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NIWA, NOAA and the RV Tangaroa

NIWA and NOAA are research organisations that are working together on the Argo Float programme.

The National Institute of Water and Atmospheric Research or NIWA, is a Crown Research Institute owned by the people of New Zealand. NIWA specialises in environmental research. It does work on seafood, oil and gas, weather forecasting, climate studies, farming, Antarctica and ocean studies.

NIWA's mission is to conduct leading environmental science to enable the sustainable management of natural resources for New Zealand and the planet. 

The National Oceanic and Atmospheric Administration or NOAA is an American research organisation. It does research into the condition of the oceans and the atmosphere. NOAA's mission is about Science, Service, and Stewardship. NOAA wants to 

  1. understand and predict changes in climate, weather, oceans, and coasts, 
  2. share that knowledge and information with others, and 
  3. conserve and manage coastal and marine ecosystems and resources.

NIWA and NOAA scientists will join Australian scientists from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) on this voyage.

RV Tangaroa

RV stands for ‘Research Vessel’. The RV Tangaroa is a deepwater, ice strengthened research ship owned by NIWA.

Some interesting facts about the RV Tangaroa:

  • weighs 2291 tonnes (fully laden)
  • is 70m long
  • can cruise at 10.5 knots (20kph)
  • carries 40 cubic metres of freshwater (40,000 litres)
  • carries 620 cubic metres of fuel (620,000 litres)
  • can remain at sea for 60 days
  • can stay stationary over a point on the sea bed (Dynamic Positioning (DP) system)
  • has a cell phone number
  • can trawl to a depth of 4,000m
  • can winch 23 tonnes from a depth of 10,000m
  • has five laboratories
  • has three lounges with television
  • has a gym and sauna

You can follow the Tangaroa’s position here at any time

Deploying Argo Floats

During this LEARNZ field trip you will take part in the deployment of six regular Argo Floats and several Deep Argo Floats from the ship Tangaroa into the Pacific Ocean, East of the Kermadec Ridge (see Google Earth map on this page). Argo Floats are placed in the ocean at a precise location. On this voyage the location will be 177°W, 36°S.

Some Floats are deployed in cardboard boxes to help protect them as they enter the water. 

Sometimes Argo Floats are deployed in cardboard boxes to help protect them when they enter the water

Calibrating an Argo Float

To make sure Argo Floats collect and send accurate data, scientists on this voyage will take their own measurements of temperature and salinity and compare them with the data sent from the Argo Float. To take their own measurements, scientists will lower a special instrument called a CTD from the ship on a long cable to collect temperature and salinity data. 

Why is the instrument called a CTD?

  • C = conductivity (salinity is measured by electrical conductivity: better conductivity = higher salinity)
  • T = temperature
  • D = depth (depth is measured by the water pressure: higher pressure = deeper water)

 

  • Deploying the CTD instrument used to help calibrate Argo Floats

Each of the sampling bottles opens and closes at specified depths to collect a small sample of sea water. The samples are analysed later for salinity and other measurements. The logger at the bottom of the carousel (the round frame) contains sensors that collect salinity and temperature data at different depths.

The accurate CTD data will enable the Argo Floats to be 'calibrated'.

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RV Tangaroa. Photo Dave Allen

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The voyage will cover 1,000 nautical miles and deploy a prototype Argo Float which will descend to 5,500m.

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The CTD is an instrument lowered off a ship by cable and measures salinity, temperature and depth

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An Argo Float ready for deployment. Can you see the antenna used to transmit data to satellites?

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A diagram of the CTD instrument showing 12 sampling bottles and underneath the device that captures the data (logger)

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RV Tangaroa . New Zealand’s only deepwater research vessel, with a dynamic positioning system and an ice-strengthened hull.  It is 70m long and well-equipped for a wide range of environmental survey and ocean science work. Image source

Next step learning: you are the Captain of the RV Tangaroa.  Write a letter welcoming the NIWA and NOAA staff on board and explain to them what the purpose of this Argo Float voyage is. You might like to invite them to join you on the bridge for a cup of tea after the ship has set sail!

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