Development and Application of a new DACOM Airborne Trace Gas Instrument based on Room-Temperature Laser and Detector Technology and all-Digital Control and Data Processin

Wednesday, 17 December 2014
Glenn S Diskin1, Glen W Sachse2, Joshua P DiGangi1, Sally E Pusede3, Thomas A Slate4 and Mario Rana4, (1)NASA Langley Research Center, Hampton, VA, United States, (2)National Institute of Aerospace, Hampton, VA, United States, (3)ORAU / NASA Langley Research Center, Hampton, VA, United States, (4)Science Systems and Applications, Inc. Hampton, Hampton, VA, United States
The DACOM (Differential Absorption Carbon monOxide Measurements) instrument has been used for airborne measurements of carbon monoxide, methane, and nitrous oxide for nearly four decades. Over the years, the instrument has undergone a nearly continuous series of modifications, taking advantage of improvements in available technology and the benefits of experience, but always utilizing cryogenically cooled lasers and detectors. More recently, though, the availability of room-temperature, higher-power single-mode lasers at the mid-infrared wavelengths used by DACOM has made it possible to replace both the cryogenic lasers and detectors with thermoelectrically cooled versions. And the relative stability of these lasers has allowed us to incorporate an all-digital wavelength stabilization technique developed previously for the Diode Laser Hygrometer (DLH) instrument. The new DACOM flew first in the summer 2013 SEAC4RS campaign, measuring CO from the DC-8 aircraft, and more recently measuring all three gases from the NASA P-3B aircraft in support of the summer 2014 DISCOVER-AQ campaign. We will present relevant aspects of the new instrument design and operation as well as selected data from recent campaigns illustrating instrument performance and some preliminary science.