Climate Change Impacts

As environmental change influences transportation, it will be paramount to see how transportation base may be affected over the short- and long haul. This segment gives assets on the conceivable effects of environmental change on U.s. transportation frameworks.

Resources

Coastal Sensitivity to Sea Level Rise: A Focus on the Mid-Atlantic Region (2009)

Ecological Protection Agency. A report by the U.s. Environmental Change Science Program and the Subcommittee on Global Change Research.

This report is proposed to give data about the affectability and flexibility of distinctive characteristic and oversaw environments and human frameworks to atmosphere and related worldwide changes by giving a nitty gritty appraisal of the impacts of ocean level climb on beachfront situations and showing a portion of the difficulties that need to be tended to adjust to ocean level ascent while ensuring ecological assets and supporting financial development.

Variables Affecting Airport Weather Delay and the Impact of Climate Change (2009)

This paper assesses the effect of changing climate on air transport operations over the advancing 50 years, utilizing a careful investigation of London's Heathrow air terminal.

Overwhelmed Bus Barns and Buckled Rails: Public Transportation and Climate Change Adaptation

This report looks at anticipated atmosphere affects on U.s. travel, environmental change adjustment exertions by household and outside travel organizations, travel adjustment methods, hazard administration devices, and joining of adjustment into travel organization authoritative structures and procedures.

Manufactured surfaces build vitality request and hotness island impacts, unfavorably effect air quality, and produce nursery gasses that help an unnatural weather change. This paper shows a strategy to gauge surface sorts in the manufactured environment and their effects on high temperature island impacts.

Worldwide Climate Change and Transportation: Coming to Terms (2001)

Transportation Research Board

This set of readings meant to manufacture expanded proficient understanding among state Dots and other transportation associations of the worldwide environmental change issues and their suggestions for transportation choices. The ENO Transportation Foundation authorized presentations of paramount parts of worldwide environmental change and their potential ramifications for the country's transportation framework.

Worldwide Climate Change Impacts in the United States (2009)

Effects of Climate Change and Variability on Transportation Systems and Infrastructure: The Gulf Coast Study

To better comprehend potential environmental change affects on transportation base and recognize adjustment techniques, the U.s. Branch of Transportation (U.s. Speck) is directing a complete, multi-stage investigation of environmental change affects in the Central Gulf Coast area. This district is home to a complex multimodal system of transportation framework and a few expansive populace focuses, and it plays a basic national financial part in the import and fare of oil and gas, horticultural items, and different merchandise. The study is supported by the U.s. Speck's Center for Climate Change and Environmental Forecasting in association with the U.s. Topographical Survey (USGS) and is overseen by FHWA.

Effects of Climate Change and Variability on Transportation Systems and Infrastructure: Gulf Coast Study (2008) (PDF 10.06mb)

U.s. Environmental Change Science Program

This multi-year examination system examined how short and long haul changes in atmosphere could influence transportation frameworks in the U.s. focal Gulf Coast area and how transportation chiefs could address conceivable effects. Included in the investigation are the influences to streets, airplane terminals, rail, travel frameworks, and ports.

Effects of Flooding and Climate Change on Urban Transportation: A System Wide Performance Assessment of the Boston Metro Area (2005)

(article accessible for buy from Sciencedirect.com)

Diary: Transportation Research Part D: Transport and Environment

This paper evaluates the potential effect of environmental change on the framework wide execution of transportation systems utilizing the Boston Metro Area as a careful investigation. The approach incorporates anticipated changes in area use, demographic and climatic conditions into the urban transportation displaying framework keeping in mind the end goal to investigate the relative effects of an Earth-wide temperature boost on the framework execution because of extra riverine and seaside flooding.

Multiagent Simulation in Transport: Impacts of Co2 Emission Trading Scheme in German Transport (2009)

This article plans to demonstrate that behavioral multi-executor models are a suitable methodology for surveying the effect of arrangement instruments to diminish Co2 outflows in street transport by presenting a multi operator model for the German street transport segment. A speculative Co2 discharge exchanging plan with an open and a shut option is connected to a Java-based recreated transport part. The impacts on endorsement costs and fuel interest are ascertained as for the individual response capacities of family units and transporters.

Getting ready for Climate Change Impacts at U.S. Ports (2009)

Transportation Research Board

U.S. ports need to better comprehend environmental change and how it may affect them. Over the nearing decades, ports are liable to encounter higher ocean levels and storm surges because of environmental change, and additionally other immediate and roundabout effects. Most ports don't have all the earmarks of being pondering, left be earnestly get ready to address, the impacts of environmental change.

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Earth’s average surface temperature

Global Warming is the rise of Earth’s average surface temperature due to result of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise get off from Earth. This is a type of green house effect. Since the early 20th century, Earth’s mean surface temperature has risen by about 0.8 °C (1.4 °F), with just about two-thirds of the increase happening since 1980. 

It's supposed that by the time a baby born today is 80 years old, the world will be 6 and a half degrees moderately hot than it is at the present.

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HOT OR COLD - GLOBAL WARMING

While there is still some disagreement about global warming, many scientists believe it is the result of changes in the earth’s atmosphere. The atmosphere creates a blanket that surrounds the earth. Sunlight passes through the greenhouse gases in the atmosphere to reach the earth’s surface and is absorbed. Once this energy is absorbed it goes through various natural processes, such as photosynthesis, and is re-released back into the atmosphere.

Some of the energy escapes the atmosphere, but a considerable amount becomes trapped by the greenhouse gases and causes the earth to warm in temperature. This is known as the greenhouse effect. The greenhouse effect is naturally occurring and vital to our survival. Without it earth would not be warm enough to sustain life. However, many scientists believe the growth of industry and urbanization has had a direct impact on the earth’s atmosphere, resulting in an unhealthy build up greenhouse gases. The general consensus about global warming points in one direction and it seems that evidence of the serious challenge it presents can be directly attributed to human activity.

Carbon dioxide, the gas released during the burning of fossil fuels, such as coal, oil and natural gas heads the list of emissions that are damaging the atmosphere. This is followed by methane, which is released primarily from landfills, mining operations and gas pipelines, chlorofluorocarbons, which have also been found to contribute to ozone depletion, and nitrous oxide, that comes from fertilizers and other chemicals.

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China Olympics Traffic Measures Cut Carbon Emissions

A new NASA-funded study of the impacts of China's traffic restrictions for the 2008 Summer Olympics in Beijing shows how widespread changes in transportation patterns could greatly reduce the threat of climate change.

New research by an international team of scientists led by the National Center for Atmospheric Research (NCAR), Boulder, Colo., indicates that China's restrictions on motor vehicles designed to improve air quality during the games had the side benefit of dramatically cutting emissions of carbon dioxide by between 26,500 and 106,000 U.S. tons (24,000 and 96,000 metric tons) during the event.

To put this in perspective, the authors note that this reduction by a single city represents more than one-quarter of one percent of the emissions cut that would be necessary worldwide, on a sustained basis, to prevent the planet from heating up by more than about 3.6 degrees Fahrenheit (2 degrees Celsius) by the end of this century. That is the amount of heating generally considered to lead to major societal impacts.

While scientists have long known that reduced traffic would lead to lower carbon-dioxide emissions, precise estimates for an actual urban area are difficult to calculate. "The Beijing Olympics allowed us to actually measure what happens when people drive much less, and it turns out that it makes quite a substantial difference to our climate," says NCAR scientist Helen Worden, the lead author. "People may think their choice of how to commute to work doesn't make a difference, whether driving their cars or riding their bikes. But on a large scale, it really does."

Recent research has confirmed that China's traffic restrictions successfully reduced levels of air pollutants such as carbon monoxide and ozone. Worden and her colleagues, using new methods in satellite observations and computer simulations, were also able to estimate the impact on carbon dioxide, a powerful greenhouse gas. Data from the NCAR/University of Toronto Measurements of Pollution in the Troposphere (MOPITT) instrument aboard NASA's Terra satellite were used to obtain the carbon monoxide estimates utilized to infer the carbon dioxide emissions.

Worden adds that the same study could not be done for this summer's London Olympics, partly because the surface and cloud conditions in London aren't as favorable for the measurements of carbon monoxide near the surface from MOPITT. In addition, London is very different from Beijing in terms of pollution controls, and it has already restricted traffic in the central city for several years.

Funded primarily by NASA, the study was published in Geophysical Research Letters, a publication of the American Geophysical Union. It was co-authored by researchers at the University of Iowa, Iowa City; the University of Tsinghua in Beijing; Argonne National Laboratory, Lemont, Ill.; and NASA's Jet Propulsion Laboratory, Pasadena, Calif. NCAR is sponsored by the National Science Foundation.

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Storm sentinels

Beginning this summer and over the next several years, NASA will be sending unmanned aircraft dubbed "severe storm sentinels" above stormy skies to help researchers and forecasters uncover information about hurricane formation and intensity changes.

Several NASA centers are joining federal and university partners in the Hurricane and Severe Storm Sentinel (HS3) airborne mission targeted to investigate the processes that underlie hurricane formation and intensity change in the Atlantic Ocean basin.

NASA's unmanned sentinels are autonomously flown. The NASA Global Hawk is well-suited for hurricane investigations because it can over-fly hurricanes at altitudes greater than 60,000 feet with flight durations of up to 28 hours - something piloted aircraft would find nearly impossible to do. Global Hawks were used in the agency's 2010 Genesis and Rapid Intensification Processes (GRIP) hurricane mission and the Global Hawk Pacific (GloPac) environmental science mission.

"Hurricane intensity can be very hard to predict because of an insufficient understanding of how clouds and wind patterns within a storm interact with the storm’s environment. HS3 seeks to improve our understanding of these processes by taking advantage of the surveillance capabilities of the Global Hawk along with measurements from a suite of advanced instruments," said Scott Braun, HS3 mission principal investigator and research meteorologist at NASA's Goddard Space Flight Center in Greenbelt, Md.

HS3 will use two Global Hawk aircraft and six different instruments this summer, flying from a base of operations at Wallops Flight Facility in Virginia.

"One aircraft will sample the environment of storms while the other will measure eyewall and rainband winds and precipitation," Braun said. HS3 will examine the large-scale environment that tropical storms form in and move through and how that environment affects the inner workings of the storms.

HS3 will address the controversial role of the hot, dry, and dusty Saharan Air Layer in tropical storm formation and intensification. Past studies have suggested that the Saharan Air Layer can both favor or suppress intensification. In addition, HS3 will examine the extent to which deep convection in the inner-core region of storms is a key driver of intensity change or just a response to storms finding favorable sources of energy.

The HS3 mission will operate during portions of the Atlantic hurricane seasons, which run from June 1 to November 30. The 2012 mission will run from late August through early October.

The instruments to be mounted in the Global Hawk aircraft that will examine the environment of the storms include the scanning High-resolution Interferometer Sounder (S-HIS), the Advanced Vertical Atmospheric Profiling System (AVAPS) also known as dropsondes, and the Cloud Physics Lidar (CPL). The Tropospheric Wind Lidar Technology Experiment (TWiLiTE) Doppler wind lidar will likely fly in the 2013 mission.

Another set of instruments will fly on the Global Hawk focusing on the inner region of the storms. Those instruments include the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) conically scanning Doppler radar, the Hurricane Imaging Radiometer (HIRAD) multi-frequency interferometric radiometer, and the High-Altitude Monolithic Microwave Integrated Circuit Sounding Radiometer (HAMSR) microwave sounder. Most of these instruments represent advanced technology developed by NASA, that in some cases are precursors to future satellite sensors.

NASA's Science Mission Directorate Global Hawk aircraft will deploy to Wallops Flight Facility from their home base at NASA's Dryden Flight Research Center on Edwards Air Force Base, Calif.


NASA's Global Hawk soars aloft from Edwards Air Force Base, Calif. The NASA Global Hawk is well-suited for hurricane investigations because it can over-fly hurricanes at altitudes greater than 60,000 feet with flight durations of up to 28 hours — something piloted aircraft would find nearly impossible to do. Credit: NASA/Tony Landis
"HS3 marks the first time that NASA's Global Hawks will deploy away from Dryden for a mission, potentially marking the beginning of an era in which they are operated regularly from Wallops," said Paul Newman, atmospheric scientist at NASA Goddard and deputy principal investigator on the HS3 mission.

NASA's Science Mission Directorate in Washington is establishing a Global Hawk operations center for science operations from Wallops. "With the Global Hawks at NASA Dryden in California, NASA Wallops will become the 'Global Hawk - Eastern' science center," Newman said.

From rockets studying the upper atmosphere to unmanned aircraft flying over hurricanes, NASA's Wallops Flight Facility is fast becoming a busy place for science. Wallops is one of several NASA centers involved with the HS3 mission. Others include Goddard, Dryden, Ames Research Center, Marshall Space Flight Center, and the Jet Propulsion Laboratory.

The HS3 mission is funded by NASA Headquarters and managed by NASA's Earth System Science Pathfinder Program at NASA's Langley Research Center, Hampton, Va. The HS3 mission also involves collaborations with various partners including the National Centers for Environmental Prediction, Naval Postgraduate School, Naval Research Laboratory, NOAA's Hurricane Research Division and Earth System Research Laboratory, Northrop Grumman Space Technology, National Center for Atmospheric Research, State University of New York at Albany, University of Maryland - Baltimore County, University of Wisconsin, and University of Utah.

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NASA's new carbon-counting instrument leaves the nest

Its construction now complete, the science instrument that is the heart of NASA's Orbiting Carbon Observatory-2 (OCO-2) spacecraft — NASA's first mission dedicated to studying atmospheric carbon dioxide — has left its nest at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and has arrived at its integration and test site in Gilbert, Ariz.

A truck carrying the OCO-2 instrument left JPL before dawn on Tuesday, May 9, to begin the trek to Orbital Science Corporation's Satellite Manufacturing Facility in Gilbert, southeast of Phoenix, where it arrived that afternoon. The instrument will be unpacked, inspected and tested. Later this month, it will be integrated with the Orbital-built OCO-2 spacecraft bus, which arrived in Gilbert on April 30.

Once technicians ensure the spacecraft is clean of any contaminants, the observatory's integration and test campaign will kick off. That campaign will be conducted in two parts, with the first part scheduled for completion in October. The observatory will then be stored in Gilbert for about nine months while the launch vehicle is prepared. The integration and test campaign will then resume, with completion scheduled for spring 2014. OCO-2 will then be shipped to Vandenberg Air Force Base, Calif., in preparation for a launch as early as the summer of 2014.

Technicians load the OCO-2 instrument and its ground support equipment aboard a moving van at JPL in preparation for its trek to Orbital Science Corporation's Satellite Manufacturing Facility in Gilbert, Ariz. Credit: NASA/JPL-Caltech.
"The OCO-2 instrument looks great, and its delivery to Orbital's Gilbert, Ariz., facility is a big step forward in successfully launching and operating the mission in space," said Ralph Basilio, OCO-2 project manager at JPL.

OCO-2 is the latest mission in NASA's study of the global carbon cycle. Carbon dioxide is the most significant human-produced greenhouse gas and the principal human-produced driver of climate change. The original OCO mission was lost shortly after launch on Feb. 24, 2009, when the Taurus XL launch vehicle carrying it malfunctioned and failed to reach orbit.

The experimental OCO-2 mission, which is part of NASA's Earth System Science Pathfinder Program, will uniformly sample the atmosphere above Earth's land and ocean, collecting more than half a million measurements of carbon dioxide concentration over Earth's sunlit hemisphere every day for at least two years. It will do so with the accuracy, resolution and coverage needed to provide the first complete picture of the regional-scale geographic distribution and seasonal variations of both human and natural sources of carbon dioxide emissions and their sinks-the places where carbon dioxide is removed from the atmosphere and stored.

Scientists will use OCO-2 mission data to improve global carbon cycle models, better characterize the processes responsible for adding and removing carbon dioxide from the atmosphere, and make more accurate predictions of global climate change.

The mission provides a key new measurement that can be combined with other ground and aircraft measurements and satellite data to answer important questions about the processes that regulate atmospheric carbon dioxide and its role in the carbon cycle and climate. This information could help policymakers and business leaders make better decisions to ensure climate stability and retain our quality of life. The mission will also serve as a pathfinder for future long-term satellite missions to monitor carbon dioxide.

Each of the OCO-2 instrument's three high-resolution spectrometers spreads reflected sunlight into its various colors like a prism, focusing on a different, narrow color range to detect light with the specific colors absorbed by carbon dioxide and molecular oxygen. The amount of light absorbed at these specific colors is proportional to the concentration of carbon dioxide in the atmosphere. Scientists will use these data in computer models to quantify global carbon dioxide sources and sinks.

For more information on the mission, visit: the JPL and NASA OCO-2 websites.

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Mild fire forecast

Forests in the Amazon Basin are expected to be less vulnerable to wildfires this year, according to the first forecast from a new fire severity model developed by university and NASA researchers.

Fire season across most of the Amazon rain forest typically begins in May, peaks in September and ends in January. The new model, which forecasts the fire season’s severity from three to nine months in advance, calls for an average or below-average fire season this year within 10 regions spanning three countries: Bolivia, Brazil and Peru.

“Tests of the model suggested that predictions should be possible before fire activity begins in earnest,” said Doug Morton, a co-investigator on the project at NASA’s Goddard Space Flight Center in Greenbelt, Md. “This is the first year to stand behind the model and make an experimental forecast, taking a step from the scientific arena to share this information with forest managers, policy makers, and the public alike.”


Gauges convey the fire severity forecast for 10 regions in the Amazon Basin where fire activity varies greatly from year to year, and where climate conditions have a significant impact on fire activity. Credit: Yang Chen/UC Irvine
The model was first described last year in the journal Science. Comparing nine years of fire data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite, with a record of sea surface temperatures from NOAA, scientists established a connection between sea surface temperatures in the Pacific and Atlantic oceans and fire activity in South America.

“There will be fires in the Amazon Basin, but our model predictions suggest that they won’t be as likely in 2012 as in some previous years,” said Jim Randerson of the University of California, Irvine, and principal investigator on the research project.

Specifically, sea surface temperatures in the Central Pacific and North Atlantic are currently cooler than normal. Cool sea surface temperatures change patterns of atmospheric circulation and increase rainfall across the southern Amazon in the months leading up to the fire season.

“We believe the precipitation pattern during the end of the wet season is very important because this is when soils are replenished with water,” said Yang Chen of UC Irvine. “If sea surface temperatures are higher, there is reduced precipitation across most of the region, leaving soils with less water to start the dry season.”

Without sufficient water to be transported from the soil to the atmosphere by trees, humidity decreases and vegetation is more likely to burn. Such was the case in 2010, when above-average sea surface temperatures and drought led to a severe fire season. In 2011, conditions shifted and cooler sea surface temperatures and sufficient rainfall resulted in fewer fires, similar to the forecast for 2012.


Improvements to the model are possible by incorporating data from the MODIS instrument on NASA's Aqua satellite, accounting for fires that occur in the afternoon when conditions are hotter and drier. Credit: Doug Morton.
Building on previous research, the researchers said there is potential to adapt and apply the model to other locations where large-scale climate conditions are a good indicator of the impending fire season, such as Indonesia and the United States.

Amazon forests, however, are particularly relevant because of their high biodiversity and vulnerability to fires. Amazon forests also store large amounts of carbon, and deforestation and wildfires release that carbon back to the atmosphere. Predictions of fire season severity may aid initiatives – such as the United Nation’s Reducing Emissions from Deforestation and forest Degradation program – to reduce the emissions of greenhouse gases from fires in tropical forests.

“The hope is that our experimental fire forecasting information will be useful to a broad range of communities to better understand the science, how these forests burn, and what predisposes forests to burning in some years and not others,” Morton said. “We now have the capability to make predictions, and the interest to share this information with groups who can factor it into their preparation for high fire seasons and management of the associated risks to forests and human health.”

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Muddled outlook

The 2012 hurricane season in North and Central America arrives with a muddled outlook. Sea surface temperatures are not particularly warm or cool, and the El Niño–Southern Oscillation (ENSO) is drifting in a neutral state that NASA climate scientist Bill Patzert playfully calls “La Nada.”

The map above shows sea surface temperatures (SSTs) in the tropical Atlantic Ocean and tropical eastern Pacific on May 30, 2012. The map was built with data from the Microwave Optimally Interpolated SST product, a NASA-supported effort at Remote Sensing Systems. Researchers combine observations and analyses from NASA’s Tropical Rainfall Measurement Mission and Aqua and Terra satellites, as well as the U.S. Navy’s WindSAT instrument on the Coriolis satellite (operated jointly with the Air Force).

Shades of blue depict water temperatures below 27.8 degrees Celsius (about 82 degrees Fahrenheit), while yellows, oranges, and reds depict waters above that threshold. Scientists generally agree that waters above that temperature are needed to build and sustain hurricanes, though there are exceptions. Of course, measurements of sea surface temperature account for only the top few millimeters of the ocean, and the amount of heat stored at greater depths (which is harder to measure) can also be a factor in hurricane development. So SSTs do not tell the whole story, but they are a fair predictor of the readiness of the ocean to sustain tropical storms.

“The waters look on the slightly cool side across some of the ‘main development region (MDR)’—the tropical band extending over the east and central Atlantic off Africa,” noted Jeff Halverson, a hurricane researcher at the University of Maryland–Baltimore County. “Whether this will persist for several months as we get into the high season, I don't know.”

The official start of hurricane season is June 1, though four named tropical storms in May—Alberto and Beryl in the Atlantic, Aletta and Bud in the Pacific—didn't wait for the calendar. The Hurricane Research Division of the National Oceanic and Atmospheric Administration (NOAA) announced on May 24, 2012, that it is expecting a near-normal season, with nine to fifteen named storms and four to eight hurricanes. According to NOAA, an average season between 1980 to 2010 produced 12 named storms with six hurricanes, including three major hurricanes.
“We shouldn't be fooled by the storms that have already developed off the southeast U.S. in May,” Halverson said. “Development can and does happen this early—albeit infrequently—and these developments are almost always not far off the U.S. mainland. They have little to do with what is coming off Africa and streaming across the MDR. So these early home-grown storms are not necessarily a predictor of the August to October season, which is dominated by Cape Verde storms.”

Meteorologists often look to ENSO for a sense of whether atmospheric weather patterns will promote or tamp down hurricane formation. In general, researchers believe that El Niño reduces hurricane activity and La Niña promotes it. But the science on the matter is not really settled, and it may be that ENSO affects the number but not necessarily the intensity of storms.

La Niña just ended earlier this spring, and the next El Niño may be some months off. “The equatorial Pacific is neutral, with no El Niño developing...not even a hint,” said Patzert, who is based at the Jet Propulsion Laboratory. “If El Niño builds, I think it will be late and whimpy.”
In the eastern Pacific, NOAA is calling for a near-normal or below-normal season. “Forecasters estimate a 70 percent chance of 12 to 18 named storms, which includes 5 to 9 hurricanes.”

Regardless of the predictions, the key to hurricane season is vigilance. “The important issue is hurricane preparedness along the coasts,” said Patzert. “All it takes is one in your neighborhood to wreak havoc. Listen to the National Hurricane Center, know your evacuation routes, and be super prepared.”

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NASA study: Earth's energy budget 'out of balance'

02.01.12
By Adam Voiland,
NASA's Earth Science News Team
A new NASA study underscores the fact that greenhouse gases generated by human activity—not changes in solar activity—are the primary force driving global warming.

The study offers an updated calculation of the Earth's energy imbalance, the difference between the amount of solar energy absorbed by Earth's surface and the amount returned to space as heat. The researchers' calculations show that, despite unusually low solar activity between 2005 and 2010, the planet continued to absorb more energy than it returned to space.


A prolonged solar minimum left the sun's surface nearly free of sunspots and accompanying bright areas called faculae between 2005 and 2010. Total solar irradiance declined slightly as a result, but the Earth continued to absorb more energy than it emit throughout the minimum. An animation of a full solar cycle is available here. Credit: NASA Goddard's Scientific Visualization Studio
James Hansen, director of NASA's Goddard Institute for Space Studies (GISS) in New York City, led the research. Atmospheric Chemistry and Physics published the study last December.

Total solar irradiance, the amount of energy produced by the sun that reaches the top of each square meter of the Earth's atmosphere, typically declines by about a tenth of a percent during cyclical lulls in solar activity caused by shifts in the sun's magnetic field. Usually solar minimums occur about every eleven years and last a year or so, but the most recent minimum persisted more than two years longer than normal, making it the longest minimum recorded during the satellite era.

Pinpointing the magnitude of Earth's energy imbalance is fundamental to climate science because it offers a direct measure of the state of the climate. Energy imbalance calculations also serve as the foundation for projections of future climate change. If the imbalance is positive and more energy enters the system than exits, Earth grows warmer. If the imbalance is negative, the planet grows cooler.

Hansen's team concluded that Earth has absorbed more than half a watt more solar energy per square meter than it let off throughout the six year study period. The calculated value of the imbalance (0.58 watts of excess energy per square meter) is more than twice as much as the reduction in the amount of solar energy supplied to the planet between maximum and minimum solar activity (0.25 watts per square meter).

"The fact that we still see a positive imbalance despite the prolonged solar minimum isn't a surprise given what we've learned about the climate system, but it's worth noting because this provides unequivocal evidence that the sun is not the dominant driver of global warming," Hansen said.

According to calculations conducted by Hansen and his colleagues, the 0.58 watts per square meter imbalance implies that carbon dioxide levels need to be reduced to about 350 parts per million to restore the energy budget to equilibrium. The most recent measurements show that carbon dioxide levels are currently 392 parts per million and scientists expect that concentration to continue to rise in the future.


Data collected by Argo floats, such as this one, helped Hansen's team improve the calculation of Earth's energy imbalance. Credit: Argo Project Office
Climate scientists have been refining calculations of the Earth's energy imbalance for many years, but this newest estimate is an improvement over previous attempts because the scientists had access to better measurements of ocean temperature than researchers have had in the past.

The improved measurements came from free-floating instruments that directly monitor the temperature, pressure and salinity of the upper ocean to a depth of 2,000 meters (6,560 feet). The network of instruments, known collectively as Argo, has grown dramatically in recent years since researchers first began deploying the floats a decade ago. Today, more than 3,400 Argo floats actively take measurements and provide data to the public, mostly within 24 hours.

Hansen's analysis of the information collected by Argo, along with other ground-based and satellite data, show the upper ocean has absorbed 71 percent of the excess energy and the Southern Ocean, where there are few Argo floats, has absorbed 12 percent. The abyssal zone of the ocean, between about 3,000 and 6,000 meters (9,800 and 20,000 feet) below the surface, absorbed five percent, while ice absorbed eight percent and land four percent.

The updated energy imbalance calculation has important implications for climate modeling. Its value, which is slightly lower than previous estimates, suggests that most climate models overestimate how readily heat mixes deeply into the ocean and significantly underestimates the cooling effect of small airborne particles called aerosols, which along with greenhouse gases and solar irradiance are critical factors in energy imbalance calculations.

"Climate models simulate observed changes in global temperatures quite accurately, so if the models mix heat into the deep ocean too aggressively, it follows that they underestimate the magnitude of the aerosol cooling effect," Hansen said.

Aerosols, which can either warm or cool the atmosphere depending on their composition and how they interact with clouds, are thought to have a net cooling effect. But estimates of their overall impact on climate are quite uncertain given how difficult it is to measure the distribution of the particles on a broad scale. The new study suggests that the overall cooling effect from aerosols could be about twice as strong as current climate models suggest, largely because few models account for how the particles affect clouds.


A chart shows the global reach of the network of Argo floats. (Credit: Argo Project Office)
"Unfortunately, aerosols remain poorly measured from space," said Michael Mishchenko, a scientist also based at GISS and the project scientist for Glory, a satellite mission designed to measure aerosols in unprecedented detail that was lost after a launch failure in early 2011. "We must have a much better understanding of the global distribution of detailed aerosol properties in order to perfect calculations of Earth's energy imbalance," said Mishchenko.

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NASA study solves case of Earth's 'missing energy'

01.31.12
By Alan Buis,
Jet Propulsion Laboratory
Two years ago, scientists at the National Center for Atmospheric Research in Boulder, Colo., released a study claiming that inconsistencies between satellite observations of Earth's heat and measurements of ocean heating amounted to evidence of "missing energy" in the planet's system.

Where was it going? Or, they wondered, was something wrong with the way researchers tracked energy as it was absorbed from the sun and emitted back into space?

An international team of atmospheric scientists and oceanographers, led by Norman Loeb of NASA's Langley Research Center in Hampton, Va., and including Graeme Stephens of NASA's Jet Propulsion Laboratory in Pasadena, Calif., set out to investigate the mystery.

They used 10 years of data—spanning 2001 to 2010—from NASA Langley's orbiting Clouds and the Earth's Radiant Energy System Experiment (CERES) instruments to measure changes in the net radiation balance at the top of Earth's atmosphere. The CERES data were then combined with estimates of the heat content of Earth's ocean from three independent ocean-sensor sources.

Their analysis, summarized in a NASA-led study published Jan. 22 in the journal Nature Geosciences, found that the satellite and ocean measurements are, in fact, in broad agreement once observational uncertainties are factored in.

"One of the things we wanted to do was a more rigorous analysis of the uncertainties," Loeb said. "When we did that, we found the conclusion of missing energy in the system isn't really supported by the data."

'Missing energy' is in the ocean

"Our data show that Earth has been accumulating heat in the ocean at a rate of half a watt per square meter (10.8 square feet), with no sign of a decline," Loeb said. "This extra energy will eventually find its way back into the atmosphere and increase temperatures on Earth."

Scientists generally agree that 90 percent of the excess heat associated with increases in greenhouse gas concentrations gets stored in Earth's ocean. If released back into the atmosphere, a half-watt per square meter accumulation of heat could increase global temperatures by 0.3 or more degrees centigrade (0.54 degree Fahrenheit).

Loeb said the findings demonstrate the importance of using multiple measuring systems over time, and illustrate the need for continuous improvement in the way Earth's energy flows are measured.

The science team at the National Center for Atmospheric Research measured inconsistencies from 2004 and 2009 between satellite observations of Earth's heat balance and measurements of the rate of upper ocean heating from temperatures in the upper 700 meters (2,300 feet) of the ocean. They said the inconsistencies were evidence of "missing energy."

Other authors of the paper are from the University of Hawaii, the Pacific Marine Environmental Laboratory in Seattle, the University of Reading United Kingdom and the University of Miami.

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NASA mission takes stock of Earth's melting land ice

02.08.12
By Alan Buis,
Jet Propulsion Laboratory

Steve Cole,
NASA Headquarters

In the first comprehensive satellite study of its kind, a University of Colorado at Boulder-led team used NASA data to calculate how much Earth's melting land ice is adding to global sea level rise.

Using satellite measurements from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE), the researchers measured ice loss in all of Earth's land ice between 2003 and 2010, with particular emphasis on glaciers and ice caps outside of Greenland and Antarctica.

The total global ice mass lost from Greenland, Antarctica and Earth's glaciers and ice caps during the study period was about 4.3 trillion tons (1,000 cubic miles), adding about 0.5 inches (12 millimeters) to global sea level. That's enough ice to cover the United States 1.5 feet (0.5 meters) deep.

"Earth is losing a huge amount of ice to the ocean annually, and these new results will help us answer important questions in terms of both sea rise and how the planet's cold regions are responding to global change," said University of Colorado Boulder physics professor John Wahr, who helped lead the study. "The strength of GRACE is it sees all the mass in the system, even though its resolution is not high enough to allow us to determine separate contributions from each individual glacier."

About a quarter of the average annual ice loss came from glaciers and ice caps outside of Greenland and Antarctica (roughly 148 billion tons, or 39 cubic miles). Ice loss from Greenland and Antarctica and their peripheral ice caps and glaciers averaged 385 billion tons (100 cubic miles) a year. Results of the study will be published online Feb. 8 in the journal Nature.

Traditional estimates of Earth's ice caps and glaciers have been made using ground measurements from relatively few glaciers to infer what all the world's unmonitored glaciers were doing. Only a few hundred of the roughly 200,000 glaciers worldwide have been monitored for longer than a decade.

One unexpected study result from GRACE was that the estimated ice loss from high Asian mountain ranges like the Himalaya, the Pamir and the Tien Shan was only about 4 billion tons of ice annually. Some previous ground-based estimates of ice loss in these high Asian mountains have ranged up to 50 billion tons annually.

"The GRACE results in this region really were a surprise," said Wahr, who is also a fellow at the University of Colorado-headquartered Cooperative Institute for Research in Environmental Sciences. "One possible explanation is that previous estimates were based on measurements taken primarily from some of the lower, more accessible glaciers in Asia and extrapolated to infer the behavior of higher glaciers. But unlike the lower glaciers, most of the high glaciers are located in very cold environments and require greater amounts of atmospheric warming before local temperatures rise enough to cause significant melting. This makes it difficult to use low-elevation, ground-based measurements to estimate results from the entire system."

"This study finds that the world's small glaciers and ice caps in places like Alaska, South America and the Himalayas contribute about 0.02 inches per year to sea level rise," said Tom Wagner, cryosphere program scientist at NASA Headquarters in Washington. "While this is lower than previous estimates, it confirms that ice is being lost from around the globe, with just a few areas in precarious balance. The results sharpen our view of land-ice melting, which poses the biggest, most threatening factor in future sea level rise."

The twin GRACE satellites track changes in Earth's gravity field by noting minute changes in gravitational pull caused by regional variations in Earth's mass, which for periods of months to years is typically because of movements of water on Earth's surface. It does this by measuring changes in the distance between its two identical spacecraft to one-hundredth the width of a human hair.

The GRACE spacecraft, developed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., and launched in 2002, are in the same orbit approximately 137 miles (220 kilometers) apart. The California Institute of Technology manages JPL for NASA.

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'First Light' Taken by NASA's Newest CERES Instrument

The doors are open on NASA's Suomi NPP satellite and the newest version of the Clouds and the Earth's Radiant Energy System (CERES) instrument is scanning Earth for the first time, helping to assure continued availability of measurements of the energy leaving the Earth-atmosphere system.

The CERES results help scientists to determine the Earth's energy balance, providing a long-term record of this crucial environmental parameter that will be consistent with those of its predecessors.


Thick cloud cover tends to reflect a large amount of incoming solar energy back to space (blue/green/white image), but at the same time, reduce the amount of outgoing heat lost to space (red/blue/orange image). Contrast the areas that do not have cloud cover (darker colored regions) to get a sense for how much impact the clouds have on incoming and outgoing energy. Credit: NASA/NOAA/CERES Team
*** Click either image to enlarge it ***



In the longwave image, heat energy radiated from Earth (in watts per square meter) is shown in shades of yellow, red, blue and white. The brightest-yellow areas are the hottest and are emitting the most energy out to space, while the dark blue areas and the bright white clouds are much colder, emitting the least energy. Increasing temperature, decreasing water vapor, and decreasing clouds will all tend to increase the ability of Earth to shed heat out to space. Credit: NASA/NOAA/CERES Team

CERES arrived in space Oct. 28, 2011, carried by NASA's newest Earth-observing satellite, the recently renamed Suomi National Polar-orbiting Partnership, or Suomi NPP. Suomi NPP is the result of a partnership between NASA, NOAA and the Department of Defense.

Instrument cover-opening activities began on the instrument at 10:12 a.m. Eastern time Jan. 26, an operation that took about three hours. The "first light" process represented the transition from engineering checkout to science observations. The next morning CERES began taking Earth-viewing data, and on Jan. 29 scientists produced an image from the scans.

"It's extremely gratifying to see the CERES FM-5 instruments on Suomi NPP begin taking measurements. We're continuing the legacy of the most accurate Earth radiation budget observations ever made," said CERES project scientist Kory Priestley, of NASA's Langley Research Center in Hampton, Va.

"It has taken an incredible team of engineers, scientists, data management and programmatic experts to get CERES to this point," he said.

MORE INFORMATION
› Suomi NPP Mission
› CERES page
› Q&A With CERES Principal Investigator
NASA instruments have provided the scientific community unprecedented observations of the Earth's climate and energy balance for nearly 30 years. The first CERES instrument was launched in 1997. Before that, the Earth Radiation Budget Experiment (ERBE) did the job beginning in 1984.

Langley Research Center has led both the ERBE and CERES experiments and provided stewardship of these critical climate observations.

For 27 years without a break, the instruments collectively have returned a vast quantity of precise data about the solar energy reflected and absorbed by Earth, the heat the planet emits, and the role of clouds in that process.

"CERES monitors minute changes in the Earth's energy budget, the difference between incoming and outgoing energy," said CERES principal investigator Norman Loeb, of Langley Research Center.

"Any imbalance in Earth's energy budget due to increasing concentrations of heat trapping gases warms the ocean, raises sea level, and causes increases in atmospheric temperature," Loeb said. "Amassing a long record of data is important in order to understand how Earth's climate is changing in response to human activities as well as natural processes."


How It Works

In addition to observing changes in Earth's radiation budget, scientists are also monitoring changes in clouds and aerosols, which strongly influence Earth's radiation budget.

"Clouds both reflect sunlight and block energy from radiating to space," Loeb said. "Which of these two effects dominates depends upon the properties of clouds, such as their amount, thickness and height."

"As the Earth's environment evolves, cloud properties may change in ways that could amplify or offset climate change driven by other processes. Understanding the influence of clouds on the energy budget is therefore a critical climate problem."

The four other CERES instruments are in orbit on NASA's Aqua and Terra satellites.


Overall Mission

The five-instrument suite on Suomi NPP collects and distributes remotely sensed land, ocean, and atmospheric data to the meteorological and global Earth system science research communities. The mission will provide atmospheric and sea surface temperatures, humidity sounding, land and ocean biological productivity, cloud and aerosol properties, total/profile ozone measurements, and monitor changes in the Earth's radiation budget.

NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Suomi mission for the Earth Science Division of the Science Mission Directorate at NASA Headquarters in Washington. The National Oceanic and Atmospheric Administration's Joint Polar Satellite System (JPSS) program provides the satellite ground system and NOAA provides operational support. Suomi NPP commissioning activities are expected to be completed by March.

NASA Langley manages the CERES experiment with additional contracted support from Science Systems and Applications, Inc. The TRW Space & Electronics Group in Redondo Beach, Calif., now owned by Northrop Grumman Aerospace Systems, built all of the CERES instruments.




Michael Finneran
NASA Langley Research Center

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Detecting detrimental change in coral reefs

02.09.12
By Laura Rocchio,
NASA Goddard Space Flight Center
Over dinner on R.V. Calypso while anchored on the lee side of Glover’s Reef in Belize, Jacques Cousteau told Phil Dustan that he suspected humans were having a negative impact on coral reefs. Dustan — a young ocean ecologist who had worked in the lush coral reefs of the Caribbean and Sinai Peninsula — found this difficult to believe. It was December 1974.


Reef environments provide habitat for hundreds of fish species including the queen angelfish shown here in the Florida Keys National Marine Sanctuary. Credit: Chris Huss.
But Cousteau was right. During the following three-plus decades, Dustan, an ocean ecologist and biology professor at the College of Charleston in South Carolina, has witnessed widespread coral reef degradation and bleaching from up close. In the late 1970s Dustan helped build a handheld spectrometer, a tool to measure light given off by the coral. Using his spectrometer, Dustan could look at light reflected and made by the different organisms that comprised the living reefs. Since then, he has watched reefs deteriorate at an alarming rate. Recently he has found that Landsat offers a way to evaluate these changes globally. Using an innovative way to map how coral reefs are changing over time, Dustan now can find 'hotspots' where conservation efforts should be focused to protect these delicate communities.


Left: A Landsat pixel-based map showing where the most change has been detected on Caryfort Reef between 1984 and 1996. Right: The spine of elevation shows where the most change has occurred; for Carysfort this change has been correlated with coral decline. Credit: Phil Dustan.
A role for remote sensing
Situated in shallow clear water, most coral reefs are visible to satellites that use passive remote sensing to observe Earth's surface. But coral reefs are complex ecosystems with coincident coral species, sand and water all reflecting light. Dustan found that currently orbiting satellites do not offer the spatial or spectral resolution needed to distinguish between them and specifically classify coral reef composition. So instead of attempting to classify the inherently complex coral ecosystem to monitor their health, Dustan has instead started to look for change — how overall reflectance for a geographic location varies over time.

Dustan uses a time series of Landsat data to calculate something called temporal texture — basically a map showing where change has occurred based on statistical analysis of reflectance information. While Dustan cannot diagnosis the type of change with temporal texture he can establish where serious changes have occurred. Coral communities have seasonal rhythms and periodicities, but larger, significant changes show up as statistical outliers in temporal texture maps and often correlate with reef decline.


There was a 92 percent loss of living coral on Carysfort between 1975 and 2000. Credit: Dustan and Halas; FKNMS Coral Reef Evaluation and Monitoring Project.
Carysfort reef — named for the HMS Carysfort, an eighteenth century British warship that ran aground on the reef in 1770 — is considered the most ecologically diverse on the Florida Keys National Marine Sanctuary’s northern seaward edge, but today it is in a state of ecological collapse.
A case study
Dustan and colleagues conducted the first quantitative field study of coral health at Carysfort in 1974. After a quarter century their studies showed that coral had declined 92 percent. The coral had succumbed to an array of stressors culminating with deadly diseases.

Using the well-characterized Carysfort reef as his control, Dustan calculated the temporal texture for the reef using a series of 20 Landsat images collected between 1982 and 1996. The resulting temporal texture maps correlated with the known areas of significant coral loss (where coral communities have turned into algal-dominated substrates) and they correctly showed that the seaward shallow regions have had the most detrimental change.

This novel approach to change detection is only possible because the long-term calibration of Landsat data assures that data from year-to-year is consistent. Dustin needs at least six to eight Landsat images to create a reliable temporal texture map, but the more data that is available, the finer the results.


Carysfort Reef is located in the eastern portion of the Florida Keys National Marine Sanctuary, offshore of Key Largo. Credit: National Oceanic and Atmospheric Administration.
Dustan tested this work in the U.S. because he had a robust study site and because prior to 1999 coverage of reefs outside of the U.S. was spotty. With the Landsat 7 launch in 1999 a new global data acquisition strategy was established and for the first time the planet’s coral reefs were systematically and regularly imaged, greatly increasing our knowledge of reefs. The Landsat archive enabled the completing of the first exhaustive global survey of reefs (Millennium Global Coral Reef Mapping Project, http://landsat.gsfc.nasa.gov/news/news-archive/news_0031.html). Efforts are currently underway to receive and ingest Landsat data collected and housed by international ground-receiving stations. International partners often downlink Landsat scenes of their countries that the U.S. does not, so it is very likely that historic reef images will be added the U.S. Landsat archive during this process.
Carrying on outside Carysfort
Temporal texture gives scientists an entirely new way to look at coral reefs. A worldwide study could help managers locate change ‘hotspots’ and could better inform conservation efforts.

Ideally, after more testing, Dustan would like to see an automatic change detection system implemented to follow major worldwide reef systems. “There is no reason that a form of temporal texture monitoring could not be implemented with current satellites in orbit,” Dustan says.

Because reefs are underwater it is difficult to grasp the extensive devastation being exacted upon them. Global temporal texture mapping could bring the ravages into focus.

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Infrared eye opens

02.09.12
By Cynthia O'Carroll, NASA Goddard Space Flight Center,
John Leslie, National Oceanic and Atmospheric Administration

A powerful new infrared instrument, flying on NASA's newest polar-orbiting satellite, designed to give scientists more refined information about Earth's atmosphere and improve weather forecasts and our understanding of climate, has started sending its data back to Earth.

The Cross-track Infrared Sounder (CrIS) joins four other new instruments aboard the Suomi National Polar-orbiting Partnership (NPP) satellite, which NASA launched on Oct. 28, 2011 from Vandenberg Air Force Base in California. The Suomi NPP mission is the bridge between NOAA's Polar Operational Environmental Satellite (POES) and NASA's Earth Observing System satellites and the next-generation Joint Polar Satellite System (JPSS).

Since it reached orbit, Suomi NPP and its suite of five instruments are undergoing extensive checkouts before starting regular science observations. Suomi NPP is the result of a partnership between NASA, NOAA and the Department of Defense.

CrIS, an advanced spectrometer with 1,305 infrared spectral channels, is designed to provide high vertical resolution information on the atmosphere's three-dimensional structure of temperature and water vapor. The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua mission, launched in 2002, demonstrated how useful this type of data could be for understanding the atmosphere. CrIS will continue this data record and provide data for use in NOAA's numerical weather prediction models to forecast severe weather days in advance.

"Significant overlap between AIRS and CrIS will provide the Earth science research community the ability to maintain the unprecedented accuracy and stability of the temperature and moisture data record initiated by AIRS," said Diane Wickland, Suomi NPP program scientist at NASA Headquarters.

"Having data from CrIS will only improve the quality, timeliness and accuracy of NOAA's weather and climate predictions, which directly affect everyone in America," said Mary Kicza, assistant administrator for NOAA's Satellite and Information Service (NESDIS).

"Over longer periods, data from CrIS will help NOAA to better understand climate phenomena such as El Niño and La Niña that impact global weather patterns," said Mitch Goldberg, NOAA's JPSS program scientist.

The Advanced Technology Microwave Sounder (ATMS), which measures temperature and humidity in both clear and cloudy conditions, was the first Suomi NPP instrument activated. ATMS and CrIS data together will be used operationally in weather forecasts beginning in the Spring of 2012.

"The instrument commissioning is going well and we are pleased that Suomi NPP is taking the next step in its mission of providing critical weather data to NOAA and global Earth system science data to the U.S. research community," stated Ken Schwer, Suomi NPP project manager. Commissioning activities will continue through February, and once completed, satellite operations will be turned over to the JPSS program. NOAA will operate the satellite and process and distribute the data to users around the world.

NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Suomi NPP mission for the Earth Science Division of the Science Mission Directorate at NASA Headquarters in Washington. NOAA provides the CrIS instrument and operational support and the JPSS program provides the satellite ground system.

NASA's Suomi NPP mission will allow us to advance our knowledge of how the entire Earth system works by providing enhanced data for our nation's weather forcasting system, providing new insight to scientists to better understand climate.

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NASA map sees Earth's trees in a new light

02.21.12
By Alan Buis,
Jet Propulsion Laboratory
A NASA-led science team has created an accurate, high-resolution map of the height of Earth's forests. The map will help scientists better understand the role forests play in climate change and how their heights influence wildlife habitats within them, while also helping them quantify the carbon stored in Earth's vegetation.

Scientists from NASA's Jet Propulsion Laboratory, Pasadena, Calif.; the University of Maryland, College Park; and Woods Hole Research Center, Falmouth, Mass., created the map using 2.5 million carefully screened, globally distributed laser pulse measurements from space. The light detection and ranging (lidar) data were collected in 2005 by the Geoscience Laser Altimeter System instrument on NASA's Ice, Cloud and land Elevation Satellite (ICESat).




Accurate measurements of the height of Earth's forests can improve global efforts to monitor how much carbon they contain, while benefitting studies of forest biodiversity. Image credit: NASA/JPL-Caltech/Josh Fisher



"Knowing the height of Earth's forests is critical to estimating their biomass, or the amount of carbon they contain," said lead researcher Marc Simard of JPL. "Our map can be used to improve global efforts to monitor carbon. In addition, forest height is an integral characteristic of Earth's habitats, yet is poorly measured globally, so our results will also benefit studies of the varieties of life that are found in particular parts of the forest or habitats."
The map, available at http://lidarradar.jpl.nasa.gov, depicts the highest points in the forest canopy. Its spatial resolution is 0.6 miles (1 kilometer). The map was validated against data from a network of nearly 70 ground sites around the world.

The researchers found that, in general, forest heights decrease at higher elevations and are highest at low latitudes, decreasing in height the farther they are from the tropics. A major exception was found at around 40 degrees south latitude in southern temperate rainforests in Australia and New Zealand, where stands of eucalyptus, one of the world's tallest flowering plants, tower much higher than 130 feet (40 meters).

The researchers augmented the ICESat data with other types of data to compensate for the sparse lidar data, the effects of topography and cloud cover. These included estimates of the percentage of global tree cover from NASA's Moderate Resolution Imaging Spectroradiometer on NASA's Terra satellite, elevation data from NASA's Shuttle Radar Topography Mission, and temperature and precipitation maps from NASA's Tropical Rainfall Measuring Mission and the WorldClim database. WorldClim is a set of freely available, high-resolution global climate data that can be used for mapping and spatial modeling.

In general, estimates in the new map show forest heights were taller than in a previous ICESat-based map, particularly in the tropics and in boreal forests, and were shorter in mountainous regions. The accuracy of the new map varies across major ecological community types in the forests, and also depends on how much the forests have been disturbed by human activities and by variability in the forests' natural height.

"Our map contains one of the best descriptions of the height of Earth's forests currently available at regional and global scales," Simard said. "This study demonstrates the tremendous potential that spaceborne lidar holds for revealing new information about Earth's forests. However, to monitor the long-term health of Earth's forests and other ecosystems, new Earth observing satellites will be needed."

Results of the study were published recently in the Journal of Geophysical Research – Biogeosciences.

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