The U.S. National Science Foundation (NSF) announced that it is funding a study with the goal of building a multi-decadal time series of Agulhas Current volume transport, which will contribute to the Global Ocean Observing System.
Led by Principal Investigator, Lisa Beal, Ph.D. of the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, the international team will include scientists from the National Oceanography Centre (Southampton, United Kingdom) and the University of Cape Town (Cape Town, South Africa).
The Agulhas Current is the “Gulf Stream” of the southern Indian Ocean, carrying warm and salty tropical waters southward along the east coast of Africa as a narrow, fast jet. At the tip of Africa the Agulhas retroflects, looping around to eventually flow eastward toward Australia. This retroflection is unstable and regularly sheds large Agulhas Rings, which carry Indian Ocean waters into the South Atlantic.
“We anticipate this study will shed light on the seasonal to decadal variability of the Agulhas,“ said Beal. “Locally, the warm waters of the Agulhas effect African rainfall rates, and globally, there is paleo-oceanographic evidence suggesting that changes in the amount of Agulhas water reaching the Atlantic may have triggered the end of the last ice age.” In addition, Beal believes there may be other, so far unstudied climatic impacts such as heat transport into the Southern Ocean via the unstable retroflection.
The Agulhas Current Time-series (ACT) project will be conducted in two phases. The first requires the deployment of an array of instruments across the Agulhas Current and along an altimeter ground track, to obtain a three-year series of transport data. Using the in situ measurements gathered, the team will embark on the second phase, to correlate the along-track satellite altimeter data with measured transports to produce a proxy for Agulhas Current transport, which can be extended forwards and backwards in time.
The ACT mooring array will be positioned offshore and to the southwest of East London, South Africa, in up to 4700 m of water. The array will consist of seven full-depth current meter moorings, spanning the mean width of the Agulhas Current, one tide gauge, plus four pressure gauge-equipped inverted echo-sounders (C-PIES) to cover the Current’s offshore meandering events cost-effectively.
On each full-depth mooring upward-looking profiling current meters will measure the top 350 m of the water column, where velocities are strongest. Below these, up to six single-point current meters will measure the rest of the water column. All current meters are acoustic, with no moving parts, measuring velocity using the principle of Doppler shift, whereby the frequency of a sound wave changes as it reflects off a moving particle in the ocean.
Offshore recirculations and meandering events will be captured using the C-PIES, which can give information about the transport over the upper 2000 m, when combined with local hydrographic data collected during each mooring cruise. The shallow-water tide gauge will be placed on the continental shelf, allowing for an hourly record of sea surface height shoreward of the Agulhas Current.
The initial deployment cruise is scheduled to leave Cape Town, South Africa, in March 2010, aboard a U.S. University-National Oceanographic Laboratory System (UNOLS) research vessel. The ACT array will be in the water until approximately March 2013.
“Ultimately, a twenty year proxy of Agulhas Current transport will provide an important climate index for the Indian Ocean, which can be linked to other climate indices, such as the Atlantic Meridional Overturning, and hopefully improve our predictive capabilities for the future,” Beal added.
The University of Miami is the largest private research institution in the southeastern United States. The University’s mission is to provide quality education, attract and retain outstanding students, support the faculty and their research, and build an endowment for University initiatives.
Founded in the 1940’s, the Rosenstiel School of Marine & Atmospheric Science has grown into one of the world's premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life.Barbra Gonzalez
Further reports about: > ACT > Agulhas Current > Agulhas Current transport > Atmospheric > Beal > C-PIES > Cape Verde Islands > Global Ocean Observing System > Gulf Stream > Indian Ocean > Marine science > NSF > Pacific Ocean > Science TV > atmospheric science > in situ measurements > last Ice Age > paleo-oceanographic evidence
Novel method for investigating pore geometry in rocks
18.06.2018 | Kyushu University, I2CNER
Decades of satellite monitoring reveal Antarctic ice loss
14.06.2018 | University of Maryland
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
20.06.2018 | Materials Sciences
20.06.2018 | Materials Sciences
20.06.2018 | Materials Sciences