Implementation of Differential Absorption LIDAR (DIAL) for Molecular Iodine Measurements Using Injection-Seeded Laser

Abstract

Differential absorption LIDAR (DIAL) is frequently used for atmospheric gas monitoring to detect impurities such as nitrogen dioxide, sulfur dioxide, iodine, and ozone. However, large differences in the on-and off-line laser wavelengths can cause serious errors owing to differential aerosol scattering. To resolve this problem, we have developed a new DIAL system for iodine vapor measurements in particular. The suggested DIAL system uses only one laser under seeded and unseeded conditions. To check the detection-sensitivity and error effects, we compared the results from a system using two seeded lasers with those from a system using a seeded and an unseeded laser. We demonstrate that the iodine concentration sensitivity of our system is improved in comparison to the conventional two seeded or two unseeded laser combinations.

Supplementary material to "Halogen activation and radical cycling initiated by imidazole-2-carboxaldehyde photochemistry"

“…The rate coefficient of the quenching of the triplet (R2) by O2 was taken as an approximation from Canonica et al (Canonica, 2000). The measurement of R3 and the guess of R4 are explained in our previous work (Corral-Arroyo, 2018). Note that in that study the rate coefficients and adjustable parameters of the model were optimized to agree with the measurements in the humidity range of 35±2 % RH, overlapping with the RH range of the present study.…”

“…The photolysis rate of iodine was calculated by integrating the irradiance spectrum ( Fig. S1) and the iodine photolysis spectrum (Choi et al, 2012) resulting in a rate of 0.01 s -1 .…”

“…As in our previous work (Corral-Arroyo, 2018), we represented the release due to diffusion by a simple first order loss rate coefficient ( ) as: Source of rate coefficients: (Bianchini and Chiappe, 1992;Bielski et al, 1985;Canonica, 2000;Choi et al, 2012;Corral-Arroyo, 2018;Ishigure et al, 1988;Maillard et al, 1983;Morrison et al, 1971;Nagarajan and Fessenden, 1985;Schwarz and Bielski, 1986;Tinel, 2014;Wagner and Strehlow, 1987) *First order rate coefficient. E Equilibrium constant…”

Active and Passive Electro-Optical Sensors for Health Assessment in Food Crops

“…Active monostatic configurations are employed with DIAL configurations for atmosphere sounding that measures not only the elastic backscatter produced along the external path but also the radiance of the illuminated Earth surface in the direction of the airborne system. In addition, numerous DIAL systems have been improved to measure the concentration/column density of different significant molecule species based on the development of powerful tuneable lasers [ 131 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 ].…”