NASA's Orbiting Carbon Observatory (OCO)-2 will measure CO2 in the atmosphere

An artists rendition of NASA's Orbiting Carbon Observatory (OCO-2), which will launch on July 1 and measure atmospheric carbon dioxide 

NASA is preparing a July 1 launch for its first satellite dedicated to measuring atmospheric levels of carbon dioxide, a greenhouse gas that plays a key role in climate change.

CO2 levels have reached their highest point in at least 800,000 years, according to the US space agency.

The Orbiting Carbon Observatory (OCO-2) satellite is very similar to its predecessor, OCO-1, which was destroyed during its launch in February 2009.

The satellite will help provide a more complete and global picture of man-made and naturally occurring CO2 emissions as well as the effects of carbon "sinks," like oceans and forests, which absorb and trap the gas.

"Carbon dioxide in the atmosphere plays a critical role in our planet's energy balance and is a key factor in understanding how our climate is changing," said Michael Freilich, director of NASA's Earth Science Division.

"With the OCO-2 mission, NASA will be contributing an important new source of global observations to the scientific challenge of better understanding our Earth and its future," he added in a statement.

The OCO-2 satellite will be launched on a United Launch Alliance Delta II rocket from Vandenberg Air Force Base in California, aiming for an orbit at 438 miles (705 kilometers) above the Earth's surface.

NRL SSULI: Satellite to measure ionosphere electron density

Says Andrew Nicholas, Principal NRL Investigator, "What we're looking at is naturally occurring air glow emissions from the upper atmosphere." 

Shown is the daily averaged electron density over two years; as a function of altitude and day of the year in the post-sunset, equatorial ionosphere. 

F18 SSULI measured the nightside oxygen 135.6 nm radiative recombination emission intensity, capturing the ionosphere's variations daily and over the long-term as associated with seasons and solar cycles. 

Credit: U.S. Naval Research Laboratory

On April 3rd, 2014, a satellite carrying a U.S. Naval Research Laboratory (NRL) space weather instrument will launch from Vandenberg Air Force Base.

Special Sensor Ultraviolet Limb Imager (SSULI)

Called the Special Sensor Ultraviolet Limb Imager (SSULI), "SSULI makes accurate measurements of the upper atmosphere and ionosphere that are ultimately useful to the warfighter," says Dr. Scott Budzien, the NRL Program Manager.

"Down in the lower atmosphere, the characteristics of weather that are important are temperature, precipitation, wind, and so on," he says.

"But in the ionosphere, the aspects that are important for our systems are electron density, the morphology and gradients of electron density, and the height where the ionosphere lies."

SSULI measures the density of the ionosphere (as ions or electrons per cubic centimeter). Says Andrew Nicholas, the Principal Investigator, "We are measuring naturally occurring airglow emissions from the upper atmosphere."

The density profiles go into the Department of Defense's weather system, which the U.S. Air Force has run since the 1940s to collect observations about terrestrial and space weather.

"SSULI helps provide a very good specification of the state of the atmosphere, a nowcast," says Budzien.

With a more accurate nowcast, forecasting models better predict space weather into the future.

Space weather is important for military operations, because how signals are transmitted or reflected influences the reliability of radar and of communication and navigation systems.

Configuration of Operational Polar Satellites

The April 3rd Defense Meteorological Satellite Program (DMSP) mission, Flight-19 (F19), is the fourth to carry a SSULI from NRL.

The DMSP satellites are low-earth orbiting satellites, flying at about 830-840 kilometers (km) above the ground.

"They fly in a sun-synchronous orbit, which means they are always at the same local time," says Budzien.

"The one we are launching in April is going into a terminator orbit, right at the day-night boundary."

NRL built five SSULIs in the early 1990s; the last launch is currently planned for 2016. But, says Budzien, "Based on the lessons learned from SSULI, we've developed the design for a smaller, more sensitive instrument."

Still just a concept, Budzien hopes to identify a sponsor who will help "to continue to provide improved products for the warfighter."

MIT Scientists develop new technique to measure mass of exoplanets

Artistic rendering of a planet's transmission spectrum. 

Credit: CHRISTINE DANILOFF /MIT, JULIEN DE WIT

To date, scientists have confirmed the existence of more than 900 exoplanets circulating outside our solar system.

To determine if any of these far-off worlds are habitable requires knowing an exoplanet's mass—which can help tell scientists whether the planet is made of gas or rock and other life-supporting materials.

But current techniques for estimating exoplanetary mass are limited. Radial velocity is the main method scientists use: tiny wobbles in a star's orbit as it is tugged around by the planet's gravitational force, from which scientists can derive the planet-to-star mass ratio.

Spitzer Space Telescope

For very large, Neptune-sized planets, or smaller Earth-sized planets orbiting very close to bright stars, radial velocity works relatively well.

But the technique is less successful with smaller planets that orbit much farther from their stars, as Earth does.

Now scientists at MIT have developed a new technique for determining the mass of exoplanets, using only their transit signal—dips in light as a planet passes in front of its star.

Julien de Wit

This data has traditionally been used to determine a planet's size and atmospheric properties, but the MIT team has found a way to interpret it such that it also reveals the planet's mass.

"With this method, we realized the planetary mass—a key parameter that, if missing, could have prevented us from assessing the habitability of the first potentially habitable Earth-sized planet in the next decade—will actually be accessible, together with its atmospheric properties," says Julien de Wit, a graduate student in MIT's Department of Earth, Atmospheric and Planetary Sciences.

De Wit is lead author on a paper published today in the journal Science, with co-author Sara Seager, the Class of 1941 Professor of Physics and Planetary Science.


Researchers at MIT explain what exactly an exoplanet or extrasolar planet is, why we study them and how you can detect them.

"The mass affects everything on a planetary level, such as any plate tectonics, its internal cooling and convection, how it generates magnetic fields, and whether gas escapes from its atmosphere," de Wit says.

"If you don't get it, there is a large part of the planet's properties that remains undetermined."

Using large telescopes such as the NASA's Spitzer and Hubble Space Telescopes, scientists have been able to analyze the transmission spectra of newly discovered exoplanets.

A transmission spectrum is generated as a planet passes in front of its star, letting some light through its atmosphere.

By analyzing the wavelengths of light that pass through, scientists can determine a planet's atmospheric properties, such as its temperature and the density of atmospheric molecules. From the total amount of light blocked, they can calculate a planet's size.

More information: "Constraining Exoplanet Mass from Transmission Spectroscopy," by J. de Wit et al. Science, 2013. DOI:10.1126/science.1245450

High-speed discovery helps measure greenhouse gases from space

Scientists have discovered how to measure greenhouse gases 200,000 times faster as the result of research by an award-winning PhD student from The University of Western Australia (UWA) and a US team.

The discovery - which is already being used by NASA scientists in Space - has major implications for global warming research, breath analysis (to detect illness), explosives detection, chemical process monitoring and a range of other applications, including fundamental quantum theory.

UWA physics graduate Gar-Wing Truong used highly-sensitive rapid laser scanning technology to help lead US scientists from National Institute of Standards and Technology (NIST) in Maryland to build new gas measurement equipment with unparalleled speed, accuracy, precision and spectral coverage.

NASA's Jet Propulsion Laboratory in California has begun using data from Mr Truong's research to calibrate carbon monitoring satellites in orbit around Earth and better understand carbon dioxide molecules.

Eric May

The research is an extension of Mr Truong's PhD project on precision spectroscopy for gas metrology, which he has conducted at the University since 2009 under the supervision of UWA Winthrop Professor Eric May and former Winthrop Professor Andre Luiten (now at University of Adelaide) , with funding from the Australian Research Council's Discovery program.

Mr Truong said better, more reliable data on global warming held significant benefit to society, helping researchers better understand its causes and accurately evaluate the impact of policy decisions.

"This research is of particular significance to Australia if it is to take the lead in global warming policy and research," Mr Truong said. "It is also highly relevant to WA, where the economy is strongly driven by oil, gas and mineral industries."

Mr Truong, who worked on the new spectroscopy technique while on a year-long Australian Fulbright Fellowship at NIST, said the breakthrough combined ideas already being developed at UWA with apparatus and methods used at NIST.

The resulting novel approach - dubbed Frequency-Agile, Rapid Scanning spectroscopy (FARS) - had greatly improved the speed at which gases could be traced without compromising on precision.

"Usually in science or engineering if you want to make measurements go faster, you have to sacrifice sensitivity," Mr Truong said.

"What we have demonstrated here is a 200,000-fold increase in speed to enable high-precision spectroscopy without degrading sensitivity - we've built a new apparatus with unparalleled speed, accuracy, precision and spectral coverage."

"The unique properties of FARS make it well suited for many existing challenges in trace gas sensing," Mr Truong wrote in a paper published online today in the journal, Nature Photonics.

"We see clear applications in the real-time measurements of greenhouse gas fluxes, as well as in the monitoring of dynamic processes such as combustion."

More information: dx.doi.org/10.1038/NPHOTON.2013.98

NASA LANDSAT-5 (LDCM) satellite takes the Salton Sea's temperature

The Salton Sea in Southern California and nearby irrigated fields stand out in this image taken March 24, 2013, by the Thermal Infrared Sensor (TIRS) instrument on the Landsat Data Continuity Mission (LDCM) satellite. 

Darker areas of the image are cooler, while lighter areas are warmer. 

Credit: USGS/NASA's Earth Observatory.

An image from an instrument aboard NASA's Landsat Data Continuity Mission or LDCM satellite may look like a typical black-and-white image of a dramatic landscape, but it tells a story of temperature.

The dark waters of the Salton Sea pop in the middle of the Southern California desert. Crops create a checkerboard pattern stretching south to the Mexican border.

If you looked at the Salton Sea in person, your eyes would not see anything presented in the LDCM image.

Instead of showing visible light, the image shows the amount of heat, or thermal energy, radiating from the landscape and detected by the Thermal Infrared Sensor, or TIRS, instrument on LDCM. Cooler areas are dark, while warm areas are bright.

The dark squares in the LDCM's image of the Salton Sea are fields where plants can absorb irrigation water before sweating it off through a process called transpiration.

Just like when people sweat, plants cool down when they transpire.

The combination of transpiration and water evaporating from the ground itself, evapotranspiration, drops the temperature of the irrigated land.

Those cool temperatures, indicating healthy, well-watered plants, are picked up by TIRS.

Dennis Reuter

"What you're looking at is infrared light that's generated by the Earth itself," said Dennis Reuter, TIRS instrument scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.

TIRS is one of two instruments on the newest spacecraft in the Landsat family, launched Feb. 11 and currently in its on-orbit calibration and checkout phase.

While its partner instrument records reflected sunlight, TIRS complements that view with temperature readings across swaths of Earth's surface.

The Goddard-designed detectors in the TIRS instruments can pick up two different bands of thermal infrared energy, which excite electrons and create an electrical signal.

With TIRS measuring the strength of those signals, corresponding to temperatures on the ground, scientists can generate images like this one of the Salton Sea.

The view you get from TIRS is similar to what you've seen on television crime shows when cops use thermal imagers to track warm-bodied suspects moving around inside of a building. With Landsat, though, scientists use the thermal bands to track down water.

Dark pixels representing cool spots and light pixels of hot spots are key to helping water managers determine where the valuable resource is being used for irrigation, especially in the arid western United States.

Scientists use A-Train satellites to measure how pollution particles affect clouds

Described as a satellite constellation, the 'A-Train' is shown in this artist's conception. 

The close timing and engineering of these satellites along a track means that they function as if they were all on the same platform. 

Data collected by the A-Train gave scientists in this CloudSat study more complete information on atmospheric particles around the globe. Photo: NASA.

Grabbing a virtual tiger by the tail, scientists led by researchers at Pacific Northwest National Laboratory directly linked a cloud's inclination to rain to its effects on the climate.

Using global satellite data and complex calculations, they were able—for the first time—to develop a proxy measurement for one of the most vexing questions in atmospheric science: how tiny particles in the atmosphere affect the amount of cloud.

Using this new metric, they showed that aerosols' effects on clouds are overestimated by as much as 30 percent in a global climate model. The results were published in the journal Geophysical Research Letters.

"Our study helps narrow the large aerosol-cloud interaction uncertainties in projections of future global warming," said Dr. Minghuai Wang, atmospheric scientist at PNNL and lead author of the study.

"Wide ranges of estimates in aerosol effects on clouds have made it challenging to understand how clouds really affect the climate." Understanding clouds and their effects on climate is a formidable challenge in trying to predict how the climate will change by the end of the century.

On the line are questions of future melting of the polar ice, drought and water shortages, and increases in extreme weather events. One particularly tough question is how tiny pollution-caused particles in the atmosphere will affect clouds.

This study shows how satellite observations can be used to hone in on aerosol effects on clouds and make it possible to better understand how clouds will affect climate.

"The use of satellite observations in studying climate processes like these is absolutely critical because it is the only way to obtain cloud and aerosol measurements over the whole globe," said Dr. Mikhail Ovchinnikov, PNNL atmospheric scientist and co-author of the study.

The study, led by PNNL scientists, constructed a new metric for rain frequency susceptibility, then closely correlated that metric to the aerosol effect on cloud amount, which is the total amount of water in the cloud and the cloud's size.

This metric, along with satellite measurements, was then used in three global climate models to find new ranges of cloud amount change due to pollution-caused aerosol particles, compared to current estimates.

The team, for the first time, used "A-Train" satellite observations which collect coincident global measurements of aerosols, clouds, and precipitation to develop a new metric, termed rain frequency susceptibility or "S-POP."

This metric provides a quantitative measure of the sensitivity of rain frequency to the amount of aerosols in clouds.

They showed how S-POP is closely correlated to aerosols' effects on cloud amount, using three global climate models, including a multi-scale aerosol climate model developed at PNNL (PNNL-MMF) that embeds a cloud-resolving model at each grid column of a host global climate model.

Finally, the relationship between S-POP and the aerosol effects on cloud amount from the global climate models together with the observed rain frequency susceptibility from A-Train observations were used to estimate aerosol effects on cloud amount in global climate models.

They showed that in one global model, the National Center for Atmospheric Research's Community Atmosphere Model version 5 (CAM5), aerosol effects on clouds were overestimated by 30 percent.

This research also provides a guide for the development and evaluation of new parameterizations, techniques to computationally represent complex small-scale systems, of aerosol effects on clouds in global climate models.

The researchers plan to apply S-POP to evaluate cloud amount based on rain frequency susceptibility in other global climate models, and guide further improvement of the aerosol indirect effects estimations in CAM5 and the PNNL-MMF multi-scale aerosol-climate model.

Read the paper: "Constraining Cloud Lifetime Effects of Aerosols Using A-Train Satellite Observations," Geophysical Research Letters 39:L15709. DOI:10.1029/2012GL052204

Lasers Measure Earth's Rotation and Wobble

The Earth spins around once every 24 hours on its axis, creating the continuous cycle of day and night but this rotation isn't as straightforward as it sounds: Forces large and small cause the Earth to wobble as it spins. This wobbling can pose a problem for navigation systems like GPS.

Scientists working with lasers and mirrors are refining a new system to track the Earth's rotation and its kinks.

The pull of gravity from the sun and the moon contribute to the planet's wobble.

So do variations in atmospheric pressure, ocean loading and the wind, which change the position of the Earth's axis relative to the surface. Together their effect is called the Chandler wobble, and it has a period of 435 days.

Another force causes the rotational axis to move over a period of a year. This "annual wobble" is due to the Earth's elliptical orbit around the sun.

Between these two effects, the Earth's axis migrates irregularly along a circular path with a radius of up to 20 feet (6 meters).

Pinning down the overall wobble of the planet's rotation is key to keeping certain tracking systems accurate.

Currently, this is now done through a complicated process that involves 30 radio telescopes around the globe that measure the direction between Earth and specific quasars, a type of galaxy that is assumed to be stationary relative to the Earth.

A better system
In the mid-1990s, scientists of Germany's Technische Universitaet Muenchen and Federal Agency for Cartography joined forces with researchers at New Zealand's University of Canterbury to develop a simpler method for tracking the Chandler wobble and annual wobble.

"We also wanted to develop an alternative that would enable us to eliminate any systematic errors," said station director, Karl Ulrich Schreiber. "After all, there was always a possibility that the reference points in space were not actually stationary."

The scientists had the idea of building a ring laser similar to ones used in aircraft guidance systems – only millions of times more exact.

"At the time, we were almost laughed off. Hardly anyone thought that our project was feasible," Schreiber said in a statement.

Yet at the end of the 1990s, work on the world's most stable ring laser got under way at Wettzell Geodetic Observatory, in the Bavarian Forest of southeast Germany.

The installation includes two counter-rotating laser beams that travel around a square path with mirrors in the corners, which form a closed beam path (hence the name "ring laser").

Ring around the laser
When the assembly rotates, the co-rotating light has farther to travel than the counter-rotating light. The beams adjust their wavelengths, causing the optical frequency to change. The scientists can use this difference to calculate the rotational velocity the instrumentation experiences.

"The principle is simple," Schreiber said. "The biggest challenge was ensuring that the laser remains stable enough for us to measure the weak geophysical signal without interference — especially over a period of several months."

With some tweaks to the system, the researchers have succeeded in corroborating the Chandler and annual wobble measurements made from the radio telescopes.

They now aim to make the apparatus even more accurate, enabling them to determine changes in the Earth's rotational axis over a single day.

The scientists also plan to make the ring laser capable of running continuously for a period of years. "In future," Schreiber said, "we want to be able to just pop down into the basement and find out how fast the Earth is accurately turning right now."

ESA Planning new Instruments to measure Volcanic Ash

Iceland's ongoing eruption is likely to press the case for new satellite instruments to monitor volcanic ash thrown into the atmosphere.

Read the ESA Article on their website

Remote sensing expert Dr Fred Prata told a major Earth sciences meeting in Vienna that current monitoring from space was good but could be improved.

ESA's ENVISAT and MetopSat are a primary tool to monitor the Earth. Visit the ESA Metop satellite site click here.

"Of the present suite of satellite instruments, none were developed for the volcanic ash problem," he said.

"Therefore, they are sub-optimal for detecting and determining quantities of volcanic ash."

Dr Prata has been speaking here at the European Geosciences Union (EGU) conference in the Austrian capital.

He is a senior scientist with the Norwegian Institute for Air Research, and leads a group called Savaa - Support to Aviation for Volcanic Ash Avoidance.

This team is supported by the European Space Agency and aims to improve the way that satellite data is collected for use in the dispersion models that help airlines and the authorities decide whether it is safe to fly planes.

Dr Prata said several space instruments currently in operation had been critical to the present monitoring efforts.

He cited the Seviri instrument on Europe's Meteosat 8 and 9 spacecraft which sit in a geostationary orbit, returning images of the Earth every 15 minutes. Seviri has helped distinguish the volcanic ash from other clouds, determining its extent - mass loading - in two dimensions.

The lidar on the Calipso spacecraft had brought a unique and extremely valuable capability, he explained.

"Because it's an active instrument that fires pulses of light down to the Earth and gets the backscatter radiation, it gives us height-resolved information.

You can see the top of the cloud and its bottom, so that means you get the thickness.

"Once we get the thickness, combining that with our two-dimensional picture of the mass loading we can get the concentration; and that's the number that the airlines would like to have."

The airlines at this time are working to a safe limit of two micrograms of ash per cubic metre of air.

The third instrument noted by Dr Prata is Iasi, an infrared sounding interferometer on Europe's polar orbiting Metop platform which he said was sending back exceptional data on the presence ash, sulphur dioxide (SO2), ice, and even the conversion of SO2 to sulphuric acid.

Click Here to see ENVISAT Instruments in a Larger Image

The downside of Metop and Calipso is that they circle the Earth and do not have permanent vision over Iceland and the rest of Europe.

A version of Iasi is due to go on the next generation of Meteosats but the first of these platforms will not fly until 2018.

Dr Prata said there was a case now for fast-tracking the launch of this instrument.

"Everyone's looking at what the best solutions might be. Nobody wants to spend lots of money so fast-tracking an existing programme would be a good solution," he said.

"Another possibility is to have a scanning lidar in space. Calipso looks straight down. If it's scanning, you'd get a lot more information."

EGU has also heard some of the latest science being done by volcanologists and seismologists at Eyjafjoll.

Dr Thor Thordarson from Edinburgh University, UK, is working with a team that is now collecting large numbers of samples of the ash fall, both in Iceland and beyond.

The group is trying to explain why precisely the volcano ejected so much fine material in the sizes that could be transported great distances.

This far-flung dust ranged in size from about 30-40 microns (millionths of a metre) down to even the sub-micron scale.

Dr Thordarson said it was clear that melt waters getting into the vent from the glacier on the volcano had contributed to the explosive fragmentation of rock, but what exactly happened remained a mystery.

"Why this event disintegrated the magma so intensely, we don't know; and it's something we desperately want to find out," he said.

"If we get enough observations from a good number of sites then we can reconstruct the total grain-size distribution that was coming out of the vent. And when you have that information, then you can start looking at models to explain the fragmentation processes involved and why they were so intense."

Astronomically Large Lenses Measure Age And Size Of Universe

When a large nearby object, such as a galaxy, blocks a distant object, such as another galaxy, the light can detour around the blockage. But instead of taking a single path, light can bend around the object in one of two, or four different routes, thus doubling or quadrupling the amount of information scientists receive.

As the brightness of the background galaxy nucleus fluctuates, physicists can measure the ebb and flow of light from the four distinct paths, such as in the B1608+656 system imaged above. (Image courtesy Sherry Suyu of the Argelander Institut fur Astronomie in Bonn, Germany.)


Using entire galaxies as lenses to look at other galaxies, researchers have a newly precise way to measure the size and age of the universe and how rapidly it is expanding, on a par with other techniques.

The measurement determines a value for the Hubble constant, which indicates the size of the universe, and confirms the age of the universe as 13.75 billion years old, within 170 million years. The results also confirm the strength of dark energy, responsible for accelerating the expansion of the universe.

These results, by researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at the US Department of Energy's SLAC National Accelerator Laboratory and Stanford University, the University of Bonn, and other institutions in the United States and Germany, will be published in The Astrophysical Journal in March.

The researchers used data collected by the NASA/ESA Hubble Space Telescope, and showed the improved precision they provide in combination with the Wilkinson Microwave Anisotropy Probe (WMAP).

The team used a technique called gravitational lensing to measure the distances light traveled from a bright, active galaxy to the earth along different paths. By understanding the time it took to travel along each path and the effective speeds involved, researchers could infer not just how far away the galaxy lies but also the overall scale of the universe and some details of its expansion.

Oftentimes it is difficult for scientists to distinguish between a very bright light far away and a dimmer source lying much closer. A gravitational lens circumvents this problem by providing multiple clues as to the distance light travels. That extra information allows them to determine the size of the universe, often expressed by astrophysicists in terms of a quantity called Hubble's constant.

"We've known for a long time that lensing is capable of making a physical measurement of Hubble's constant," KIPAC's Phil Marshall said. However, gravitational lensing had never before been used in such a precise way. This measurement provides an equally precise measurement of Hubble's constant as long-established tools such as observation of supernovae and the cosmic microwave background. "Gravitational lensing has come of age as a competitive tool in the astrophysicist's toolkit," Marshall said.

Climate Control: Scientists measure methane at the source

In a lush pasture near Buenos Aires, this cow and its compatriots are digesting important information: how much methane—a greenhouse gas 20 times as potent as carbon dioxide—is released by the country’s 55 million bovines.

Researchers from Argentina’s National Institute of Agricultural Technology connected inflatable tanks to the cows’ first stomach, where methane is made, through a small hole between their ribs.

By measuring methane production directly inside each cow, biologist Silvia Valtorta hopes to more accurately determine the country’s overall agricultural contribution to global warming. According to the data, an average cow releases more than 70 gallons of the stuff every day. But a change in diet could reduce that. Cows that eat mostly grain produce 20 to 25 percent less methane than grazing cows, and adding tannin—a bitter chemical found in wine—to the feed could lower it further.