A slant‐stack procedure for point‐source data

Geophysics ◽  
1986 ◽  
Vol 51 (7) ◽  
pp. 1370-1386 ◽  
Author(s):  
Henry Brysk ◽  
Douglas W. McCowan
Keyword(s):  
Point Source ◽  
Computationally Efficient ◽  
West Florida Shelf ◽  
Florida Shelf ◽  
Lamb’S Problem ◽  
Amplitude Versus Offset ◽  
Surface Data ◽  
Source Data ◽  
Bessel Transforms ◽  
Slant Stacking

The proper implementation of the τ-p method for surface data excited by a point source requires a cylindrical slant stack. Usually the common (Cartesian) slant stack is computed instead as an approximation to the geometrically correct procedure. Here we describe a formulation of the cylindrical slant stack as a weighted sum of Cartesian slant stacks; our cylindrical slant stack is computationally efficient to perform. We show how, although the usefulness of the slant stack is most easily seen with Cartesian coordinates, it can also be used with Fourier‐Bessel transforms. An example of the method shows results computed from data recorded on the West Florida Shelf. Severe edge‐effect noise which overwhelms the Cartesian slant stack is attenuated by the cylindrical slant‐stacking. Applications of the cylindrical slant stack to other seismological calculations, such as Lamb’s problem, are also discussed. In particular, we prove that the plane‐wave reflection coefficients apply exactly in the τ-p domain; hence an amplitude‐versus‐offset analysis is unambiguous in that domain.

Reply by the authors to Douglas W. McCowan

Geophysics ◽  
1990 ◽  
Vol 55 (3) ◽  
pp. 379-379 ◽  
Author(s):  
Rakesh Mithal ◽  
Emilio E. Vera
Keyword(s):  
Plane Wave ◽  
Point Source ◽  
Seismic Data ◽  
Wave Reflection ◽  
Suitable Alternative ◽  
Plane Wave Decomposition ◽  
Main Emphasis ◽  
Source Data ◽  
Wave Decomposition ◽  
Slant Stacking

In his discussion, McGowan directs his attention exclusively to which method should be used to produce a plane-wave decomposition of point-source seismic data. Although the choice of method is an important point, it was not the main emphasis of our paper which, as its title indicates, was the comparison between plane-wave decomposition (cylindrical slant stacking) and simple slant stacking. We demonstrated the differences between these two processes and clearly indicated the necessity of using cylindrical slant stacking in order to get the correct plane-wave reflection response of point-source data. McGowan criticizes our method because it makes use of the standard asymptotic approximation of the Bessel function [Formula: see text] and considers only outward traveling waves. In our paper we acknowledged that these simplifications do not produce accurate results for ray parameters near zero and explicitly mentioned the method of Brysk and McGowan (1986) as a suitable alternative to deal with this problem.

USGS field activity 09FSH02 on the west Florida shelf, Gulf of Mexico, in August 2009

Data Series ◽  
2009 ◽  
Author(s):  
Lisa L. Robbins ◽  
Paul O. Knorr ◽  
Xuewu Liu ◽  
Robert H. Byrne ◽  
Ellen A. Raabe
Keyword(s):  
Gulf Of Mexico ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Field Activity

USGS Field Activities 11CEV01 and 11CEV02 on the West Florida Shelf, Gulf of Mexico, in January and February 2011

Data Series ◽  
10.3133/ds711 ◽  
2014 ◽  
Author(s):  
Lisa L. Robbins ◽  
Paul O. Knorr ◽  
Kendra L. Daly ◽  
Carl A. Taylor
Keyword(s):  
Gulf Of Mexico ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf

High-Frequency Radar Mapping of Surface Currents Using WERA

2007 ◽  
Vol 24 (3) ◽  
pp. 484-503 ◽  
Author(s):  
Lynn K. Shay ◽  
Jorge Martinez-Pedraja ◽  
Thomas M. Cook ◽  
Brian K. Haus ◽  
Robert H. Weisberg
Keyword(s):  
Time Series ◽  
High Frequency ◽  
Tidal Currents ◽  
Tropical Storm ◽  
Surface Velocity ◽  
Surface Currents ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
East West

Abstract A dual-station high-frequency Wellen Radar (WERA), transmitting at 16.045 MHz, was deployed along the west Florida shelf in phased array mode during the summer of 2003. A 33-day, continuous time series of radial and vector surface current fields was acquired starting on 23 August ending 25 September 2003. Over a 30-min sample interval, WERA mapped coastal ocean currents over an ≈40 km × 80 km footprint with a 1.2-km horizontal resolution. A total of 1628 snapshots of the vector surface currents was acquired, with only 70 samples (4.3%) missing from the vector time series. Comparisons to subsurface measurements from two moored acoustic Doppler current profilers revealed RMS differences of 1 to 5 cm s−1 for both radial and Cartesian current components. Regression analyses indicated slopes close to unity with small biases between surface and subsurface measurements at 4-m depth in the east–west (u) and north–south (υ) components, respectively. Vector correlation coefficients were 0.9 with complex phases of −3° and 5° at EC4 (20-m isobath) and NA2 (25-m isobath) moorings, respectively. Complex surface circulation patterns were observed that included tidal and wind-driven currents over the west Florida shelf. Tidal current amplitudes were 4 to 5 cm s−1 for the diurnal and semidiurnal constituents. Vertical structure of these tidal currents indicated that the semidiurnal components were predominantly barotropic whereas diurnal tidal currents had more of a baroclinic component. Tidal currents were removed from the observed current time series and were compared to the 10-m adjusted winds at a surface mooring. Based on these time series comparisons, regression slopes were 0.02 to 0.03 in the east–west and north–south directions, respectively. During Tropical Storm Henri’s passage on 5 September 2003, cyclonically rotating surface winds forced surface velocities of more than 35 cm s−1 as Henri made landfall north of Tampa Bay, Florida. These results suggest that the WERA measured the surface velocity well under weak to tropical storm wind conditions.

scholarly journals A loop current-induced jet along the edge of the West Florida Shelf

1999 ◽  
Vol 26 (15) ◽  
pp. 2239-2242 ◽  
Author(s):  
Robert D. Hetland ◽  
Ya Hsueh ◽  
Robert R. Leben ◽  
Pearn P. Niiler
Keyword(s):  
Loop Current ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf

scholarly journals Spatial allocation of anthropogenic carbon dioxide emission statistics data fusing multi-source data based on Bayesian network

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianbin Tao ◽  
XiangBing Kong
Keyword(s):  
Carbon Dioxide ◽  
Land Cover ◽  
Point Source ◽  
Bayesian Network ◽  
Prior Knowledge ◽  
Carbon Dioxide Emissions ◽  
Spatial Allocation ◽  
Source Data ◽  
Anthropogenic Carbon ◽  
Anthropogenic Carbon Dioxide

AbstractA gridded social-economic data is essential for geoscience analysis and multidisciplinary application. Spatial allocation of carbon dioxide statistics data is an important issue in the context of global climate change, which involves the carbon emissions accounting and decomposition of responsibility for carbon emission reductions. In this research a new spatial allocation method for non-point source anthropogenic carbon dioxide emissions (ACDE) fusing multi-source data using Bayesian Network (BN) was introduced. In addition to common-used DMSP (Defense Meteorological Satellite Program), PD (population density) and GDP (Gross Domestic Production) data, the land cover and vegetation data was imported into the model as prior knowledge to optimize the model fitting. The prior knowledge here was based on the understanding that ACDE was dominated by human activities and has strong correlations with land cover and vegetation conditions. A 1 km gridded ACDE map integrated emissions form point-source and non-point source was generated and validated. The model predicts ACDE with high accuracies and great improvement can be observed when fusing land cover and vegetation as prior knowledge. The model can achieve successful statistics data downscaling on national scale provided adequate sample data are available, offering a novel method for ACDE accounting in China.

The role of the West Florida Shelf topography on the Loop Current system variability

2021 ◽  
Author(s):  
Nektaria Ntaganou ◽  
Vassiliki Kourafalou ◽  
Matthieu Le Hénaff ◽  
Yannis Androulidakis
Keyword(s):  
Current System ◽  
Loop Current ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
System Variability

Evaluation of Satellite-Derived SST Products in Identifying the Rapid Temperature Drop on the West Florida Shelf Associated With Hurricane Irma

2018 ◽  
Vol 52 (3) ◽  
pp. 43-50 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg ◽  
Jason Law ◽  
Boyin Huang
Keyword(s):  
Temperature Drop ◽  
Coastal Ocean ◽  
Sea Surface ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Time Period ◽  
Rapid Temperature ◽  
Ocean Observations ◽  
Hurricane Irma

AbstractSatellite-derived daily sea surface temperature (SST) products are compared with moored SST observations on the West Florida Shelf during the time period of Hurricane Irma. Most of the SST products compare reasonably well with the moored data at the location of 25-m depth, where SST dropped by about 1°C after the hurricane passage. However, most of the SST products did not show the rapid SST drop at the location of 50-m depth where the surface water was cooled by about 4°C within 1 day in response to the hurricane passage. This finding has important implications to air-sea interaction studies and hurricane simulations, in which SST data play an important role. The limitations of the popular satellite products call for additional coastal ocean observations as well as proper inclusion of the real-time observations in satellite-derived products.

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