NASA’s Orbiting Carbon Observatory-2 / Aura satellite

NASA’s Orbiting Carbon Observatory-2: Data to lead scientists forward into the past

Date: July 20, 2014

Source: NASA/Jet Propulsion Laboratory

Summary: NASA’s Orbiting Carbon Observatory-2, which launched on July 2, will soon be providing about 100,000 high-quality measurements each day of carbon dioxide concentrations from around the globe. Atmospheric scientists are excited about that. But to understand the processes that control the amount of the greenhouse gas in the atmosphere, they need to know more than just where carbon dioxide is now. They need to know where it has been. It takes more than great data to figure that out.

Scientists will use measurements from the Orbiting Carbon Observatory-2 to track atmospheric carbon dioxide to sources such as these wildfires in Siberia, whose smoke plumes quickly carry the greenhouse gas worldwide. The fires were imaged on May 18 by NASA’s Moderate Resolution Imaging Spectrometer instrument on the Terra satellite. Credit: NASA/LANCE/EOSDIS Rapid Response 

NASA’s Orbiting Carbon Observatory-2, which launched on July 2, will soon be providing about 100,000 high-quality measurements each day of carbon dioxide concentrations from around the globe. Atmospheric scientists are excited about that. But to understand the processes that control the amount of the greenhouse gas in the atmosphere, they need to know more than just where carbon dioxide is now. They need to know where it has been. It takes more than great data to figure that out.

“In a sense, you’re trying to go backward in time and space,” said David Baker, a scientist at Colorado State University in Fort Collins. “You’re reversing the flow of the winds to determine when and where the input of carbon at the Earth’s surface had to be to give you the measurements you see now.”

Harry Potter used a magical time turner to travel to the past. Atmospheric scientists use a type of computer model called a chemical transport model. It combines the atmospheric processes found in a climate model with additional information on important chemical compounds, including their reactions, their sources on Earth’s surface and the processes that remove them from the air, known as sinks.

Baker used the example of a forest fire to explain how a chemical transport model works. “Where the fire is, at that point in time, you get a pulse of carbon dioxide in the atmosphere from the burning carbon in wood. The model’s winds blow it along, and mixing processes dilute it through the atmosphere. It gradually gets mixed into a wider and wider plume that eventually gets blown around the world.”

Some models can be run backward in time — from a point in the plume back to the fire, in other words — to search for the sources of airborne carbon dioxide. The reactions and processes that must be modeled are so complex that researchers often cycle their chemical transport models backward and forward through the same time period dozens of times, adjusting the model as each set of results reveals new clues. “You basically start crawling toward a solution,” Baker said. “You may not be crawling straight toward the best answer, but you course-correct along the way.”

Lesley Ott, a climate modeler at NASA’s Goddard Space Flight Center, Greenbelt, Maryland, noted that simulating carbon dioxide’s atmospheric transport correctly is a prerequisite for improving the way global climate models simulate the carbon cycle and how it will change with our changing climate. “If you get the transport piece right, then you can understand the piece about sources and sinks,” she said. “More and better-quality data from OCO-2 are going to create better characterization of global carbon.”

Baker noted that the volume of data provided by OCO-2 will improve knowledge of carbon processes on a finer scale than is currently possible. “With all that coverage, we’ll be able to resolve what’s going on at the regional scale,” Baker said, referring to areas the size of Texas or France. “That will help us understand better how the forests and oceans take up carbon. There are various competing processes, and right now we’re not sure which ones are most important.”

Ott pointed out that improving the way global climate models represent carbon dioxide provides benefits far beyond the scientific research community. “Trying to figure out what national and international responses to climate change should be is really hard,” she said. “Politicians need answers quickly. Right now we have to trust a very small number of carbon dioxide observations. We’re going to have a lot better coverage because so much more data is coming, and we may be able to see in better detail features of the carbon cycle that were missed before.” Taking those OCO-2 data backward in time may be the next step forward on the road to understanding and adapting to climate change.

To learn more about the OCO-2 mission, visit these websites:

NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA’s Earth science activities in 2014, visit:http://www.nasa.gov/earthrightnow

OCO-2 is managed by NASA’s Jet Propulsion Laboratory, Pasadena, California.

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A 10-year endeavor: NASA’s Aura and climate change

Date: July 18, 2014

Source: NASA/Jet Propulsion Laboratory

Summary: Celebrating its 10th anniversary this week, NASA’s Aura satellite and its four onboard instruments measure some of the climate agents in the atmosphere, including greenhouse gases, clouds and dust particles. These global datasets provide clues that help scientists understand how Earth’s climate has varied and how it will continue to change.

NASA’s 10-year-old Aura satellite, which studies Earth’s atmosphere, continues to help scientists understand Earth’s changing climate. Credit: NASA

Nitrogen and oxygen make up nearly 99 percent of Earth’s atmosphere. The remaining one percent comprises gases that — although present in small concentrations — can have a big impact on life on Earth. Trace gases called greenhouse gases warm the surface, making it habitable for humans, plants and animals. But these greenhouse gases, as well as clouds and tiny particles called aerosols in the atmosphere, also play vital roles in Earth’s complex climate system.

Celebrating its 10th anniversary this week, NASA’s Aura satellite and its four onboard instruments measure some of the climate agents in the atmosphere, including greenhouse gases, clouds and dust particles. These global datasets provide clues that help scientists understand how Earth’s climate has varied and how it will continue to change.

Measuring Greenhouse Gases

When the sun shines on Earth, some of the light reaches and warms the surface. The surface then radiates this heat back outward, and greenhouse gases stop some of the heat from escaping to space, keeping the surface warm. Greenhouse gases are necessary to keep Earth at a habitable temperature, but since the Industrial Revolution, greenhouse gases have increased substantially, causing an increase in temperature. Aura provides measurements of greenhouse gases such as ozone and water vapor, helping scientists understand the gases that influence climate.

People, plants and animals live in the lowest layer of the atmosphere, called the troposphere. In this layer, the temperature decreases with altitude, as mountain climbers experience. The temperature starts to increase again at the tropopause, about 8 miles (12.9 kilometers) above the surface at temperate latitudes, like those of the United States and Europe. Closer to the equator, the tropopause is about 11 miles (17.7 kilometers) from the surface.

In the middle and upper troposphere, ozone acts as a greenhouse gas, trapping heat in Earth’s atmosphere. Tropospheric ozone is one of the most important human-influenced greenhouse gases.

Aura’s Tropospheric Emission Spectrometer (TES) instrument, built and managed by NASA’s Jet Propulsion Laboratory, Pasadena, California, delivers global maps showing annual averages of the heat absorbed by ozone, in particular in the mid troposphere. Using these maps and computer models, researchers learned that ozone trapped different amounts of heat in Earth’s atmosphere depending on its geographic location. For instance, ozone appeared to be a more effective greenhouse gas over hotter regions like the tropics and cloud-free regions like the Middle East.

“If you want to understand climate change, you need to monitor the greenhouse gases and how they change over time,” said Bryan Duncan, an atmospheric scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Along with ozone, Aura measures other important greenhouse gases such as methane, carbon dioxide and water vapor.

Improving Climate Models

In addition to greenhouse gases, Aura measures several other constituents relevant to climate — smoke, dust and clouds including the ice particles within the clouds — that are important for testing and improving climate models.

“If you don’t have any data, then you don’t know if the models are right or not,” said Anne Douglass, Aura project scientist at Goddard. “The models can only be as good as your knowledge.”

The way clouds affect Earth’s climate depends on their altitude and latitude. Two of Aura’s instruments have provided information about tropical clouds. Like greenhouse gases, high, thin clouds in the tropics absorb some of Earth’s outgoing heat and warm the surface. Aura’s High Resolution Dynamics Limb Sounder (HIRDLS) instrument provided global maps showing cirrus clouds in the upper altitudes in the tropics. Researchers have used these data along with data records from previous satellites going back to 1985 to show that the tropical cirrus cloud distribution has been steady, giving scientists information about the interplay among water vapor, ice and the life cycle of these clouds.

Aura’s Microwave Limb Sounder (MLS) instrument, also built and managed by JPL, made the first global measurements of cloud ice content in the upper troposphere, providing new data input for climate models. MLS showed cloud ice is often present over warm oceans. Along with satellite rainfall data, MLS shows that dirty, polluted clouds rain less than clean clouds. The novel relationships obtained from HIRDLS and MLS connect ocean temperatures with clouds and ice and quantify effects of pollution on tropical rainfall — which are important assessments for climate models.

Aerosols influence climate, but their influence is challenging to decipher because they play several different roles. Aerosols reflect radiation from the sun back into space; this tends to cool Earth’s surface. Aerosols such as dust and smoke also absorb radiation and heat the atmosphere where they are concentrated. Aura’s Ozone Monitoring Instrument (OMI) is especially good at observing these absorbing aerosols above clouds and bright deserts. Both OMI and TES also provide data on gases, such as sulfur dioxide and ammonia, which are primary ingredients for other types of less-absorbing aerosols. Aura data, in conjunction with other satellite data, are helping scientists understand how aerosols interact with incoming sunlight in Earth’s atmosphere; this, in turn, helps scientists improve long-term predictions in climate models.

Learning from Long Data Sets

Researchers investigated how natural phenomena such as El Niño affect tropospheric ozone concentrations — a study made possible by Aura’s extensive data set.

El Niño is an irregularly occurring phenomenon associated with warm ocean currents near the Pacific coast of South America that changes the pattern of tropical rainfall. The occasional appearance of areas of warmer temperatures in the Pacific Ocean shifts the stormiest area from the west to the east; the region of upward motion — a hallmark of low ozone concentrations over the ocean — moves along with it.

Without a decade-long data record, researchers would not be able to conduct such a study. Using the extensive data set, researchers are able to separate the response of ozone concentrations to the changes in human activity, such as biomass burning, from its response to natural forcing such as El Niño.

“Studies like these that investigate how the composition of the troposphere responds to a natural variation are important for understanding how the Earth system will respond to other forcing, potentially including changes in climate,” said Douglass. “The Earth system is complex, and Aura’s breadth and the length of the composition data record help us to understand this important part of the system.”

For more information on Aura, visit: http://aura.gsfc.nasa.gov/

For more on TES, visit: http://tes.jpl.nasa.gov/

For more on MLS, visit: http://mls.jpl.nasa.gov/index-eos-mls.php

NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA’s Earth science activities in 2014, visit:http://www.nasa.gov/earthrightnow

*   *   *

Ten-year endeavor: NASA’s Aura tracks pollutants

Date: July 18, 2014

Source: NASA/Jet Propulsion Laboratory

Summary: NASA’s Aura satellite, celebrating its 10th anniversary on July 15, has provided vital data about the cause, concentrations and impact of major air pollutants. With instruments providing key measurements of various gases — including two built and managed by NASA’s Jet Propulsion Laboratory: the Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) — Aura gives a comprehensive view of one of the most important parts of Earth — the atmosphere.

The maps show the Antarctic ozone hole on September 16 in 2006 and 2011, the two years with the lowest ozone concentrations ever measured. They were made with data from the Ozone Monitoring Instrument on Aura. Credit: NASA’s Earth Observatory

NASA’s Aura satellite, celebrating its 10th anniversary on July 15, has provided vital data about the cause, concentrations and impact of major air pollutants. With instruments providing key measurements of various gases — including two built and managed by NASA’s Jet Propulsion Laboratory: the Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) — Aura gives a comprehensive view of one of the most important parts of Earth — the atmosphere.

Aura has improved our understanding of ozone, a versatile gas that both benefits and harms the atmosphere, depending on its location. Near the ground, ozone is a pollutant that damages plants and can decrease lung function in humans. Somewhat higher in the atmosphere, ozone affects climate as a greenhouse gas. Aura’s TES instrument provides measurements of ozone and other greenhouse gases.

The majority of ozone, about 90 percent, is even higher — in the stratosphere, 12 to 90 miles above the surface — where it shields us from the sun’s ultraviolet light and makes life possible on Earth. Over the Antarctic, cold temperatures and human-produced chlorine gases destroy ozone each spring. Scientists use Aura’s Microwave Limb Sounder (MLS) instrument to measure ozone and other trace gases in and around the ozone hole every year. In 2006 and 2011, Aura’s instruments revealed two of the largest and deepest ozone holes in the past decade, and also helped scientists understand the different causes of the two large holes.

Shortly after Aura’s launch, the Ozone Monitoring Instrument (OMI) began monitoring levels of another major pollutant — nitrogen dioxide. This brownish gas can lead to respiratory problems and is an ingredient in ground-level ozone pollution. OMI data show that nitrogen dioxide levels in the United States decreased 4 percent per year from 2005 to 2010, a time when stricter policies on power plant and vehicle emissions came into effect. As a result, concentrations of ground-level ozone also decreased. During the same period, global nitrogen dioxide levels increased a little over half a percent per year. China’s level increased about 6 percent per year.

OMI also measures sulfur dioxide, a gas that combines with other chemicals in clouds to produce acid rain or reacts to form sulfate aerosols, which affect health and climate. OMI has identified large concentrations of sulfur dioxide around power plants and volcanoes.

Aura’s decade of work has set the stage for future air quality monitoring instruments. The European Space Agency will be launching the follow-up TROPOspheric Monitoring Instrument, which will continue Aura’s OMI measurements with better ground resolution and precision. NASA plans to launch the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, which will observe ozone, nitrogen dioxide, sulfur dioxide, formaldehyde and aerosols over the United States, Canada and Mexico.

“Pollution is a global issue because it can travel long distances in the wind,” said Anne Douglass, Aura project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “By using satellites, we can develop a valuable global inventory of pollutants and understand how air quality may be changing.”

For more on Aura’s 10-year contribution to atmospheric chemistry research, visit:

For more on TES, visit: http://tes.jpl.nasa.gov/

For more on MLS, visit: http://mls.jpl.nasa.gov/index-eos-mls.php

NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA’s Earth science activities in 2014, visit: http://www.nasa.gov/earthrightnow

 

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