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Climate scientists study equatorial storms between Indian and Pacific Oceans

Scientists hope to better understand how tropical weather develops, affects global climate

September 30, 2011 Share This!

  • A sunny day on Gan Island, home of the 2011 AMIE-Gan field campaign. Photo courtesy of Chuck Long.

  • A rocky beach on Gan Island will host the X-Ka band scanning ARM cloud radar during AMIE-Gan. Photo courtesy of Chuck Long

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ADDU ATOLL, Republic of Maldives – Scientists from two dozen research organizations have gathered here to study Indian Ocean weather for six months. Representing 16 countries, the international team will be using airplanes, ships, radars, and almost 1,500 weather balloons to study how tropical storms brew, move and die along the equator, events that affect weather worldwide.

Stretching from the Maldives to Papua New Guinea, the field campaign will help improve long-range weather forecasts and seasonal outlooks and help scientists refine computer climate models. The campaign will run Oct. 1, 2011 through March 31, 2012 and opening ceremonies on Oct. 8 will celebrate the international cooperation that will lead to a better understanding of Earth's climate.

"It's truly amazing that we've been able to bring all these resources to this area," said Chuck Long of the Department of Energy's Pacific Northwest National Laboratory. Long leads the AMIE team, one of three groups studying a weather disturbance known as the Madden-Julian Oscillation, or MJO.

The MJO initiates every 30 to 90 days and affects regional weather phenomenon such as the Asian and Australian monsoons. Farther away, it can enhance hurricane activity in the northeast Pacific and Gulf of Mexico, trigger torrential rainfall at the west coast of North America. It can also affect the onset of El Niño, the periodic warming of the Pacific Ocean that causes havoc with rain patterns.

AMIE, using mobile laboratories from the Department of Energy, has set up radars and other instruments along an eight kilometer path on the Atoll. AMIE will take data continuously in the Maldives and on Manus Island in Papua New Guinea for the six-month period. The data will provide clues to the MJO's entire life cycle.

"The MJO fires up primarily in the Indian Ocean during winter in the northern hemisphere, covering an area several thousand kilometers across. It moves eastward and when it hits the maritime continent -- all those islands in Southeast Asia, it weakens. Why?" asked Long. "And why does it initiate in the Indian, not in the equatorial Atlantic or Pacific? What is so special about the conditions in the Indian Ocean? These are some of the questions we must answer to understand the MJO and represent it in forecast and climate models."

AMIE will be working with two other research collaborations during this Indian Ocean campaign, DYNAMO and CINDY. DYNAMO's team is being led by the University of Miami. CINDY is an overarching international effort and is being led by the Japan Agency for Marine-Earth Science and Technology.

"The Madden-Julian Oscillation has a huge impact all over the globe," said UM's Chidong Zhang, DYNAMO's chief scientist. "It connects weather and climate, and it is important to their forecast."

DYNAMO will provide intense scrutiny of the developing MJO, with two aircraft and three ships off the southern tip of India. The National Center for Atmospheric Research is providing major observing facilities to the science team and helping to oversee operations and data management for the project.

At the campaign Super Site on Gan Island, a meteorological radar array with seven different frequencies will be used to scan clouds, precipitation, and water vapor as the MJO moves through the region. The array's range of frequencies will allow the team to gather information on microscopic physical properties of clouds all the way up to full-size rain drops and ice crystals.

 "Observing the start of an MJO with this incredible array of remote sensing instruments will help us answer questions about how the MJO develops," said PNNL atmospheric scientist Sally McFarlane, a member of the AMIE steering committee. "Previous studies weren't able to observe the details of the non-raining clouds and how they move water vapor from the ocean's surface to the middle atmosphere, which we think plays an important role in the development of the MJO but isn't captured well in climate models."

AMIE and DYNAMO are jointly supported by several United States agencies including the Department of Energy's Office of Science, National Science Foundation, Office of Naval Research, National Oceanic and Atmospheric Administration, and National Aeronautics and Space Administration.

A total of 16 countries (Australia, China, France, India, Indonesia, Japan, Kenya, South Korea, Maldives, Papua New Guinea, Seychelles, Singapore, Sri Lanka, Taiwan, the United Kingdom, and the United States) are providing staff, facilities or observations to the international collaborative effort. U.S. scientists, students, engineers, and staff from 16 universities and 11 national laboratories and centers are participating in the field campaign.

The main observation sites will be based in the Maldives (with the major radar array and surface observations Super Site located on Addu Atoll's Gan Island), Diego Garcia, the maritime continent, and Manus Island, as well as aboard research ships and aircraft in the Indian Ocean.

The U.S. researchers are collaborating heavily with their Maldivian hosts. The Maldives Meteorological Service is providing local weather knowledge, meeting and operations space, and facilities; the researchers in turn will offer training on radar and other instrumentation to local meteorologists.

The expanded names of the research teams are:

AMIE — ARM MJO Investigation Experiment

DYNAMO — Dynamics of the Madden-Julian Oscillation

CINDY — Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011

Tags: Environment, Fundamental Science, Climate Science, Atmospheric Science

Interdisciplinary teams at Pacific Northwest National Laboratory address many of America's most pressing issues in energy, the environment and national security through advances in basic and applied science. Founded in 1965, PNNL employs 4,300 staff and has an annual budget of more than $1 billion. It is managed by Battelle for the U.S. Department of Energy’s Office of Science. As the single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time. For more information on PNNL, visit the PNNL News Center, or follow PNNL on Facebook, Google+, LinkedIn and Twitter.

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