Navigation Links
Evidence of past Southern hemisphere rainfall cycles related to Antarctic temperatures
Date:1/17/2012

AMHERST, Mass. Geoscientists at the University of Massachusetts Amherst and the University of Minnesota this week published the first evidence that warm-cold climate oscillations well known in the Northern Hemisphere over the most recent glacial period also appear as tropical rainfall variations in the Amazon Basin of South America. It is the first clear expression of these cycles in the Southern Hemisphere.

The work by Stephen Burns and his doctoral student Lisa Kanner at UMass Amherst is reported in the current issue of ScienceXpress. Burns says, "The study also demonstrates that rainfall in the Southern Hemisphere of South America is, though to a lesser extent, also influenced by temperature changes in the Antarctic, which has not been previously observed."

The last glacial period, from about 10,000 to about 120,000 years ago, saw North America and Western Europe covered in a thick continental ice sheet, the geoscientist points out. Yet climate was also highly unstable during the period, cycling every few thousand years between warm and cold, dry periods in the high northern latitudes. Temperatures could change by as much as 10 to 15 degrees Celsius.

Known as Dansgaard/Oeschger (D/O) cycles, these millennial-scale rapid climate events were first recognized in the Greenland ice cores, but have since been found throughout the Northern Hemisphere, Burns points out.

The UMass Amherst climate researcher is an expert in reading past climate data from the ratio of oxygen isotopes found in calcite in speleothems, another name for stalagmites, stalactites and other water-deposited cave features. Analyzing radioactive isotopes and stable oxygen isotopes in the calcite sampled from ancient cave formations can provide information on past rainfall over many thousands of years, Burns says.

He and Kanner used oxygen isotopic analyses from a 16-centimeter (about 6.3 inches) stalagmite recovered from a cave 2.4 miles (3,800 meters) above sea level in the Peruvian Andes for this study. The sample grew from 49,500 to 16,000 years ago, providing a 34,000-year-long record of rainfall changes in the Amazon Basin. Kanner and colleagues found that cold periods in the high Northern latitudes are associated with an increase in precipitation, the South American Summer Monsoon, in the Amazon Basin.

They found that cold periods in the Northern Hemisphere are associated with an increase in precipitation, the South American Summer Monsoon, in the Amazon Basin.

"This relationship is the exact opposite of changes in rainfall in the Northern Hemisphere tropics, where cold intervals result in a decrease in rainfall," Burns says.

Revised chronology for several major climate events that took place in the last glacial period proposed in this study could lead to a better understanding of Antarctic warming during the same period and its relationship to warming the subtropical North Atlantic, the authors state.


'/>"/>

Contact: Janet Lathrop
jlathrop@admin.umass.edu
413-545-0444
University of Massachusetts at Amherst
Source:Eurekalert  

Related biology news :

1. Genetic evidence for avian influenza movement from Asia to North America via wild birds
2. Mounting evidence shows health benefits of grape polyphenols
3. New evidence that people make aspirins active principle -- salicylic acid
4. Evidence of the Lost World -- did dinosaurs survive the end Cretaceous extinctions?
5. University of Leicester archaeologist uncovers evidence of ancient chemical warfare
6. New study provides further evidence that apple juice can delay onset of Alzheimers disease
7. New lab evidence suggests preventive effect of herbal supplement in prostate cancer
8. DNA evidence is in, newly discovered species of fish dubbed H. psychedelica
9. Polar research reveals new evidence of global environmental change
10. Evidence of earliest known domestic horses found in Kazakhstan
11. Researchers find the earliest evidence of domesticated maize
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Evidence of past Southern hemisphere rainfall cycles related to Antarctic temperatures
(Date:6/22/2016)... 22, 2016   Acuant , the ... solutions, has partnered with RightCrowd ® ... Visitor Management, Self-Service Kiosks and Continuous Workforce ... add functional enhancements to existing physical access ... venues with an automated ID verification and ...
(Date:6/16/2016)... 16, 2016 The global ... to reach USD 1.83 billion by 2024, according ... Inc. Technological proliferation and increasing demand in commercial ... to drive the market growth.      ... The development of advanced multimodal techniques for biometric ...
(Date:6/7/2016)...  Syngrafii Inc. and San Antonio Credit Union ... integrating Syngrafii,s patented LongPen™ eSignature "Wet" solution into ... result in greater convenience for SACU members and ... existing document workflow and compliance requirements. ... Highlights: ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... CAMBRIDGE, Mass. , June 23, 2016 /PRNewswire/ ... the development of novel compounds designed to target ... compound, napabucasin, has been granted Orphan Drug Designation ... in the treatment of gastric cancer, including gastroesophageal ... cancer stemness inhibitor designed to inhibit cancer stemness ...
(Date:6/23/2016)... , June 23, 2016  The Prostate Cancer Foundation (PCF) ... precise treatments and faster cures for prostate cancer. Members of the Class of ... 15 countries. Read More About the Class of 2016 ... ... ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... In a ... Hospital in Denmark detail how a patient who developed lymphedema after being treated for ... The results could change the paradigm for dealing with this debilitating, frequent side effect ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the ... Convention Center and will showcase its product’s latest features from June 26 to ... a scientific poster on Disrupting Clinical Trials in The Cloud during the conference. ...
Breaking Biology Technology: