Abstract
We have developed a low-cost, miniaturized laser heterodyne radiometer for highly sensitive measurements of carbon dioxide (CO2) in the atmospheric column. In this passive design, sunlight that has undergone absorption by CO2 in the atmosphere is collected and mixed with continuous wave laser light that is step-scanned across the absorption feature centered at 1,573.6 nm. The resulting radio frequency beat signal is collected as a function of laser wavelength, from which the total column mole fraction can be de-convolved. We are expanding this technique to include methane (CH4) and carbon monoxide (CO), and with minor modifications, this technique can be expanded to include species such as water vapor (H2O) and nitrous oxide (N2O).
Highlights
Surface-observing networks have made major contributions to understand the carbon cycle as well as atmospheric distributions of key gases such as CO2, CH4, and carbon monoxide (CO)
We have developed a low-cost, miniaturized laser heterodyne radiometer for highly sensitive measurements of carbon dioxide (CO2) in the atmospheric column
The LHR instrument is comprised of an AERONET sun tracker and a weatherproof module that houses the laser, the chopper, the InGaAs detectors, and the electronic components of the instrument
Summary
Surface-observing networks have made major contributions to understand the carbon cycle as well as atmospheric distributions of key gases such as CO2, CH4, and CO. These observations have not been sufficient to constrain regional CO2 fluxes, and many parameters related to the emission of these gases still vary widely. A more recent study by Chevallier et al [7] used data from 14 TCCON [8] stations to estimate fluxes and compared the results with estimates based on surface and aircraft observations. Changes in the diffuse radiative flux fraction (DRF) due to aerosol loading have the potential to alter the terrestrial carbon exchange [6, 14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
