AER Contributes to Landmark Study on Earth’s Greenhouse Effect

Eli Mlawer
February 25, 2015

Scientists who research thermal radiation in the Earth’s atmosphere are confident that we have a very detailed and accurate understanding of the nature of the greenhouse effect of carbon dioxide (CO2), including the impact of rising CO2 levels. 

Recently I participated in a study that provided the first direct observation at the surface of the Earth’s increased greenhouse effect due to rising CO2 levels. This represents an important milestone in the detection of the increased greenhouse effect due to fossil fuel emissions.

Another key result of our study was that the measured trend agreed with theoretical calculations of AER’s highly accurate Line-By-Line Radiative Transfer Model (LBLRTM).

The study “Observational Determination of Surface Radiative Forcing by CO2 from 2000 to 2010",  published this week in the journal Nature, was led by Dr. Daniel Feldman of the US Department of Energy’s Lawrence Berkeley National Laboratory. (Please see press release "First Direct Observation of Carbon Dioxide’s Increasing Greenhouse Effect at the Earth’s Surface" summary of this research from Berkeley Lab.)

Thermal radiation exiting from the top of our atmosphere cools the planet, balancing out the radiant energy received from the sun. Rising CO2 levels lower this outgoing thermal energy (i.e. increasing the greenhouse effect), thereby affecting our planet’s energy balance and causing an overall rise in global temperatures. This same greenhouse effect physics also causes an increase in thermal radiation at the surface when CO2 rises.

In our study, an analysis of thermal radiation measurements at two surface locations, one in Oklahoma and one on the North Slope of Alaska, determined that increases in CO2 between 2000 and 2010 led to a rise in the observed thermal radiation, as expected. As each gas in the atmosphere has a particular “fingerprint” with regards to its absorption and emission of different wavelengths of thermal radiation, we were able to distinguish the impact of changes in CO2 from other effects. 

The accuracy of AER’s LBLRTM was critical in this analysis.  The foundation of the LBLRTM’s accuracy are laboratory measurements and theoretical calculations by scientists in the field of molecular spectroscopy, as well as extensive comparisons with spectral radiation measurements, such as in the recent study led by Dr. Matthew Alvarado of AER.  Many improvements to LBLRTM have been made as a result of such studies, and the model is widely utilized and relied on by atmospheric scientists.  Our fast radiation code RRTMG, which is incorporated in many global models used for climate prediction, is also based on LBLRTM. 

Our Nature article provides further confirmation that today’s climate models correctly represent the impact of CO2 on Earth’s radiation balance.  Although the impacts of rising greenhouse gases on Earth’s climate are very complex, it is important to understand that the driving force behind climate change is the simple concept of energy balance.  This study confirms that we have an excellent understanding of the direct impact of rising greenhouse gases like CO2 on Earth’s radiation energy.


AER research team contributes to Harvard-led study on natural gas leaks in Boston region

Thomas Nehrkorn
February 2, 2015

Scientists from AER's greenhouse gas (GHG) research team participated in a Harvard-led study ("Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts") just published  in the Proceedings of the National Academy of Sciences (PNAS). The study found that about 2.7 percent of all natural gas delivered to the region was being lost to leaks from a range of  sources in the area, including homes, businesses, and electricity  generation facilities, substantially more than previously estimated  by state and federal authorities (1.1 percent).

Co-author Dr. Thomas Nehrkorn and contributors Dr. Jennifer Hegarty, Marikate Mountain, John Henderson, and the late Dr. Janusz Eluszkiewicz adapted, ran, and evaluated the results of the WRF-STILT transport model. The coupled WRF-STILT model is the linchpin of multiple GHG-related efforts worldwide and has been developed at AER over the past decade with support from NSF, NASA, NOAA, the intelligence community, and private industry. Among on-going applications of WRF-STILT are studies of methane emissions over the Arctic, and of carbon dioxide emissions over the Northeast corridor of the US.

Read the Harvard summary of the research study: "Boston’s natural gas infrastructure releases high levels of heat-trapping methane" in the Harvard Gazette.

Read The Boston Globe article about the research study: "Leaks in Boston area gas pipes exceed estimates" in The Boston Globe.

Read the research study, “Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts”, published  in the Proceedings of the National Academy of Sciences (PNAS).

Note: AER greenhouse gas research team. Thomas Nehrkorn (top left), John Henderson, Marikate Mountain (lower left), and Jennifer Hegarty.



AER authors 43 oral/poster presentations at AGU Fall Meeting & AMS Annual Meeting

Ron Isaacs
December 4, 2014

We look forward to seeing colleagues at both the AGU Fall Meeting and the AMS Annual Meeting and hope you'll take a few moments to stop by some of AER's technical presentations.

As always, scientists and software engineers from Atmospheric and Environmental Research (AER) are contributing significantly to the meetings, giving 43 oral and/or poster presentations over the course of these two scientific conferences. In all, 38 AER authors contributed to this research.

American Geophysical Union, December 15-19

AER scientists and software engineers will author and/or coauthor a total of 25 oral and poster presentations on cutting-edge environmental research at the 2014 American Geophysical Union (AGU) Fall Meeting in San Francisco. The AER papers represent a broad set of key research undertakings in the environmental sciences, including important advances in:

  • Remote sensing and quantitative retrieval of atmospheric constituents (including carbon dioxide and methane) and land surface properties from satellite instruments,
  • Understanding and modeling of atmospheric pollutants for air quality applications,
  • Meteorological measurements, data assimilation, and numerical weather prediction,
  • Characterization and prediction of solar flares and energetic particle events, as well as other studies of the space environment, and
  • Searching for climate signals in the fluctuations and distributions of oceanic mass and density.

See details about AER’s topics at AGU.

American Meteorological Society, January 5-8

Our scientists and software engineers will author and/or coauthor 18 oral and poster presentations at the 2015 American Meteorological Society (AMS) Annual Meeting in Phoenix. In addition to many of the interesting topics mentioned above for the Dec. 2014 AGU conference, the AER papers at the AMS meeting will describe key findings on the following subjects:

  • Observing System Simulation Experiment (OSSE) systems, and determining the impacts of new sensors on numerical weather prediction,
  • Algorithms and products for the new GOES-R satellite system,
  • Active remote sensing of atmospheric carbon dioxide using LIDAR techniques, and
  • Science support to operational weather analysis and forecasting.

View the topics and AER authors at AMS.

See you in San Francisco and/or Phoenix! Drop us a note if you would like to connect while there.

Ron Isaacs
Atmospheric and Environmental Research (AER), a division of Verisk Climate

Verisk Climate’s Atmospheric and Environmental Research Adds Winter Temperature Animation to Arctic Oscillation Blog

Judah Cohen
December 3, 2014

We created a new animation that shows the observed evolution of temperature anomalies throughout the Northern Hemisphere landmasses based on snow cover alone. We composited daily temperatures (using a five day filter) of years with observed high Eurasian October snow cover minus low Eurasian October snow cover.  The animation runs from September 1 through February 28. You can view it on the Arctic Oscillation blog toward the bottom of the page.

Given the high snow cover observed this past October, the animation may provide insight into periods and regions when strong temperature anomalies are favored based on snow cover alone.  This is not a temperature forecast and of course many other factors influence observed temperature anomalies including global sea surface temperatures, the stratosphere, sea ice and the random nature of the atmospheric circulation.

The Arctic Oscillation is the climate mode most highly correlated with surface temperatures across the Northern Hemisphere continents. Drs. Judah Cohen and Jason Furtado from Atmospheric and Environmental Research (AER is a division of Verisk Climate) are analyzing and predicting the variability in the Arctic Oscillation (AO), the dominant mode of atmospheric variability in the Northern Hemisphere, in a new blog series.  AER’s published research shows that October Eurasian snow cover is a leading indicator of the mean winter Arctic Oscillation.

AER launches Arctic Oscillation Analysis and Forecasts blog

Judah Cohen
November 5, 2014

Drs. Judah Cohen and Jason Furtado from Atmospheric and Environmental Research (AER), a division of Verisk Climate, are analyzing and predicting the variability in the Arctic Oscillation (AO), the dominant mode of atmospheric variability in the Northern Hemisphere, in a new blog series Arctic Oscillation Analysis and Forecasts.  The blog will also discuss the climate impact associated with AO variability: the AO has a strong relationship with temperature variability across the entire Northern Hemisphere.  The time period discussed will be from the more immediate (the next several days) to the longer term (a season ahead). 

Motivations for the AO blog have been recent advances in understanding significant climate variability associated with the AO and in predicting the AO using dynamical models and statistical techniques.  Leading up to the winter months, we will focus on Eurasian snow cover, which has been shown to be a skillful predictor of the winter AO and of winter temperatures across northern Eurasia and the Eastern United States.  On cue to help generate enthusiasm for this blog, Eurasian snow cover has advanced rapidly this past October, clocking in with the second highest total since record keeping began back in the late 1960’s (See Figure), promising to make for interesting observation of the AO variability this winter.

Ron Isaacs appointed as IEEE GRSS Corporate Liaison

Brenda Kelly
March 3, 2014

Ron Isaacs has been appointed the Director of Corporate Relations for the IEEE Geoscience and Remote Sensing Society (GRSS). Ron is responsible for maintaining and enhancing the relationship between GRSS and private sector organizations involved in geoscience and remote sensing activities.

Ron's IEEE GRSS involvement spans numerous roles. He was elected a Senior Member of the GRSS in 2007 and served on the local organizing committee for IGARSS08, the society’s annual meeting, when it was held in Boston.

Under Ron's guidance, AER along with their government, academic and private sector partners, have been at the forefront of innovations in remote sensing and geoscience for more than 35 years. Fifteen staff at AER are members of IEEE.

IEEE GRSS subscribers can read more about AER's innovations in remote sensing and geoscience in the industry spotlight article "A Geoscience and Remote Sensing Research Paradigm in Industry".

NSF website features AER research on worst-case “exigent” weather forecasting

Daniel Gombos
January 8, 2014

Research performed by AER scientists Dr. Daniel Gombos and Dr. Ross Hoffman is featured on the NSF Science, Engineering, and Education (SEE) innovation website.

The NSF website reports on a new technique developed by AER scientists called exigent analysis (EA) that produces a forecast map of worst-case or “exigent” damages for a particular weather event based on an ensemble of forecasts.  For any chosen forecast confidence level, EA supplies an upper bound of the number of people and value of property that the storm would affect at each location.  The resulting exigent damage map gives the worst-case damage scenario for a given probability, or equivalently, the most likely pattern of damage for a given value of area-wide damage.

This research has direct application for emergency situations affecting life and property.  In advance of a disaster, emergency responders could use exigent damage maps as extreme but plausible scenarios, and agencies such as the Federal Emergency Management Agency and the Red Cross could use exigent forecasts to preposition resources and personnel.

Drs. Gombos and Hoffman applied EA to several recent major weather events including Superstorm Sandy (2012).  In the figure that appears at the SEE website and reproduced here, the left panel shows the ensemble mean forecast wind damage to households for Superstorm Sandy based on the ECMWF ensemble forecasts of 10-meter wind from 00 UTC 26 October 2012, approximately 96 hours before New Jersey landfall.  In the most likely scenario (left panel), total residential property damage is forecast to be $5.8B, with damage concentrated along the mid-Atlantic and New England coasts and Chesapeake and Delaware Bays.  The exigent damage at the 90% risk level (right panel) is greater than the most likely scenario at these locations and more inland penetration of damage in all areas north of the landfall location and especially near New York Harbor.  The total forecast damage for the exigent scenario is $16.5B.

AER Recognized by Northrop Grumman for Supplier Excellence

Brenda Kelly
December 19, 2013

AER has received a highly coveted Supplier Excellence Award from Northrop Grumman Corporation’s Information Systems (NGIS) sector for technical innovation and quality products and services.

AER was recognized for its work on the System Engineering Maintenance and Sustainment (SEMS) II program at the U.S. Air Force Weather Agency, the largest supplier of terrestrial and space weather data for military users worldwide.

Under the SEMS II program, AER provides subject matter expertise and development support to Northrop Grumman’s team, including those members assigned to the Cloud Depiction and Forecast System (CDFS) II. CDFS II, based on AER-developed science algorithms, is the world’s only operational, hourly, global cloud analysis and forecast system.

“This award from Northrop Grumman underscores AER’s ability to innovate and solve operational problems that affect the Air Force’s ability to provide warfighters with value-added environmental data for efficient decision making. The close collaboration between our companies not only translates into good science and engineering but also provides a substantial increase in Air Force Weather capabilities, with across-the-board benefits to defense and national programs,” said Ron Isaacs, president of AER.



AER SEMS II Team:Standing: Marc Hidalgo, Mark Conner, Eric Hunt.Seated: Becky Selin, Suseela Sarasamma.


Trent Dalton from Northrop Grumman (far right) presented the award to AER team members Suseela Sarasamma, Becky Selin, and Marc Hidalgo.

AER SEMS team members Bob d'Entremont, Gary Gustafson, and Hilary (Ned) Snell.


33 AER scientists contribute 28 research studies at AGU Fall Meeting 2013

Eli Mlawer
December 12, 2013

AER is proud that 10 of our scientists were the lead authors presenting their research on a wide range of topics at the American Geophysical Union (AGU) annual Fall meeting. In all, 33 AER scientists contributed to 28 research studies in 7 science categories ranging from greenhouse gases to land surface processes to space weather.

Science category AER studies contributed AER is lead author and presenter
AER science research presented at AGU
Greenhouse gases 10 2
Climate analysis 3 1
Numerical Weather Prediction 3 1
Land Surface Processes 5 3
Air Quality 4 1
Space Weather 2 2
Gravity and geodesy 1 0
Total 28 10

Click here to view the authors and their research topics in each science category.

AER scientists at the cutting edge of GHG research

Janusz Eluszkiewicz
November 26, 2013

AER scientists involved in greenhouse gas (GHG) research, Janusz Eluszkiewicz and Thomas Nehrkorn, are co-authors of a Harvard-led study "Anthropogenic emissions of methane in the United States" just published in the Proceedings of the National Academy of Sciences (PNAS) and receiving considerable attention worldwide for its conclusion that methane emissions in the U.S. are significantly greater than previous estimates.

AER's contribution to this research was the development of the atmospheric transport simulations that underlie the study. These simulations utilize the Stochastic Time Inverted Lagrangian Transport (STILT) model driven by customized meteorological fields from the Weather Research and Forecasting (WRF) mesoscale model. The coupled WRF-STILT model is the linchpin of multiple GHG-related efforts worldwide and has been developed at AER over the past decade with support from NSF, NASA, NOAA, the intelligence community, and private industry. Among on-going applications of WRF-STILT are urban methane leaks, monitoring, reporting, and verification (MRV) of CO2 emissions in the Boston-DC corridor, and GHG sources in the Arctic.

Besides Janusz and Thomas, scientists contributing to GHG research at AER include John Henderson, Marikate Ellis Mountain, Jennifer Hegarty and Scott Zaccheo.

Additional information about this study can be viewed in many news sources including: