Posted on by Nancy Atkinson

Earth’s Upper Atmosphere is Cooling

New measurements from a NASA satellite show a dramatic cooling in the upper atmosphere that correlates with the declining activity of the current solar cycle. For the first time, researchers can show a timely link between the Sun and the climate of Earth’s thermosphere, the region above 100 km, an essential step in making accurate predictions of climate change in the high atmosphere. This finding also correlates with a fundamental prediction of climate change theory that says the upper atmosphere will cool in response to increasing carbon dioxide.

Earth’s thermosphere and mesosphere have been the least explored regions of the atmosphere, in fact some have called it the “ignorosphere.” The NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission was developed to explore the Earth’s atmosphere above 60 km altitude and was launched in December 2001. One of four instruments on the TIMED mission, the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, was specifically designed to measure the energy budget of the mesosphere and lower thermosphere. The SABER dataset now covers eight years of data and has already provided some basic insight into the heat budget of the thermosphere on a variety of timescales.

The extent of current solar minimum conditions has created a unique situation for recent SABER datasets. The end of solar cycle 23 has offered an opportunity to study the radiative cooling in the thermosphere under exceptionally quiescent conditions.

“The Sun is in a very unusual period,” said Marty Mlynczak, SABER associate principal investigator and senior research scientist at NASA Langley. “The Earth’s thermosphere is responding remarkably — up to an order of magnitude decrease in infrared emission/radiative cooling by some molecules.”

The TIMED measurements show a decrease in the amount of ultraviolet radiation emitted by the Sun. In addition, the amount of infrared radiation emitted from the upper atmosphere by nitric oxide molecules has decreased by nearly a factor of 10 since early 2002. These observations imply that the upper atmosphere has cooled substantially since then. The research team expects the atmosphere to heat up again as solar activity starts to pick up in the next year.

While this warming has no implications for climate change in the troposphere, a fundamental prediction of climate change theory is that the upper atmosphere will cool in response to increasing carbon dioxide. Emissions of carbon dioxide may warm the lower atmosphere, but they cool the upper atmosphere, because of the density of the atmospheric layer.

As the atmosphere cools the density will increase, which ultimately may impact satellite operations through increased drag over time.

The SABER dataset is the first global, long-term, and continuous record of the Nitric oxide (NO) and Carbon dioxide (CO2) emissions from the thermosphere.

“We suggest that the dataset of radiative cooling of the thermosphere by NO and CO2 constitutes a first climate data record for the thermosphere,” says Mlynczak.

The TIMED data provide a fundamental climate data record for validation of upper atmosphere climate models which is an essential step in making accurate predictions of climate change in the high atmosphere. SABER provides the first long-term measurements of natural variability in key terms of the upper atmosphere climate. As the TIMED mission continues, these data derived from SABER will become important in assessing long term changes due to the increase of carbon dioxide in the atmosphere.

The findings were presented at the American Geophysical Union fall meeting in San Francisco.

Source: NASA Langley

Posted on by Nancy Atkinson

UFOs This Weekend? No, Just an Experiment

Black Brandt rocket. Credit: NASA


Reports of UFOs skyrocketed last weekend along the east coast of the US after a NASA launched an experiment to study an unusual phenomenon called noctilucent clouds, or ‘night shining’ clouds. The Charged Aerosol Release Experiment (CARE) was conducted by the Naval Research Laboratory and the Department of Defense Space Test Program, created artificial noctilucent cloud using the exhaust particles of the rocket’s fourth stage at about 173 miles altitude. It created a bright object with a fan-shaped tail, prompting calls of concern from residents in Virginia and Massachusetts to local authorities. But this object was definitely identified.

The experiment used a Black Brant XII Sounding Rocket launched from NASA’s Wallops Flight Facility in Virginia on September 19, 2009 at 7:46 p.m. EDT (2346 GMT).
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Scientists aren’t sure what causes noctilucent clouds. Some think they’re seeded by space dust. Others suspect they’re a telltale sign of global warming.

See our previous post with pictures about noctilucent clouds.

Data collected during the experiment will provide insight into the formation, evolution, and properties of noctilucent clouds, which are typically observed naturally at high latitudes. In addition to the understanding of noctilucent clouds, scientists will use the experiment to validate and develop simulation models that predict the distribution of dust particles from rocket motors in the upper atmosphere.

Natural noctilucent clouds, also known as polar mesospheric clouds, are found in the upper atmosphere as spectacular displays that are most easily seen just after sunset. The clouds are the highest clouds in Earth’s atmosphere, located in the mesosphere around 50 miles altitude.

They are normally too faint to be seen with the naked eye and are visible only when illuminated by sunlight from below the horizon while the Earth’s surface is in darkness.

A team from government agencies and universities, led by the Naval Research Laboratory, is conducting the experiment. In addition to the Naval Research Laboratory, participants include the DoD STP, NASA, University of Michigan, Air Force Research Laboratory, Clemson University, Stanford University, University of Colorado, Penn State University and Massachusetts Institute of Technology/Haystack Observatory.

Source: NASA

Posted on by Nancy Atkinson

Climate Change and Earth’s Cryosphere


Even though most of us do not live in the polar regions or don’t even see icebergs or ice sheets very often, no matter where you live, the snow and ice of the Earth’s cryosphere has an impact on your climate. NASA released an amazing new view of Earth’s frozen regions today, using visual satellite data to show, among other things, how sea ice is disappearing and glaciers are shrinking. These changes in the cryosphere have had a major impact on global climate, as the cryosphere is interconnected with other parts of the Earth system. Scientists are currently studying just how much the frozen places on Earth affect global warming, and the best way to view the remote icy parts of our planet is from space. This video shows satellite data in action, with striking high definition visuals and charts.
Continue reading “Climate Change and Earth’s Cryosphere”

Posted on by Nancy Atkinson

Researchers Say Sun Cycle Alters Earth’s Climate

The sunspot cycle from 1995 to the present. The jagged curve traces actual sunspot counts. Smooth curves are fits to the data and one forecaster's predictions of future activity. Credit: David Hathaway, NASA/MSFC

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If the energy from the sun varies by only 0.1 percent during the 11-year solar cycle, could such a small variation drive major changes in weather patterns on Earth? Yes, say researchers from the National Center for Atmospheric Research (NCAR) who used more than a century of weather observations and three powerful computer models in their study. They found subtle connections between solar cycle, the stratosphere, and the tropical Pacific Ocean that work in sync to generate periodic weather patterns that affect much of the globe. Scientists say this will help in predicting the intensity of certain climate phenomena, such as the Indian monsoon and tropical Pacific rainfall, years in advance.

“The Sun, the stratosphere, and the oceans are connected in ways that can influence events such as winter rainfall in North America,” says NCAR scientist Gerald Meehl, the lead author. “Understanding the role of the solar cycle can provide added insight as scientists work toward predicting regional weather patterns for the next couple of decades.”

The new study looked at the connection between the Sun’s impact on two seemingly unrelated regions. Chemicals in the stratosphere and sea surface temperatures in the Pacific Ocean respond during solar maximum in a way that amplifies the Sun’s influence on some aspects of air movement. This can intensify winds and rainfall, change sea surface temperatures and cloud cover over certain tropical and subtropical regions, and ultimately influence global weather.

The team first confirmed an earlier theory, that the slight increase in solar energy during the peak production of sunspots is absorbed by stratospheric ozone. The energy warms the air in the stratosphere over the tropics, where sunlight is most intense, while also stimulating the production of additional ozone there that absorbs even more solar energy. Since the stratosphere warms unevenly, with the most pronounced warming occurring at lower latitudes, stratospheric winds are altered and, through a chain of interconnected processes, end up strengthening tropical precipitation.

At the same time, the increased sunlight at solar maximum causes a slight warming of ocean surface waters across the subtropical Pacific, where Sun-blocking clouds are normally scarce. That small amount of extra heat leads to more evaporation, producing additional water vapor. In turn, the moisture is carried by trade winds to the normally rainy areas of the western tropical Pacific, fueling heavier rains and reinforcing the effects of the stratospheric mechanism.

The top-down influence of the stratosphere and the bottom-up influence of the ocean work together to intensify this loop and strengthen the trade winds. As more sunshine hits drier areas, these changes reinforce each other, leading to less clouds in the subtropics, allowing even more sunlight to reach the surface, and producing a positive feedback loop that further magnifies the climate response.

These stratospheric and ocean responses during solar maximum keep the equatorial eastern Pacific even cooler and drier than usual, producing conditions similar to a La Nina event. However, the cooling of about 1-2 degrees Fahrenheit is focused farther east than in a typical La Nina, is only about half as strong, and is associated with different wind patterns in the stratosphere.

Earth’s response to the solar cycle continues for a year or two following peak sunspot activity. The La Nina-like pattern triggered by the solar maximum tends to evolve into a pattern similar to El Nino as slow-moving currents replace the cool water over the eastern tropical Pacific with warmer water. The ocean response is only about half as strong as with El Nino and the lagged warmth is not as consistent as the La Nina-like pattern that occurs during peaks in the solar cycle.

Solar maximum could potentially enhance a true La Nina event or dampen a true El Nino event. The La Nina of 1988-89 occurred near the peak of solar maximum. That La Nina became unusually strong and was associated with significant changes in weather patterns, such as an unusually mild and dry winter in the southwestern United States.

The Indian monsoon, Pacific sea surface temperatures and precipitation, and other regional climate patterns are largely driven by rising and sinking air in Earth’s tropics and subtropics. Therefore the new study could help scientists use solar-cycle predictions to estimate how that circulation, and the regional climate patterns related to it, might vary over the next decade or two.

The team used three different computer models to look at all the variables and each came up with the same result, that even a small variablilty in the sun’s energy could have profound effects on Earth.

“With the help of increased computing power and improved models, as well as observational discoveries, we are uncovering more of how the mechanisms combine to connect solar variability to our weather and climate,” Meehl says.

The team’s research was published in the Journal Science.

Posted on by Nancy Atkinson

Watermelons: The Newest Renewable Energy Source

This has nothing to do with space or astronomy, but is perhaps one of the juiciest pieces of new I have ever read. Could we one day be driving cars fueled by watermelons? Researchers say that watermelon juice can be a valuable source of biofuel, as it can be efficiently fermented into ethanol. But have no fear, using watermelons for biofuel wouldn’t cut into the amount of watermelons available for the public to eat. This research evaluated the biofuel potential of juice from ‘cull’ watermelons – those not sold due to cosmetic imperfections, and currently ploughed back into the field. Wayne Fish from the US Department of Agriculture said, “About 20% of each annual watermelon crop is left in the field because of surface blemishes or because they are misshapen. We’ve shown that the juice of these melons is a source of readily fermentable sugars, representing a heretofore untapped feedstock for ethanol biofuel production.”

The researchers conclude that at a “production ratio of ~0.4 g ethanol/g sugar, as measured in this study, approximately 220 L/ha of ethanol would be produced from cull watermelons.”

As well as using the juice for ethanol production, either directly or as a diluent for other biofuel crops, Fish suggests that it can be a source of lycopene and L-citrulline, two ‘nutraeuticals’ for which enough demand currently exists to make extraction economically worthwhile. After these compounds have been removed from the ‘cull’ juice, it can still be fermented into ethanol.

Read the “juicy” paper here.

Posted on by Anne Minard

A Day for Earth, but a Whole Week for Dark Skies

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Wednesday is Earth Day, but all week — Monday, April 20 through Saturday, April 26 — is National Dark Sky Week in America, when people are asked to dim the lights to see more stars.

If enough people participate, backyard and professional astronomers might be treated with a week of darker, starrier skies. The bigger idea is to raise awareness about sensible lighting practices, so skies might get a little bit darker all the time. And not just for astronomy buffs. Besides aesthetics, evidence is mounting that light pollution could have far-reaching effects for the environment and even public health.

milky-way
360-degree panoramic picture of the Milky Way as seen from Death Valley. Credit: Dan Duriscoe, National Park Service.

Jennifer Barlow, founder of the event, said the only way National Dark Sky Week can succeed is if more people participate every year. “No reduction in light pollution can be made unless a significant number of people turn off their lights,” she said.

Besides turning out the lights, the participating groups are encouraging people to attend star parties, visit local observatories, or “dust off the old telescope from the attic,” Barlow said.

Year-round, the International Dark Sky Association encourages people to shield lights, or use fixtures that focus light downward instead of up into the sky. Reducing extraneous light, especially at ball fields, is a major step in the right direction. And certain types of lighting — like low-pressure sodium — are better than others.

Flagstaff, Arizona became the world’s first International Dark-Sky City in 2001, owing to the presence of several important observatories — it’s the home of Lowell Observatory and the U.S. Naval Observatory — along with the dedicated efforts of a handful of astronomers. The city government and the vast majority of businesses have readily complied with responsible lighting codes to protect views of the night sky for residents and astronomers alike. 

The skies are noticeably dark over Flagstaff; the stars are rich at night. The Grand Canyon is even more impressive, especially on the north side. The views after dark are as stunning and magical as those during  the day.

But even those skies aren’t as good as they could be, because light pollution from cities up to 200 miles away — including Las Vegas and Phoenix — is gradually creeping in. Chad Moore, a dark skies advocate who works for the National Park Service in Denver, has spent nearly a decade documenting the skies over 55 of the nation’s parks, which are usually the best places to see stars.

Parts of rare parks — Capitol Reef, Great Basin and Big Bend among them — boast truly dark skies, he said.

Moore pointed out there are reasons besides beauty to rein in light pollution: “In the last 10 years there has been a revolution in our understanding of animal habitat and what animals require,” he said. “There are links between artificial light and cancer in humans. There’s a lot we didn’t know about.”

Second photo caption: 360-degree panoramic picture of the Milky Way as seen from Death Valley. Credit: Dan Duriscoe, National Park Service.

For more information:

National Dark Sky Week 
International Dark-Sky Association
IYA Dark Skies Awareness
Starlight Initiative
World Night in Defense of Starlight
American Astronomical Society
Astronomical League
NASA IYA site


Posted on by Nancy Atkinson

Aerosols Could Be Responsible For Arctic Warming

Researchers used an electron microscope to capture these images of black carbon attached to sulfate particles. The spherical structures in image A are sulfates; the arrows point to smaller chains of black carbon. Black carbon is shown in detail in image B. Image C shows fly ash, a product of coal-combustion, that's often found in association with black carbon. While black carbon absorbs radiation and contributes to warming, sulfates reflect it and tend to cool Earth. Credit: Peter Buseck, Arizona State University

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Since the 1890s, surface temperatures on Earth have risen faster in the Arctic than in other regions of the world. Usually, discussions on global warming tend to focus on greenhouse gases as the culprit for the trend. But new NASA research suggests about half the atmospheric warming measured in the Arctic is due to airborne particles called aerosols.

Aerosols are emitted by both natural and human sources. They can influence cli­mate by reflecting or absorbing sunlight. The particles also affect climate by changing cloud properties, such as reflectivity. There is one type of aerosol that, according to the study, reductions rather than increases in its emissions seem to have promoted warming.

The research team, led by climate scientist Drew Shindell of the NASA Goddard Institute for Space Studies used a computer model to investigate how sensitive different regional climates are to changes in levels of carbon dioxide, ozone, and aerosols.

They found that Earth’s middle and high latitudes are particularly responsive to changes in aerosol levels. The model suggests aerosols likely account for 45 % or more of the warming measured in the Arctic since 1976.

Though there are several types of aerosols, previous research indicates two in particular, sulfates and black carbon, play leading roles in climate. Both are products of human activity. Sulfates, which come mainly from the burning of coal and oil, scatter sun­light and cool the air. Over the past three decades, the Un­ited States and European countries have passed clean-air laws that have halved sulfate emis­sions.

Since the 1890s, surface temperatures have risen faster in the Arctic than in other regions of the world. In part, these rapid changes could be due to changes in aerosol levels. Clean air regulations passed in the 1970s, for example, have likely accelerated warming by diminishing the cooling effect of sulfates. Credit: Drew Shindell, Goddard Institute for Space Studies
Since the 1890s, surface temperatures have risen faster in the Arctic than in other regions of the world. In part, these rapid changes could be due to changes in aerosol levels. Clean air regulations passed in the 1970s, for example, have likely accelerated warming by diminishing the cooling effect of sulfates. Credit: Drew Shindell, Goddard Institute for Space Studies

The models showed that regions of Earth that showed the strongest responses to aerosols in the model are the same regions that have witnessed the greatest actual temperature increases since 1976, specifically the Arctic. However in the Antarctic, aerosols play less of a role.

Researchers with the NOAA, the National Oceanic and Atmospheric Administration reported in the April 3 issue of the jour­nal Geophysical Research Letters that Arctic summers may be ice-free in as few as 30 years.

The Arctic region has seen its surface air temperatures rise by 1.5 C (2.7 F) since the mid-1970s. In the Antarctic, sur­face air temperature has in­creased about 0.35 C (0.6 F). That makes sense, Shin­dell said, be­cause the Arctic is near North America and Europe, highly industrialized regions that produce most of the world’s aerosols.

“In the mid-latitudes of the Northern Hemi­sphere and in the Arctic, the impact of aerosols is just as strong as that of the greenhouse gases,” said Shindell. “We will have very little leverage over climate in the next couple of decades if we’re just looking at carbon dioxide. If we want to try to stop the Arctic summer sea ice from melting completely over the next few decades, we’re much better off looking at aerosols and ozone.”

Aerosols tend to be short lived, staying in the atmosphere for just days or weeks, whereas greenhouses gases can persist for centuries. Atmospheric chem­ists thus think the climate may respond most quickly to changes in aerosol levels.

NASA’s upcoming Glory satellite is de­signed to enhance current aerosol measurement capabilities to help scientists reduce uncertainties about aerosols by measuring the distribution and properties of the particles.

Source: NASA

Posted on by Anne Minard

Ozone Success Story: NASA Video of Enviro Action That Worked

Ozone layer hole. Image credit: NASA
Ozone layer hole. Image credit: NASA

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Imagine the year 2065. Two-thirds of Earth’s ozone is gone. The infamous ozone hole over Antarctica is a year-round fixture with a twin over the North Pole. People living in mid-latitude cities like Washington, D.C., get sunburned after five minutes. DNA-mutating UV radiation is up 650 percent, with likely harmful effects on plants, animals and human skin cancer rates.

Such is the world we would have inherited if 193 nations had not agreed to ban ozone-depleting substances, according to atmospheric chemists at NASA, Johns Hopkins University in Baltimore and the Netherlands Environmental Assessment Agency in Bilthoven. The researchers have unveiled new computer simulations this week of a worldwide disaster that humans managed to avoid.

In retrospect, the researchers say, the Montreal Protocol was a “remarkable international agreement that should be studied by those involved with global warming and the attempts to reach international agreement on that topic.”

ozone-simulation
This time series from the ozone "World Avoided" model shows the concentration of ozone over the South Pole at four key times. Reds represent normal to high concentrations; blues show depleted areas. Credit: NASA Goddard's Scientific Visualization Studio

Ozone is Earth’s natural sunscreen, absorbing and blocking most of the incoming UV radiation from the sun and protecting life from DNA-damaging radiation. The gas is naturally created and replenished by a photochemical reaction in the upper atmosphere where UV rays break oxygen molecules into individual atoms that then recombine into three-part molecules (O3). As it is moved around the globe by upper level winds, ozone is slowly depleted by naturally occurring atmospheric gases. It is a system in natural balance.

But chlorofluorocarbons — invented in 1928 as refrigerants and as inert carriers for chemical sprays — upset that balance. Researchers discovered in the 1970s and 1980s that while CFCs are inert at Earth’s surface, they are quite reactive in the stratosphere (10 to 50 kilometers altitude, or 6 to 31 miles), where roughly 90 percent of the planet’s ozone accumulates. UV radiation causes CFCs and similar bromine compounds in the stratosphere to break up into elemental chlorine and bromine that readily destroy ozone molecules. 

In the 1980s, ozone-depleting substances opened a wintertime “hole” over Antarctica and opened the eyes of the world to the effects of human activity on the atmosphere.  In January 1989, the Montreal Protocol went into force, the first-ever international agreement on regulation of chemical pollutants.

In the new study, published online in the journal Atmospheric Chemistry and Physics, Goddard scientist Paul Newman and his team simulated “what might have been” if chlorofluorocarbons (CFCs) and similar chemicals were not banned. The simulation used a comprehensive model that included atmospheric chemical effects, wind changes, and radiation changes. The “World avoided” video can be viewed here in Quicktime (for more formats, go here).

By the simulated year 2020, 17 percent of all ozone is depleted globally. An ozone hole starts to form each year over the Arctic, which was once a place of prodigious ozone levels.

By 2040, global ozone concentrations fall below the same levels that currently comprise the “hole” over Antarctica. The UV index in mid-latitude cities reaches 15 around noon on a clear summer day, giving a perceptible sunburn in about 10 minutes. Over Antarctica, the ozone hole becomes a year-round fixture.

By the end of the model run in 2065, global ozone drops 67 percent compared to 1970s levels. The intensity of UV radiation at Earth’s surface doubles; at certain shorter wavelengths, intensity rises by as much as 10,000 times. Skin cancer-causing radiation soars.

“Our world avoided calculation goes a little beyond what I thought would happen,” said Goddard scientist and study co-author Richard Stolarski, who was among the pioneers of atmospheric ozone chemistry in the 1970s. “The quantities may not be absolutely correct, but the basic results clearly indicate what could have happened to the atmosphere.”

“We simulated a world avoided,” added Newman, “and it’s a world we should be glad we avoided.”

As it is, production of ozone-depleting substances was mostly halted about 15 years ago, though their abundance is only beginning to decline because the chemicals can reside in the atmosphere for 50 to 100 years. The peak abundance of CFCs in the atmosphere occurred around 2000, and has decreased by roughly 4 percent to date. Stratospheric ozone was depleted by 5 to 6 percent at middle latitudes, but has somewhat rebounded in recent years.

Posted on by Anne Minard

At Last: Successful Launch for European Climate Satellite

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Europe’s Gravity field and steady-state Ocean Circulation Explorer (GOCE) is headed into orbit, after a successful launch at 10:21 a.m. EDT (14:21 GMT) on Tuesday from the Plesetsk Cosmodrome in northern Russia. 

The successful liftoff came after delays stretching back to last September, but Tuesday’s launch went off without any complications.

“It was a nice liftoff,” said Mission Scientist Mark Drinkwater.

Monday’s launch failed to progress when the doors of the launch service tower simply did not open. That after a previous failure last September, when problems cropped up with the guidance and navigation subsystems on the Russian Breeze KM rocket. 

GOCE is the first of a new family of ESA satellites, called Earth Explorers, designed to study our planet and its environment in order to improve our knowledge and understanding of Earth-system processes and their evolution, to characterize the challenges of global climate change. Its specific mission is to map Earth’s gravity field with unprecedented accuracy, providing insight into ocean circulation, sea-level change, climate change, volcanism and earthquakes.

Source: ESA