Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists look at moon to shed light on Earth’s climate

28.05.2004


According to a new NASA-funded study, insights into Earth’s climate may come from an unlikely place: the moon.


Researchers Look at Moon for Climate Answers
This composite image of the dark side’s Earthshine (left of image) and bright side’s Moonshine (right of image) illustrates what scientists are looking at. Researchers used a blocking filter to dim the Moonshine crescent, typically about 10,000 times brighter than Earthshine.
Credit: BBSO/NJIT



Scientists looked at the ghostly glow of light reflected from Earth onto the moon’s dark side. During the 1980s and 1990s, Earth bounced less sunlight out to space. The trend reversed during the past three years, as the Earth appears to reflect more light toward space.

Though not fully understood, the shifts may indicate a natural variability of clouds, which can reflect the sun’s heat and light away from Earth. The apparent change in the amount of sunlight reaching Earth in the 1980s and 1990s is comparable to taking the effects of greenhouse gas warming since 1850 and doubling them. Increased reflectance since 2001 suggests change of a similar magnitude in the opposite direction.


Researchers from the New Jersey Institute of Technology (NJIT), Newark, N.J., and California Institute of Technology (Caltech), Pasadena, Calif., combined NASA cloud data from satellites with records of Earth’s reflectance off the moon, called earthshine. The study, funded by NASA’s Living With a Star Program, appears May 28 in the journal Science.

"Using a phenomenon first explained by Leonardo DaVinci, we can provide valuable data on the overall reflectance of the Earth, and indirectly, on global cloud cover," said Phil Goode, a physicist at NJIT, one of the paper’s authors. He is director of Big Bear Solar Observatory (BBSO), Big Bear City, Calif. "Our method has the advantage of being very precise, and light reflected by large portions of Earth can be observed simultaneously," he said.

Recent news reports suggested sunshine reaching Earth declined from the late 1950s to the early 1990s. This new study suggests the opposite. Earth’s surface may have been sunnier, or less cloudy, in the 1980s and 1990s. BBSO has conducted precision earthshine observations since 1994. Regular observations began in late 1997.

The research team improved upon an old method for monitoring earthshine. They compared earthshine measurements from 1999 to mid-2001 with overlapping satellite observations of global cloud properties. The cloud satellite record from 1983 to 2001 came from the NASA-managed International Satellite Cloud Climatology Project. By matching these two records, the researchers used the cloud data to extend the record and construct a substitute measure of Earth’s albedo, the fraction of light reflected by a body or surface.

The data showed a steady decrease in Earth’s albedo from 1984 to 2000. Between 1995 and 1996, Earth dimmed even more sharply. The data were consistent with satellite measurements of changing global properties. From 1997 to 2000, Earth continued to dim. The researchers suggest, during this time period, the decreases in Earth’s reflectance may be related to an observed accelerated increase in mean global surface temperatures. From 2001 to 2003, Earth brightened to pre-1995 values. The researchers attributed the brightening to changes in cloud properties.

"At the moment, the cause of these variations is not known, but they imply large shifts in Earth’s radiative budget," said co-author Steven Koonin, a Caltech physicist. "Continued observations and modelling efforts will be necessary to learn their implications for climate."

The research offers evidence Earth’s average albedo varies considerably from year to year, and from decade to decade. "Our most likely contribution to the global warming debate is to emphasize the role of clouds in climate change must be accounted for, illustrating that we still lack the detailed understanding of our present and past climate system to confidently model future changes," said Enric Palle, a postdoctoral associate at NJIT, lead author of the paper. Pilar Montan~es-Rodriguez, a postdoctoral associate at NJIT, is another co-author.

"Even as the scientific community acknowledges the likelihood of human impact on climate, it must better document and understand climate changes," Koonin said. "Our ongoing earthshine measurements will be an important part of that process."

BBSO, operated by NJIT, is partially supported by NASA. NASA’s Living with a Star Program develops the scientific understanding necessary to effectively address those aspects of the connected sun-Earth system that directly affect life and society.

Krishna Ramanujan | EurekAlert!
Further information:
http://www.gsfc.nasa.gov/topstory/2004/0528earthshine.html

More articles from Earth Sciences:

nachricht Live from the ocean research vessel Atlantis
13.12.2018 | National Science Foundation

nachricht NSF-supported scientists present new research results on Earth's critical zone
13.12.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

UNLV study unlocks clues to how planets form

13.12.2018 | Physics and Astronomy

Live from the ocean research vessel Atlantis

13.12.2018 | Earth Sciences

Stanford researcher deciphers flows that help bacteria feed and organize biofilms

13.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>