogenesis

2005 ◽  
Vol 133 (8) ◽  
pp. 2494-2501 ◽  
Author(s):  
Neil A. Jacobs ◽  
Gary M. Lackmann ◽  
Sethu Raman
Keyword(s):  
North Carolina ◽  
Gulf Stream ◽  
Additional Data ◽  
Large Fraction ◽  
Coastal Region ◽  
Western Boundary ◽  
Absolute Vorticity ◽  
Surface Cyclone ◽  
Cape Hatteras ◽  
Upper Level

Abstract The Atlantic Surface Cyclone Intensification Index (ASCII) is a forecast index that quantifies the strength of low-level baroclinicity in the coastal region of the Carolinas. It is based on the gradient between the coldest 24-h average air temperature at Cape Hatteras and Wilmington, North Carolina, and the temperature at the western boundary of the Gulf Stream. The resulting prestorm baroclinic index (PSBI) is used to forecast the probability that a cyclone in the domain will exhibit rapid cyclogenesis. The initial ASCII study covered the years 1982–90. This dataset was recently expanded to cover the years 1991–2002, which doubled the number of cyclone events in the sample. These additional data provide similar position and slope of the linear regression fits to the previous values, and explain as much as 30% of the variance in cyclone deepening rate. Despite operational value, the neglect of upper-tropospheric forcing as a predictor in the original ASCII formulation precludes explanation of a large fraction of the deepening rate variance. Here, a modified index is derived in which an approximate measure of upper-level forcing is included. The 1991–2002 cyclone events were separated into bins of “strongly forced,” “moderately forced,” and “weakly forced” based on the strength of the nearest upstream maximum of 500-mb absolute vorticity associated with the surface low. This separation method reduced the scatter and further isolated the contributions of surface forcing versus upper-level forcing on extratropical cyclogenesis. Results of the combined upper-level index and surface PSBI demonstrate that as much as 74% of the deepening rate variance can be explained for cases with stronger upper-level forcing.

Hydrokinetic Energy Resource Assessment of the Gulf Stream Near Cape Hatteras, North Carolina

2014 ◽  
Author(s):  
Asif Kabir ◽  
Ivan J. Lemongo ◽  
Arturo Fernandez
Keyword(s):  
North Carolina ◽  
Gulf Stream ◽  
Energy Resource ◽  
Resource Assessment ◽  
Ocean Model ◽  
Likelihood Method ◽  
Ocean Current ◽  
Hydrokinetic Energy ◽  
Cape Hatteras ◽  
Promising Source

The Gulf Stream near the coasts of North Carolina is considered a promising source of hydrokinetic energy. A statistical analysis is conducted to assess the energy available for extraction in this region. Weibull distribution is used as the Probability Density Function (PDF) for this purpose. The ocean current velocity data are collected from the ‘HYbrid Coordinate Ocean Model (HYCOM)’. The data are collected at a depth of 20 m from the sea surface which is considered a good position for energy extraction. The Weibull parameters from the analysis are calculated using the maximum likelihood method. The direction of the ocean current was found to be mostly uniform in this region. The theoretical power density of this region was estimated to be more than 275 W/m2 around 70% of the time and exceeded 2000 W/m2 around 10% of the time.

Gulf stream marine hydrokinetic energy resource characterization off Cape Hatteras, North Carolina USA

2016 ◽  
Author(s):  
Ruoying He ◽  
John Bane ◽  
Mike Muglia ◽  
Sara Haines ◽  
Caroline Lowcher ◽  
...  
Keyword(s):  
North Carolina ◽  
Gulf Stream ◽  
Energy Resource ◽  
Hydrokinetic Energy ◽  
Cape Hatteras ◽  
Marine Hydrokinetic

scholarly journals Effects of a scientific echo sounder on the behavior of short-finned pilot whales (Globicephala macrorhynchus)

2017 ◽  
Vol 74 (5) ◽  
pp. 716-726 ◽  
Author(s):  
Nicola Quick ◽  
Lindesay Scott-Hayward ◽  
Dina Sadykova ◽  
Doug Nowacek ◽  
Andrew Read
Keyword(s):  
North Carolina ◽  
Generalized Estimating Equations ◽  
Marine Mammals ◽  
Hidden Markov ◽  
Experimental Conditions ◽  
Cape Hatteras ◽  
Consistent Increase ◽  
Pilot Whales ◽  
Acoustic Recording ◽  
Echo Sounder

Active echo sounding devices are often employed for commercial or scientific purposes in the foraging habitats of marine mammals. We conducted an experiment off Cape Hatteras, North Carolina, USA, to assess whether the behavior of short-finned pilot whales (Globicephala macrorhynchus) changed when exposed to an EK60 scientific echo sounder. We attached digital acoustic recording tags (DTAGs) to nine individuals, five of which were exposed. A hidden Markov model to characterize diving states with and without exposure provided no evidence for a change in foraging behavior. However, generalized estimating equations to model changes in heading variance over the entire tag record under all experimental conditions showed a consistent increase in heading variance during exposure over all values of depth and pitch. This suggests that regardless of behavioral state, the whales changed their heading more frequently when the echo sounder was active. This response could represent increased vigilance in which whales maintained awareness of echo sounder location by increasing their heading variance and provides the first quantitative analysis on reactions of cetaceans to a scientific echo sounder.

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