Ocean Tides for and from TOPEX/POSEIDON

Comparisons of TOPEX/POSEIDON tidal solutions derived from the data of the first year of this altimetric mission with the best previous models and with in situ data show very substantial improvements. Typically, the gain in accuracy for the major lunar tidal component M(2) is 30 percent in root-mean-square differences with reference to a standard ground truth data set from 78 stations distributed over the world ocean. This is a major step, obtained because of the high quality of these altimetric data. The combination of these data with recent numerical models through assimilation methods is pointing toward solutions at the ultimate limits of practical accuracy.     

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.     

Diurnal and Semidiurnal Variations in the Earth's Rotation Rate Induced by Oceanic Tides

Recent space-geodetic observations have revealed daily and subdaily variations in the Earth's rotation rate. Although spectral analysis suggests that the variations are primarily of tidal origin, comparisons to previous theoretical predictions based on various ocean models have been less than satisfactory. This disagreement is partly caused by deficiencies in physical modeling. Rotation predictions based on a reliable tidal-height model, with corresponding tidal currents inferred from a modified form of Laplace's momentum equations, yield predictions of tidal variations in Universal Time that agree with very long baseline interferometer observations to 2 microseconds. This agreement resolves a major discrepancy between theory and observation and establishes the dominant role of oceanic tides for inducing variation in the Earth's rotation at these frequencies.     

Melting of io by tidal dissipation

The dissipation of tidal energy in Jupiter's satellite Io is likely to have melted a major fraction of the mass. Consequences of a largely molten interior may be evident in pictures of Io's surface returned by Voyager I.     

Yearly seismic energy release: world totals versus ridge system totals

Yearly seismic energy totals for many different regions of the earth show highs in 1965 and lows in 1967. Correlations found between totals for ridge systems and for the world are attributed to ambient stresses, which are close to those needed for failure in the lithosphere underlying those ridge systems. Energy highs for many different plate edges are thought to be the result of triggering by the large Alaskan earthquake of 1964. Other suggestions of triggering by major earthquakes are found in 1969 and 1971.     

不同播种及栽培方式对大豆产量的影响

针对黑龙江省目前的几播种方法和栽培方式对大豆产量的影响进行了试验研究,在垄三栽培的基础上,设定了三种处理:常规垄作、45cm平播密植后起垄、常规垄作行间覆膜3种栽培方式,试验设计采用大区对比法。试验结果是45cm平播密植后起垄效果最好、其次是常规垄作行间覆膜。     

宁德市沿海滩涂资源开发与利用

沿海滩涂不仅是一种重要的后备土地资源,而且蕴藏着丰富的水生物、港口、再生能源、矿产、旅游等资源,具有巨大的开发潜力。宁德市位于福建省东北部,地理位置优越,滩涂资源丰富,随着基础设施的不断完善和改革开放的深入,尤其是高速公路同三线福建省境内的全线贯通,为宁德滩涂养殖业带来了新的机遇和挑战。宁德沿海滩涂资源的开发利用经历了新中国成立初期的粗放开发阶段,20世纪50年代中期到80年代的传统利用阶段和90年代以来的综合开发利用阶段,同时滩涂资源开发利用过程中存在着缺乏统一的开发利用总体规划、滩涂产业结构层次低、科技投入不足产值规模小、生态环境日趋恶化、浅海滩涂网箱养殖环境日益突出等问题。为此笔者认为新时期宁德市沿海滩涂资源开发利用应当坚持调整产业结构,培育滩涂主导产业,合理布局科学养殖,实施科技兴滩战略,优化滩涂湿地环境、建设和维护良好的生态环境,提高区域滩涂开发效益。     

河北省二氧化碳排放驱动因素研究——基于STIRPAT模型

首次以河北省为研究对象,基于扩展的STIRPAT模型,应用岭回归分析,对1980~2011年二氧化碳排放驱动因素进行研究,然后结合河北省产业布局和特点,提出碳减排政策建议。结果表明,经济增长是二氧化碳排放量增多的决定性因素;城市化水平、能源强度和人口规模是重要因素;第三产业比重、第二产业比重和能源消费结构对碳排放影响不显著。     

How did venus lose its angular momentum?

Venus now has a retrograde and negligible spin, but it very likely started with a typical planetary spin: prograde and with a 10- to 20-hour period. The usually assumed mechanism of solar tidal friction is quite insufficient to remove this angular momentum. Instead, we postulate capture of a moonlike object from an initially retrograde orbit: it would despin Venus and suddenly transform the planet's rotational kinetic energy into internal heat, which would lead to volcanism and the liberation of large amounts of volatiles. The moon would disappear by crashing into the surface of Venus.     

长江潮位预报方法

本文根据长江感潮段的水力特点,以潮流界区分为感潮上段(潮流界至潮区界)与感潮下段(潮流界至河口),阐明了长江感潮段的潮汐是上游的径流与海外潮波的复合,指出潮位可分解为径流与天文潮两种因素。并应用微机以时间序列分析和调和分析法相结合的方法进行潮位预报。     

潮流能发电装置性能综合评估方法研究

目前,我国还没有建成为潮流能发电装置提供试验、测试与评估的海上测试场。潮流能发电装置性能综合评估方法的研究是海上测试场建设理论研究的重要组成部分,为改进潮流能发电装置的性能提供可靠依据。文章在模糊综合评判模型的基础上利用灰色关联理论修正主观权重,分析了潮流能发电装置性能各项指标,给出装置性能评估的层次模型。通过对原始指标数据的标准化处理,使指标数值均处于(0,1)内,降低了计算的复杂度;利用变异系数和关联度修正初始权重,得到潮流能装置多指标的综合权重量化值以及最终评估结果。该方法简化了标准层次分析法中一致性检验过程,同时提高了评估结果的客观性及模糊综合评判的可信度。最后对两台潮流能发电装置实测数据进行评估分析,验证了该评估方法的有效性。     

沿海滩涂发展能源植物的潜力分析

发展生物质能源对缓解中国的矿质能源压力、减轻能源污染具有重要意义。在分析了发展生物质能源的迫切性的基础上,介绍了利用中国丰富的沿海滩涂土地资源和植物资源开发能源植物的潜力。同时,从滩涂资源的有效利用、盐生植物中能源植物的发掘和通过转基因技术提高能源植物耐盐性及改良盐生植物生产能源物质的特性等方面提出了沿海滩涂发展能源植物的资源潜力。     

春玉米套种夏大豆不同模式对大豆产量的影响

[目的]研究春玉米后期套种夏大豆不同种植模式对大豆产量的影响,为春玉米合理套种夏大豆提供科学依据.[方法]以广西夏大豆主推品种桂夏1号和玉米品种正大619为供试材料,于2011年在广西3个有代表性的夏大豆产区进行春玉米套种夏大豆不同模式试验,研究适宜与春玉米后期套种夏大豆的最佳种植模式.[结果]垄上双行种植平均产量最高为2754.87 kg/ha,垄沟单行种植(CK)平均产量为2466.57 kg/ha,最低为垄上双行隔行种植,产量为2160.70kg/ha.[结论]春玉米后期套种夏大豆最为适宜的种植模式为春玉米后期垄上双行套种夏大豆.     

甘薯双垄旋耕起垄覆膜机的设计及试验研究

针对传统甘薯双垄旋耕起垄覆膜机具存在结构强度差、作业效率不高、垄体不规范等问题,研究设计一款与55~80kW大型拖拉机配套的新型甘薯双垄旋耕起垄覆膜机。采用理论设计与试验相结合的方法,对起垄覆膜的影响因子及各部件间最优结构参数、工作参数、协调关系进行研究分析。结果表明:甘薯种植起垄覆膜不规范、效果差主要与机具前进速度、压膜机构高度及旋耕深度有很大关系,主次因素顺序为:前行速度压膜机构高度旋耕深度,优选组合为:前行速度0.3m/s、压膜机构高度360mm、旋耕深度400mm。     

长江大通站水文系列的组成与感潮段主副港预报研究

本文根据大通站水文系列组成的分析,提出了长江感潮段潮位的主、副港预报方法和原理。主港为河口的吴淞和湖区界的大通;副港为沿江各港(站),建立了一系列多元回归函数预报副港的潮位,精度符合要求。     

基于最大类间方差法和数学形态学的遥感图像潮沟提取方法

潮沟作为潮滩的主要地貌类型之一,以长江口九段沙为研究对象,利用2015年2月15日获取的Landsat 8分辨率为15 m的全色波段遥感数据为数据源,选取了3条发育不同的潮沟。首先利用顶帽变换来消除直接利用最大类间方差法对图像亮度背景不均匀不能准确分割的问题,然后通过最大类间方差法找到一个最佳的阈值使潮沟和背景之间方差最大,得到二值化图像;接着通过形态膨胀对断裂的潮沟进行连接,并用形态去除方法剔除非目标;最后对潮沟进行骨架化提取和去除短枝处理,得到完整的潮沟信息骨架图。采用视觉分析和定量分析对提取的潮沟信息进行精度评价。结果表明,最大类间方差法和数学形态学的结合对潮沟信息提取有较好的效果,平均准确度达到93.0%,遗漏误差和冗余误差分别为7.0%和0.5%。     

旱地鲜食籽瓜起垄覆膜方式比较初报

在会宁县进行了旱地鲜食籽瓜7种起垄覆膜方式比较试验,结果表明,籽瓜折合产量以全膜垄上微沟栽培模式最高,为52 933.3 kg/hm~2,较半膜平铺(CK)增产26.03%。采用全膜垄上微沟栽培鲜食籽瓜,不但可缩短其生育期,及早上市,而且该栽培方式的集雨保墒效果最好。因此综合考虑认为全膜垄上微沟栽培方式是会宁县旱地鲜食籽瓜最佳的优化覆膜方式,应大力推广。     

Atmospheric dynamics of the outer planets

Despite major differences in the solar and internal energy inputs, the atmospheres of the four Jovian planets all exhibit latitudinal banding and high-speed jet streams. Neptune and Saturn are the windiest planets, Jupiter is the most active, and Uranus is a tipped-over version of the others. Large oval storm systems exhibit complicated time-dependent behavior that can be simulated in numerical models and laboratory experiments. The largest storm system, the Great Red Spot of Jupiter, has survived for more than 300 years in a chaotic shear zone where smaller structures appear and dissipate every few days. Future space missions will add to our understanding of small-scale processes, chemical composition, and vertical structure. Theoretical hypotheses about the interiors provide input for fluid dynamical models that reproduce many observed features of the winds, temperatures, and cloud patterns. In one set of models the winds are confined to the thin layer where clouds form. In other models, the winds extend deep into the planetary fluid interiors. Hypotheses will be tested further as observations and theories become more exact and detailed comparisons are made.     

大豆暗垄密群体内田间小气候变化

暗垄密是大豆产栽培技术,与对照相比单产平均增加20%,为了探讨其增产机理,对暗垄密群体内田间小气候变化进行了调查,结果表明:暗垄密群体前期比对照封垄早(提前10d),后期衰落慢,提高了光能利用率;两种栽培模式生育中期冠中层及冠下层(冠内地表)的光照强度均较低,冠层内的通风性差异不明显;暗垄密群体耕层土壤的保水力较强。     

Predictable upwelling and the shoreward transport of planktonic larvae by internal tidal bores

Internal tidal bores have a crucial role in the transport of drifting larvae to marine nearshore populations, a key factor in structuring benthic communities. Shoreward transport of larvae and abrupt surface temperature drops lasting days can be explained by invoking the advection of subsurface cold water to the shore by internal tidal bores. This process is predictable within the lunar cycle and brings deep water to the surface (upwelling) in a direction perpendicular to the coastline.