Indian Ocean GO-SHIP: IIOE-2 planning
April 7, 2014 (GO-SHIP Executive Group)
Introduction
Global hydrographic surveys, including the Indian Ocean, have been carried out approximately every
decade since the 1960s through research programs such as IIOE, GEOSECS, WOCE / JGOFS, and CLIVAR.
In 2009 the Global Ocean Ship-based Hydrographic Program (GO-SHIP) was established as part of theGlobal Ocean Observing System under the WCRP to provide international coordination and scientificoversight of the decadal global ocean survey.
GO-SHIP aims to develop a globally coordinated network of sustained hydrographic sections as part of
the global ocean/climate observing system including physical oceanography, the carbon cycle, marine
biogeochemistry and ecosystems. GO-SHIP provides approximately decadal resolution of the changes ininventories of heat, freshwater, carbon, oxygen, nutrients and transient tracers, covering the ocean
basins from coast to coast and full depth (top to bottom) ,with global measurements of the highest
required accuracy to detect these changes.
GO-SHIP Observation Strategy
GO-SHIP Reference Sections (figure 1) are full-depth repeat hydrographic sections that are coast-tocoast or coast-to-ice, along specific lines with small modifications as necessary for territorial waters, icecoverage, etc. Two types of surveys comprise the GO-SHIP scientific objectives: (1) decadal surveys and(2) a sub-set of the decadal survey lines sampled at high frequency (repeats every 2-5 years). Station
sampling along the section is nominally 30 nautical miles (nm) for physical measurements and 60 nm (orbetter) for carbon and tracer measurements.

Figure 1 Global GO-SHIP sections as of March 2014. See www.go-ship.org for more information

Level 1 data are of highest priority. GO-SHIP recommends that level 1 data should be collect at least
once per decade on all sections. Sections occupied at higher frequencies (yearly, biennial) do not needto undertake all level 1 measurement on all re-occupations.
Level 1 data:
••
•
•••
•
•
••
•
•
•

CTD pressure, temperature, salinity (calculated from conductivity, temperature and pressure)
CTD oxygen (sensor)
Bottle salinity
Nutrients by standard auto analyzer (NO3/NO2, PO4, SiO3)
Dissolved oxygenDissolved inorganic carbon (DIC)*
Total Alkalinity (TAlk)*
pH**(note any two of the above carbon related observations)
Chlorofluorocarbons (CFC-11, -12) and SF6
Surface underway system (T, S, pCO2)
ADCP shipboard
ADCP lowered
Underway navigation and bathymetry
Meteorological data.

Level 2 data are highly desirable. GO-SHIP recommends that level 2 should be collected when possible.
Level 2 data:
••
•
•
••
•
•
•

Discrete pCO2
14C (by AMS)
CCl4
∂13C of DIC
Dissolved organic carbon
Dissolved organic nitrogenFe/trace metals
CTD Transmissometer
Surface underway system (nutrients, O2, Chl, skin temperature).

Level 3 data are ancillary measurements are done according to opportunity and space available. They
should not significantly interfere with Level 1 or 2 data collection, and may be regional or specific to anindividual cruise.
The GO-SHIP data policy for its basic parameter set is stringent and geared towards rapid, open
dissemination, with a clear structure for all data to undergo quality control, and to be sent to andavailable from recognized data centers. A summary of the data types and data management structures
can be found on the GO-SHIP website (www.go-ship.org). (Links to national programs can be found on
the GO-SHIP website.)GO-SHIP: Indian Ocean
GO-SHIP has a number of lines in the Indian Ocean that are part of the global decadal survey. A numberof these lines have national commitment for occupation during the IIOE-2 timeframe (Table 1).
Collaboration between GO-SHIP and IIOE-2 provides a unique opportunity for (1) addition ofmeasurement (level 3) to the GO-SHIP observation suite and (2) leveraging national support to complete
the Indian Ocean survey.

Figure 2 GO-SHIP Indian Ocean survey.

Figure 2 GO-SHIP section that will be part of the IIOE-2. Some sections have nationalcommitments (see table 1).

Table 1. GO-SHIP sections to be occupied during IIOE-2.

GO-SHIPsection
I08S
I09N
I01E
I09S
I05
I06S
I08N
I07N

Nominal location

Year

Country

95°E south of 32°S
95°E north of 32°S
10°N Bay of Bengal
115°E
32°S
30°E
90°E north of 32°S
60°E

2015-2016
U.S.A.
2015-2016
U.S.A.
2016
U.S.A.
2017
Australia
2018
U.S.A.
2019
U.S.A.
2015 or 2018Japan/India
No commitment (due toSee ^security reasons)
I10/IR06
Java to NW Australia (110oE)
2015 or 2018
JapanoI03
20 S Australia to Madagascar
No commitment
See #S04I
62oS
No commitment
I01W
10°N Arabian Sea
No commitment^ Although not in the USA planning, they will do the section if international security warnings areremoved.
# Under discussion between Indian partners and UK IIOE2.

Summary
GO-SHIP is an integral component of the IIOE-2 project, providing high quality, comprehensive samplingof the Indian Ocean along dedicated repeated hydrographic lines. It will provide the fourthcomprehensive high-quality survey after GEOECS, WOCE/WHP, and CLIVAR CO2/GO-SHIP from which
the anthropogenic climate change signals into the deep and intermediate ocean can be quantified.
Working with the IIOE-2, GO-SHIP suggests we define a list of ancillary measurements that can beincluded in the Indian Ocean. These ancillary measurements may include improved biological sampling
including bio-optical and water samples, and nutrients dynamics focuses on the large denitrification
signal in the Northern Indian Ocean.
Any proposed additional data collection that adds ship-time to GO-SHIP voyages should be agreed uponno later than 18 months in advance of a voyages in order to work with national funding agencies to gain
the additional ship time and/or support for the technical groups to participate on the voyage.