Publisher: U.S. Geological Survey, Coastal and Marine Geology Program
Larger_Work_Citation:
Citation_Information:
Originator: Larry Poppe
Originator: Ralph S. Lewis
Originator: Jane F. Denny
Originator: Kenneth F. Parolski
Originator: Mary L. DiGiacomo-Cohen
Originator: Douglas S. Tolderlund
Publication_Date: 1998
Title:
Sidescan sonar image, surficial geologic interpretation, and bathymetry of the Long Island Sound sea floor in Niantic Bay and vicinity, Connecticut
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: Geologic Investigations Series Map
Issue_Identification: I-2625
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey, Coastal and Marine Geology Program
Description:
Abstract:
Because of the enormous surrounding population of
Long Island Sound, large inputs of anthropogenic
wastes (e.g. fertilizers and sewage) and toxic
chemicals have produced stresses on the environment
of the Sound, causing degradation and potential loss
of benthic habitats. Anthropogenic wastes, toxic
chemicals, and changes in land use patterns from
residential, commercial, and recreational development
have stressed the environment of the Sound causing
degradation and potential loss of benthic habitats.
These studies build upon cooperative research with
the State of Connecticut that was initiated in 1982.
The mosaic presented herein, which covers the sea
floor in and adjacent to Niantic Bay, enables us to
define the geological variability of the sea floor,
which is one of the primary controls of benthic
habitat diversity. It also provides a detailed
framework for future research, monitoring, and
management activities, and it improves our
understanding of the processes that control the
distribution of bottom sediments, benthic habitats,
and associated infaunal community structures.
Because precise information on environmental setting
is important to the selection of sampling sites and
to the accurate interpretation of point measurements,
the sidescan sonar mosaics also act as base maps for
subsequent sedimentological, biological, and
geochemical observations.
Purpose:
This dataset presents the completed sidescan sonar
mosaic for Niantic, Connecticut study area
Supplemental_Information:
Distinctive acoustic patterns revealed by this
mosaic include the following; complex patches of
high and low backscatter that coincide with areas
where the prolonged facies crops out (bedrock,
and boulders and gravel); elongate patches of
alternating high and low backscatter (sand waves);
areas of low backscatter (dark tone on image;
probably finer grained sediment); and isolated
spots of high backscatter (light tone on image;
interpretation is problematic). Ship wakes are
common on the image, notably in Niantic Bay, and
faint trawl marks are present east of Black Point. Turbulence associated with the strong tidal
currents appears as streaks of high backscatter
around Millstone Point.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19950506
Ending_Date: 19960612
Currentness_Reference: Ground Condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -072.207856
East_Bounding_Coordinate: -072.116186
North_Bounding_Coordinate: +41.325097
South_Bounding_Coordinate: +41.258431
Keywords:
Theme:
Theme_Keyword_Thesaurus: General
Theme_Keyword: USGS
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: Coastal and Marine Geology Program
Theme_Keyword: Long Island Sound Research Center
Theme_Keyword: Connecticut Geological and Natural History Survey
Theme_Keyword: sidescan sonar
Theme_Keyword: estuary
Theme_Keyword: benthic habitat
Theme_Keyword: hypoxia
Theme_Keyword: sediment distribution
Theme_Keyword: benthic community
Theme_Keyword: surficial geology
Place:
Place_Keyword_Thesaurus: General
Place_Keyword: Long Island Sound
Place_Keyword: Connecticut
Place_Keyword: Niantic Bay
Place_Keyword: estuary
Place_Keyword: Eastern Long Island Sound
Place_Keyword: Twotree Island Channel
Place_Keyword: Bartlett Reef
Access_Constraints: None
Use_Constraints:
The U.S. Geological Survey must be referenced as the
originator of the dataset in any future products or
research derived from these data.
Although this derived data set and it's lineage dataset
have been used by the USGS, no warrant, expressed
or implied, is made by the USGS as to the accuracy
of the data and/or related materials. The act of
distribution shall not constitute any such warranty,
and no responsibility is assumed by the USGS in the use
of these data or related materials.
The sidescan sonar data were collected using a
100-kHz Klein sidescan sonar system set to sweep
100-m to either side of the ship's track.
These data were logged digitally to 8-mm tape
on a QMIPS data acquisition system. Ship position
was determined with a differential Global
Positioning System (GPS) and was logged on a
computer at 10-s intervals.
Type_of_Source_Media: cartridge tape
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19950506
Ending_Date: 19960612
Source_Currentness_Reference: Ground Condition
Source_Citation_Abbreviation: QMIPS
Source_Contribution:
These data were processed to apply radiometric and
geometric corrections. The processed swaths were
then mapped and digitally mosaicked to complete
the sidescan sonar mosaic for the study area.
Process_Step:
Process_Description:
QMIPS data were processed through a median
filtering routine to suppress speckle noise.
Navigation merged into the header record portion
of the data were plotted and checked. The QMIPS
data were exported for import to the WHIPS
processing.
Source_Used_Citation_Abbreviation: QMIPS
Process_Date: Unknown
Source_Produced_Citation_Abbreviation: WHIPS
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jane Denny
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02532-1598
Country: USA
Contact_Voice_Telephone: (508) 548-8700 x2311
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: jdenny@usgs.gov
Process_Step:
Process_Description:
The individual sidescan swaths were processed
to apply a slant-to-ground range correction,
shading correction and striped noise removal.
the geometrically and radiometrically enhanced
swaths were then individually mapped to a user
specified scale and projection.
Source_Used_Citation_Abbreviation: WHIPS
Process_Date: Unknown
Source_Produced_Citation_Abbreviation: WHIPS
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jane Denny
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02532-1598
Country: USA
Contact_Voice_Telephone: (508) 548-8700 x2311
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: jdenny@usgs.gov
Process_Step:
Process_Description:
The individually mapped swaths were imported
into a PCI "pix" database file for digital
mosaicking. The mosaicking procedure included
trimming off unwanted data where two sonar images
overlapped, tone matching the adjacent sonar
images if there are differences, and combining
the individual strips together into a
composite image.
Utilizing the PCI Remote Sensing Software
reprojection utility, the completed and
archived mosaic was reprojected to UTM to
be consistent with current Long Island
Sound GIS datasets.
Although this derived data set and it's lineage
dataset have been used by the USGS, no warranty,
expressed or implied, is made by the USGS as to
the accuracy of the data and/or related materials.
The act of distribution shall not constitute any such
warranty, and no responsibility is assumed by the USGS
in the use of these data or related materials.
The sidescan sonar mosaic is available as a
GEOTIFF image with accompanying world file and
georeference report. To utilize this data, the user
must have an image viewer, image processing or
GIS software package capable of importing a
GEOTIFF image. If the georeferencing information
cannot be imported, the user may wish to obtain
the georeference information contained in a separate
file, georep.txt, included in the zip file.
