2016 NASA Atmospheric Infrared Sounder (AIRS) Spring Science Team Meeting
Meeting Agenda (updated 3/17/16)
Eric J. Fetzer, NASA/Jet Propulsion Laboratory
The NASA Atmospheric Infrared Sounder (AIRS) Science Team Meeting was held March 22-24, 2016 at the California Institute of Technology’s Beckman Institute in Pasadena, CA. The AIRS Project at NASA/Jet Propulsion Laboratory (JPL) hosted the meeting. While the unifying theme of the meeting was atmospheric observations from AIRS, there were presentations about data from other sounders as well. There was also a special session devoted to AIRS Applications. Speakers at the meeting shared results from a broad range of scientific and technical disciplines.
There were 38 presentations spread across 6 themed sessions during the meeting. The sessions included:
• Introductory Remarks/Project Status;
• Atmospheric Composition;
• Weather and Climate;
• AIRS Applications;
• Product Development; and
• Product Validation.
This report focuses on four invited presentations related to two of the six sessions that took place during the meeting, and two additional presentations that were noteworthy. The meeting agenda is available at http://airs.jpl.nasa.gov/events/36; most of the presentations from this and related earlier meetings can be downloaded from http://airs.jpl.nasa.gov/resources/presentations.
The first day of the meeting began with introductory remarks and updates on the AIRS Project. The AIRS instrument on NASA’s Aqua platform has been operational since late August 2002 and has a lifetime expected to last into the early 2020s. AIRS data continue to make significant contributions to global forecasting skill and support a large community of researchers in weather, climate, and atmospheric composition disciplines. Two sessions made up the remainder of the first day: Atmospheric Composition, which included one invited presentation (which had to be delayed until the third day), and Weather and Climate.
In the Atmospheric Composition session, Dejian Fu [JPL] described an algorithm to retrieve ozone from collocated radiance observations from AIRS and the Ozone Monitoring Instrument (OMI) onboard NASA’s Aura platform. Because Aqua and Aura fly in the A-Train constellation2, the radiances from the two instruments are obtained within a minute of each another. One of the analyses shown in the presentation demonstrated the synergy of the two sets of observations. Retrievals using the combined radiances have higher information content than the combination of retrievals based on separate radiances. During the Weather and Climate session, Xun Jiang [University of Houston] showed how carbon dioxide (CO2) observed in the middle troposphere by AIRS over the southwestern U.S. is correlated with regional drought. She attributed the higher CO2 amounts to increased production by wildfires and reduced uptake by drought-stressed vegetation.
The AIRS Applications session comprised the entire second day of the meeting, which included three invited presentations (described in some detail below), as well as other presentations on other related topics.
Pietro Ceccato [International Research Institute/ Columbia University] described the challenges and benefits of using remote sensing data to monitor atmospheric conditions that affect food security, human health, and disaster management. He described examples of how vector-borne diseases and locust swarms in Africa are affected by variations in local temperature, humidity, and rainfall. Ceccato noted that there are many locations around the world where such observations are available only from satellite instruments. Many of these areas are also regions of lower socioeconomic development, where resilience to natural stressors tends to be more limited. Of particular value is that information about the atmosphere obtained by satellites can be rapidly disseminated to local communities via near-ubiquitous cellular telephone networks.
Chris Barnet [Science and Technology Corporation] described his experience in incorporating retrievals from AIRS and other sounders into forecast systems run by the National Oceanic and Atmospheric Administration (NOAA) and related contracting organizations. Barnet described many challenges, including very diverse user needs and a complex forecast system containing a large number of datasets for assessment. These challenges are being met through close collaboration and careful communication between forecasters and data providers. Barnet also gave several examples of how the forecast community uses sounder information, including atmospheric river monitoring over the Pacific, measurements of cold air aloft near Alaska, and observations of severe summertime weather over the Midwestern U.S.
Amir AghaKouchak [University of California, Irvine] examined drought indicators using AIRS and other information sources. He showed that AIRS near-surface relative humidity can provide improved drought forecast skill over the U.S. as compared to precipitation-based indicators, particularly when warm, dry atmospheric conditions cause plant stress. AghaKouchak described efforts to incorporate AIRS observations into an operational drought monitoring and prediction system.
In addition to the invited presentations, the Applications session also included presentations on a wide range of topics featuring AIRS data, including forecast improvements, using ozone amounts to detect stratospheric air intrusions, visualizing and distributing near-real-time products, incorporating sounder data into geographical information systems, and monitoring volcanic plumes.
David Crisp [JPL] opened the third day’s sessions with the fourth invited presentation addressing Atmospheric Composition—which had been delayed from day one. He showed analyses of Orbiting Carbon Observatory-2 (OCO-2) satellite observations of atmospheric CO2. Crisp described his team’s work to validate OCO-2 against in situ observations. He also shared preliminary global maps of CO2 from OCO-2, and compared those with maps of AIRS mid-tropospheric CO2. Crisp also described the first efforts to use OCO-2 observations to close the atmospheric carbon budget (which is the primary scientific goal of OCO-2). He also showed global maps of solar-induced chlorophyll fluorescence—a measure of plant activity—also from OCO-2.
The remainder of the third day was devoted to the Product Development and Product Validation sessions. During the Product Development session, H. H. Aumann [JPL] discussed the challenges of developing an AIRS forward model that includes the effects of clouds, noting that this would permit the simultaneous retrieval of clouds and other atmospheric variables. During the Product Validation session, Chris Wilson [JPL] described the validation of AIRS cloud-cleared radiance, which is a retrieved estimate of infrared emission from cloud-free parts of AIRS scenes. He collocated radiance observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua with similar observations from AIRS, and then spectrally smoothed the AIRS radiances; this approach allows direct comparison of radiances between the two instruments. The results showed good agreement in all MODIS channels, with better agreement for AIRS scenes flagged as having higher-quality retrievals.
The AIRS instrumental record now extends nearly 14 years and contains approximately 3 million spectra observed daily for a total of nearly 15 billion spectra to date. Three related hyperspectral infrared sounders, several lower-spectral-resolution infrared and microwave sounders, and related instruments, e.g., OCO-2, are currently operated by NASA and by other space agencies around the world. (See the Fall 2015 Sounder Science Team meeting summary referenced earlier for a list of these related sounder instruments.) These marvelous machines provide a detailed record of weather and climate phenomena extending over decades. The next Sounder Science Team Meeting, where the more-extended sounder community will share results, is planned for September 2016 in Greenbelt, MD.