Radio Refractivity Profiles Deduced from Lidar Measurements
Abstract
Measurements are presented of the returns from a vertically pointing lidar, along with simultaneous radiosonde measurements of meteorological parameters on 13 cloud-dree days near the ocean at San Diego, California. Linear regression analyses between the lidar range-compensated power, S(R), and the relative humidity, RH, gave high coefficients of correlation for individual days, but the magnitudes of the regression constants differed from day to day, indicating differing properties of the aerosols for each day. The combined data set was used to derive a linear relationship between S(R) at different altitudes and the corresponding values of RH. This resulted in a correlation coefficient of 0.73. Using standard vertical lapse rates of temperature and pressure with the profiles of relative humidity determined from the lidar returns, the modified radio refractivity (M-units) variations with altitude were determined for each of the days. These M-unit profiles were then compared to the corresponding values calculated from the radiosonde data. While the absolute values differed with altitude in most cases, the gradients in M-units with altitude corresponded remarkably well. Using a ray-trace computer program, two- dimensional (altitude-versus-range) plots of the radio signal coverage were determined by using the M-unit profiles determined by the two methods. The plots in both cases show similar ducting conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1990
- Accession Number
- ADA221727
Entities
People
- H. G. Hughes
- M. R. Paulson