Depth soundings from a single beam echo sounder collected around the nearshore areas of Timor-Leste in 2012 and 2013

This dataset contains singlebeam bathymetry data acquired during small-boat surveys conducted from October 20-26, 2012 and June 4-27, 2013 in Timor-Leste by the NOAA Coral Reef Ecosystem Program (CREP). Data was acquired with a HydroLite-TM Echosounder Kit by Seafloor Systems, a small boat Hydro Survey System using Ohmex SonarMite echosounder and Trimble ProXT receiver. The singlebeam bathymetry was used to ground-truth bathymetry derived from WorldView-2 satellite imagery by CREP for the near-shore areas (0-20 m depths) around Timor-Leste.

In 2011, NOAA and the United States Agency for International Development (USAID) Timor-Leste Mission formed a 5-year bi-lateral partnership agreement from 2012 to 2016, in support of the Government of Timor-Leste—particularly the Ministry of Agriculture and Fisheries (MAF)—by addressing significant information gaps in their nearshore marine ecosystems. Specifically, MAF asked NOAA to address the following questions:

1. Where are the nearshore marine resources?

2. What are the nearshore marine resources?

3. How are they changing over time and what threats are potentially causing these changes?

4. What approaches are needed to manage and conserve the nearshore marine resources?

With financial support from USAID and in-kind support from the NOAA Coral Reef Conservation Program (CRCP), the NOAA Coral Reef Ecosystem Program (NOAA-CREP) conducted baseline ecosystem assessment surveys to inform ecosystem-based management planning in Timor-Leste. The primary activities conducted by NOAA to answer these questions included:

1. satellite mapping of nearshore habitats,

2. conducting coral reef ecosystem assessments,

3. establishing ecological baselines for climate change, and

4. building management capacity by developing a spatial data framework

The singlebeam bathymetry data described herein resulted from the first activity to conduct satellite mapping for the nearshore waters around Timor-Leste.

Pacific Islands Fisheries Science Center. 2017. Interdisciplinary baseline ecosystem assessment surveys to inform ecosystem-based management planning in Timor-Leste: Final Report. Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-17-002, 234 p. https://doi.org/10.7289/V5/SP-PIFSC-17-002.

Mission ID, 2012: SBP1215

Mission ID, 2013: SBP1310

Surveys were conducted from local Timorese boat charters:

2012/2013: Lancet, 27’ Boston Whaler for shore-based surveys

2012: Cattitude, 40’ live-aboard catamaran

2013: Sundancer NT, 50’ live-aboard catamaran

The singlebeam bathymetry includes the date and time the data were collected, the location, and the depths. The 2012 data includes GPS information (fix, satellitles, HDOP), and the 2013 data includes the record type (depth only [D], or depth linked to GPS [L]) and the return signal strength (the higher the number the better).

While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

Timor-Leste

Not applicable

Not applicable

NOAA Coral Reef Ecosystem Program (CREP) Data Sharing Recommendations, version 9.0 updated August 12, 2015:

CREP welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. CREP has a very diverse set of field activities that generates large volumes of data using an array of data collection protocols.

The following recommendations are for your consideration as you use this data:

1) Data analyses should take all field exigencies into account. The most effective way to do this would be active collaboration with CREP principal investigators.

2) In all presentations, product releases, or publications using data generated by CREP, proper acknowledgement of both CREP and the individuals responsible for data collection is expected. Citing the DOI (if available) is preferred, a non-DOI example is listed below.

3) If you collect or generate data for the same study areas, CREP requests that you share relevant information on complimentary data collections.

4) Those receiving data are strongly urged to inform the CREP Data Management Team of any errors and discrepancies that are discovered during the course of using these data. They are further urged to bring to the attention of the Team all problems and difficulties encountered in using these data. This information is necessary in order to improve the collections and to facilitate more efficient and economical data processing and retrieval. The users are asked to supply copies of any missing data that may be located, and to provide information as to significant subsets and special aggregations of data that are developed in using the material provided.

Example citation:

"This publication makes use of data products provided by the Coral Reef Ecosystem Program (CREP), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), with funding support from the United States Agency for International Development (USAID). The analysis and interpretations presented here are solely that of the current authors.”

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive

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Please cite NOAA Coral Reef Ecosystem Program (CREP) when using the data.

Example

Coral Reef Ecosystem Program; Pacific Islands Fisheries Science Center (2017). Singlebeam bathymetry for Timor-Leste (2012 and 2013). NOAA's National Centers for Environmental Information. Dataset. https://www.fisheries.noaa.gov/inport/item/25307

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Singlebeam bathymetry data collected using HydroLite-TM Sonarmite Echosounder Kit by Seafloor Systems, which includes:

1) SonarMite BT-TM system, portable bluetooth echo sounder

2) SonarMite Transducer w/mount

3) Trimble Pro6T GNSS Receiver

4) Recon/GPS controller

5) Survey pole w/transom mount

Echosounder specs:

Frequency: 200 KHz

Beam width: 4 degree

Ping rate: 6-Hz

Depth accuracy: 1 cm /0.1% of depth,

Output: NMEA, ASCII, Quality

Depth range: 0.3-75 m

Data from the 2012 surveys was processed in May 2013 by Julia Ehses using version 7 of the processing script. 2012 data log files saved on PIFSC network at \\PICMAKAI\General\Cruise\CruiseData\CTI_TIM_SBP1215\Trimble_Data_Logger_Downloads\

Data from the 2013 surveys was processed in December 2017 by Annette DesRochers using SonarVista - SonarMite Edit software (v6.12) from Seafloor Systems. 2013 source data files saved on PIFSC network at \\PICMAKAI\General\Cruise\CruiseData\CTI_TIM_SBP1310\Mapping\Hydrolite_Ecosounder\data_output\Timor_Leste\

Timor-Leste project on PIFSC network: \\picGoldFish\General\ProjectGroup\Coral Triangle\Timor Leste\Spatial_Data_Framework\

Depth: The HydroLite-TM Echosounder Kit, Sonarmite Echosounder has a depth accuracy of 1 cm / 0.1% of depth.

2012: The fix type, number of satellites, and HDOP are provided in the dataset. HDOP is a measure of the geometric quality of a GPS satellite configuration in the sky. HDOP is a factor in determining the relative accuracy of a horizontal position. The smaller the DOP number, the better the geometry.

2013: The type and QA is provided in the dataset. Records with a type = L indicate the depth record includes the GPS location and has a QA = 1 (NMEA tag for GPS fix). There are two 'type = D' records for every 'type = L' record (D=Depth), because the sonar pings every half second, which is more frequent than the GPS. For the 'type=D' records, the higher the QA, the better the return signal strength. QA=70 is low signal strength (not as good), QA = 130 is high return signal strength (better).

The HydroLite-TM Echosounder Kit, Sonarmite Echosounder has a depth range of 0.3 m – 75 m.

Obviously erroneous data based on the coordinates were cleaned from the dataset (coordinates outside the expected range for Timor-Leste; 0,0 pairs, etc).

As the survey was not conducted to meet IHO standards, all users should independently analyze the dataset according to their own needs and standards to determine data usability.

All components of the HydroLite-TM Echosounder Kit was tested and calibrated in advance of surveys. The singlebeam bathymetry data were lightly processed and cleaned post-mission (obviously erroneous points based on spatial coordinates were removed).

In 2013, instrument to water surface offsets were applied (20 or 30 cm), and a sound velocity calibration factor was applied (1590 m/s, instead of the default 1500 m/s).

NOAA IRC and NOAA Fisheries ITS resources and assets.

Singlebeam bathymetry data collected using HydroLite-TM Echosounder Kit by Seafloor Systems, a small boat Hydro Survey System using Ohmex SonarMite echo sounder and Trimble ProXT receiver. Data was collected following procedures established by Seafloor Systems, and the HydroLite-TM system was tested and calibrated in advance of the surveys. Soundings were recorded in meters. Data collected in 2012 were processed using a different method from that used in 2013 as described in the process steps.