The Mobile Atmospheric Pollutant Mapping (MAPM) System: A Coherent CO, Dial System

William B. Grant

doi:10.1117/12.951877

25 July 1989 The Mobile Atmospheric Pollutant Mapping (MAPM) System: A Coherent CO₂ Dial System

William B. Grant

Proceedings Volume 1062, Laser Applications in Meteorology and Earth and Atmospheric Remote Sensing; (1989) https://doi.org/10.1117/12.951877
Event: OE/LASE '89, 1989, Los Angeles, CA, United States

Abstract

CO₂ laser systems are particularly useful for remote measurement of atmospheric trace gases because of several factors: 1. many molecular species have absorption features in the 9-11 micron spectral region; 2. the atmosphere is relatively transparent; 3. CO2 lasers are discretely tunable in this spectral region, and are reasonably powerful or energetic. Indeed, CO₂ laser systems have been applied to measuring a number of molecular species: water vapor, ethylene, ozone, ammonia, hydrazines , freons, methanol, and sulfur hexafluoride(SF₆). While most of this work has been with direct detection, some work has been reported using heterodyne detection. In direct detection, a receiver acts as a "light bucket," detecting photons in a wide bandwidth, typically tens to hundreds of wavenumbers (cm^-1 where 1 cm^-1 = 30 GHz). In heterodyne detection, the detection region is narrowed to a few MHz by use of a local oscillator laser and RF-detection electronics so that the thermal background radiation is kept to a minimum. Thus, in direct detection, measurements are typically limited to ranges of 1-3 km, while in heterodyne detection, measurements can be made to ranges of 5-10 km. In the sections that follow, the hardware for the Mobile Atmospheric Pollutant Mapping (MAPM) System is described, along with measurement results using it, the absorption coefficients and measurement sensitivities for a number of molecular species, and the factors that limit measurement accuracy and range.

Citation Download Citation

William B. Grant "The Mobile Atmospheric Pollutant Mapping (MAPM) System: A Coherent CO₂ Dial System", Proc. SPIE 1062, Laser Applications in Meteorology and Earth and Atmospheric Remote Sensing, (25 July 1989); https://doi.org/10.1117/12.951877

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

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.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available