AIRS and Climate Science
The Atmospheric Infrared Sounder, AIRS, flying on a NASA weather and climate research satellite called Aqua, is the first spaceborne instrument designed specifically to measure the most critical global climate change indicators. AIRS' cutting edge technology allows it to measure the amounts of water vapor and greenhouse gases with remarkable precision and accuracy. As a result, we are now beginning to gather data from space of the quality that will allow us to address many of the scientific questions related to Earth's climate and global change in the atmosphere.
AIRS had demonstrated exceptional accuracy and yield, providing over 300,000 temperature and water vapor profiles globally with accuracies comparable to radiosondes-even from uninhabited or totally inaccessible areas. The AIRS “satellite-sondes” enable direct observation of atmospheric events and processes related to severe weather and climate. For the first time we are forming a precise picture of the three-dimensional global distribution of water vapor and carbon dioxide, the primary greenhouse gases.
Climate Processes and Model Validation
The largest uncertainties in global climate models are associated with cloud and water vapor feedback processes. Until now, measurements of water vapor from the atmosphere's upper troposphere have been limited, and as a result accurate modeling of water vapor feedbacks with increasing surface temperature a problem for global climate models. Since its launch in 2002, the AIRS instrument has been able to provide data which has shown a positive correlation between sea surface temperature and water vapor at 250 millibar, indicating a "positive" upper tropospheric water vapor feedback with increased surface warming. Other studies using AIRS data have confirmed that water vapor feedback is positive with increased global warming.
Cloud Observations and Atmospheric Processes
Clouds play a very important role in the climate sciences. They modulate incoming solar radiation (visible and near infrared) by reflecting about 30% of the total amount of sunlight reaching Earth.
The hyper-spectral infrared observations of the AIRS instrument are exceedingly adept at detecting and characterizing cirrus clouds. These clouds create a positive feedback (warming effect) in Earth’s atmosphere since they radiate at lower temperatures and are not an effective barrier to incoming solar radiation.