Publications

Yang, J; Zheng, HY; Ma, Y; Zhao, PF; Zhou, H; Li, S; Wang, XH (2023). Examining the Consistency of Lidar Attenuation Coefficient Klidar From ICESat-2 and Diffuse Attenuation Coefficient Kd From MODIS. IEEE GEOSCIENCE AND REMOTE SENSING LETTERS, 20, 6500905.

Abstract
The new generation photon-counting lidar on Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) can obtain the subsurface optical properties of sea waters. Recent studies highlight the applications of deriving the lidar attenuation coefficient K-lidar and then substituting K-lidar into the bio-optical model to obtain more information of sea waters. As commonly used bio-optical models are built for the diffuse attenuation coefficient K-d that are traditionally derived by passive ocean color sensors, whether K-lidar derived from ICESat-2 can be directly used as K-d is a fundamental question. Given that K-d is an apparent optical property (AOP) in the water column rather than an inherent optical property (IOP), K-d is closely related to the zenith angle of the incident light. The zenith angle of the incident light of the sunlight is normally tens of degrees for ocean color sensors, while the maximum laser off-nadir angle is similar to 1.5 degrees for the ICESat-2 lidar. To demonstrate this issue, we select hundreds of ground tracks of ICESat-2 in both open ocean and coastal sea waters and compare the derived K-lidar with their corresponding Moderate Resolution Imaging Spectroradiometer (MODIS)-derived K-d. The results indicate that the corrected results of 1.2 x K-lidar, instead of the direct results of K-lidar, are more consistent with MODIS K-d. This study is of great significance to the better fusion of active lidar data and passive optical data in ocean observations.

DOI:
10.1109/LGRS.2023.3284199

ISSN:
1558-0571