China’s spectacular economic growth during the last decade has brought many benefits – and some challenges. Global atmospheric mapping of nitrogen dioxide pollution performed by ERS-2’s GOME and Envisat’s SCIAMACHY reveals the world’s largest amount of NO2 hanging above Beijing and northeast China, as reported in Nature this week.

As part of ESA’s Dragon Programme, European and Chinese researchers are using results returned from the Global Ozone Mapping Experiment (GOME) on ERS-2 and the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) on Envisat to monitor and forecast Chinese air quality.

In this context, researchers at the University of Bremen, the Max-Planck Institute of Meteorology in Hamburg and France’s Centre National de la Recherche Scientifique (CNRS) have been studying the retrieval of nitrogen dioxide variability from space and modelling its global behaviour.

The team have published an article in the 1 September 2005 edition of the science journal Nature about the global changes in nitrogen dioxide observed in the last decade from space and highlighted the dramatic changes over China.

Nitrogen dioxide (NO2) is associated with nitrogen oxide (NO2) in the atmosphere and the sum of the two is called NOX. This is released into the troposphere from power plants, heavy industry and road transport, along with biomass burning, lightning in the atmosphere and microbial activity in the soil. The emission of nitrogen oxides has increased about six-fold since pre-industrial times and in cities above a thousand times more NOX is present than in the pristine and remote marine boundary layer.

Exposure to nitrogen dioxide in large quantities is known to cause lung damage and respiratory problems, although little is known about the consequences of long term exposure to elevated atmospheric amounts. The presence of this gas is a significant driver of the production of low-level ozone, which, within the troposphere (the lowest part of the atmosphere, extending eight to 16 kilometres in height) is itself a harmful toxic pollutant, a major ingredient of photochemical smog.

“While nitrogen dioxide vertical column concentrations above central and eastern Europe and parts of the East Coast of the United States have been either static or exhibiting a small decrease, there is a clear and significant increase over China,” explains John Burrows of the University of Bremen’s Institute of Environmental Physics, SCIAMACHY’s Principal Investigator.

“Before SCIAMACHY was flying we previously retrieved NO2 data from its precursor instrument, GOME on ESA’s ERS-2 mission. Although GOME had lower resolution, the article shows that China’s nitrogen dioxide retrievals from the two instruments overlap seamlessly.

“What the combined data show are that nitrogen dioxide levels have risen by around 50% since 1996, and this behaviour is continuing.”

Space-based sensors are the only way to carry out effective global and regional monitoring of the atmosphere. While GOME demonstrated the first satellite sensitivity to tropospheric nitrogen dioxide, SCIAMACHY possesses superior performance, with a spatial resolution of 60 x 30 kilometres compared to 320 x 40 km for its predecessor.

SCIAMACHY also observes the atmosphere in two different ways – downwards or nadir-sounding’ as well as ‘limb-sounding’ along the direction of flight – and with a larger spectral range than its predecessor.

The increase in nitrogen dioxide levels seen is an unfortunate side effect of economic success. China’s industrial boom has seen it become the world’s largest consumer of copper, aluminium and cement and the second bigger importer of oil. Car ownership within the country has been doubling every few years.

“China’s nitrogen dioxide concentration varies according to season,” Burrows adds. “There is more in the winter as a result of differing emission patterns and meteorology. For example more fuel is burned for heating and nitrogen dioxide persists longer in the atmosphere at that less sunny time of year – lasting around a day rather than hours, as in the summer.

“Meteorology also plays a role. There is a peak before Christmas: this is not because industrial activity, domestic heating or transportation is suddenly reduced after the holiday season but because there is an eastward outflow of air that was previously revolving around Asia. This is the same type of phenomenon that carries dust from the Gobi Desert across to the West Coast of the US.”

China is reliant on coal to meet 75% of its national energy needs, and that means high levels of another atmospheric pollutant called sulphur dioxide (SO2) also detectable by SCIAMACHY. Large SO2 sources over China that overlap with nitrogen dioxide plumes are linked to power plants. Further to the west there is also sulphur dioxide produced from smouldering underground coal seam fires.

Burrows is the scientist who – supported by an international team – proposed both GOME and SCIAMACHY to national space agencies and ESA in the first place. He explained that the two instruments were originally chosen to fly because of their ability to measure stratospheric ozone, but were also selected in order to investigate the amount of useful information that could be retrieved from the troposphere.

“The instruments are now being used to monitor a significant number of key tropospheric trace gases including formaldehyde, methane, sulphur dioxide and carbon monoxide and dioxide,” Burrows remembers. “Back when we were starting out, many people thought it would be impossible to get any useful results out of the troposphere. There are many important issues to deal with, such as cloud cover and the highly variable reflectivity of the surface, as well as having the absorption or emission of stratospheric and upper atmospheric species situated between the troposphere and the instrument.

“First with GOME and now much better with SCIAMACHY we are demonstrating it can be done. The success so far is an important step on the way to establishing an operational global observing system for the Earth’s atmosphere. This is something we need as we enter the geological age of the Anthropocene, where the activities of mankind and its interactions with natural phenomena are the driving force in global climate change.

“Next we are hoping for follow-up satellite missions, in particular from geostationary orbit to monitor atmospheric pollution, which has a strong diurnal variation and thereby determine objectively the changing atmospheric composition.”

SCIAMACHY: surveying the world in six days

SCIAMACHY is a spectrometer, and it works by measuring sunlight – either transmitted, reflected or scattered by the Earth’s atmosphere or surface in the ultraviolet, visible and near infrared regions. Mathematical inversion of these data yields the amounts and distribution of trace gases, ozone and related chemicals, clouds and dust particles throughout the atmosphere. With a 960-km swath and alternate limb and nadir observations, SCIAMACHY covers the entire world every six days at the equator and more often at high latitudes.

This versatile instrument represents a national contribution to ESA’s Envisat mission. It was funded by the German government through the German Aerospace Center (DLR), the Dutch government through the Netherlands Agency for Aerospace Programmes (NIVR) and also the Belgian government through the Belgian Institute for Space Aeronomy (BIRA-IASB).

SCIAMACHY is part of a family of atmospheric sounders that also includes GOME on ERS-2 and also the forthcoming GOME-2 instrument due to launch next year aboard ESA’s and EUMETSAT’s first MetOp spacecraft.

About Dragon

The Dragon Programme is a joint undertaking between ESA, the Ministry of Science and Technology (MOST) of China and the National Remote Sensing Centre of China (NRSCC). Its purpose is to encourage increased exploitation of ESA space resources within China as well as stimulate increased scientific co-operation in the field of Earth Observation science and applications between China and Europe.

Original press release: Breath of the dragon: ERS-2 and Envisat Reveal Impact of Economic Growth on China’s Air Quality (ESA)

Climate change will wreak havoc on the United Kingdom’s marine environment, deepening the decline of cod, threatening the future survival of some sea bird colonies, and causing wide-scale coastal disruption, a new WWF report has found.

The report — Climate change: Plunging our Seas into Deeper Crisis — notes that an increase in sea surface temperature will be a major factor in further disrupting the breeding, feeding, and growing cycles of fish, and in turn sea birds. This will be spurred by impacts on plankton, the major food source of many fish and the foundation of the entire marine environment.

The report also found that major storm surges — temporary increases in sea level caused by atmospheric pressures and strong winds — will have destructive impacts on coastal areas as they become more frequent. Storm surges could cause flooding events in the east of England and in the London area. Sea level rise is also likely to reduce coastal habitats of sea birds through erosion and damage to nesting sites. Sandeels, a major food source for birds and fish, which breed in shallow sand banks, may also be affected.

“Our seas are already under severe pressure from a number of activities such as fishing, oil and gas exploration, and coastal development,” said Andrew Lee, Director of Campaigns at WWF-UK.

“This report shows that climate change has the power to deepen this crisis and to completely turn our marine world upside down, disrupting and changing the entire ecosystem.”

The North Sea, where plankton is reported to have already changed dramatically, is likely to be hit the hardest by climate change. This will have direct impacts on cod stocks, in addition to the existing pressures from fisheries, according to the report.

“This heightens the urgency for government action to both significantly reduce the UK’s CO2 emissions and to bring forward a new Marine Bill, which will protect our marine wildlife and reform the way our seas are planned and managed to ensure they are economically productive and sustainable for future generations,” Lee added.

The group of scientists who contributed to the report also highlighted ocean acidification as a major concern. The acidity (pH) of the sea has already reduced from 8.3 to 8.2 and is predicted to decline to 7.6 by the end of the century. This would be beyond any level of acidity experienced by current marine wildlife and is likely to impact corals, sea urchins and shell fish as well as breeding success of fish, such as cod.

Harbour porpoises and fin whales are most likely to be affected by climate change through the combined impacts of pollution and reduced food supply. This will threaten their breeding success, and in the case of harbour porpoises, this is likely to accelerate their decline.

“Climate change will cause dramatic disruption to our seas over the coming years,” said Emily Lewis-Brown, WWF-UK’s Marine Research Officer.

“Future planning of our marine environment must take into account the effects of climate change to help our seas adapt to the challenges that will come.”

Original press release: Climate Change to Cause Chaos in UK Seas (WWF)

NASA is marshaling agency resources to assist Gulf Coast-area facilities that suffered damage from Hurricane Katrina. The agency is preparing to provide help for NASA employees and contractors whose homes were damaged or destroyed.

Monday’s storm hit NASA’s Stennis Space Center in Mississippi and Michoud Assembly Facility in New Orleans, which is operated by Lockheed Martin. Both facilities are closed during recovery efforts. During the storm, hundreds of people including employees, family members and others took shelter at Stennis. A small contingency of NASA employees and contractors rode out the storm at Michoud. There are no reports of any injuries at NASA facilities.

“My heart goes out to all the people affected by this hurricane,” said NASA Administrator Michael Griffin. “I will be visiting Stennis and the Michoud Assembly Facility soon to talk with our people.”

NASA’s Marshall Space Flight Center, Huntsville, Ala., sustained minor damage and is providing support to Stennis and Michoud. Two helicopter flights from Marshall were delivering communication equipment and other supplies to the facilities today. Initial damage assessments indicate some buildings at Stennis sustained water and roof damage, but the exact extent has not been determined.

The Federal Emergency Management Agency is using the center as a staging area for local recovery efforts. The center’s Space Shuttle main engine test stands do not appear to be damaged.

At Michoud, which makes the Space Shuttle’s external fuel tanks, several buildings suffered window and roof damage. It appears that space flight hardware was not damaged, but a preliminary assessment has not been completed. The facility has no electrical power and communication is limited. Debris on roadways is restricting transportation around the facility.

Original press release: NASA Assesses Hurricane Katrina Damage (NASA)

New results shed light on how Antarctica became the icy, barren continent that we know today. British Antarctic Survey (BAS) scientists have discovered that 30-50 million years ago, South America and Antarctica split apart very rapidly. This formed the Drake Passage and resulted in a major global cooling. The findings are published in the latest issue of Earth and Planetary Science Letters.

Lead Author Dr Roy Livermore says ‘we deciphered the remarkable ‘herringbone’ pattern of ridges that were etched into the Earth’s crust beneath the remote Weddell Sea when South America moved away from Antarctica. This revealed that the two continents separated extremely quickly in geological time forming a shallow ‘gateway’ between the Pacific and Atlantic oceans. We estimate that this happened some ten to twenty million years earlier than the previous oldest estimate. Even a shallow (less than 1000 metres) gateway would have had a profound effect on Southern Ocean circulation and subsequently climate”.

Such a gateway, by completing a circuit of water around Antarctica, eventually led to the formation of the Antarctic Circumpolar Current, the world’s largest deep current which now transports some 130 million cubic metres of water through the Drake Passage every second. The effect was to cut Antarctica off from warm southward flowing currents leaving it frozen and desolate.

This new research reinforces findings from deep-sea sediments cores taken from the Southern Ocean and supports the theory that the opening of the Drake Passage could have triggered the abrupt global cooling event and extensive growth of the Antarctic ice sheet 33-34 million years ago.

Original press release: Early Drake Passage Opening Led to Global Change (BAS - British Antarctic Survey)

Real-time radar data and high-tech communications were the keystones to success this past weekend as the Rainband and Intensity Change Experiment (RAINEX) project began its research with Hurricane Katrina. The project is funded by the National Science Foundation (NSF).

RAINEX became the first hurricane research project to fly planes nearly simultaneously inside and outside a hurricane’s principal rainband, gathering information that will help scientists to better understand changes in a hurricane’s intensity.

RAINEX is studying the interaction between hurricane winds and rain, using data recorded from hurricane research flights, according to Steve Nelson, program director in NSF’s atmospheric sciences division, which funded RAINEX. For six weeks of this year’s active hurricane season, two research aircraft will fly simultaneously into hurricanes before the storms make landfall.

Flying in the hurricane’s outer bands and eyewall on most flights, the aircraft are using sophisticated Doppler radar and Global Positioning System dropsondes to record wind speed and direction, temperature, humidity, atmospheric pressure, and other critical data.

“While the forecasting of hurricane tracks has come a long way, that kind of information results from a variety of variables external to the hurricane,” says Robert Houze, an atmospheric scientist at the University of Washington and a RAINEX principal investigator. “Intensity is driven in part by internal dynamics between the rainbands and the eyewall - something that is very hard to get to - so this is landmark information that will help us to understand this phenomenon better.”

Shuyi Chen, a meteorologist and physical oceanographer at the University of Miami Rosenstiel School of Marine and Atmospheric Sciences (RSMAS), also a RAINEX principal investigator, developed a fine-resolution, coupled atmosphere-wave-ocean computer model to study hurricane intensity changes. While most models estimate atmospheric activity down to tens of kilometers, her model goes further - down to a kilometer or two, filling in information gaps and providing realistic rainband and eyewall structure simulation. Researchers are able to use the model in combination with airborne Doppler radar measurements to better understand hurricane intensity changes.

“The airborne radar data come into our operations center in real-time,” said Chen. “We process it, and then share it with the research planes within a few minutes. This helps the planes navigate and position themselves appropriately, and it helps us guide planes to exactly the area of the hurricane where we want to take measurements. It’s the first time we have ever tried this new way of communicating from the ground to planes flying in a hurricane.”

RAINEX also involves scientists from the National Center for Atmospheric Research (NCAR) in Boulder, Colo., the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Navy.

Original press release: Hurricane Katrina: Scientists Fly Into Eye of the Storm (NSF)

This season’s Antarctic ozone hole has swollen to an area of ten million square kilometres from mid-August - approximately the same size as Europe and still expanding. It is expected to reach maximum extent during September, and ESA satellites are vital for monitoring its development.

This year’s hole is large for this time of year, based on results from the last decade: only the ozone holes of 1996 and 2000 had a larger area at this point in their development.

Envisat’s Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) routinely monitors ozone levels on a global basis, continuing a dataset of measurements stretching back to mid-1995, previously made by the Global Ozone Monitoring Experiment (GOME) aboard the earlier ESA spacecraft ERS-2.

ESA data form the basis of an operational near-real time ozone monitoring and forecasting service forming part of the PROMOTE (PROtocol MOniToring for the GMES Service Element) consortium, made up of more than 30 partners from 11 countries, including the Royal Dutch Meteorological Institute (KNMI).

As part of the PROMOTE service, the satellite results are combined with meteorological data and wind field models so that robust ozone and ultraviolet forecasts can be made. In a first for ESA, these results are being used by the World Meteorological Organisation (WMO) to compile their regularly-updated Antarctic Ozone Bulletin.

The precise time and range of Antarctic ozone hole occurrences are determined by regional meteorological variations. During the southern hemisphere winter, the atmospheric mass above the Antarctic continent is kept cut off from exchanges with mid-latitude air by prevailing winds known as the polar vortex. This leads to very low temperatures, and in the cold and continuous darkness of this season, polar stratospheric clouds are formed that contain chlorine.

The stratospheric ozone layer that protects life on Earth from harmful ultraviolet (UV) radiation is vulnerable to the presence of certain chemicals in the atmosphere such as chlorine, originating from man-made pollutants like chlorofluorocarbons (CFCs).

Now banned under the Montreal Protocol, CFCs were once widely used in aerosol cans and refrigerators. CFCs themselves are inert, but ultraviolet radiation high in the atmosphere breaks them down into their constituent parts, which can be highly reactive with ozone.

As the polar spring arrives, the combination of returning sunlight and the presence of polar stratospheric clouds leads to splitting of chlorine into highly ozone-reactive radicals that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.

The PROMOTE atmospheric ozone forecast seen here has atmospheric ozone measured in Dobson Units (DUs), which stands for the total thickness of ozone in a given vertical column if it were concentrated into a single slab at standard temperature and atmospheric pressure – 400 DUs is equivalent to a thickness of four millimetres, for example.

Developing out of the successful precursor Tropospheric Emission Monitoring Information Service (TEMIS), PROMOTE is a portfolio of information services covering the atmosphere part of the Earth System, operating as part of ESA’s initial Services Element of Global Monitoring for Environment and Security (GMES). This is a joint initiative between ESA and the European Commission to combine all available ground- and space-based information sources and develop a global environmental monitoring capability for Europe.

Original press release: South Polar Ozone Hole Makes Big Comeback (ESA)