A Brighter Moon

NASA - Cassini Mission to Saturn patch.

Nov. 17, 2015

Although Dione (near) and Enceladus (far) are composed of nearly the same materials, Enceladus has a considerably higher reflectivity than Dione. As a result, it appears brighter against the dark night sky.

The surface of Enceladus (313 miles or 504 kilometers across) endures a constant rain of ice grains from its south polar jets. As a result, its surface is more like fresh, bright, snow than Dione's (698 miles or 1123 kilometers across) older, weathered surface. As clean, fresh surfaces are left exposed in space, they slowly gather dust and radiation damage and darken in a process known as "space weathering."

This view looks toward the leading hemisphere of Enceladus. North on Enceladus is up and rotated 1 degree to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 8, 2015.

The view was acquired at a distance of approximately 52,000 miles (83,000 kilometers) from Dione. Image scale is 1,600 feet (500 meters) per pixel. The distance from Enceladus was 228,000 miles (364,000 kilometers) for an image scale of 1.4 miles (2.2 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image, Text, Credits: NASA/JPL-Caltech/Space Science Institute/Tony Greicius.

Greetings, Orbiter.ch

Cool New Batteries for Solar Impulse

SolarImpulse - Around the World patch.

November 17, 2015

After several months of designing and testing, it’s now time to get Solar Impulse back on its feet! And to avoid the batteries overheating again, our engineers have upgraded the whole battery system and integrated a cooling system. Take a look at how and when the repair work will take place to get the plane ready for part 2 of the round the world tour.

As you may have heard, Solar Impulse has been hangared in Hawaii since July – not the worst place to be stranded we reckon – because its batteries overheated during the 5-day and night record breaking flight from Nagoya, Japan. Since the plane had been exposed to harsh weather conditions from Nanjing to Nagoya, we decided to do a test flight before leaving for Hawaii. Having to perform a test flight followed by a mission flight had not been taken into account in the design process of the battery system, which did not allow the batteries to cool down in between the two.

Technicians carrying out maintenance work on the batteries in Hawaii in July

But the show must go on, and for the plane to be back in the air by April 2016, our technical team still has a lot on its plate. Why wait until spring? Because the days are longer, which means more daylight hours to recharge the batteries during flight periods.

Let’s remember that we are at the limits of technology: each morning the charge goes down to 10% of battery capacity.

Imagine how you feel when you realize that the battery level of your cell phone is red and that you only have a few minutes left before it shuts down! The first batch of upgraded elements, five in total (four to replace the plane’s damaged ones, and one for testing), is currently under construction. The second one, the four spare parts, will be hatched beginning of 2016.

Let’s take a look at the planning concerning the first round. The three types of elements are designed separately and then mounted together before being integrated into the aircraft.

1. The key components, the batteries, have been produced by our supplier Kokam, and are now on their way to Germany to be tested, assembled, and placed in their boxes. They are similar to the former ones.

Battery dummy cells made out of aluminum sheet metal for thermal tests

2. In parallel, the battery containers, are being built and undergoing shock testing in Dübendorf, Switzerland. They will be ready at the end of November, and the batteries will thus be encapsulated in December. Like the previous ones, they contain silver (a good electrical conductor), but the novelty lies in a fail-safe system which should safeguard us from anymore temperature-related glitches in case we have to follow a different mission profile than the one foreseen. It can be controlled from the cockpit and includes a cooling and backup system. In case the cooling system breaks down, the backup one steps in and allows the pilot to control the opening so that it doesn’t stay completely open, which would cause freezing, or closed, leading to another overheating scenario. Indeed, this could "Jeopardise" the continuation of the flight which would be critical if the airplane was flying over an ocean.

Structural load test of the new battery box: 1000 kg towards the ground, 370 kg to the side

3. The last level is the engine housing (or gondola), which shelters both battery and engine, seeing as the former powers the latter at night. A few adjustments concerning the electronics have been made and an air vent has been added to let air flow into the battery’s cooling system. The gondolas are also currently being pieced together in Dübendorf, by our hard working engineers and technicians.

Air inlet on gondola front part for the new battery cooling system

And for now, you can give the world leaders a hand by voting here for the solutions to tackle climate change you think most efficient. We will take the most popular ones to the UN climate conference COP21: http://www.futureisclean.org/solutions?utm_source=blog&utm_medium=banner&utm_content=batteries&utm_campaign=solutions

For more information about Solar Impulse Around the World, visit: http://www.solarimpulse.com/

Images, Text, Credit: SolarImpulse.

Greetings, Orbiter.ch

NASA's Curiosity Mars Rover Heads Toward Active Dunes

NASA - Mars Science Laboratory  (MSL) patch.

Nov. 16, 2015

Image above: This Sept. 25, 2015, view from the Mast Camera on NASA's Curiosity Mars rover shows a dark sand dune in the middle distance. Image Credits: NASA/JPL-Caltech/MSSS.

On its way to higher layers of the mountain where it is investigating how Mars' environment changed billions of years ago, NASA's Curiosity Mars rover will take advantage of a chance to study some modern Martian activity at mobile sand dunes.

In the next few days, the rover will get its first close-up look at these dark dunes, called the "Bagnold Dunes," which skirt the northwestern flank of Mount Sharp. No Mars rover has previously visited a sand dune, as opposed to smaller sand ripples or drifts. One dune Curiosity will investigate is as tall as a two-story building and as broad as a football field. The Bagnold Dunes are active: Images from orbit indicate some of them are migrating as much as about 3 feet (1 meter) per Earth year. No active dunes have been visited anywhere in the solar system besides Earth.

Image above: The dark band in the lower portion of this Martian scene is part of the "Bagnold Dunes" dune field lining the northwestern edge of Mount Sharp. Image Credits: NASA/JPL-Caltech/MSSS.

"We've planned investigations that will not only tell us about modern dune activity on Mars but will also help us interpret the composition of sandstone layers made from dunes that turned into rock long ago," said Bethany Ehlmann of the California Institute of Technology and NASA's Jet Propulsion Laboratory, both in Pasadena, California.

As of Monday, Nov. 16, Curiosity has about 200 yards or meters remaining to drive before reaching "Dune 1." The rover is already monitoring the area's wind direction and speed each day and taking progressively closer images, as part of the dune research campaign. At the dune, it will use its scoop to collect samples for the rover's internal laboratory instruments, and it will use a wheel to scuff into the dune for comparison of the surface to the interior.

Curiosity has driven about 1,033 feet (315 meters) in the past three weeks, since departing an area where its drill sampled two rock targets just 18 days apart. The latest drilled sample, "Greenhorn," is the ninth since Curiosity landed in 2012 and sixth since reaching Mount Sharp last year. The mission is studying how Mars' ancient environment changed from wet conditions favorable for microbial life to harsher, drier conditions.

Image above: This view taken from orbit around Mars shows the sand dune that will be the first to be visited by NASA's Curiosity Mars Rover along its route to higher layers of Mount Sharp. Image Credits: NASA/JPL-Caltech/Univ. of Arizona.

Before Curiosity's landing, scientists used images from orbit to map the landing region's terrain types in a grid of 140 square quadrants, each about 0.9 mile (1.5 kilometers) wide. Curiosity entered its eighth quadrant this month. It departed one called Arlee, after a geological district in Montana, and drove into one called Windhoek, for a geological district in Namibia. Throughout the mission, the rover team has informally named Martian rocks, hills and other features for locations in the quadrant's namesake area on Earth. There's a new twist for the Windhoek Quadrant: scientists at the Geological Society of Namibia and at the Gobabeb Research and Training Center in Namibia have provided the rover team with a list of Namibian geological place names to use for features in this quadrant. The Windhoek theme was chosen for this sand-dune-bearing quadrant because studies of the Namib Desert have aided interpretation of dune and playa environments on Mars.

Animation above: This animation flips back and forth between views taken in 2010 and 2014 of a Martian sand dune at the edge of Mount Sharp, documenting dune activity. Animation Credits: NASA/JPL-Caltech/Univ. of Arizona.

What distinguishes actual dunes from windblown ripples of sand or dust, like those found at several sites visited previously by Mars rovers, is that dunes form a downwind face steep enough for sand to slide down. The effect of wind on motion of individual particles in dunes has been studied extensively on Earth, a field pioneered by British military engineer Ralph Bagnold (1896-1990). Curiosity's campaign at the Martian dune field informally named for him will be the first in-place study of dune activity on a planet with lower gravity and less atmosphere.

Observations of the Bagnold Dunes with the Compact Reconnaissance Imaging Spectrometer on NASA's Mars Reconnaissance Orbiter indicate that mineral composition is not evenly distributed in the dunes. The same orbiter's High Resolution Imaging Science Experiment has documented movement of Bagnold Dunes.

"We will use Curiosity to learn whether the wind is actually sorting the minerals in the dunes by how the wind transports particles of different grain size," Ehlmann said.

Image above: This map shows the route driven by NASA's Curiosity Mars rover from the location where it landed in August 2012 to its location in mid-November 2015, approaching examples of dunes in the "Bagnold Dunes" dune field. Image Credits: NASA/JPL-Caltech/Univ. of Arizona.

As an example, the dunes contain olivine, a mineral in dark volcanic rock that is one of the first altered into other minerals by water. If the Bagnold campaign finds that other mineral grains are sorted away from heavier olivine-rich grains by the wind's effects on dune sands, that could help researchers evaluate to what extent low and high amounts of olivine in some ancient sandstones could be caused by wind-sorting rather than differences in alteration by water.

Ehlmann and Nathan Bridges of the Johns Hopkins University's Applied Physics Laboratory, Laurel, Maryland, lead the Curiosity team's planning for the dune campaign.

"These dunes have a different texture from dunes on Earth," Bridges said. "The ripples on them are much larger than ripples on top of dunes on Earth, and we don't know why. We have models based on the lower air pressure. It takes a higher wind speed to get a particle moving. But now we'll have the first opportunity to make detailed observations."

JPL, managed by Caltech for NASA, built Curiosity and manages the project for NASA's Science Mission Directorate in Washington. For more information about Curiosity, visit:

http://www.nasa.gov/msl

http://mars.jpl.nasa.gov/msl/

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

http://www.twitter.com/marscuriosity

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/Guy Webster/Martin Perez.

Best regards, Orbiter.ch

Space-Grown Flowers Will be New Year Blooms on International Space Station

NASA - Veggie Mission patch.

November 16, 2015

Flowers could be blooming on the International Space Station after the New Year.

This morning, NASA astronaut Kjell Lindgren activated the Veggie plant growth system and its rooting “pillows” containing Zinnia seeds on the space station.

It is the first time that a flowering crop experiment will be grown on the orbiting laboratory. Growing Zinnias in orbit will help provide precursory information about other flowering plants that could be grown in space.

“Growing a flowering crop is more challenging than growing a vegetative crop such as lettuce,” said Gioia Massa, NASA Kennedy Space Center payload scientist for Veggie. “Lighting and other environmental parameters are more critical.”

Veggie Activated to Grow Fresh Plants on Space Station. Image Credit: NASA

Lindgren will turn on the red, blue and green LED lights, activate the water and nutrient system to Veggie, and monitor the plant growth. The Zinnias will grow for 60 days, which is twice as long as the first and second crop of Outredgeous red romaine lettuce that grew on the space station.

During the growth cycle, the LED lights will be on for 10 hours and off for 14 hours in order to stimulate the plants to flower.

“Growing the Zinnia plants will help advance our knowledge of how plants flower in the Veggie growth system, and will enable fruiting plants like tomatoes to be grown and eaten in space using Veggie as the in-orbit garden,” said Trent Smith, Veggie program manager at Kennedy.

Researchers also hope to gather good data regarding long-duration seed stow and germination, whether pollen could be an issue, and the impacts on crew morale. Growing tomato plants on the space station is planned for 2017.

The Veggie system was developed by Orbital Technologies Corp. (ORBITEC) in Madison, Wisconsin, and tested at Kennedy before flight. Veggie, along with two sets of pillows containing romaine seeds and one set of zinnias, was delivered to the station by SpaceX on the third cargo resupply mission in April 2014.

Related links:

The Vegetable Production System (Veggie): http://www.nasa.gov/mission_pages/station/research/experiments/383.html

International Space Station (ISS): http://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credits: NASA/Linda Herridge.

Greetings, Orbiter.ch

Another Dimension: 3D visualisation redefines Milky Way's local architecture

ESA - Gaia Mission patch.

16 November 2015

Astronomers have used modern techniques to visualise data from ESA's Hipparcos space astrometry mission in three dimensions. The treatment of the data has offered insights into the distribution of nearby stars and uncovered new groupings of stars in the solar neighbourhood, shedding light on the origins of the stars in Orion and calling into question the existence of the Gould Belt – an iconic ring-shaped structure of stars in the Milky Way. The results show the potential of 3D visualisation of the solar neighbourhood, an approach which is of particular relevance to ESA's Gaia mission which will map the Milky Way and Local Group in 3D with unprecedented sensitivity and accuracy.

Image above: Visualising the local solar neighbourhood in 3D. Image Credits: ESA. Acknowledgement: H. Bouy (CSIC-INTA) & J. Alves (U. Vienna).

 In a new study published in Astronomy & Astrophysics researchers have created a 3D map [1] of massive O and B type stars (sometimes referred to as OB stars) using data from ESA's Hipparcos satellite, launched in 1989 and operated until 1993. These stars, which live for a maximum of only a few tens of millions of years, are important markers of recent star formation and much can be learnt from studying their distribution in the solar neighbourhood.

Previous studies have looked for groupings of these stellar giants by seeking out concentrations of them in 2D projections. Astronomers use these 2D projections to look at the position and velocity of the stars in a given region and pick out stars that are moving together, and are thus most likely members of the same stellar group.

"Mapping data from missions like Hipparcos in two dimensions has allowed us to identify and classify numerous stellar groups and has profoundly changed our knowledge and understanding of the solar vicinity," explains Hervé Bouy from the Center for Astrobiology (CSIC-INTA), Spain, lead author of the study. "But it comes with significant drawbacks. 2D projections are just not capable of describing all the features of 3D space and using them to model distributions can cause artificial structures to appear and important structures to be hidden in the projection and lost."

Among other drawbacks, all 2D projection methods, including those not described here [2], can be affected by the presence of companion stars. Binary stars – two stars which orbit one another – can interfere with measurements of the motion of the stars in a group causing smaller or less tightly bound groups to be missed when searching for them solely on the basis of their common motion. In this study, rather than project the data onto a series of 2D planes, the astronomers used the measured distances to O and B type stars in the data to map the density and position of the stars in three dimensions. The 3D data analysis and interactive visualisation techniques used in this study, combined with a lack of reliance on velocities as a discovery criterion for the stellar groups, led to several discoveries that had been missed in 25 years of 2D analysis of the data.

"Our study has shown just how different the architecture of the solar neighbourhood looks when mapped in three dimensions," explains João Alves from the University of Vienna, Austria, co-author of the paper. "We have produced a 3D visualisation of all of the Hipparcos O and B type stars within around 1500 light years of the Sun and in doing so have found evidence for new structures in the distribution of nearby hot stars, and new and surprising theories of how those stars formed."

The team found that the solar neighbourhood is dominated by three huge stream-like galactic structures made up of dense clusters and loose associations of young, blue, O and B type stars. These contain several tens of O and B type stars, most of the local well-known clusters, and some previously unreported stellar groups. The first structure runs from the constellation Scorpius to the constellation Canis Majoris covering more than 1100 light years and at least 65 million years of star formation history. The second, located in the constellation Vela, covers at least 500 light years and 30 million years of history. Although all three of the newly discovered streams have a story to tell, it is the third structure, located in the constellation Orion, that is perhaps the most significant due to its mystery-solving qualities.

The origin of the blue supergiants that define the body and belt of the Orion constellation has long been a mystery. The five giant O and B type stars are located between around 250 and 800 light years from Earth and as a result it was assumed that their origin was not, despite their name, in the prolific Orion Nebula star-forming region, which lies around 1300 light years from Earth. However, the discovery of the Orion stream offers a simple solution. It implies that these relatively distant populations are in fact linked as part of a large galactic structure, which spans more than 1000 light years and at least 25 million years of star formation history.

The origin of the body and belt are not the only answers this study might hold for the birth of the Hunter.

"One exciting find from this study relates to Betelgeuse, the red giant in the arm of Orion," remarks Bouy. "The origin of this star has always been shrouded in mystery but through this study we have uncovered a new loosely organised group – or OB association – named Taurion which we believe to be Betelgeuse's birthplace and to contain its sibling stars."

By using modern full-3D data analysis, Bouy and Alves have not only uncovered the previously unknown, they may also have identified a significant visual illusion produced by previous 2D methods. In the 19th century, British astronomer John Herschel and then American astronomer Benjamin Gould identified a 3000 light-year-long partial ring of O and B type stars in the Milky Way. This belt, projected on the sky, was thought to be a grouping of stars and has come to be known as the Gould Belt – a famous and prominent structure in the Milky Way. Now, Bouy and Alves have shown that when mapped in three dimensions this model does not in fact provide a good fit for the distribution of O and B type stars, potentially disproving the existence of this galactic icon and calling for a new interpretation of stellar groups in the solar neighbourhood.

Gaia mapping the stars of the Milky Way. Image Credit: ESA

"The Gould Belt is the perfect example of how 2D projections can deceive astronomers," argues Alves. "Our results imply that it is just a projection effect produced by the Sun's position between two of the streams of stars, rather than representing the architecture of the solar neighbourhood itself."

The results published in this study include caveats and possible sources of error in part due to the extinction in the Hipparcos data, in other words the amount of light that was absorbed and scattered by dust on its way to the telescope, compromising the quality of the data. The study is also biased towards young stars, due to its focus on O and B type stars, and dense stellar groups. Despite this, the results show that our current models of the solar neighbourhood are not sufficient to uncover the true structure of how its stellar inhabitants are distributed or trace the history of their formation and evolution, there is significantly more to learn about our local environment.

"These results show just what 3D visualisation can deliver, and how much further it can take us," explains Jos de Bruijne, ESA's Gaia system scientist, also acting as ESA liaison scientist for the Hipparcos mission. "It provides an even stronger case for focussing on the local neighbourhood and, in particular, for doing so in three dimensions. This study really raises the expectations for what the Gaia mission will produce."

Gaia was launched in 2013 with the aim of unveiling the origin and evolution of our Galaxy. It will provide measurements of the positions and velocities with respect to Earth of up to one billion stars in our Galaxy and Local Group with unprecedented accuracy and sensitivity. The three-dimensional map produced by Gaia will far outdo any current or foreseen maps of the stars in the Milky Way. It will include non-O and-B type stars and be able to identify clusters and groups not dense enough to register in the Hipparcos map.

The success of the Hipparcos study in highlighting the benefits of visualising 25-year-old data using modern visualisation methods emphasises the potential of stellar mapping in 3D and Gaia will provide the data needed to peer further into the origin, evolution and structure of our Galaxy.

An interactive tool showing the Hipparcos data represented in three dimensions is available online: http://sci.esa.int/hipparcos/ob-stars-interactive

Notes:

[1] Hervé Bouy and João Alves have created an interactive tool to show the distribution of O and B stars in the solar neighbourhood. A low-resolution version (quicker loading time) is available here; a high-resolution version is available here:
http://sci.esa.int/hipparcos/ob-stars-interactive
http://sci.esa.int/hipparcos/ob-stars-interactive-hr

[2] Astronomers also use what is called the convergent point method, a method which is responsible for identifying most of the O and B type star associations and clusters discovered so far. Whilst unrelated stars will move in random directions, those in a group will move towards a convergence point where the paths of all its members will intersect.

More Information:

"Cosmography of OB stars in the solar neighbourhood" by H. Bouy and J. Alves is published in Astronomy & Astrophysics, November 2015:
http://dx.doi.org/10.1051/0004-6361/201527058

ESA's Hipparcos space astrometry mission was a pioneering European project which pinpointed the three-dimensional positions of more than one hundred thousand stars with high precision, and more than one million stars with lesser precision. Launched in August 1989, Hipparcos successfully observed the celestial sphere for 3.5 years before operations ceased in March 1993. Calculations from observations by the main instrument generated the Hipparcos Catalogue of 118 218 stars charted with the highest precision. An auxiliary star mapper pinpointed many more stars with lesser but still unprecedented accuracy, in the Tycho Catalogue of 1 058 332 stars. The Tycho 2 Catalogue, completed in 2000, brings the total to 2 539 913 stars, and includes 99 per cent of all stars down to magnitude 11, almost 100 000 times fainter than the brightest star, Sirius.

Gaia is an ESA mission to survey one billion stars in our Galaxy and local galactic neighbourhood in order to build the most precise 3D map of the Milky Way and answer questions about its origin and evolution. Launched in December 2013, Gaia's routine science operations began in July 2014. The mission's primary scientific product will be a catalogue with the positions, motions, brightnesses, and colours of the surveyed stars. An intermediate version of the catalogue will be released in 2016.

For more information about Gaia mission, visit: http://sci.esa.int/hipparcos/ and http://www.esa.int/Our_Activities/Space_Science/Gaia

Images (mentioned), Text, Credits: ESA/Jos de Bruijne/University of Vienna/João Alves/Center for Astrobiology (CSIC-INTA)/Herve Bouy.

Best regards, Orbiter.ch

A black hole in action

ESA - Hubble Space Telescope patch.

Nov. 16, 2015

A supermassive black hole in action

Scientists often use the combined power of multiple telescopes to reveal the secrets of the Universe – and this image is a prime example of when this technique is strikingly effective.

The yellow-hued object at the centre of the frame is an elliptical galaxy known as Hercules A, seen by the Earth-orbiting NASA/ESA Hubble Space Telescope. In normal light, an observer would only see this object floating in the inky blackness of space.

However, view Hercules A with a radio telescope, and the entire region is completely transformed. Stunning red–pink jets of material can be seen billowing outwards from the galaxy – jets that are completely invisible in visible light. They are shown here as seen by the Karl G. Jansky Very Large Array radio observatory in New Mexico, USA. These radio observations were combined with the Hubble visible-light data obtained with the Wide Field Camera 3 to create this striking composite.

The two jets are composed of hot, high-energy plasma that has been flung from the centre of Hercules A, a process that is driven by a supermassive black hole lurking at the galaxy’s heart. This black hole is some 2.5 billion times the mass of the Sun, and around a thousand times more massive than the black hole at the centre of our Milky Way galaxy.

Hercules A’s black hole heats material and accelerates it to nearly the speed of light, sending it flying out into space at phenomenally high speeds. These highly focused jets lose energy as they travel, eventually slowing down and spreading out to form the cloud-like lobes seen here.

Hubble orbiting Earth

The multiple bright rings and knots seen within these lobes suggest that the black hole has sent out numerous successive bursts of material over the course of its history. The jets stretch for around 1.5 million light-years – roughly 15 times the size of the Milky Way.

Hercules A, also known as 3C 348, lies around two billion light-years away. It is one of the brightest sources of radio emission outside our Galaxy.

This image was originally published in November 2012.

Related link:

Karl G. Jansky Very Large Array radio observatory: http://www.vla.nrao.edu/

For images and more information about Hubble, visit: http://www.nasa.gov/hubble and http://hubblesite.org/ and http://www.spacetelescope.org

Image, Video, Text, Credits: NASA, ESA, S. Baum & C. O’Dea (RIT), R. Perley & W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA).

Greetings, Orbiter.ch

Public release of whole-atmosphere monthly mean carbon dioxide concentration

JAXA - SATellite "IBUKI" (GOSAT) logo.

November 16, 2015

Public release of whole-atmosphere monthly mean carbon dioxide concentration based on observations by Greenhouse gases Observing Satellite "IBUKI" (GOSAT)

The project of the Greenhouse gases Observing SATellite "IBUKI" (GOSAT), the world’s first satellite designed specifically for monitoring greenhouse gases from space, is jointly promoted by the Ministry of the Environment, Japan, the National Institute for Environmental Studies, and Japan Aerospace Exploration Agency. The satellite has been in operation since its launch on January 23, 2009.

 SATellite "IBUKI" (GOSAT)

The whole-atmosphere monthly mean concentration of carbon dioxide (CO₂), calculated by using GOSAT data that reflect CO₂ levels in all layers of the atmosphere, was found to have reached 398.8 ppm in May 2015, while showing seasonal oscillation and yearly rise over the analyzed period. It was also confirmed that the trend line of the whole-atmosphere CO₂ mean, derived by removing averaged seasonal fluctuations from the monthly CO₂ time series, had reached 398.2 ppm in July 2015. The trend line is expected to exceed 400 ppm within the year 2016, given that the rising trend continues. The GOSAT observation elucidates for the first time that CO₂ concentration averaged over all layers of the atmosphere will soon reach the level of 400 ppm, and demonstrates the importance of global greenhouse gas monitoring from space.

About Greenhouse gases Observing SATellite “IBUKI”

The Greenhouse gases Observing SATellite "IBUKI" (GOSAT) is the world's first satellite designed specifically for the monitoring of greenhouse gases from space. Its primary purpose is to measure the atmospheric concentration of carbon dioxide (CO₂) and methane from space so as to improve the estimation of the surface fluxes of these two gases and, further, to contribute to refining the prediction of future carbon cycle. The satellite has been in operation since its launch on January 23, 2009. The GOSAT Project is jointly promoted by the Ministry of the Environment, Japan, the National Institute for Environmental Studies (NIES), and Japan Aerospace Exploration Agency (JAXA) (hereafter the three parties).

Characteristics and significance of greenhouse gas observation by GOSAT

CO₂ changes at surface-level monitoring sites and the global CO₂ mean based on those observations have long been reported by the World Meteorological Organization and several other meteorological agencies around the world. To further facilitate an understanding of overall trends for CO₂ in the atmosphere, knowledge of “whole-atmosphere” CO₂ mean is necessary, and for this, more CO₂ information in the vertical direction is needed. In fact, from past measurements taken by aircraft, CO₂ levels are known to vary with altitude. Model predictions of whole-atmosphere CO₂ mean have appeared in the fifth assessment report by the Intergovernmental Panel on Climate Change, as they are important for predicting the risk of global warming due to rising greenhouse gas levels. This is where CO₂ observation by GOSAT comes in useful, as the satellite measurement encompasses levels from the surface to the top of the atmosphere and provides CO₂ concentration averaged over an entire atmospheric column (this is referred to as column-averaged CO₂ concentration).

Whole-atmosphere monthly mean CO₂ concentration as seen by GOSAT

The whole-atmosphere mean CO₂ concentration was calculated based on GOSAT measurement. Observational data collected by the satellite over a period exceeding six years, between May 2009 and July 2015, were used for this calculation. Over the analyzed period, the monthly mean CO₂ concentration continually rose, with seasonal fluctuations due to photosynthetic activity by plants that intensifies and subsides over a single year in the Northern Hemisphere. The monthly mean reached 398.8 ppm in May 2015. The trend line of the global CO₂ mean, obtained by subtracting averaged seasonal fluctuations from the monthly CO₂ time series, reached 398.2 ppm in July 2015 1). It was also found that the trend line will exceed 400 ppm within the year 2016, if the rising trend continues. It is expected that the monthly mean concentration will reach 400 ppm earlier than the trend line does. We note here that areas that GOSAT measurement can cover are limited to parts of the globe without cloud cover and where the local solar altitude is above a specific threshold. Therefore, the global distribution of column-averaged CO₂ concentration, needed for the calculation of the whole-atmosphere mean CO₂ concentration, was estimated from GOSAT data 2). Shown below are the time series of the monthly mean CO₂ concentration and the trend line calculated from the monthly time series 3). The values shown here are found to be smaller by 1-2 ppm than those based on CO₂ measurements at the surface level 4).

Note: The error bar on the red circle indicates uncertainty (one standard deviation) associated with the whole-atmosphere monthly mean.

Public release of GOSAT observation results

The three parties will publicly release the above-mentioned whole-atmosphere monthly mean CO₂ concentration, estimated from GOSAT observations collected over clear-sky areas of the globe. The data will be released on November 16, 2015 from the website of the NIES GOSAT Project. The released data will be updated regularly over the remaining lifetime of the satellite. This public release is intended to highlight the reality of rising CO₂ levels and to contribute to efforts for reducing greenhouse gas emissions.

The released data can be obtained from the webpage “Whole-atmosphere monthly mean CO₂ concentration” (http://www.gosat.nies.go.jp/en/recent-global-co2.html) found on the NIES GOSAT Project website.

The three parties will continue the public dissemination of new findings from GOSAT observation. Also, the parties plan to continue the ongoing space-based greenhouse gas observation with the GOSAT successor (GOSAT-2), which is planned to be launched in 2018. Results of the continued observation will be utilized for the elaboration and refinement of global warming predictions.

Notes:

1) Some of the GOSAT data used in this analysis, dated after February 2015, are still preliminary, pending final validation.
2) See Appendix for more details on the estimation approach used.
3) Result for January 2015 is missing due to lacking data for instrument adjustment
4) US National Oceanic and Atmospheric Administration reported that global mean CO₂ concentration based on surface level measurements reached 400 ppm in March 2015.
Source: http://research.noaa.gov/News/NewsArchive/LatestNews/TabId/684/ArtMID/1768/ArticleID/11153/Greenhouse-gas-benchmark-reached-.aspx

Related link:

Greenhouse gases Observing SATellite "IBUKI" (GOSAT): http://global.jaxa.jp/projects/sat/gosat/

Image, Graphic, Text, Credits: Japan Aerospace Exploration Agency (JAXA)/National Research and Development Agency/National Institute for Environmental Studies（NIES)/Ministry of the Environment, Japan (MOE).

Greetings, Orbiter.ch