Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Indian Ocean Sea Level Rise Threatens Coastal Areas

16.07.2010
Indian Ocean sea levels are rising unevenly and threatening residents in some densely populated coastal areas and islands, a new study concludes. The study, led by scientists at the University of Colorado at Boulder (CU) and the National Center for Atmospheric Research (NCAR), finds that the sea level rise is at least partly a result of climate change.

Sea level rise is particularly high along the coastlines of the Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra and Java, the authors found. The rise-which may aggravate monsoon flooding in Bangladesh and India-could have future impacts on both regional and global climate.

The key player in the process is the Indo-Pacific warm pool, an enormous, bathtub-shaped area spanning a region of the tropical oceans from the east coast of Africa to the International Date Line in the Pacific. The warm pool has heated by about 1 degree Fahrenheit, or 0.5 degrees Celsius, in the past 50 years, primarily because of human-generated emissions in greenhouses gases.

"Our results from this study imply that if future anthropogenic warming effects in the Indo-Pacific warm pool dominate natural variability, mid-ocean islands such as the Mascarenhas Archipelago, coasts of Indonesia, Sumatra, and the north Indian Ocean may experience significantly more sea level rise than the global average," says lead author Weiqing Han of CU's atmospheric and oceanic sciences department.

While a number of areas in the Indian Ocean region are experiencing sea level rise, sea level is lowering in other areas. The study indicated that the Seychelles Islands and Zanzibar off Tanzania's coast show the largest sea level drop.

"Global sea level patterns are not geographically uniform," says NCAR scientist Gerald Meehl, a co-author. "Sea level rise in some areas correlates with sea level fall in other areas."

The new study was published this week in Nature Geoscience. Funding came from the National Science Foundation, NCAR's sponsor, as well as the Department of Energy (DOE) and NASA.

Wind and sea level

The patterns of sea level change are driven by the combined enhancement of two primary atmospheric wind patterns known as the Hadley circulation and the Walker circulation. The Hadley circulation in the Indian Ocean is dominated by air currents rising above strongly heated tropical waters near the equator and flowing poleward at upper levels, then sinking to the ocean in the subtropics and causing surface air to flow back toward the equator.

The Indian Ocean's Walker circulation causes air to rise and flow westward at upper levels, sink to the surface and then flow eastward back toward the Indo-Pacific warm pool.

"The combined enhancement of the Hadley and Walker circulation forms a distinct surface wind pattern that drives specific sea level patterns," Han says.

In the Nature Geoscience article, the authors write, "Our new results show that human-caused changes of atmospheric and oceanic circulation over the Indian Ocean region-which have not been studied previously-are the major cause for the regional variability of sea level change."

The new study indicates that in order to anticipate global sea level change, researchers also need to know the specifics of regional sea level changes.

"It is important for us to understand the regional changes of the sea level, which will have effects on coastal and island regions," says NCAR scientist Aixue Hu.

The research team used several sophisticated ocean and climate models for the study, including the Parallel Ocean Program-the ocean component of the widely used Community Climate System Model, which is supported by NCAR and DOE. In addition, the team used a wind driven, linear ocean model for the study.

The complex circulation patterns in the Indian Ocean may also affect precipitation by forcing even more atmospheric air than normal down to the surface in Indian Ocean subtropical regions, Han speculates.

"This may favor a weakening of atmospheric convection in subtropics, which may increase rainfall in the eastern tropical regions of the Indian Ocean and drought in the western equatorial Indian Ocean region, including east Africa," Han says.

The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under sponsorship by the National Science Foundation. Any opinions, findings and conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

About the article:

Title:
Indian Ocean Sea Level Change in a Warming Climate
Authors:
Weiqing Han, Gerald Meehl, Balaji Rajagopalan, John Fasullo, Aixue Hu, Jialin Lin, William Large, Jih-wang Wang, Xiao-Wei Quan, Laurie Trenary, Alan Wallcraft, Toshiaki Shinoda, and Stephen Yeager
Publication:
Nature Geoscience, July 11, 2010

David Hosansky | Newswise Science News
Further information:
http://www.ucar.edu

More articles from Earth Sciences:

nachricht PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target
22.05.2018 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

nachricht Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Designer cells: artificial enzyme can activate a gene switch

22.05.2018 | Life Sciences

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>