Additionally, the researchers found that sunlight scattered by clouds — the reason why beachgoers can get sunburned on overcast days — is an important component of cloud contributions to Earth’s energy balance. Capturing such contributions will increase the accuracy of climate models, the team from the Department of Energy’s Pacific Northwest National Laboratory reported in Geophysical Research Letters earlier this month.

“The amount of the sun’s energy that reaches the Earth’s surface is the main driver of the Earth’s temperature. Clouds are one of the least understood aspects of climate change. They can block the sun, but light can also bounce off one cloud into another cloud’s shadow and increase the solar energy hitting earth,” said PNNL atmospheric scientist Evgueni Kassianov.

White clouds

Clouds both cool down and warm up Earth’s surface. They cool Earth by reflecting some sunlight up into outer space, and they warm it by bouncing some sunlight down to the surface. Overall, most clouds have a net cooling effect, but atmospheric scientists need to accurately measure when they cool and warm to produce better climate models that incorporate clouds faithfully.

But it’s a hard number to get. Fair-weather clouds are big puffy white objects that bounce a lot of light around. They can make the sky around them look brighter when they’re there, but they float about and reform constantly. Cloud droplets and aerosol particles in the sky — tiny bits of dirt and water in the air that cause haziness — scatter light in three dimensions, even into cloud shadows.

To determine the net cloud effect, researchers need two numbers. First they need to measure the total amount of sunlight in a cloudy sky. Then they need to determine how bright that sky would be without the clouds, imagining that same sky to be blue and cloudless, when aerosols are in charge of a sky’s brightness. The difference between those numbers is the net cloud effect.

Rainbow energy

Researchers have traditionally estimated the net cloud effect by measuring a broad spectrum of sunlight that makes it to Earth’s surface, from ultraviolet to infrared. But clouds are white — that’s because the large water droplets within them scatter light of all colors almost equally in the visible spectrum, the part of the electromagnetic spectrum that includes the colors of the rainbow.

On the other hand, aerosols — both within clouds and in the open sky — bounce different-colored light unequally. Broadband measurements that fail to distinguish color differences might be covering up important details, the researchers thought.

Instead of taking one broadband measurement that covers everything from ultraviolet to infrared, Kassianov and crew wanted to determine how individual wavelengths contribute to the net cloud effect. To do so, the team used an instrument that can measure brightness at four different wavelengths of color — violet, green, orange, red — and two of infrared.

In addition, this instrument, a spectral radiometer at DOE’s Atmospheric Radiation Measurement Climate Research Facility located on the southern Great Plains in Oklahoma, allowed the team to calculate what the brightness would be if the day sported a cloudless, blue sky. The spectral measurements taken by the radiometer can be converted into the amount and properties of aerosols. Then aerosol properties can be used to calculate clear blue sky brightness.

Clouds Gone Wild

Comparing measured values for cloudy sky to the calculated values for clear sky, the researchers found that, on average, puffy fair-weather clouds cool down Earth’s surface by several percent on a summer day. Although clouds cool overall, two components that the researchers looked at — from direct and scattered sunlight — had opposite effects.

The direct component accounts for the shade provided by clouds and cools Earth. The second component accounts for the sunlight scattered between and under clouds, which makes the sky brighter, warming Earth.

“The sunlight scattered by clouds can heat the surface,” said Kassianov. “We all know that we can still get sunburned on cloudy days. This explains why.”

In the Oklahoma summer, the scattered-light effect measured by the researchers could be quite large. For example, if a cloud passed over the instrument, the measured cloudy sky brightness exceeded calculated clear sky value by up to 30 percent. Kassianov attributes that large difference to scattered sunlight being “caught on tape” by the radiometer.

“Sunlight scattered by three-dimensional, irregular clouds is responsible for the observed large difference. The one-dimensional cloud simulations currently used in large-scale climate models don’t capture this diffuse light,” said Kassianov.

Aerosols’ Day in the Sky

The team also found that the effect changed depending on the measured visible-spectrum wavelength, and whether the light was direct or scattered.

With direct light, the cooling caused by clouds was weakest on the violet end of the spectrum and strongest at infrared. With scattered light, warming caused by clouds was also weakest at violet and the strongest at infrared. Overall, the least cooling and warming occurred at violet, and the most cooling and warming occurred at infrared.

Because large droplets in clouds scatter sunlight almost uniformly across the spectrum, the clouds themselves can’t be the reason why different wavelengths contribute differently to the net cloud effect. Compared to cloud droplets, aerosols are more than 100 times smaller and scatter wavelengths differently. These results suggest that aerosols — which not only cause haziness but contribute to cloud formation as well — are responsible for the wavelength differences, something researchers need to be aware of as they study clouds in the sky.

“If you want to study how aerosols and clouds interact,” said Kassianov, “you need to look in the region of the spectrum where aerosol effects are significant. If you want to fish, you go where the fish are biting.”

This work was supported by the U.S. Department of Energy Office of Science.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by DOE/Pacific Northwest National Laboratory.

Journal Reference:

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

A trial to generate biogas from local livestock has been given the go-ahead.

Chicken litter, cow dung and pig slurry will be used by a local anaerobic digestion plant in the village of Hatherop in the Cotswolds and converted into biogas for around 175 homes in the area.

According to farmers Jeremy Iles and James Hart, who built and own the biogas plant, local power is produced as distributed energy, which reduces energy waste, as well as energy imports and costs.

It also reduces the reliance on fossil fuels for energy.

Funded by the Rural Development Programme for England and the European Agricultural Fund for European Development, the plant also has a combined heat and power system which burns waste smells enclosed in the plant.

Another project aiming to reduce energy bills and supply renewable energy for tenants in Sheffield.

Meeting Level 3 of the Code for Sustainable Homes, 54 properties will have solar hot water systems and a Sustainable Urban Drainage Scheme system.

Posted by Emily Thomas

Sign up to receive regular e-news

For more information please see: Sheffield development

View the original article here

Two eco homes have been given the green light to be built in Coventry.

Run as an experiment, the buildings in Canley will be monitored for their energy efficiency, even when they are let out to council tenants.

The Coventry Telegraph reported that a post-graduate student at Coventry University will collate data from the buildings and see which is the most efficient.

One of the homes will be built to Passivhaus standards, while the other will be built to Level 6 of the Code for Sustainable Homes.

Work will begin in July after the city council approved the project.

Councillor Marcus Lapsa, shadow cabinet member for housing, sustainability and infrastructure, told the news provider: “With the Canley Regeneration Project stalling a little because of the housing market, this is an excellent opportunity.

“Going forward with this project will shine the spotlight on Coventry. It’s really positive stuff.”

It is hoped that the builders and suppliers of the projects will gain experience and develop skills in low carbon homes ahead of the 2016 deadline to build all new homes to a zero carbon standard.

Posted by Emily Thomas

Sign up to receive regular e-news

For more information please see: Coventry Telegraph

View the original article here

A tidal power system situated off the coast of Wales has been given the go-ahead by energy secretary Chris Huhne.

The 1.2MW DeltaStream device will be created by Tidal Energy Ltd and installed in Ramsey Sound, off the coast of Pembrokeshire. During the construction phase it will also bring a number of jobs to the area.

It will undergo a 12-month trial and could generate enough green electricity to power up to 1,000 homes.

“The UK’s great marine heritage and our engineering genius make the potential for wave and tidal energy here vast,” commented Mr Huhne.

“We must make the most of our natural marine resource, not just to cut our emissions, but to boost energy security and create jobs.”

Wales is set to become a major resource of marine energy as plans have been submitted for a tidal farm by Marine Current Turbines and RWE npower Renewables.

It hopes to deploy underwater turbines as part of a £70 million project off the coast of Anglesey, supplying power for up to 10,000 homes in the local area.

Posted by Mark Stephens

Sign up for regular email updates to help you save money and energy

For more information please see: Consent for DeltaStream

View the original article here

The study is published in the journal PLoS ONE.

“Lake Baikal has the greatest biodiversity of any lake in the world,” explained co-author Stephanie Hampton, deputy director of UC Santa Barbara’s National Center for Ecological Analysis & Synthesis (NCEAS). “And, thanks to the dedication of three generations of a family of Russian scientists, we have remarkable data on climate and lake temperature.”

Beginning in the 1940′s, Russian scientist Mikhail Kozhov took frequent and detailed measurements of the lake’s temperature. His descendants continued the practice, including his granddaughter, Lyubov Izmest’eva at Irkutsk State University. She is a co-author of the study and a core member of the NCEAS team now exploring this treasure trove of scientific and historical records.

First author Steve Katz, of NOAA’s Channel Islands National Marine Sanctuary, explained that the research team discovered many climate variability signals, called teleconnections, in the data. For example, changes in Lake Baikal water temperature correlate with monthly variability in El Niño indices, reflecting sea surface temperatures over the Pacific Ocean tens of thousands of kilometers away. At the same time, Lake Baikal’s temperatures are influenced by strong interactions with Pacific Ocean pressure fields described by the Pacific Decadal Oscillation.

“Teasing these multiple signals apart in this study illuminated both the methods by which we can detect these overlapping sources of climate variability, and the role of jet stream variability in affecting the local ecosystem,” said Katz.

Hampton added: “This work is important because we need to go beyond detecting past climate variation. We also need to know how those climate variations are actually translated into local ecosystem fluctuations and longer-term local changes. Seeing how physical drivers of local ecology — like water temperature — are in turn reflecting global climate systems will allow us to determine what important short-term ecological changes may take place, such as changes in lake productivity. They also help us to forecast consequences of climate variability.”

The scientists found that seasonality of Lake Baikal’s surface water temperatures relate to the fluctuating intensity and path of the jet stream on multiple time scales. Although the lake has warmed over the past century, the changing of seasons was not found to trend in a single direction, such as later winters.

The climate indices reflect alterations in jet stream strength and trajectory, and these dynamics collectively appear to forecast seasonal onset in Siberia about three months in advance, according to the study. Lake Baikal’s seasonality also tracked decadal-scale variations in Earth’s rotational velocity. The speed of Earth’s rotation determines the length of a day, which differs by milliseconds from day to day depending on the strength of atmospheric winds, including the jet stream. This scale of variability was also seen to affect the timing variability in seasonal lake warming and cooling, reinforcing the mechanistic role of the jet stream.

“Remarkably, the temperature record that reflects all these climate messages was collected by three generations of a single family of Siberian scientists, from 1946 to the present, and the correlation of temperature with atmospheric dynamics is further confirmation that this data set is of exceptionally high quality,” said Katz. “This consistent dedication to understanding one of the world’s most majestic lakes helps us understand not only the dynamics of Lake Baikal over the past 60 years, but also to recognize future scenarios for Lake Baikal. The statistical approach may be used for similar questions in other ecosystems, although we recognize that the exceptional quality and length of the Baikal data was one of the keys to our success.”

Marianne V. Moore, of Wellesley College, is a leader of the NCEAS team and a co-author of this paper.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California – Santa Barbara.

Journal Reference:

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

• 35 watts.
• Bi-pin base.
• Dimmable.
• Average life is 4000 hours.
• UV filter.

Product Description ECO HALOSTAR? Is? n? Saving energy? Bulb? OSRAM. It? Bi-pin basis? bulb? ? Is? ideal p? r “Starlight nadstre? Furniture Nice,” The lamps and chandeliers. Technologies t? her t? new, p? rfshir? from dressing site infra t? red. This ecological ki friends? ments? bulb? reduces consumption? Energy her p? r 30% n? compared with the lamp? usually term? with manufacturing t? one? JT?. average? nj? this jet? bulbs? is? or 4000?. It? is? it? bulb? infinite? wholly dimmable (from 100% n? 0%). 35 watts. Bi-pin basis?. dimmable. Average n? l … You would?>>>

Osram HALOSTAR ECO 35 Watt Energy Saving Light Bulb

• Super bright 100,000 hour LEDs
• Glass protected multi crystal solar panel designed for outdoor applications
• 20-Foot Extension cord allows solar panel to be placed in direct sunlight
• Features two power settings
• Can be wall or pole mounted up to 20 feet away from fixture

Product light? DescriptionBring t? err? your t t? shed, without having? p? r t? on n? local network? N?. That light? LED molding knows? Features 10 LEDs t? q bright? are? can? Powered by solar panels. The panel will power? set n? direct sunlight with p? rfshir? expand on? 20-k? Mb?, Or cable. Mount one? light? n? ceiling or wall p? r maximum flexibility, or ep? rdorin at? like a computer? p tool? r t? light table?. T? Rhiqe chain t? allows? easy? n? and abroad? “Page. Nd? Rprerje? On the body allows? P? Rzgjidhni n? Between t? 10-LED which lasts p? R 2 or?… You will?>>>

Designers Edge L-949 10 LED Rechargeable Solar Panel Shed Light Model