Project Abstract

Importance of deep ocean observations by deep floats and Deep NINJA

The importance of deep ocean observations has been gradually recognized to understand oceanic effects on anthropogenic climate change accurately, especially the oceanic heat content and the sea level rise. To make such observations, deep floats are among the most suitable devices to observe deep ocean at reasonable cost and a monitoring network with numerous such deep floats, "Deep Argo", is urgently needed. Until recently, there were no such floats available for waters below 2,000 m in depth, but now a number of international universities, institutes, and float makers are developing such deep floats.The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and Tsurumi-Seiki Co., Ltd. (TSK) began work on the development of a deep float in 2010, and ultimately succeeded with "Deep NINJA" in April 2013 (Figure 1). Deep NINJA is capable of observing the ocean at depths up to 4,000 m globally, except for those seas that are covered by ice throughout the year. Figure 2 shows a schematic view of a Deep NINJA float in operation in the ocean alongside a normal (Argo) float.

Deep ocean observations by Deep NINJA floats operated by JAMSTEC

To date, JAMSTEC has deployed 14 Deep NINJA floats (including two prototypes) in collaboration with TSK, primarily in the Southern Ocean. As of July 25, 2014, these floats have/had continued to operate well and have observed more than 190 oceanic profiles. Notably, one Deep NINJA float (S/N 6) deployed off the Adelie Coast of Antarctica measured deep profiles under sea ice throughout an Antarctic winter and continued to observe seasonal changes of the deep/bottom waters for more than one year.This website introduces the Deep NINJA float itself (some photos at deployment, Figures 3 and 4) and provides listings of the Deep NINJA observations. These include the dates and locations of float deployments and observation parameters such as observation cycle and profile depth. Additionally, there are several figures showing observation results, such as float movement trajectories, temporal changes of temperature and salinity profiles as measured by the floats.

Figure 1:Deep NINJA

  • Specifications of Deep NINJA
  • Maximum operating depth:4,000dbar(~4,000m)
  • Size:210 cm long and 50 kg in air
  • Sensor:SBE41CP for deep float (Sea-Bird Electronics, US)
  • Transmission:Iridium, Short Burst Data Service (two-way)
  • Positioning:Global Positioning System
  • Service life:More than one year, powered by lithium batteries

Figure 2:Schematic overview of a Deep NINJA observation float in operation alongside an Argo float.
Click image to enlarge
Figure 3:Deployment of the first Deep NINJA from R/V Wakataka-maru in August 2012.
Click image to enlarge
Figure 4:Deployment of Deep NINJA off the Adelie Coast, Antarctica, from R/V Mirai in December 2012.
Click image to enlarge

©Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 2017

Inventory Data

Serial No. Date for deployment Area for deployment Position for deployment Deploy ship name / cruise Cycle Parking depth Profile depth(s) Number of profiles Status
(day) (dbar) (dbar) (that of deep profiles)
1* 2012/8/29 Subarctic, North Pacific 40° 40.00 N, 144°46.18 E Wakataka-maru WK1208 5 1000 4000 1 (1) Dead (failure at communication unit?)
2* 2012/8/29 Subarctic, North Pacific 40° 40.00 N, 144°46.18 E Wakataka-maru WK1208 10 1000 2000/4000 21 (16) Dead (Energy consumption?)
3 2012/12/19 Off the Adelie Coast, Antarctica 60° 00.62 S, 139°56.12 E Mirai MR12-05 15 2000 4000 15 (9) Dead (unknown)
4 2012/12/5 South of NZ, Southern Ocean 56° 59.87 S, 173°59.31 E Mirai MR12-05 15 2000 2000/4000 50 (25) Dead (energy consumption?)
5 2012/12/17 Off the Adelie Coast, Antarctica 62° 00.38 S, 137°00.42 E Mirai MR12-05 30 2000 4000 14 (10) Dead (accident at sea ice?)
6 2012/12/16 Off the Adelie Coast, Antarctica 62° 45.73 S, 143°36.05 E Mirai MR12-05 30 2000 4000 27 (23) Dead (accident at sea ice?)
7 2013/7/17 Subtropcal, North Pacific 30° 03.91 N, 144°58.09 E Mirai MR13-04 10 3000 4000 33 (33) Dead (energy consumption?)
8 2014/3/6 Off the Adelie Coast, Antarctica 63°40.55 S 148°35.65 E Shirase JARE55 20 3000 4000 3 (3) Dead (accident at sea ice?)
9 2014/3/7 Off the Adelie Coast, Antarctica 59° 14.34 S, 150°08.85 E Shirase JARE55 20 2500 4000 23 (23) Dead (unknown)
10 2014/1/23 Off the Budd Coast, Antarctica 62° 55.0659 S, 109°59.8474 E Umitaka-maru UM041 20 2000 4000 0 (0) Dead (unknown)
11 2014/1/19 Off the Budd Coast, Antarctica 60° 03.4988 S, 109°53.3204 E Umitaka-maru UM041 20 3500 4000 10 (10) Dead (accident at sea ice?)
12 2014/1/22 Off the Budd Coast, Antarctica 62° 00.4176 S, 110°00.1893 E Umitaka-maru UM041 20 3500 4000 5 (5) Dead (accident at sea ice?)
13 2014/1/27 Off the Budd Coast, Antarctica 64° 15.8987 S, 107°41.9985 E Umitaka-maru UM041 20 3000 4000 24 (24) Dead (accident at sea ice?)
14 2014/1/24 Off the Budd Coast, Antarctica 64° 05.3637 S, 109°51.0107 E Umitaka-maru UM041 20 3000 4000 40 (40) Dead (energy consumption?)
15 2014/12/6 Off the Budd Coast, Antarctica 59° 59.96 S, 109°51.92 E Shirase JARE56 20 3500 4000 44 (44) Dead (energy consumption?)
16 2016/1/31 Western Indian Ocean 29°59.98S 52°32.01E Hakuho-maru KH-16-1 30 2000 4000 18 (18) Dead (unknown)
17 2016/2/2 Western Indian Ocean 40°41.49S 45°54.43E Hakuho-maru KH-16-1 30 2000 4000 32 (32) Active
18 2016/3/2 Subtropical, North Pacific 29°56.31N 147°27.26E Ryofu-maru 1602 30 2000 4000 18 (18) Dead (unknown)
20 2017/2/19 South Pacific, Southern Ocean 60°58.01S 125°59.98E Mirai MR16-09 10 2000 4000 5 (5) Dead (unknown)
21 2017/7/10 North Pacific 47°0.108N 154°59.406W Hakuhomaru KH-17-3 10 2000 4000 3 (3) Dead (unknown)
22 2018/2/3 Off the Adelie Coast, Antarctica 65°0.036S 145°30.108E INVESTIGATOR 10 2000 4000 1 (1) Active
23 2017/7/23 North Pacific 47°0.012N 160°1.332E Mirai MR17-04 10 2000 4000 9 (9) Dead (unknown)
24 2018/1/29 Off the Adelie Coast, Antarctica 63°21.312S 139°49.830E INVESTIGATOR 10 2000 4000 2 (2) Active
25 2018/2/5 Off the Adelie Coast, Antarctica 63°30.156S 149°59.838E INVESTIGATOR 10 2000 4000 1 (1) Active
26 2017/12/1 North Indian Ocean 5°3.582S 95°2.712E Mirai MR17-08 10 2000 4000 8 (8) Active
*:Prototype As of Feb 13, 2018

©Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 2017

Trajectory Map

Deployment Map

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©Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 2017

Time-Depth Section

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©Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 2017

Data

Release of scientifically quality-controlled data of Deep NINJA observations

Observations using Deep NINJA floats are carried out as part of the Japan Argo Project. Herein, we provide a quality-controlled dataset of Deep NINJA observations for convenient use on scientific/educational purposes. The quality-control effort led by JAMSTEC was based primarily on comparisons with highly accurate shipboard conductivity-temperature-depth (CTD) observations conducted nearby float observations. For permission to access this data, please contact us after reviewing and confirming your acceptance of the Terms and Conditions provided below.
All raw and officially quality-controlled data of the Deep NINJA observations are expected to be made available to the public via the Argo Global Data Assembly Centers (GDACs) in the near future, probably under the same framework as International Argo. Note that the (raw) measurements of Deep NINJA still include some issues that need to be resolved and examined on their quality as follows:

  1. The Deep NINJA CTD sensor, which is the current standard model for deep floats, was developed originally for "Argo floats," which operate in water depths shallower than 2,000 m. Its performance under high pressure in deep ocean waters has not been examined sufficiently.
  2. Temperature and salinity measurements of the CTD sensor seem to have a bias that depends on pressure. JAMSTEC has found that the salinity measurements of Deep NINJA tend to be fresher at higher pressure.
  3. International Argo has no consensus related to data quality criteria for measurements at depths greater than 2,000 dbar. Thus, there are no standard of quality control for the deep observations.See also the official announcement at Argo Project Office (http://www.argo.ucsd.edu/deepArgo_data.html).

Terms and conditions

The copyrights for the quality-controlled data of Deep NINJA floats belong exclusively to JAMSTEC.

  • The usage of the data is allowed for scientific and/or educational purposes only.
  • JAMSTEC endeavors to make the data scientifically accurate, but JAMSTEC shall not be held liable for any loss, damage, and problems arising as a result of the use of the data.
  • It is forbidden to manipulate, redistribute, deliver, or sell the data to any third party.
  • The data may be changed without notice.

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