Scientists demonstrate the sharpest measurement of ice crystals in clouds

Jul 17, 2008

Scientists have created an instrument designed to help determine the shapes and sizes of tiny ice crystals typical of those found in high-altitude clouds, down to the micron level (comparable to the tiniest cells in the human body), according to a new study in Optics Letters, a journal published by the Optical Society. The data produced using this instrument likely will help improve computer models used to predict climate change.

Among the hundreds of factors climate scientists must take into account in modeling weather, the nature of clouds is one of the most important and least understood. The best researchers could do in the past to measure cloud ice crystals was to try to record images of them, but for crystals below 25 microns, the images were too blurred to allow accurate determination of the crystal's shape.

Researchers need to know the shape and sizes of these ice crystals because these properties influence how much incoming sunlight gets absorbed in the atmosphere and how much gets reflected right back out into space. This, in turn, can have a huge impact on the magnitude of possible global warming or cooling.

Now scientists from the University of Hertfordshire and the University of Manchester in the United Kingdom and Colorado State University in the United States have developed an optical scattering instrument that can evaluate the size of the crystals in a different way. Using this instrument, the researchers have been able to determine sizes and shapes of cloud ice crystals all the way down to the tiniest micron levels.

The research team actually has built two versions of the instrument: one designed to operate on ground-based cloud simulation chambers or to operate in the fuselage of research aircraft; the other, an aerodynamic version that fits under the wing of the aircraft and measures the cloud particles directly as the aircraft flies through the cloud. Neither instrument attempts to make a full image of the ice crystal, since this would suffer the same resolution limits of existing instruments. Instead they record the detailed pattern of scattered light from each individual crystal and then interpret these patterns using either theoretical models or by comparison with recorded patterns from known crystal shapes. From this data a crystal census of varying sizes and shapes can be made.

"The new instruments should help map out a more complete understanding of complex crystal shapes found in atmospheric clouds, especially cirrus clouds, which on any day can cover more than 20 percent of the Earth's surface," says one of the researchers, Hertfordshire scientist Paul Kaye. "We believe that this optical scattering instrument could help climate modelers reduce one of the greatest areas of uncertainty in interpreting the influence of clouds and in making more accurate climate predictions."

In addition, recent reports have examined the effect that pollution and the clouds caused by pollution have on reducing solar radiation reaching the ground, a development that may counterbalance global warming to some extent, and this new technology could help scientists better monitor and understand this situation.

Source: Optical Society of America

Explore further: Strong quake hits east Indonesia; no tsunami threat

add to favorites email to friend print save as pdf

Related Stories

Melt ponds shine in NASA laser altimeter flight images

Aug 05, 2014

Even from 65,000 feet above Earth, aquamarine melt ponds in the Arctic stand out against the white sea ice and ice sheets. These ponds form every summer, as snow that built up on the ice melts, creating crystal ...

Digging deep in search of water on the moon

May 19, 2014

One of the main aims of the Apollo missions of the 1960s was to determine whether the moon had any water on it. If man were to build a colony on the moon, having water present would make living there easier.

Ganymede may harbor 'club sandwich' of oceans and ice

May 01, 2014

(Phys.org) —The largest moon in our solar system, a companion to Jupiter named Ganymede, might have ice and oceans stacked up in several layers like a club sandwich, according to new NASA-funded research ...

Recommended for you

Strong quake hits east Indonesia; no tsunami threat

17 hours ago

A strong earthquake struck off the coast of eastern Indonesia on Sunday evening, but there were no immediate reports of injuries or damage, and authorities said there was no threat of a tsunami.

Scientists make strides in tsunami warning since 2004

Dec 19, 2014

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

Dec 19, 2014

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

seanpu
not rated yet Jul 18, 2008
they need also to determine the electrical properties of the cloud crystals and the cloud in general. the electrical nature of the atmosphere has been near completely overlooked; only last year the implications of electric field around dust storms, dust devils, tornadoes, hurricanes and most wind phenomena, has started to been acknowledged and investigated. Paul Kaye and his team should bite the bullet and investigate this now, rather than later.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.