Abstract: To meet the requirements of ubiquitous coverage in sixth-generation mobile communication (6G), the space-air-ground-sea integrated network (SAGSIN) has emerged as a key enabling technology. To meet the requirements of ubiquitous coverage in sixth-generation mobile communication (6G), the space-air-ground-sea integrated network (SAGSIN) has emerged as a key enabling technology. As an integral component of SAGSIN, reliable air-sea communications rely on an in-depth understanding of air-sea channel propagation characteristics. To reveal the propagation mechanisms of air-sea communication links, this paper focuses on two typical dynamic air-sea channel scenarios. A time-domain channel measurement platform was employed to conduct a measurement campaign in the 2 GHz frequency band, followed by extraction and statistical analysis of large-scale and small-scale channel parameters. The analysis results show that the measured path loss is close to the free-space path loss. The small-scale fading envelope is best fitted by the Rician distribution, verifying that the air-sea wireless channel is dominated by a strong line-of-sight (LoS) path. Comparison between the Doppler shift of the main path and the mean Doppler shift (MDS) at corresponding instants reveals that the main path Doppler shift has a decisive influence on the MDS. The Doppler spread is best fitted by the Gamma distribution, with relatively small mean and standard deviation values indicating low frequency dispersion and limited multipath components in the air-sea channel.