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 New plate adds plot twist to ancient tectonic tale
15.08.2017 | Rice University

nachricht Global warming will leave different fingerprints on global subtropical anticyclones
14.08.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>