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Climate: Indian Ocean temps drive East African droughts

Study may unlocks new climate clues

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Wet conditions in coastal East Africa are associated with cool sea surface temperatures in the eastern Indian Ocean and warm sea surface temperatures in the western Indian Ocean, which cause ascending atmospheric circulation over East Africa and enhanced rainfall. (Courtesy Jessica Tierney, et al, 2013)

By Summit Voice

FRISCO — A new study may help forecast drought conditions in the oft famine-stricken and geopolitically crucial Horn of Africa. More than 40 million people in the region often live in exceptional drought conditions, most recently in 2010-2011, when the worst drought in decades triggered a humanitarian crisis.

It’s long been clear that El Niño can affect precipitation in the region, very little is known about the drivers of long-term shifts in rainfall. But the study suggests that temperatures in the Indian Ocean may be the key to understanding precipitation patterns in East Africa.

“The problem is, instrumental records of temperature and rainfall, especially in East Africa, don’t go far enough in time to study climate variability over decades or more, since they are generally limited to the 20th century,” said Woods Hole Oceanographic Institution geologist Jessica Tierney, lead author of the paper published in the journal Nature. Continue reading

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Global warming could dry up Asian monsoon

A NASA map shows patterns of monsoon rain distribution.

Study shows how warming temps will displace critical high pressure systems

By Summit Voice

Global warming could cause frequent and severe failures of the Indian summer monsoon in the next two centuries, according to researchers with the Potsdam Institute for Climate Impact Research and Potsdam University.

The effects of these unprecedented changes would be extremely detrimental to India’s economy which relies heavily on the monsoon season to bring fresh water to the farmlands.

“Our study points to the possibility of even more severe changes to monsoon rainfall caused by climatic shifts that may take place later this century and beyond.,” said lead author Jacob Schewe. Continue reading

Whale culture: Singing a different tune

Study sheds light on Indian Ocean humpback whales

Humpback whales are slowly recovering from near extinction and new research on Indian Ocean populations may help inform conservation efforts. PHOTO COURTESY NOAA.

By Summit Voice

SUMMIT COUNTY —Humpback whales on opposite sides of the Indian Ocean are singing different songs, a team of marine biologists say, explaining that that their findings are unusual because humpbacks in the same ocean usually all sing very similar tunes.

The differences in song between the Indian Ocean humpback populations most likely indicate a limited exchange between the two regions and may shed new light on how whale culture spreads. Continue reading

Global warming forces elephant seals to dive deeper

Elephant seal. PHOTO COURTESY NOAA.

Southern ocean study offers detailed data on foraging patterns

By Summit Voice

SUMMIT COUNTY —The deep-diving elephant seals of Marion Island, in the southwestern Indian Ocean, are going to even greater depths to find prey like squid, as global warming heats up the water.

Scientists with the Alfred Wegener Institute for Polar and Marine Research who have been tracking the pinnipeds for the past few years say that warming in the upper levels of the ocean has pushed prey to greater depths than ever before, forcing the elephant seals to follow. Continue reading

Indian Ocean study key to understanding global weather

A NOAA graph shows how cyclical pulses of atmospheric energy from the Indian Ocean influence the formation of the Pineapple Express weather pattern that can slam the West Coast with intense precipitation.

Pulses of energy from the Madden-Julian oscillation in the Indian Ocean thought to influence weather worldwide

By Summit Voice

SUMMIT COUNTY — A team of international researchers is heading to the Indian Ocean to learn more about the genesis of the Madden-Julian oscillation, a cyclical climate phenomenon believed to be the greatest driver of atmospheric variability in the one- to three-month time frame, linking weather and climate.

The pulses of atmospheric energy that move around the globe from the Indian Ocean are believed to be linked with the famed Pineapple Express weather events that bring tremendous amounts of precipitation to the western U.S.. They also  influence the formation of hurricanes, and even the intensity of Colorado’s summer monsoon.

Understanding the origins of the oscillation could help forecasters pinpoint when major winter storms will hit the U.S.
Using aircraft, ships, moorings, radars, numerical models and other tools the six-month mission will study how tropical weather brews in the region and then moves eastward along the equator, with reverberating effects around the globe. Continue reading

South Atlantic current a big player in global climate

Warm, salty water from the south could balance impacts of melting polar ice cap

Agulhas Current system and its "leakage" into the Atlantic Ocean, affecting climate. Credit: Erik van Sebille, RSMAS.

By Summit Voice

SUMMIT COUNTY — Leakage from an ocean current running along the east coast of Africa could ameliorate some anticipated global warming impacts in the northern hemisphere, according to University of Miami researchers, who recently published a study in the journal nature suggesting that the Agulhas Current could be a significant player in global climate variability.

The Agulhas Current transports warm and salty waters from the tropical Indian Ocean to the southern tip of Africa. There most of the water loops around to remain in the Indian Ocean (the Agulhas Retroflection), while some water leaks into the fresher Atlantic Ocean via giant Agulhas rings.

Once in the Atlantic, the salty Agulhas leakage waters eventually flow into the Northern Hemisphere and act to strengthen the Atlantic overturning circulation by enhancing deep-water formation. Recent research points to an increase in Agulhas leakage over the last few decades, caused primarily by human-induced climate change. Continue reading

Monitoring network boosts Indonesian tsunami warnings

A graphic depiction of the 2004 tsunami.

Short lead time for near-shore quakes still poses a challenge for residents

By Summit Voice

SUMMIT COUNTY — Six years ago, when the Sumatra-Andaman earthquake caused a devastating tsunami to sweep through the Indian Ocean, I was sitting on a beach in Mexico. I didn’t want to believe that another coastal area halfway around the world was being washed away by an almost unimaginable force of nature. It didn’t seem right be enjoying tropical drinks and kayaking on a gentle swell while thousands of people were dying on the other side of the ocean. For the next few days, I kept one uneasy eye on the sea while scouting the nearby hills for a quick route to higher ground.

Since then, scientists have been working on improving early warning systems for similar situations, and this week, a German research institute announced that a new early warming system for the Indian Ocean has been completed.

“The innovative technical approach of the German-Indonesian Tsunami Early Warning System is based on a combination of different sensors, whose central element is a fast and precise detection and analysis of earthquakes, supported by GPS measurements,” said Professor Reinhard Hüttl, Scientific Director of the GFZ German Research Centre for Geosciences in Potsdam. “The GFZ-developed evaluation of Seismology via the SeisComP3 system proved to be so fast and reliable that it has now been installed in over 40 countries,” Hüttl said. Continue reading

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