The design and evaluation of a prototype fiber-based lidar system for auton
omous measurement of atmospheric water vapor are presented. The system comp
onents are described, along with current limitations and options for improv
ement. Atmospheric measurements show good agreement with modeled signal ret
urns from 400 to 1000 m but are limited below 400 m as a result of errors i
n signal processing caused by violation of the assumptions used in the deri
vation of the differential absorption lidar equation. (C) 2001 Optical Soci
ety of America.