The first observation of the atmospheric tides in the mesosphere and lower thermosphere over Hainan,China

Fuke (19.5°N, 109.1°E) meteor radar is the first radar of the low latitudes of China, which is used to detect the wind in the meso- sphere and lower thermosphere. In this paper, by using the wind data near three months (1 February-20 April, 2009), we first present the variation of the atmospheric diurnal tide, semidiurnal tide and mean wind in the height range 80-100 km over the low latitudes of China. The results from our analysis are summarized below. During spring months, there are quite strong tides in ...     

F2层临界频率的太阴半日周期扰动分析

大气太阴潮汐对ES层和F2层有影响,在ES层和F2层的参数中均发现以太阴半日周期的振荡.通过分析中低纬地区10个台站F2层临界频率(foF2)的太阴半日分量变化,得到以下结论:foF2太阴半日潮有日变化和季节变化.不同的纬度,太阴半日潮的日变化、季节变化不同.武汉foF2太阴半日潮出现最强的月份、武汉中层低热层大气太阴半日潮汐风最强的月份、武汉ES层参数的太阴半日潮最大值出现的月份均相同,这表明,中层和低热层大气太阴半日潮汐和ES层、F2层的太阴半日潮汐有非常强的相关性.     

烟台外海潮波的特征

在烟台外海,潮汐属于正规半日潮性质,而潮流属于日潮流性质.用数值模拟和实测潮流分析两种方法研究了该特征并解释造成这一现象的原因:在烟台外海M2分潮具有驻波振动,存在着M2分潮流的辐聚、辐散现象,因而该海域M2分潮流很小.该海域日分潮流没有辐聚、辐散现象,因而日分潮流相对较强,从而造成了该海域的潮汐、潮流性质相异的特殊现象.     

基于高频地波雷达观测的粤港澳大湾区春季海表流特征研究

基于高频地波雷达系统监测得到的海表流资料, 选取907个高密度空间点, 运用调和分析等方法, 探究粤港澳大湾区2020年3月的潮流特征。结果表明, 该海域潮流以不规则半日潮M2分潮为主, 且浅水分潮影响显著。主要全日分潮和半日分潮的倾角都在120°~160°之间, 即最大流速都为西北?东南流向, 表现为向岸?离岸流动的趋势。随着与海岸线距离的增加, 潮型系数和浅水系数逐渐增大, 区域南部离岸区表现出不规则全日潮的特征。可能最大流速和实测最大流速的范围分别为0.33~71.01 cm/s和58.63~149.99 cm/s, 其大值都分布于研究区的西北部和南部。     

Nonlinear interactions between gravity waves and background winds

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.     

Potential relationships between atmospheric particulate matter transported by winter monsoons and red tides in the East China Sea

Combining numerical diagnosis from atmospheric science with biogeochemical methods,a model of the potential correlation of monsoons with red tide emergence in the East China Sea is constructed.The model is designed based on an in-depth investigation of the time-space relationship of aerosol and red tide events in the East China Sea from 2005 to 2006,and a continuous monitoring of atmospheric particulates at two stations.The study shows that every red tide event investigated has a close relationship with aerosols coming from the northwest (wind direction in winter) along with subsidence flow.The elemental abundance of total suspended particulate in Hangzhou and Tiantai is different from that of soil background levels,indicating atmospheric particulates there are brought in by winter winds.There is a significant correlation between the content of iron and phosphorous in atmospheric particulates,which mainly exist in binding materials between particulates.In addition,the confined absorption of iron and phosphorous by red tides is related to the intensity of sunlight.These results provide new information regarding the mechanism for the high frequency of red tides in the East China Sea.The results also provide a scientific basis for establishing new pathways for pre-warning and forecasting of red tide disasters.     

Nonlinear interactions between gravity waves and background winds

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.     

台州湾附近海域潮汐、潮流特性

利用临时验潮站横门站的1a潮位观测资料、下大陈站长期验潮资料以及4个垂线测站的大、中、小潮潮流同步观测资料,分析了台州湾附近海域的潮汐、潮流特征,并探讨了海平面空间分布特征的影响因素.结果表明:横门站与下大陈站的潮汐类型均属于正规半日潮类型;横门站年平均潮差大于下大陈站4 cm;2站平均涨、落潮历时相当;台州湾除T-1...     

中国大陆境内的O1分波应变负荷潮

根据Schwideiski海潮图,本文根据作者提出的积分Green函数方法计算了全球海潮O_1分波在中国大陆产生的应变负荷潮,并绘制了应变负荷潮在中国大陆的分布图。分布图表明,中国大陆全境的O_1分波应变负荷潮受太平洋海潮的控制,在中国南部沿海地区南海海潮的作用非常显著,此处应变负荷潮的振幅可以接近甚至超过固体潮的振幅,即使在大陆西部内陆地区,负荷潮的振幅亦可达固体潮振幅的百分之几。要合理解释应变固体潮的观测结果,正确考虑负荷潮的影响是十分必要的。     

元坝地区珍珠冲段天然气优势运移通道探讨

川东北元坝地区下侏罗统自流井组珍珠冲段储层具有一定的天然气资源潜力,但天然气分布规律不清,制约 了勘探方向的选择,亟待开展与天然气分布密切相关的优势通道的研究。利用钻井、地震等资料,通过对元坝地区珍 珠冲段储层中影响天然气运移方向的地质因素的分析,明确了较高孔渗输导砂体、断层、不整合面、构造背景及盖层底 面构造形态等5 种主控因素。同时对各种主控因素与天然气运移方向相互关系的综合分析,提出了元坝地区珍珠冲 段储层中天然气优势运移通道的2 种模式：（1）沿砂体断层复合通道运移;（2）沿砂体不整合面复合通道运移;其 中第一种模式更有利于天然气富集高产。进而分层次指明下一步勘探的方向。     

Numerical study of the propagation of small-amplitude atmospheric gravity wave

By using a two-dimensional fully nonlinear compressible atmospheric dynamic numerical model, the propagation of a small amplitude gravity wave packet is simulated. A corresponding linear model is also developed for comparison. In an isothermal atmosphere, the simulations show that the nonlinear effects impacting on the propagation of a small amplitude gravity wave are negligible. In the nonisothermal atmosphere, however, the nonlinear effects are remarkable. They act to slow markedly down the propagation velocity of wave energy and therefore reduce the growth ratio of the wave amplitude with time. But the energy is still conserved. A proof of this is provided by the observations in the middle atmosphere.     

广西北部湾近岸海域近20年赤潮灾害特征分析

本研究对广西北部湾近岸海域2002-2021年发生的20次赤潮灾害进行综合分析,结果表明：近20年广西近岸海域赤潮平均每年发生1次,发生面积约为384 km²,持续时间为3.65 d,主要集中在春夏季,近10年（2012-2021年）相对前10年（2002-2011年）赤潮发生面积增加（18倍）。引发赤潮的生物种类共有10种,其中次数最多的是球形棕囊藻（Phaeocystis globosa）,其次是夜光藻（Noctiluca scintillans）、水华微囊藻（Microcystis flos-aquae）和红海束毛藻（Trichodesmium erythraeum）,但近10年不断有新的赤潮藻种出现。赤潮发生总数中,有毒或有害赤潮11次,分别为球形棕囊藻4次,夜光藻和水华微囊藻各3次,链状裸甲藻（Gymnodinium catenatum）1次。广西近岸海域赤潮发生的分布范围广,2008年以前主要发生在北海市涠洲岛海域,2008年以后钦州市三娘湾和三墩岛海域、北海市廉州湾及防城港市防城湾陆续开始发生赤潮。通过综合分析近20年北部湾近岸海域赤潮发生和分布的基本特征,为北部湾赤潮预警预报及治理工作提供科学依据。     

Characteristics of tidal gravity changes in Lhasa, Tibet, China

Tidal gravity changes arise from the response of the solid Earth to the tidal forces of the Sun,Moon and planets close to the Earth,and are a comprehensive reflection of the structure and distribution of physical properties of the Earth’s interior.As a result,observations of tidal gravity changes are the basis of studies on other global and/or regional dynamic processes.The characteristics of tidal gravity changes in the region of the Tibetan Plateau were investigated through continuous gravity measurements recorded with a superconducting gravimeter (SG) installed in Lhasa over a year.Through contrast measurements with a spring gravimeter LaCoste-Romberg ET20 at the same site,the gravity observations in Lhasa were scaled to the international tidal gravity reference in Wuhan.Meanwhile,the scale factor of the SG was determined accurately as-777.358 ± 0.136 nm s-2V-1,which is about 2.2% less than the value provided by the manufacturer.The results indicate that the precision of the tidal gravity observations made with the SG in Lhasa was very high.The standard deviation was 0.459 nm s-2,and the uncertainties of for the four main tidal waves (i.e.O 1,K 1,M 2 and S 2) were better than 0.006%.In addition,the observations of the diurnal gravity tides had an obvious pattern of nearly diurnal resonance.As a result,it is affirmed that the Lhasa station can provide a local tidal gravity reference for gravity measurements on the Tibetan Plateau and its surrounding regions.The loading effects of oceanic tides on tidal gravity observations in Lhasa are so weak that the resulting perturbations in the gravimetric factors are less than 0.6%.However,the loading effects of the local atmosphere on either the tidal or nontidal gravity observations are significant,although no seasonal variations were found.After removal of the atmospheric effects,the standard deviation of the SG observations in Lhasa decreased obviously from 2.009 to 0.459 nm s-2.Having removed the loading effects of oceanic tides and local atmosphere,it was found that the tidal gravity observations made with the SG in Lhasa significantly differed by about 1% from those expected theoretically,which may be related to active tectonic movement and the extremely thick crust in the region of the Tibetan Plateau.A more-certain conclusion requires longer accumulation of SG data and further associated theoretical studies.     

Observation of internal tides and near-inertial motions in the upper 450 m layer of the northern South China Sea

Mooring ADCP current observations from August to November are used to study the barotropic tides, baroclinic tides and near-inertial motions in the upper 450 m layer of the northern South China Sea. The barotropic and baroclinic tides at the mooring station are all dominated by M2, K1, O1, P1, with the barotropic amplitudes being 7.8 cm·s^-1, 7.0 cm·s^-1, 5.4 cm·s^-1 and 3.5 cm·s^-1 respectively. The amplitudes of M2, K1, O1, P1 internal tides vary greatly, which are 12--15 cm·s^-1 in the thermocline, and then decrease with increasing depth. The amplitude of the barootropic near-inertial motions is less than 1 cm·s^-1, contributing little to the barotropic currents. However, that of the baroclinic nearinertial motions can be as large as 5 cm·s^-1. The inclination of tidal ellipse tends to increase with increasing depth, implying upward propagation of energy, while that of the near-inertial ellipse tends to decrease with increasing depth, implying downward propagation of energy.     

基于关联规则的MODIS影像绿潮检测

由于缺乏对绿潮灾害的深入认识和有效的监视监测,海域管理部门的决策管理和防治措施还处于被动局面。为解决这一现状,选取青岛附近海域的3景MODIS影像作为实验数据,分析了浒苔的光谱特性并对浒苔进行了特征选择,然后运用关联规则挖掘出浒苔及其光谱之间的关联关系,并使用发现的关联规则对浒苔进行检测,检测结果相比同类研究具有较高的精确度。对提高绿潮研究的科学性和深入性具有重要意义。     

20世纪社会主义运动两次低潮的比较与启示

简要回顾 2 0世纪世界社会主义运动的进程 ,对 2 0世纪社会主义运动出现的两次低潮进行了比较分析 ,指出两次低潮的具体过程虽然不同 ,但存在许多共同的特点 ,通过分析可以对现实社会主义运动提供许多启示     

PVFS数据访问的负载平衡

分析了并行文件系统PVFS中存在负载不均衡的情况,提出了根据负载情况迁移数据或做热点的副本的负载平衡方法．描述了迁移过程中考虑到迁移代价,选取最优迁移方式．提出由执行I／O的10D节点统计负载情况并传输到元数据管理节点MGR,MGR节点实现迁移和制作副本,还要维护副本的一致性的策略．     

Diurnal freeze/thaw cycles of the ground surface on the Tibetan Plateau

The exchange of energy and water between the lithosphere and atmosphere mainly takes place at the ground surface. Therefore, freeze/thaw condition at the ground surface is an important factor in ex- amining the interactions between the land surface and atmosphere. Based on the observation data obtained by CEOP/CAMP-Tibet, the diurnal freeze/thaw cycles of the ground surface near Naqu, central Tibetan Plateau was preliminarily analyzed. The results show that the surface layer was completely frozen for approximately one month. However, the time that the ground surface experienced diurnal freeze/thaw cycles was about 6 months. The high frequency of freeze/thaw cycles at the ground surface significantly influences water and energy exchanges between ground and atmosphere over half a year. The interaction processes between the ground and atmosphere under different soil conditions (such as complete thaw, complete freeze and diurnal freeze/thaw cycles) are issues worthy of further examina- tion.     

基于MLS卫星临边探测数据研究大气OH时空分布

 OH自由基是大气中重要的氧化剂,对大气中其他气体成分和气溶胶的形成和转化起着重要作用。本文利用MLS(micro-wave limb sounder)卫星观测资料,对大气平流层上层和中间层OH自由基的时空分布和变化以及中国上空OH自由基的垂直分布进行分析。结果显示,大气平流层上层和中间层OH自由基含量存在明显的季节变化和昼夜变化,在空间上的分布也随着太阳直射点的不同而呈现一定的周期性。比较了中国上空与同纬度纬向平均值,发现白天和夜间的观测值只有个别位置有较明显偏差,中国地区上空的OH含量比在整体上与同纬度比起来无明显异常,中国局地上空廓线的比较更加详细地反映了OH自由基的昼夜垂直结构。总之,中层大气OH自由基含量存在显著的昼夜变化、季节变化,同时也受太阳活动的影响,年际变化则不明显。     

基于钦州湾验潮站2008-2020年潮位序列的潮汐特征研究

潮汐是钦州湾的主要海洋动力,对物质输运、海洋工程、海洋生态环境等都有重要影响。本研究基于钦州湾验潮站2008-2020年共13年的水位观测资料,利用潮汐调和分析、偏度计算和线性回归等方法,分析钦州湾长时间的潮汐变化、潮不对称性特征及海平面变化趋势。结果表明,钦州湾验潮站潮汐以O₁、K₁分潮占优,属于规则全日潮。主要分潮振幅有显著的年际变化,2008年为最小值,O₁为95.82 cm, K₁为88.18 cm, M₂为39.53 cm; 2016年达到最大值,O₁为104.27 cm, K₁为95.15 cm, M₂为46.16 cm,这一变化与月赤纬角的变化有关。钦州湾潮不对称现象显著,涨潮历时比落潮历时多2-3 h,造成该现象的主要原因是受到半日分潮和全日分潮之间相互作用的影响,其中主要贡献来源于O₁、K₁、M₂之间的相互作用,占总潮汐偏度的80.97%-83.51%。钦州湾海平面有逐年上升的趋势,平均上升速率约为0.96 cm/a,高于同期南海沿海海平面的平均上升速率。研究成果可为钦州湾防灾减灾和港口工程建设提供科学依据。