Small footprint airborne laser scanning (ALS) is widely used to collect topographic data over large areas. ALS point
clouds provide high resolution datasets for variety of scientific and engineering applications, e.g. geomorphology,
geodynamics and forestry. ALS can also be used for monitoring coastal processes. For many marine applications,
however, the sea surface heights (SSH) are often requested. Satellite altimetry (SA) has been used to monitor SSH
globally. But in regional scale, especially in the coastal areas and enclosed water bodies, the usability of SA is limited
due to poor accuracy. Alternatively, our experiments have demonstrated that the water surface in the nadir range can be
registered using small footprint ALS. Therefore, a special case study was carried out to analyze SSH determination from
ALS measurements. Three profile-wise ALS measurements were carried out in the eastern shores of the Baltic Sea.
Along flight trajectories 100 m wide corridors of ALS points were formed. Shorter wavelength signals, like sea wave
oscillation, were removed by a low-pass averaging filter. The achieved SSH were verified against a high resolution
regional geoid model and also with high-frequency tide gauge observations. Comparisons revealed that the ALS-based
sea level-corrected SSH agree with the regional geoid model with standard deviation as of ±1…±2 cm. Thus, small
footprint ALS measurements could be applied to determine SSH in regions where SA has limited quality, e.g. in coastal
areas and enclosed water bodies.