NATSUSHIMA NT13-21 Leg1 Bathymetry (MBES)

Last Modified: 2014-08-27
: NT13-21 Leg1
: Processed (DMO)-Basic
: Depth

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Multi-narrow beam echo sounder
 The data provided here are the bathymetric data obtained from the multibeam echo sounder system (MBES). The system transmits the shape echo sounder beam from the transmitter and receives the beam reflected from the seabed using the hydrophone. The water depth is calculated from the travel time of the beam between the transmitter and the receiver. Having many transmitters make fan beams across the keel, this system can obtain a lot of bathymetric data on a wide angle at once.
 The travel time of the beam (from the transmitter to the seabed and from the seabed to the receiver) is corrected using the vertical profile of the sound velocity obtained from the in situ observations. (see section Sound velocity profile correction). The raw data with the low reliability such as the noise are removed using the software (see section Processed data).
Manufacturer: Reson Inc.
Type : SeaBat 8160
Frequency : 50kHz
Swath angle: Max 130°
Beam angle: 1.5 * 1.5°
Beam number: 126
Range: 10m - 3,000m
Resolution (Depth) : 1.4cm/2.9cm/8.6cm (It depends on depth.)
 In the survey area, the sound velocity profile correction is made using the XBT data acquired during the cruise. On the other hand, in the transit area, e.g., from the survey area to the port, where we do not conduct the XBT observations, the data are corrected using the historical XBT data or the Argo float data.
 Following raw data with the low reliability are removed using the processing software "HIPS and SIPS" of CARIS Inc:
· Navigation error data.
· Data more than manufacturer specification (see section Measurement System)
· Spike noise data (If both of slopes calculated from the evaluated beam and prior/post one on the same swath are less than 5 degrees.)
· Side beam (Beam No.1-20,107-126 : Starboard is No.1 beam.)
 The data quality is different in the survey and transit area because of the difference of the temperature data for the sound velocity profile correction. Therefore, we open the survey and transit area data separately. The rule of the file name is as follows.

File name :
· Survey area data : YYYYMMDD.dat
· Transit area data : TYYYYMMDD.dat
YYYY: year, MM: month, DD: day
"T" of the header indicates the transit area data.

(1) Geodetic system: WGS84
(2) The tide is not corrected.
(3) These data are compressed in zip format, please use that after unpacking.
(4) If you would like the raw data set, please contact us from "Contact Us" above.
: NT13-21 Leg1
: Processed (DMO)-Basic
: Depth

Observation Map

Imagery reproduced from ...

Data List

File names
: NT13-21 Leg1
: Processed (DMO)-Basic

Bathymetry XYZ

The one record length of the Processed Data file is 33 bytes.
No. Column Description Format Unit Remarks
1 1 - 11 Longitude f11.6 degree + : Eastern hemisphere
- : Western hemisphere
2 13 - 22 Latitude f10.6 degree + : Northern hemisphere
- : Southern hemisphere
3 24 - 31 Depth f9.3 m
4 32 - 33 Terminator a2

Related Information

Cruise Data Dive Data

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