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:3/23/2017)... , Mar. 23, 2017 Research and ... System Market Analysis & Trends - Industry Forecast to 2025" ... ... grow at a CAGR of around 8.8% over the next decade ... industry report analyzes the market estimates and forecasts for all the ...
(Date:3/20/2017)... , March 20, 2017 At this year,s CeBIT ... -based biometrics manufacturer DERMALOG. The Chancellor came to the DERMALOG stand together ... is this year,s CeBIT partner country. At the largest German biometrics company ... use: fingerprint, face and iris recognition as well as DERMALOG´s multi-biometrics system.   ... ...
(Date:3/9/2017)... , Australia , March 9, 2017 ... data at the prestigious World Lung Imaging Workshop at ... Andreas Fouras , was invited to deliver the latest ... medicine. This globally recognised event brings together leaders at ... the latest developments in lung imaging. ...
Breaking Biology News(10 mins):
(Date:4/27/2017)... ... April 27, 2017 , ... ... comprehensive rebrand and a name change to Fluence Analytics. , Fluence ... monitoring of polymer and biopharmaceutical manufacturing processes and R&D applications. The company’s ...
(Date:4/26/2017)... ... April 26, 2017 , ... Looking for gift ideas ... events company, offers one-of-a-kind gifts, ranging from gourmet cooking experiences to Farmer’s Market ... guests leave inspired with new cooking tips and techniques, thanks to Chef Jodi ...
(Date:4/26/2017)... Kong (PRWEB) , ... April 26, 2017 , ... ... hosted in EMEA and North America this May on ... May 16-18 , Donald H. Taylor, Chairman of the Learning and Performance Institute ...
(Date:4/25/2017)... , ... April 25, 2017 , ... ... Healthcare, is pleased to announce the company is now a certified iMedNet eClinical ... iMedNet software certification enables the company’s clinical research team to build, customize and ...
Breaking Biology Technology: