3.6.2. Tides

Tidal analysis of the pressure data explained 87.2% and 95.6% of the pressure fluctuations with 28 and 22 significant constituents at SLM and MLM, respectively. At both lander sites, the semidiurnal (M2) signal generated the largest amplitude of 0.34 dbar. The other significant constituents were diurnal, semidiurnal, and higher frequency constituents (Table 4).

**Table 4.** Tidal analysis for bottom pressure and flow record based on the harmonic analysis toolbox T\_Tide [82]. Shown are the harmonics with amplitudes >0.02 dbar and >1.5 cm s−<sup>1</sup> for pressure and flow, respectively, in three categories: diurnal, semidiurnal, and short period constituents. Explained variance through the tidal model in percent is given next to the parameter. Abbreviations: p: pressure, ue un: bottom horizontal flow.


The analyses of the tidal constituents from the near bottom horizontal velocity records revealed a different picture with more significant higher frequency harmonics than in pressure. With 14 and 12 significant tidal constituents, tidal analysis explained 7.2% and 14.1% of the horizontal bottom velocity fluctuations at SLM and MLM, respectively. The M2 generated amplitudes of ~5 cm s−<sup>1</sup> with flow direction to NNW (330◦–341◦), the opposite of the mean flow direction (Table 4).
