Mathematical limits to accuracy of the DIAL equation set by resolution limits due to sampling requirements.
Spatial resolution of DIAL measurements is limited by the requirement that the return signal be integrated over a range cell DeltaR to eliminate aliasing by electrical noise or spatial features with frequencies above the sampling frequency of the system. The mean value of absorber is not uniquely given by this integral if its concentration varies appreciably over DeltaR. The error in its mean value is calculated for a few simulated cases in which absorber concentration is varied over DeltaR. A very high degree of accuracy is necessary for DIAL measurements of T-profiles to be useful as input data for weather forecasts. An expression is derived for the ratio of the two on-line absorption coefficients to include a correction for absorber optical depth within a single range cell.
Braun
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