Differential Absorption LIDAR for Greenhouse Gas Detection

Our goal is to develop and characterize measurement technology for ground-based quantification of greenhouse-gas emissions from natural and anthropogenic sources and sinks. Toward this end, we are developing a differential absorption LIDAR (DIAL) system capable of remote measurements of atmospheric levels of the major greenhouse gases with 10-100 meter range resolution over distances of several kilometers. Our DIAL system operates in the eye safe 1600 nm wavelength region where three critical greenhouse gases, carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) have vibrational absorption bands. Our final system will be capable of measuring both concentration and wind speed to determine gas fluxes. The system has potential to serve as validation for other methods of remote sensing. This talk will discuss the development of our high energy infrared transmitter and receiver, novel detection strategies, recent results, and our 100 meter long indoor test facility. The test facility will enable careful characterization of the DIAL system and may serve as a reference for other remote sensing systems. 11:25 Absolute Radiance Re-calibration of FIRST Harri Latvakoski, Jason Swasey, Kendall Johnson – USU/Space Dynamics Laboratory; Martin Mylnczak, David Johnson, Richard Cageao – NASA Langley Research Center ABSTRACT: The FIRST (Far-InfraRed Spectroscopy of the Troposphere) instrument is a 10 to 100 micron spectrometer with 0.64 micron resolution designed to measure the complete mid and far-infrared radiance of the Earth\u27s Atmosphere. FIRST has been successfully used to obtain high-quality atmospheric radiance data from the ground and from a high-altitude balloon. A Fourier transform interferometer is used to provide the spectral resolution and two on-board blackbodies are used for calibration. This presentation will discuss the recent re-calibration of FIRST at Space Dynamics Laboratory for absolute radiance accuracy. The calibration used the LWRICS (Long Wave Infrared calibration source) blackbody, which NIST testing shows to be accurate to the ~100 mK level in brightness temperature. There are several challenged to calibrating FIRST, including the large dynamic range, out of phase light, and drift in the interferogram phase. The accuracy goal for FIRST was 0.2 K over most of the 10 to 100 micron range, and results show FIRST meets this goal for a range of target temperatures