A new high-accuracy pure rotational Raman (PRR) lidar system at a laser wavelength of 532.25 nm, based on a
technique of wavelength division multiplexing (WDM), has been designed for profiling the atmospheric temperature of
the low troposphere. A special WDM, which was usually used in fiber communication field, is designed to separate two
PRR signals of N2 and O2 for temperature retrieval, and to simultaneously block Mie- and Rayleigh-scattering signals
with a rejection rate of large than 107. A numerical calculation is simulated to verify the feasibility of the lidar system,
and the results showed that the PRR lidar based on spectroscopic characteristic of the WDM is capable of measuring the
atmospheric temperature vertical profiles in the low troposphere, and a statistical temperature error less then 1K was
achieved up to a height of 3.3 km and 5 km for daytime and nighttime measurement, respectively, under conditions of
300 mJ laser energy, 25-cm-diameter telescope, 10 min observation time, solar radiance of 3×108 Wm-2sr-1nm-1 and
atmospheric backscattering ratio less then 3.4.
|