Bathymetry Retrieval Without In-Situ Depth Using an ICESat-2 Assisted Dual-Band Model

Abstract

Many current satellite-derived bathymetry methods usually rely on in-situ water depth, which limits their applications. In this study, an ICESat-2 assisted dual-band model (IDBM) is proposed, which can be used to derive bathymetry independent of in-situ water depth. First, the Sentinel-2 blue and green band diffuse attenuation coefficient is derived using ICESat-2 lidar photon data from adjacent deep water according to the Jerlov ${{K}_d}$ spectral curves and the sensor spectral response function. Then, these two coefficients are applied to the IDBM model to derive the water depth. Datasets for four study areas are used to validate the feasibility of the proposed IDBM model, in addition, the original QAA (quasi-analytical algorithm) assisted dual-band model (QDBM) is also used to derive bathymetry for comparison purposes. Experiment results show that the proposed IDBM model is effective and can achieve higher or similar accuracy compared to the original QDBM model. The average mean absolute error (MAE) and root mean square error (RMSE) of the IDBM model reach 1.23 and 1.67 m, while those of the QDBM model are 1.44 and 1.91 m, respectively. The performance of the IDBM model has improved to some extent. Especially for the SI case, the MAE and RMSE of the QDBM model are 1.46 and 2.00 m, while those of the IDBM model are 0.99 and 1.55 m, which are reduced by 0.47 and 0.45 m. In conclusion, the proposed IDBM model is feasible and effective to derive bathymetry without in-situ water depth.

Keywords

• Bathymetry retrieval
• $K_d$ )%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> diffuse attenuation coefficient (<named-content xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" content-type="math" xlink:type="simple"> <inline-formula> <tex-math notation="LaTeX">$K_d$</tex-math> </inline-formula> </named-content>)
• ICESat-2
• ICESat-2 assisted dual-band model (IDBM)