Findings published in Nature Geoscience also indicate a way to make more accurate predictions about future climate trends
An international team of scientists, including Minghua Zhang, Dean and Director of Stony Brook University’s School of Marine and Atmospheric Sciences (SoMAS), has found that man-made aerosol emissions from industrial processes have changed the relationship between temperature and precipitation in the northing tropics. The findings, published early online in Nature Geoscience, may help to indicate the shifts in seasonal rainfall in Central America, which is critical for agriculture in the region.
Professor Minghua Zhang, right, and graduate student Tingyin Xiao, discovered that industrial emissions of aerosols over the last 100 years dramatically changed the atmospheric asymmetry between the North Atlantic and South Atlantic and thus the relationship between temperature and precipitation in the northern tropics.
The team reconstructed rainfall patterns and temperature over 450 years by analyzing the chemical composition of a stalagmite recovered from a cave in Belize in Central America. Stalagmite in the cave was formed through deposition of calcium carbonate and other minerals, which precipitated from mineralized water solutions. These water solutions contain oxygen and carbon.
The team used the oxygen and carbon isotopic ratios from each layer of stalagmite deposits to recover the cumulative signals of climatic and hydrogeological variations over the past 450 years that include rainfall and temperature. Because of the unique seasonal variation of precipitation in Belize, the researchers were able to accurately date the layers of deposits.
Professor Zhang and Tingyin Xiao, a Stony Brook SoMAS graduate student, conducted research that found out-of-phase relationships between temperature and rainfall within the last 100 years in the northern tropics that is contrary to how the atmospheric dynamical system is expected to work.
The stalagmite analysis indicated a shift in the relationship between temperature and rainfall after the industrial revolution. The team then explained that aerosols from industrial emissions have changed the hemispheric contrast of radiative energy between the northern tropics and southern tropics that shifted the relationship between temperature and rainfall.
“We found an unexpected relationship between temperature and rainfall in the northern tropics with a systemic trend of decreasing rainfall,” said Professor Zhang. “This corroborated with what the entire research team found over a much longer period of time based on the cave data.”
Lead author, Dr. Harriet Ridley, from the Department of Earth Sciences at Durham University in the United Kingdom, which led the study, added “The research presents strong evidence that industrial sulphate emissions have shifted this important rainfall belt, particularly over the last 100 years.”
In the paper, titled “Aerosol forcing of the position of the intertropical convergence zone since AD 1550,” the researchers also identified a substantial drying trend from 1850 onwards, coinciding with a steady rise in sulphate aerosols building in the atmosphere as a result of burning fossil fuels during the European and American Industrial Revolution.
Professor Zhang explained that sulphate aerosols from emissions moderated temperatures in the Northern Hemisphere by reflecting the Sun’s radiation. This resulted in the Intertropical Convergence Zone – a tropical rainfall belt near the equator – to be shifted toward the warmer Southern Hemisphere, which leads to drier conditions in the northern tropics.
The international research team included scientists from Durham University, Stony Brook University, the University of New Mexico, Pennsylvania State University, Northern Arizona University, ETH Zurich, and the Potsdam Institute for Climate Impact Research.
The work was funded in part by the National Science Foundation.
Manager of Media Relations, School of Medicine
Gregory Filiano | newswise
Abrupt cloud clearing events over southeast Atlantic Ocean are new piece in climate puzzle
23.07.2018 | University of Kansas
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
23.07.2018 | Science Education
23.07.2018 | Health and Medicine
23.07.2018 | Life Sciences