Optimum wavelength of spaceborne oceanic lidar in penetration depth

•The global distribution of ocean penetration depth and the corresponding optimum wavelength bands are calculated for spaceborne photon-counting oceanic lidar.•Wavelength bands of 488 nm and 443 nm have good penetration ability and by taking advantage of the characteristic of solar Fe Fraunhoferline (438.355 nm) and H-β Fraunhoferline (486.134 nm), the background light can be suppressed and the penetration depth can be further increased.•Wavelength of 486.134 nm is the optimum wavelength of single-wavelength lidar and the combination of 486.134 nm and 438.355 nm is a good choice for dual-wavelength lidar for purpose of global ocean detection.