cicsmd

 



Ocean Data Stewardship: Development of a Global Thermosalinograph (TSG) Database

Research Topic: Climate Data & Information Records/Scientific Data Stewardship
Task Leader: Zhankun Wang
CICS Scientist: Zhankun Wang
Sponsor: NESDIS NCEI
Published Date: 9/26/2017
EBEB_NODC__14tn

2017 ANNUAL REPORT

Background

Ocean surface is the location of strong exchanges with the atmosphere but also with ice and continents. Ship-based thermosalinograph measurements can make a significant contribution to the observation of this very active layer if the quality of the datasets produced is in accordance with current research standards. The sea surface salinity and temperature from thermosalinograph can be used to validate and calibrate the remote sensing data from satellites or other devices. They can also be used for global water cycle studies.

One of the motivations of developing this global thermosalinograph database is to conduct an in-situ/satellite matchup research of Sea Surface Salinity observations. This database will be one of the fundamental in-situ components for the Satellite SSS Quality Monitor (4SQM) project.  Data are from different data assemble centers including GOSUD (IODE), SAMOS and AOML.  NCEI Archive Management System has large amount of raw TSG data that are not included in any of the TSG data assembly centers. The goal of this project is to provide a well-organized, uniformly quality-controlled TSG database for the user community with granule search capability.

Data sources for the TSG database:

  • NCEI Archiving Management System, over 1300 accessions
  • International Oceanographic Data and Information Exchange (IODE) Global Ocean Surface Underway Data (GOSUD), LEGOS (Laboratoire d’Etudes en Géophysique et Océanographie Spatiales) data has been included in the GOSUD.
  • Atlantic Oceanographic & Meteorological Laboratory (AOML) TSG
  • Shipboard Automated Meteorological and Oceanographic System (SAMOS), Florida State University
  • Other data could be included:

o   Wave glider data

o   Unmanned Surface Vehicle (USV) data

o   Ferrybox data

o   Surface bucket data

Accomplishments

I have constructed a Global Thermosalinograph Database (NCEI­TSG) to facilitate access to the in situ sea­surface salinity and temperature measurements. This database provides a comprehensive set of quality­controlled in situ sea­surface salinity (SSS) and temperature (SST) measurements collected from over 200 vessels during the period 1989 to the present.  Figure 1 shows the spatial distribution of the NCEI-TSG with color-coded data sources.

Compared to other TSG datasets, these data have several advantages:

  1. The NCEI­TSG is the world's most complete TSG dataset, containing all data from the different TSG data assembly centers, e.g. Shipboard Automated Meteorological and Oceanographic System (SAMOS), Global Ocean Surface Underway Data (GOSUD) and Atlantic Oceanographic and Meteorological Laboratory (AOML), with more historical data from NCEI’s archive to be added.
  2. When different versions of a dataset are available, the dataset with the highest resolution is always chosen.
  3. All data are converted to a common NetCDF format, employing enhanced metadata, following Attribute Convention for Dataset Discovery (ACDD) and Climate and Forecast (CF) conventions, to increase the overall quality and searchability of both the data and metadata.
  4. All data are processed using the same 11­step quality control procedures and criteria and flagged using a two­level flag system to provide a well­organized, uniformly quality­controlled TSG dataset for the user community.

The NCEI­TSG, a unique dataset for in situ sea­surface observations, serves as a significant resource for establishing match­ups with satellite SST and SSS observations for validation and comparisons. The NCEI­TSG database will significantly contribute to the in situ component of the NOAA Satellite SSS Quality Monitor (4SQM) project (under development). This dataset facilitates assessments of global SST and SSS variability and the analysis of patterns and trends at various regional and temporal scales, enabling new insights in climate change, the global water cycle, air­sea interaction, etc. The NCEI­TSG database is freely accessible via the NCEI website (https://archive.nodc.noaa.gov/archive/ingest/0156189/) and will be maintained with newly received TSG data, as well as further expanded with more historical data from NCEI’s archive.

I have developed several python modules to manage and provide quality controls to this large datasets. The python modules process different formats of raw data and convert them to the same NCEI netCDF format. Uniformly quality controls are applied to all the data. I am working with the NCEi ingest team to set up automations for the entire process. Fig 2 shows the flow-chart of the NCEI-TSG database from data sources to data users.

A NCEI geo-portal based search portal has also been developed to improve the discoverability and access of the NCEI-TSG database.  The portal is now under NCEI security review and will become publicly available when it passed all the codes and security reviews.

EBEB_NODC_14A   

Figure 1. Spatial distribution of the NCEI-TSG dataset. The data are color-coded with data sources.

EBEB_NODC_14B

Figure 2. Flowchart of the NCEI-TSG dataset from data sources, data processing, data product and data usages.

Planned work        

  • Database daily updates/maintenance
  • Expand the database
    • with more historical data from NCEI archive (1300+ accessions)
    • Adding atmospheric and biochemical data concurrently collected, e.g. Chl a, Dissolved Oxygen, air tem etc.
    • Replacing averaged low-resolution data with raw high resolution data
    • Adding surface data from other instruments/platforms
    • Wave glider data
    • Unmanned surface vehicle (USV) data
    • Ferrybox data
    • Surface bucket data
  • Metadata enhancement, e.g. water intake depth, instr. setup etc. 
  • QC updates/improvements
  • Scientific Research, e.g. in-situ/satellite match-up, water-front, global water cycle etc.

Products      

  • NCEI-TSG database
  • NCEI Thermosalinograph Portal

Presentations       

  • Wang, Z.(2016), Potential NCEI contributions to GOSUD project, 6th Session of the IODE Steering Group for the GOSUD Project. November 2016, Oostende, Belgium (invited).
  • Wang, Z.(2016), NCEI-TSG: A Global in situ Sea-surface Salinity and Temperature Database of Thermosalinograph (TSG) Observations,  2016 CICS Science Conference, November 2016, College Park, MD.
  • Wang, Z., T. Boyer, H. Zhang, E. J. Bayler, M. Biddle, S. Baker-Yeboah, Y. Zhang (2016)., NCEI-TSG: A Global in situ Sea-surface Salinity and Temperature Database of Thermosalinograph, December 2016, 2016 AGU Fall Meeting, San Francisco, CA.

Other              

I became a member of the Global Ocean Surface Underway Data (GOSUD) Project steering group to represent NOAA NCEI. Global Ocean Surface Underway Data (GOSUD) is an initiative of the International Oceanographic Data and Information Exchange (IODE) of the Intergovernmental Oceanographic Commission (IOC) programme.

close (X)