The tides of Titan

We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k(2) = 0.589 ± 0.150 and k(2) = 0.637 ± 0.224 (2σ). Such a large response to the tidal field requires that Titan's interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth.     

World ocean tides synthesized from normal modes

Sixty oceanic normal modes are used to synthesize the M(2) and K(1) (principal lunar semidiurnal and declinational diurnal) tides. The ten most energetic modes in the M(2) synthesis account for 87 percent of the energy; the corresponding figure for K(1) is 93 percent, two-thirds of which is contributed by a single mode whose natural period is about 29 hours. Model calculations indicate that the quality (Q) of the ocean response to tidal forcing resembles that of a frictionally controlled oscillator. In particular, for M(2) the global Q is about 10.     

From tides to mixing along the Hawaiian ridge

The cascade from tides to turbulence has been hypothesized to serve as a major energy pathway for ocean mixing. We investigated this cascade along the Hawaiian Ridge using observations and numerical models. A divergence of internal tidal energy flux observed at the ridge agrees with the predictions of internal tide models. Large internal tidal waves with peak-to-peak amplitudes of up to 300 meters occur on the ridge. Internal-wave energy is enhanced, and turbulent dissipation in the region near the ridge is 10 times larger than open-ocean values. Given these major elements in the tides-to-turbulence cascade, an energy budget approaches closure.     

Earth tides can trigger shallow thrust fault earthquakes

We show a correlation between the occurrence of shallow thrust earthquakes and the occurrence of the strongest tides. The rate of earthquakes varies from the background rate by a factor of 3 with the tidal stress. The highest correlation is found when we assume a coefficient of friction of mu = 0.4 for the crust, although we see good correlation for mu between 0.2 and 0.6. Our results quantify the effect of applied stress on earthquake triggering, a key factor in understanding earthquake nucleation and cascades whereby one earthquake triggers others.     

The shaping of continental slopes by internal tides

The angles of energy propagation of semidiurnal internal tides may determine the average gradient of continental slopes in ocean basins (approximately 2 to 4 degrees). Intensification of near-bottom water velocities and bottom shear stresses caused by reflection of semi-diurnal internal tides affects sedimentation patterns and bottom gradients, as indicated by recent studies of continental slopes off northern California and New Jersey. Estimates of bottom shear velocities caused by semi-diurnal internal tides are high enough to inhibit deposition of fine-grained sediment onto the slopes.     

Earth tides, global heat flow, and tectonics

The power of a heat engine ignited by tidal energy can account for geologically reasonable rates of average magma production and sea floor spreading. These rates control similarity of heat flux over continents and oceans because of an inverse relationship between respective depth intervals for mass transfer and consequent distributions of radiogenic heat production.     

卵甲藻Exuviaella cordata 和Exuviaella marina赤潮的初步研究

报道了由心形卵甲藻（Exuviaella cordata）和海洋卵甲藻（Exuviaella marina)引发的赤潮，（前者于1991年发生在庄河青堆水产公司虾池中，后者于1999年7月发生在大连湾），并对赤潮发生的原因，危害进行了分析，对引发赤潮藻类的形态和生活习性进行了描述，对大连湾赤沓区养殖的3种贝类进行了贝毒检测。     

Maintenance of strong rotational winds in venus' middle atmosphere by thermal tides

The cloud-level atmosphere of Venus takes little more than 4 days to complete one rotation, whereas the solid planet below has a 243-day period. Computer simulations of the circulation of the Venus middle atmosphere between 40 and 85 kilometers, as driven by solar radiation absorbed in the clouds, reproduce (i) the observed cloud-level rotation rate, (ii) strong vertical shears above and below the cloud tops, and (iii) midlatitude jets and strong poleward flow on the day side. Simulated circulations converge to yield nearly the same zonal winds when initialized with both stronger or weaker rotation rates. These results support the hypothesis that the observed cloud-top rotation rate is maintained by statistical balance between fluxes of momentum by thermal tides and momentum advection by mean meridional circulation.     

Thermal tides in the dusty martian atmosphere: a verification of theory

Major features of the daily surface pressure oscillations observed by the Viking landers during the two great dust storms on Mars in 1977 can be explained in terms of the classical atmospheric tidal theory developed for the earth's atmosphere. The most dramatic exception is the virtual disappearance of only the diurnal tide at Viking Lander 1 just before the second storm. This disappearance is attributed to destructive interference between the usually westward-traveling tide and an eastward-traveling diurnal Kelvin mode generated by orographically induced differential heating. The continuing Viking Lander 1 pressure measurements can be used with the model to monitor future great dust storms.     

渤海潮汐潮流的数值研究

基于POM数值模式构建了区域为(117.5°E~122.5°E,37°N~41°N)水平分辨率为2.5'的潮波数值模式,模拟了渤海M2、S2、K1、O14个主要分潮。模拟结果与19个验潮站观测资料拟合较好。渤海潮汐以半日潮为主,M2分潮占主导地位,渤海沿岸及海湾顶潮差大,中央海区潮差小;潮流以半日潮流为主,M2分潮潮流最强,最大流速达到96 cm/s,在渤海中央海域潮流呈现为旋转流,在海湾多为往复流,最大可能潮流流速存在3个强流区,分别为:老铁山水道及北侧海域、长岛和黄河口附近海域。     

Ocean science. Enhanced: internal tides and ocean mixing

Recent satellite and in situ observations have shown that at ocean ridges and other seafloor topographic features, a substantial amount of energy is transferred from the main ocean tides into "internal tides." In his Perspective, Garrett explains how these internal waves with tidal periods propagate through the density-stratified deep ocean and eventually break down into turbulence. The resulting mixing affects ocean stratification and ocean circulation. It thus influences climate as well as biological production. The energy for the internal tides is derived from the rotational energy of the Earth-Moon system changes of the length of the day and the distance to the Moon.