Argo world 


News Archive
September 17, 2018 Message to Argo users about an increased occurrence of salinity erros in the real time Argo data stream
August 10, 2018 China Argo will host the AST-20 meeting in Hangzhou, China
on 11 - 15 March, 2019
August 9, 2018 Abstract deadline moved to 27 August, 2018 and registration deadline moved to 30 September, 2018 for the 6th Argo Science Workshop hosted by JAMSTEC and the Japanese Argo Promotion Committee in Tokyo, Japan on October 22-24, 2018.
August 8, 2018 Argo bibliography, Argo in press and Argo thesis list updated.
Inform argo@ucsd.edu of changes.
July 17, 2018 Notice of an error in pressure calibration of SBE Argo CTDs manufactured between September 2015 and June 2018
June 29, 2018 Argo will stop sending TESAC messages on the GTS on 2 July, 2018
Thereafter, only BUFR messages will be sent on the GTS
June 26, 2018 Argo GitHub repository set up with the first contribution: updated Matlab OW software
June 26, 2018 AST-19 meeting report published
April 16, 2018 Scripps Institution of Oceanography will host the ADMT-19 meeting
on 2 - 7 December, 2018
April 11, 2018 In Loving Memory of Steve Piotrowicz
April 3, 2018 Remembering Steve Piotrowicz
January 17, 2018 Dean Roemmich to receive the 2018 Alexander Agassiz Medal of the National Academy of Sciences
January 9, 2018 Announcement for 6th DMQC Workshop to be held in conjunction with ADMT-19 later this year

What is Argo?

Argo is a global array of 3,800 free-drifting profiling floats that measures thetemperature and salinity of the upper 2000 m of the ocean.  This allows, for the first time, continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection.

Positions of the floats that have delivered data within the last 30 days :

Maps displaying statistics about the Argo array, including its extensions into high latitudes and marginal seas, bio-geochemical sensors, communication systems, float type, etc., can be found in the map section on the Argo Information Centre website.

Why do we need Argo?

We are increasingly concerned about global change and its regional impacts. Sea level is rising at an accelerating rate of 3 mm/year, Arctic sea ice cover is shrinking and high latitude areas are warming rapidly. Extreme weather events cause loss of life and enormous burdens on the insurance industry. Globally, 8 of the 10 warmest years since 1860, when instrumental records began, were in the past decade.

These effects are caused by a mixture of long-term climate change and natural variability. Their impacts are in some cases beneficial (lengthened growing seasons, opening of Arctic shipping routes) and in others adverse (increased coastal flooding, severe droughts, more extreme and frequent heat waves and weather events such as severe tropical cyclones).

Understanding (and eventually predicting) changes in both the atmosphere and ocean are needed to guide international actions, to optimize governments' policies and to shape industrial strategies. To make those predictions we need improved models of climate and of the entire earth system (including socio-economic factors).

Lack of sustained observations of the atmosphere, oceans and land have hindered the development and validation of climate models. An example comes from a recent analysis which concluded that the currents transporting heat northwards in the Atlantic and influencing western European climate had weakened by 30% in the past decade. This result had to be based on just five research measurements spread over 40 years. Was this change part of a trend that might lead to a major change in the Atlantic circulation, or due to natural variability that will reverse in the future, or is it an artifact of the limited observations?

In 1999, to combat this lack of data, an innovative step was taken by scientists to greatly improve the collection of observations inside the ocean through increased sampling of old and new quantities and increased coverage in terms of time and area.

That step was Argo.

Argo animationargo.avi is a float animation that explains the purpose and method of Argo.


Where is Argo now?

Argo deployments began in 2000, and by November 2007, the millionth profile was collected. Today, even with close to 4000 active floats, there are still some areas of the ocean that are over-populated while others have gaps that need to be filled with additional floats. Today's tally of floats is shown in the figure above and additional float statistics can be found here. To maintain the Argo array, national programs need to provide about 800 floats per year.

The original global Argo array was designed for the open ocean excluding seasonal sea-ice zones and marginal seas. Thanks to both two-way communication and ice-sensing algorithms on floats, these technical limitations are largely mitigated. The concept of Argo has always been of a spatially complete global array. Therefore, including seasonal sea-ice zones and marginal seas moves the target number of Argo floats from 3000 to 3800.

In addition to the globalization of core Argo described above, there are several Argo enhancements that are in various stages of development and implementation. These include extended coverage to the ocean bottom, additional floats equipped with bio-geochemical sesnors, and enhanced spatial coverage in boundary current regions and equatorial regions.

Besides float deployment, Argo has worked hard to develop two separate data streams: real time and delayed mode. A real time data delivery and quality control system has been established that delivers 90% of profiles to users via two global data centers (GDACs) within 24 hours. A delayed mode quality control system (DMQC) has been established and 65% of all eligible profiles have had DMQC applied.

Float reliability has improved almost every year and the float lifetime has been extended. Argo has developed a large user community in universities, government labs and meteorological/climate analysis/forecasting centers. The need for global Argo observations will continue indefinitely into the future, though the technologies and design of the array will evolve as better instruments are built, models are improved, and more is learned about ocean variability.

Who Collaborates with Argo?

Argo is a major contributor to the WCRP 's Climate Variability and Predictability Experiment (CLIVAR) project and to the Global Ocean Data Assimilation Experiment (GODAE). The Argo array is part of the Global Climate Observing System/Global Ocean Observing System OceanView GCOS /GOOS).