Atmospheric Turbulence-Induced Radiometric Distortion of Spaceborne Lidars

Atmospheric turbulence is a significant factor that affects the radiometry of spaceborne laser pulses. Depending on the meteorological data from the National Centers for Environmental Prediction (NCEP) dataset and phase screens simulated from fractal interpolation method, the optical fields of a transmitted laser pulse propagating through the turbulence are modeled in this study. By calculating the ratio of the received energy with and without turbulence, an energy index is introduced to quantitatively evaluate the turbulence impact. Taking the ICESat-2 Lidar as an example, the distributions of the energy index at three simulated areas with weak, moderate, and strong turbulence are investigated. The results indicate that the means of energy index reaches 0.90 for moderate and weak turbulences, which corresponds to 10% laser energy loss, but would decrease to 0.70 for strong turbulence corresponding to 30% laser energy loss. It implies that the strong turbulence impact should be compensated for the radiometric correction of laser pulses. In addition, the proposed method is validated by comparing the energy index and the atmospheric transmittance derived from the ATL09 data over three areas with different surface types. The mean absolute percentage errors (MAPEs) are below 5% and the root mean square errors (RMSEs) are less than 0.05, which proves that our proposed method is effective for simulating the influence of atmospheric turbulence on the radiometry of spaceborne laser pulses.