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1.
Hourly sea level records from three stations in eastern Canada (Québec-Lauzon, Harrington-Harbour and Halifax) are analyzed both in frequency domain from 1970 to 1979 and in time domain during 1973. At the three stations, the deterministic model explains 90 to 96% of the total variability of sea level. The semidiurnal and diurnal tides contribute largely to its variations. The residual series, less than 10% of the initial variations of sea level, contain irregular values including extreme values of seiches and storm surges. Such random variations are analyzed and modeled following the method described by Box and Jenkins (1976). The long period variations (2 to 30 days) can be attributed to meteorological forcing (atmospheric pressure and winds). The short period variations (some hours to one day) can be attributed to longitudinal seiches, semidiurnal and diurnal atmospheric tides, and inertial oscillations. The water discharge from the St. Lawrence River contributes 29% of the monthly residual sea level at Qué 相似文献
2.
《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(9):1474-1485
In an attempt to understand the causes of the sea-level seasonal cycle in the Persian Gulf, we investigated the relationships of sea-level data from 11 stations with atmospheric pressure and thermosteric level. Sea level is significantly correlated among all stations. The mean trend in sea level for the Persian Gulf is about 2.34 mm/year. The thermosteric sea-level variability is estimated from temperature profiles at one-degree grid points. Contour maps of thermosteric level show that the height due to thermal expansion is high in summer and autumn, and low during winter and spring. The monthly mean thermostric height ranges from +2.2 cm in July to −2.1 cm in February. The major change in sea level due to the thermosteric level seems to be associated with the large change of the thermohaline circulation in the Persian Gulf. The maximum expansion occurs in summer, and the maximum contraction occurs in winter.Results of the regression analysis demonstrate that from 62% to 90.2% of the variance in the seasonal cycle is due to atmospheric pressure. The inclusion of the thermosteric sea level as a secondary forcing in the regression model improves the variance explained to 78.1–90.7%. The remaining change should be due to the halosteric effect and upwelling. Tide-gauge stations located at the Gulf's head show high correlation with Ekman vertical velocity. There are two distinct tide gauge stations in the Persian Gulf. One is found in the first cyclonic gyre and the other in the second gyre. The inclusion of Ekman upwelling to the model, improves significantly the variations explained as well, from 82.3% to 91.9%. 相似文献
3.
This paper deals with the variations of the monthly mean sea level of the seas near China. The distribution charts of mean, sea level in winter and in summer are given. The monthly mean sea level variations are mainly caused by monsoon, sea currents and the fluctuation of atmosphen'c pressure. The annual range of monthly mean sea level is 50 -70 cm in the northern part of the seas near China, and 20-40 cm in the southern part. The variation period of the monthly mean sea level of the seas near China is principally annual one. 相似文献
4.
Response of the low-frequency fluctuations of sea level to atmospheric forcing along the coasts of the Huanghai Sea and the East China Sea 总被引：1，自引：0，他引：1
In this paper, the low-frequency fluctuations of sea level and their relationship to atmospheric forcing along the coasts of the Huanghai Sea and the East China Sea are studied. Spectrum analyses are made for the time series of daily mean sea level, atmospheric pressure and wind stress at seven coastal stations. It is found that at all the stations, the main part of the energy of the sea level fluctuations, within the (2-60)-day period, is concentrated on the (12-60)-day period band and that an obvious spectral peak appears at the 3-day period. Along the coast of the Huanghai Sea, variations in the sea level are greater in winter than in summer. In winter, along the coasts of the Huanghai Sea and the East China Sea there is a kind of sea level fluctuations propagating southwards. Among the many factors causing sea level variation, the most obvious one is atmospheric pressure, followed next by the alongshore wind stress. 相似文献
5.
《Estuarine, Coastal and Shelf Science》2003,56(3-4):861-867
The study examines the occurrence of Proudman resonance in front of the Split harbour (Adriatic Sea). The dataset comprises air and sea pressure (sea level) data collected at the harbour entrance during August to October 2000 and is characterized by rather strong synoptic disturbances that took place over the harbour. The analyses encompass empirical tools, such as time-series analysis, high- and band-pass filtering, spectral and wavelet analyses, while the theoretical approach includes the conceptual model of the resonance. Resonance appears in front of the harbour and then propagates inward, covering periods between 7.7 and 28.5 min as a result of complex atmospheric gravity wave structure. Gain between sea level and air pressure equals 0.05–0.40 dbar/hPa (5–40 cm/hPa). 相似文献
6.
太平洋海域海平面变化的灰色系统分析 总被引：3，自引：1，他引：3
应用灰色系统理论，对太平洋海域４８个长期验潮站的月均海平面分别建立了ＧＭ（１，１）模型。ＧＭ（１，１）模型能较好地反映太平洋海域的海平面变化的趋势，它除了能给出连续的海平面变化速率外，同时能方便地给出海平面变化的加速率。模拟结果表明，在太平洋地壳均衡假设下，太平洋海域的月均海平面以平均速率０．１７ｃｍ／ａ上升。在太平洋海域所取的４８个长期验潮站中，有４０个站在加速上升，全部站的平均加速度为０．０００２９ｃｍ／ａ２。且加速率逐渐增大。当然这些加速率都很小，但作为一种普遍性的趋势，这已足以说明：太平洋海域的海平面在加速上升 相似文献
7.
Shigehisa Nakamura 《Marine Geodesy》2013,36(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
8.
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9.
Neil J Holbrook Ian D GoodwinShayne McGregor Ernesto MolinaScott B Power 《Deep Sea Research Part II: Topical Studies in Oceanography》2011,58(5):547-558
The connection between East Australian Current (EAC) transport variability and Australia’s east coast sea level has received little treatment in the literature. This is due in part to the complex interacting physical processes operating in the coastal zone combined with the sparsity of observations available to improve our understanding of these possible connections. This study demonstrates a statistically significant (at the >90% level) relationship between interannual to decadal time scale variations in observed estimates of the EAC transport changes and east coast sea level measured at the high-quality, long record Fort Denison tide-gauge in Sydney Harbour, Australia (33°51′18″S, 151°13′32″E). We further demonstrate, using a linear reduced-gravity ocean model, that ENSO to decadal time-scale variations and the ocean-adjusted multi-decadal trend (approx. 1 cm/decade) in observed sea level at Fort Denison are strongly connected to modulations of EAC transports by incoming westward propagating oceanic Rossby waves. We show that EAC transport and Fort Denison sea level vary in a manner expected from both Tasman Sea generated Rossby waves, which account for the interannual and multi-annual variability, and remotely forced (from east of New Zealand) Rossby wave connections through the mid-latitudes, accounting for the ocean-adjusted multi-decadal trend observed at the New South Wales coast - with the regional-Tasman Sea forcing explaining the greatest overall proportion of EAC transport and sea-level variances. 相似文献
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11.
东海沿海季节性海平面异常成因 总被引：1，自引：0，他引：1
Based on the analysis of sea level, air temperature, sea surface temperature(SST), air pressure and wind data during 1980–2013, the causes of seasonal sea level anomalies in the coastal region of the East China Sea(ECS) are investigated. The research results show:(1) sea level along the coastal region of the ECS takes on strong seasonal variation. The annual range is 30–45 cm, larger in the north than in the south. From north to south, the phase of sea level changes from 140° to 231°, with a difference of nearly 3 months.(2) Monthly mean sea level(MSL)anomalies often occur from August to next February along the coast region of the ECS. The number of sea level anomalies is at most from January to February and from August to October, showing a growing trend in recent years.(3) Anomalous wind field is an important factor to affect the sea level variation in the coastal region of the ECS. Monthly MSL anomaly is closely related to wind field anomaly and air pressure field anomaly. Wind-driven current is essentially consistent with sea surface height. In August 2012, the sea surface heights at the coastal stations driven by wind field have contributed 50%–80% of MSL anomalies.(4) The annual variations for sea level,SST and air temperature along the coastal region of the ECS are mainly caused by solar radiation with a period of12 months. But the correlation coefficients of sea level anomalies with SST anomalies and air temperature anomalies are all less than 0.1.(5) Seasonal sea level variations contain the long-term trends and all kinds of periodic changes. Sea level oscillations vary in different seasons in the coastal region of the ECS. In winter and spring, the oscillation of 4–7 a related to El Ni?o is stronger and its amplitude exceeds 2 cm. In summer and autumn, the oscillations of 2–3 a and quasi 9 a are most significant, and their amplitudes also exceed 2 cm. The height of sea level is lifted up when the different oscillations superposed. On the other hand, the height of sea level is fallen down. 相似文献
12.
Altimetry-observed semi-annual cycle in the South China Sea: Real signal or alias of K1 tidal error?
There have been a number of applications of satellite altimetry to seasonal and interannual sea level variability in the South China Sea. However, these applications usually exclude shallow waters along the coast, with one of the concerns being large aliased tide-correction error. In this study the authors analyzed 14 years of merged satellite altimeter data to obtain the amplitude and phase of the semi-annual cycle and to examine the variation at the K1 alias frequency (close to the semi-annual frequency). The results indicate that the amplitude of the semi-annual cycle ranges from 3-7 cm, substantial compared with that of the annual cycle; while the amplitude at the K1 alias frequency (error of the K1 tidal correction) is essentially 1 cm only. Altimeter–derived semi-annual cycle is in good agreement with that from independent tide-gauge observations, pointing to the competent ability of satellite altimetry in observing semi-annual sea level variations in the South China Sea. 相似文献
13.
基于美国国家冰雪数据中心 （NSIDC） 海冰资料、美国国家环境预报中心 （NCEP） 再分析格点数据和黄渤海近岸13个气象站点逐日气温数据，通过相关分析和合成分析，研究了 2007-2018 年黄渤海海冰范围的变化特征，探讨了近 12 年黄渤海海冰范围对近岸陆地气温、大气环流和局地天气过程的响应。结果表明: （1） 黄渤海海冰范围年际振荡明显，近 12 年呈现先增加后减小的趋势，与同期黄渤海近岸气温呈显著负相关关系；每年 1 月下旬至 2 月下旬是一年中海冰范围最大的时期。（2） 海冰范围偏大与偏小年份东亚地区 500 hPa 大气环流形势呈现出近乎相反的分布。 （3） 东亚阻塞形势的建立是黄渤海海冰范围爆发性增大的一个前兆信号，它带来的大风降温天气是造成黄渤海海冰范围爆发性增大的重要原因. 相似文献
14.
LIN Rongcheng HUANG Dingyong GUO Yuqing CHANG Yu CAO Yinkun WANG Jianjia 《海洋学报(英文版)》2014,33(6):90-94
The metazoan meiofauna in the Chukchi Sea were collected from seven shallow water stations(depths ranging 46 to 52 m) and five deep sea stations(depths ranging between 393 and 2 300 m) during the 4th Chinese National Arctic Research Expedition in 2010. The results showed that abundance of meiofauna was higher in shallow water sediments(average of 2 445 ind./(10 cm2)) than in deep sea sediments(407.06 ind./(10 cm2)). A UNIANOVA test for difference between the two different regions was highly significant(F=101.15, p0.01). Nematodes were numerically dominant, representing(96.6±4.6)% of the total meiofaunal abundance at the shallow water stations and(98.90±1.42)% at deep sea stations. The number of higher taxonomic groups and abundance of meiofauna were higher at Stas CC1, CC4, and R06 near the Bering Strait and the continent, than at the rest of the shallow water and deep sea stations. The primary factors causing the differences were concentrations of nutrients P and Si of bottom seawater(R=0.831, p0.003), followed by depth(R=-0.655, p0.05) and sand fractions of sediments(R=0.632, p 0.05). The numbers of meiofauna on the 65 μm and 32 μm sieves were significantly higher than those on the rest of the screens. Differences in numbers of meiofauna retained on screens with different mesh openings were highly significant among all sampling stations(F=31.60, p0.01). The highest numbers of individuals on screens with 32 μm mesh openings were found at deep sea stations. The number of meiofauna in the top 0–1, 1–2, and 2–4 cm segments constituted 84.4% of the total and was significantly higher than those in the bottom 4–6 and 6–10 cm segments(F=15, p0.01). 相似文献
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16.
The sea level variations along Visakhapatnam coast are governed by astronomical tides and nontidal oscillations including atmospheric pressure, winds, coastal currents, Ekman Pumping, and river influx. Tidal and nontidal sea level oscillations are usually studied separately because of the vastly different ways in which they are forced. In this study the tidal oscillations along Visakhapatnam are analyzed using GOTIC2 tidal model. The correlation between monthly mean sea level and monthly mean tides is 47% (r = 0.68) and increases to 54% (r = 0.74) when applied for inverse-barometric effect. The major six partial tides are computed and presented. The tidal variations from Neap tide to Spring tide are studied. 相似文献
17.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
18.
Sea level changes in the Baltic Sea are dominated by internal, short-term variations that are mostly caused by the ephemeral nature of atmospheric conditions over the Baltic area. Tides are small and their influence decreases from western parts of the Baltic Sea to the Baltic Proper. Superimposed to the large short-term sea level changes (up to few decimeters from day to day) are seasonal and interannual variations (centimeters to decimeters). This study focuses on the comparison of sea surface heights obtained from observations and from a high resolution oceanographic model of the Baltic Sea. From this comparison, the accuracy of the modeled sea surface variations is evaluated, which is a necessary precondition for the further use of the oceanographic model in geodetic applications. The model reproduces all observed Baltic sea level variations very reliably with an accuracy of 5 to 9 cm (rms) for short-term variations (up to 2 months) and 8 cm (rms) for long-term variations (>2 months). An additional improvement of the model can be attained by including long-period sea level variations of the North Sea. The model performs well also in the case of extreme sea level events, as is shown for a major storm surge that occurred at the southern coast of the Baltic Sea in November 1995. 相似文献
19.
珠江磨刀门河口亚潮频率水位的控制论研究 总被引：3，自引：0，他引：3
本文应用现代控制论研究河口非潮汐海平面变化及其与影响要素的关系。两年连续的水位及水文气象要素资料表明,在0.01—0.50cpd的频带上水位有相当高能的波动,这些波动的能量主要直接或间接来自风应力、河流径流以及河口外的海平面波动。本文应用1982年时间序列辨识了五个二阶的MISO CAR模型,系统输出是河口亚潮频率海平面;系统输入是河流人注流量、风应力和气压。模型检验后对1983年亚潮频率海平面进行一步和多步后报,符合良好。系统仿真定量地估计了各控制因素对水位的相对重要性。频域和时域分析都表明河口水位系统具有振荡特性。 相似文献
20.
Mean sea level variations in the eastern Asia region during 1950 to 1991 are investigated with the use of observed sea level data at 16 stations. It is suggested from the data analysis, that the main cause of long-term sea level variation in this region may be the plate tectonic processes. The mean sea levels along the eastern coasts of Japan and the Philippines, and that along the southern coast of Indonesia have risen due to the subsidence of Pacific, Philippine and Australian plates under the Eurasian plate, respectively. On the other hand, the mean sea levels along the western coasts of Japan and the Philippines, and that along the northern coast of Indonesia have fallen. The distribution map of mean sea level rise at the year 2030 from 1985 in this region is presented on the basis of the results of this work and IPCC (1990). 相似文献