The optical depth must be inverted from the backscatter signal, a process which is complicated by the fact that both molecular and aerosol backscatter signals are present. The HSRL has the advantage of allowing these two signals to be separated.
Depolarization is used to determine the nature of hydrometeors present.
Experiments show that water clouds must almost always be taken into account during cirrus observations. This peak can be removed by an iodine vapor absorption cell, which leaves only the wings of the broad molecular signal intact. The full molecular signal can be restored if the atmospheric pressure and temperature profiles are known. Successive pulses are horizontally and vertically polarized allowing fast depolarization measurements. Aerosol backscatter signal strength is used to measure cloud optical depth.