Refractive Propagation Effects Measured by Lidar
Document ID: 349
Philbrick, C. Russell1
Blood, David W.
1 Hosted Applied Research Laboratories
Presented: Austin Texas, August 2-4 1994
Abstract
A multi-wavelength Raman lidar has been developed and used to measure the profiles of water vapor, temperature and other atmospheric properties in the troposphere under a wide range of geophysical conditions. Tue LAfv1P lidar instrument is transportable and has been used to make measurements at several locations in addition to our local site, including shipboard measurements between Arctic and Antarctic and in a coastal environment at Point Mugu, CA Tue Raman technique provides an accurate way to measure the profiles of water vapor from the ratio of the Raman vibrational back scatter signal from water vapor to that of nitrogen. The lidar has been used both to obtain water vapor profiles from molecular Raman vibrational scattering at several wavelengths, and temperature profiles from Raman rotational scattering at 528 and 530 run. The water vapor measurements have been made using the vibrational Raman back scatter intensity from the 660/607 ratio from the 532 nm, 407/387 ratio from 355 nm, or the 294/283 ratio from 266 nm laser radiation.
Lidar measurements of the atmospheric refractive environment of particular interest were made during 1993 at Point Mugu. CA. including the period of Project VOCAR (Variability of Coastal Atmospheric Refractivity). The data were averaged and used to compute profiles of refractivity, N, and modified refractivity, M. at 75 m resolution in the lower tropospheric region (0 - 5000 m). The lidar data is stored at one minute intervals and the temporal variation of refractive index is typically examined at intervals of 30 minutes. Both the lidar and balloon (radiosonde) tropospheric measurements have been used for analysis of the propagation conditions through the use of the Navy's RPO, IREPS and EREPS PC programs.
| Citation: | "Refractive Propagation Effects Measured by Lidar", Philbrick, C. R., D. W. Blood, Beyond Line-of-Sight Conference, publisher?, August 1994, pp. 1 - 21 |