More than five years of CO retrievals from the Atmospheric InfraRed Sounder (AIRS) onboard NASA's
Aqua satellite reveal variations in tropospheric CO on timescales from twelve hours to five years and on
spatial scales from local to global. The shorter timescales are invaluable to monitor daily variations in
CO emissions, to enable three-dimensional tracking of atmospheric motions, and to enhance insights into
atmospheric mixing. Previous studies have utilized AIRS CO retrievals over the course of days to weeks
to track plumes from large forest fires. On the local scale, we will present AIRS observations of pollution
from several northern hemisphere Megacities. On the regional scale, we will present AIRS observations
of the Mexico City pollution plume. We will illustrate global scale AIRS CO observations of interannual
variations linked to the influence of large-scale atmospheric perturbations from the El Nino Southern
Oscillation (ENSO). In particular, we observe a quasi-biennial variation in CO emissions from Indonesia
with varying magnitudes in peak emission occurring in 2002, 2004, and 2006. Examining satellite
rainfall measurements over Indonesia, we find the enhanced CO emission correlates with occasions of
less rainfall during the month of October. Continuing this satellite record of tropospheric CO with
measurements from the European IASI instrument will permit construction of a long time-series useful
for further investigations of climatological variations in CO emissions and their impact on the health of
the atmosphere.
The Atmospheric Infrared Sounder (AIRS) sounding suite, launched in 2002, is the most advanced atmospheric
sounding system to date, with measurement accuracies far surpassing those of current operational weather satellites.
From its sun-synchronous polar orbit, the AIRS system provides more than 300,000 all-weather soundings covering
more than 90% of the globe every 24 hours. Usage of AIRS data products, available to all through the archive system
operated by NASA, is spreading throughout the atmospheric and climate research community. An ongoing validation
effort has confirmed that the system is very accurate and stable and is close to meeting the goal of providing global
temperature soundings with an accuracy of 1 K per 1-km layer and water vapor soundings with an accuracy of 20%
throughout the troposphere, surpassing the accuracy of radiosondes. This unprecedented data set is currently used for
operational weather prediction in a number of countries, yielding significant positive impact on forecast accuracy and
range. It is also enabling more detailed investigations of current issues in atmospheric and climate research. In addition
to the basic soundings related to the hydrologic cycle, AIRS also measures a number of trace gases, the latest such
product being the global distribution of carbon dioxide. We discuss some examples of recent research with AIRS data.
The Earth Science and Meteorological communities are taking great interest in a new instrument released by NASA. The Atmospheric Infrared Sounder (AIRS), launched on the EOS Aqua Spacecraft on May 4, 2002, is a high spectral resolution infrared imaging spectrometer with over 2300 distinct infrared wavelengths ranging from 3.7 μm to 15.4 μm. AIRS is unique in that it provides the highest infrared spectral resolution to date while also providing coverage of over 95% of the Earth's surface every day at 15 km spatial resolution. The AIRS project is currently managed by NASA's Jet Propulsion Laboratory in Pasadena, California1. The AIRS is providing a wealth of scientific data to the Earth Science community including upper atmospheric water vapor and atmospheric composition on key greenhouse gases. It is also improving weather forecasting and the studies of processes affecting climate and weather.
One goal of the atmospheric infrared sounder (AIRS), scheduled to fly on the EOS-PM1 satellite in 2000, is the global measurement of the atmospheric abundance of carbon monoxide (CO). ALthough it is primarily a temperature and humidity sounder for EOS, AIRS can resolve individual CO lines in a portion of the 1-0 vibration-rotation band of CO between 2170 and 2200 cm-1, but with significant noise. Taking advantage of the almost regular spacing of these lines, we have developed an algorithm to retrieve the column density of CO from AIRS spectra using standard signal processing techniques for noise reduction. Detailed simulations indicate the capability to retrieve total column densities of CO to an accuracy of approximately 10 percent. Validation of our CO retrieval algorithm has been accomplished using a combination of in situ CO profiles acquired by an instrumented Cessna and nearly coincident infrared spectra obtained by the University of Wisconsin Madison's High-resolution Interferometer Sounder (HIS) flying onboard a NASA ER-2 during the Second Convection and Moisture Experiment in August, 1995. Excellent agreement was obtained between the retrieved CO abundance, approximately 90 ppbv, and the in situ profile above the boundary layer, approximately 80-100 ppbv. Additional HIS spectra obtained near Long Island, NY show enhanced CO levels, 1400-4300 ppb if confined to portions of the boundary layer, in the smoke plume downwind from forest fires near Westhampton, NY on August 25, 1995.
The next generation of atmospheric temperature and humidity sounders will have thousands of radiometrically accurate spectral channels throughout the infrared. The retrieval of atmospheric parameters from these radiances will stress both the accuracy and efficiency of forward model radiative transfer algorithms. We are developing a forward model for the Atmospheric Infrared Sounder (AIRS) which will fly on the EOS PM platform. The work presented here is based on algorithms developed over a number of years by McMillin, Fleming, and others for low resolution infrared sounders (HIRS) and microwave sounders. We have developed tow 'high resolution' AIRS forward model algorithms for water vapor, one based on atmospheric layers with fixed pressures and variable water amounts, and other based on layers of fixed absorber amount but with variable pressures. These algorithms are compared for speed, accuracy, ease of development, and other factors that must be considered in developing a complex operational retrieval system.
Conference Committee Involvement (1)
Remote Sensing of Aerosol and Chemical Gases, Model Simulation/Assimilation, and Applications to Air Quality
13 August 2006 | San Diego, California, United States
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.