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Mediterranean sea level trends from long-period tide gauge time series

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Acta Oceanologica Sinica 2020年第1期39卷 157-165页

作者： Haddad Mahdi Taibi Hebib Centre of Space Techniques Algerian Space Agency

The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean sea level, through the analysis of historical tide gauge records. In this framework, 14 tide gauge monthly series selected from the Permanent Service of the Mean sea level(PSMSL) database were used. The search for the presence or not of trends within these series, that have a temporal coverage from 59 to 142 years, was carried out using the Mann-Kendall test and the Sen’s slope estimator. The obtained results show that the Split Rt Marjana series are the only ones which does not exhibit a significant trend. The other 13 series show significant increasing trends. This result seems sufficient to suppose the presence, in the past century, of a new climatic phase on the scale of the Mediterranean basin, where the rising sea level is one of the consequences.

关键词： sea level tidal heights trend analysis Mann-Kendall test Sen’s slope estimates

Effect of sea level Variation on Calculation of Design Water level

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China Ocean Engineering 2001年第3期16卷 383-394页

作者：左军成于宜法鲍献文刘德辅 Department of Oceanography Ocean University of Qingdao

The long-term variation and seasonal variation of sea level have a notable effect on the calculation of engineering water level. Stich an effect is first analyzed in this paper. The maximal amplitude of inter-annual anomaly of monthly mean sea level along the China coast is larger than 60 cm. Both the storm surge disaster and cold wave disaster are seasonal disasters in various regions, so the water level corresponding to the 1% of the cumulative frequency in the cumulative frequency curve of hourly water level data for different seasons in various sea areas is different from design water level., for example, the difference between them reaches maximum in June, July and August for northern sea area, and maximum in September, October and November for Southern China sea, The hourly water level data of 19 gauge stations along the China coast are analyzed. Firstly, the annual mean sea level for every station is obtained; secondly, linear changing rates of annual mean sea level are obtained with the stochastic dynamic method; thirdly, the astronomical tide and storm surge tide are obtained by subtracting the linear fitting part from the original hourly data, finally, two distributions corresponding to the astronomical tide and wind tide are obtain ed according to whether the astronomical tide and storm tide are correlative or not. So the two check water levels are obtained with the joint probability method, The maximal difference between the two water levels of 100 years' recurrence is more than 30 cm. Both of the two check water levels have disadvantages in the use of observation data, so the mean value is suggested to be taken as the final check water level. A comparison between the two check-water levels indicates that the effect of sea level variation upon design water level and check water level is larger than 80 cm at some stations.

关键词： engineering water level sea level stochastic dynamic residual level joint probability

Climate-Induced Variability of sea level in Stockholm: Influence of Air Temperature and Atmospheric Circulation

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Advances in Atmospheric Sciences 2005年第5期22卷 655-664页

作者： Deliang CHEN Anders OMSTEDT Earth Sciences Centre Goteborg University Sweden Laboratory for Climate Studies/National Climate Center China Meteorological Administration Beijing 100081

This study is focused on climate-induced variation of sea level in Stockholm during 1873-1995. After the effect of the land uplift, is removed, the residual is characterized and related to large-scale temperature and atmospheric circulation. The residual shows an overall upward trend, although this result depends on the uplift rate used. However, the seasonal distribution of the trend is uneven. There are even two months （June and August） that show a negative trend. The significant trend in August may be linked to fresh water input that is controlled by precipitation. The influence of the atmospheric conditions on the sea level is mainly manifested through zonal winds, vorticity and temperature. While the wind is important in the period January-May, the vorticity plays a main role during June and December. A successful linear multiple-regression model linking the climatic variables （zonal winds, vorticity and mean air temperature during the previous two months） and the sea level is established for each month. An independent verification of the model shows that it has considerable skill in simulating the variability.

关键词： sea level Baltic sea atmospheric circulation temperature Stockholm

Validation of sea level Data in the East Asian Marginal seas: Comparison between TOPEX/POSEIDON Altimeter and In-Situ Tide Gauges

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Advances in Atmospheric Sciences 2003年第4期20卷 650-660页

作者： Yong-Hoon YOUN Im Sang OH Ki-Hyun KIM Young-Hyang PARK Jong Woo KIM Meteorological Research Institute/Korea Meteorological Administration SeoulKoreaResearch Institute of OceanographySeoul National UniversitySeoulKoreaDepartment of Earth SciencesSejing UniversitySeoulKoreaLaboratoire d'Oceanographie PhysiqueMuseum National d'Histoire NaturelleParisDepartment of Earth SciencesSejong UniversitySeoulKorea

In an effort to assess the reliability of satellite altimeter systems, the authors conduct a comparative analysis of sea level data that were collected from the TOPEX/POSEIDON (T/P) altimeter and 10 tide gauges (TG) near the satellite passing ground tracks. The analysis is made using datasets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Proper treatment of tidal errors is a very critical step in data processing because the study area has very strong tide. When the T/P data are processed, the procedures of Park and Gamberoni (1995) are adapted to reduce errors associated with the tide. When the T/P data are processed in this way, the alias periods of M2, S2, and K1 constituents are found to be 62.1, 58.7, and 173 days repectively. The compatibility of the T/P and TG datasets are examined at various filtering periods. The results indicate that the low-frequency signals of the T/P data can be interpreted more safely with longer filtering periods (such as up to the maximum selected value of 200 days). When RMS errors for the 200-day low-pass filter period are compared with all 10 tidal stations, the values span the range of 2.8 to 6.7 cm. The results of a correlation analysis for this filtering period also show a strong agreement between the T/P and TG datasets across all stations investigated (e.g.,p- values consistently less than 0.001). Hence according to the analysis, the conclusion is made that the analysis of surface sea level using satellite altimeter data can be made safely with reasonably extended filtering periods such as 200 days.

关键词： sea level TOPEX/POSEIDON altimeter tide gauge

Sampling errors of the global mean sea level derived from TOPEX/Poseidon altimetry

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Acta Oceanologica Sinica 2011年第6期30卷 12-18页

作者： WAGNER Carl National Oceanic and Atmospheric Administration National Environmental Stellite Data and Information Service

Sampling errors of the global mean sea level derived from TOPEX/Poseidon （T/P） altimetry are explored using 31/ 4a of eddy-resolving numerical model outputs for sea level. By definition, the sampling errors would not exist if data were available everywhere at all times. Four problems with increasing and progressively added complexities are examined to understand the causes of the sampling errors. The first problem （P1） explores the error incurred because T/P with turning latitudes near 66° latitudes does not cover the entire globe. The second problem （P2） examines, in addition, the spatial sampling issue because samples are only available along T/P ground tracks. The third problem （P3） adds the additional complexity that sea level at any along track location is sampled only once every 10 d versus every 3 d for the model （i.e., the temporal sampling issue）. The fourth problem （P4） incorporates the full complexity with the addition of real T/P data outages. The numerical model （Los Alamos POP model Run 11） conserves the total water volume, thus generating no global mean sea level variation. Yet when the model sea level is sampled in the four problems （with P4 using the real T/P sampling）, variations occur as manifestations of the sampling errors. The results show root-mean-squares （rms） sampling errors for P1 of 0.67 （0.75） mm for 10 d （3 d） global mean sea level, 0.78 （0.86） mm for P2, 0.79 mm for P3, and 1.07 mm for P4, whereas the amplitudes of the sampling errors can be as large as 2.0 （2.7） mm for P1, 2.1 （2.7） mm for P2, 2.2 mm for P3, and 2.5 mm for P4. The results clearly show the largest source of the sampling errors to be the lack of global coverage （i.e., P1）, which the model has actually underestimated due to its own less-than-global coverage （between latitudes about 77° latitudes）. We have extrapolated that a truly global model would show the rms sampling error to be 1.14 （1.28） mm for P1, thus implying a substantially larger sampling error for P4.

关键词： sea level global warming remote sensing physical oceanography

Projection of the Zhujiang(Pearl) River Delta's potential submerged area due to sea level rise during the 21st century based on CMIP5 simulations

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Acta Oceanologica Sinica 2015年第9期34卷 78-84页

作者： XIA Jiangjiang YAN Zhongwei ZHOU Wen FONG Soi Kun LEONG Ka Cheng TANG Iu Man CHANG S W LEONG W K JIN Shaofei Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences Guy Carpenter Asia-Pacific Climate Impact Centre School of Energy and EnvironmentCity University of Hong Kong Macao Meteorological and Geophysical Bureau

Projections of potential submerged area due to sea level rise are helpful for improving understanding of the influence of ongoing global warming on coastal areas. The Ensemble Empirical Mode Decomposition method is used to adaptively decompose the sea level time series in order to extract the secular trend component. Then the linear relationship between the global mean sea level （GMSL） change and the Zhujiang （Pearl） River Delta （PRD） sea level change is calculated： an increase of 1.0 m in the GMSL corresponds to a 1.3 m （uncertainty interval from 1.25 to 1.46 m） increase in the PRD. Based on this relationship and the GMSL rise projected by the Coupled Model Intercomparison Project Phase 5 under three greenhouse gas emission scenarios （representative concentration pathways, or RCPs, from low to high emission scenarios RCP2.6, RCP4.5, and RCP8.5）, the PRD sea level is calculated and projected for the period 2006-2100. By around the year 2050, the PRD sea level will rise 0.29 （0.21 to 0.40） m under RCP2.6, 0.31 （0.22 to 0.42） m under RCP4.5, and 0.34 （0.25 to 0.46） m under RCP8.5, respectively. By 2100, it will rise 0.59 （0.36 to 0.88） m, 0.71 （0.47 to 1.02） m, and 1.0 （0.68 to 1.41） m, respectively. In addition, considering the extreme value of relative sea level due to land subsidence （i.e., 0.20 m） and that obtained from intermonthly variability （i.e., 0.33 m）, the PRD sea level will rise 1.94 m by the year 2100 under the RCP8.5 scenario with the upper uncertainty level （i.e., 1.41 m）. Accordingly, the potential submerged area is 8.57x103 km2 for the PRD, about 1.3 times its present area.

关键词： sea level Zhujiang (Pearl) River Delta (PRD) representative concentration pathways (RCPs) CMIP5 submerged area Ensemble Empirical Mode Decomposition (EEMD)

Climate Variabilities of sea level around the Korean Peninsula

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Advances in Atmospheric Sciences 2004年第4期21卷 617-626页

作者： Yong-HoonYOUN ImSangOH Young-HyangPARK andKi-HyunKIM MeteorologicalResearchInstitute KoreaMeteorologicalAdministrationSeoulKorea ResearchInstituteofOceanography SeoulNationalUniversitySeoulKorea Laboratoired＇OeeanographiePhysique MuseumNationald＇HistoireNaturelleParis DepartmentofEarth＆EnvironmentalSciences SejongUniversitySeoulKorea

In order to study the climate variabilities of the sea level around the Korean Peninsula, tidal data observed at local stations in Korea were compared against those obtained using TOPEX/POSEIDON (T/P) altimetric sea level data. In the course of our study, the amount of sea level rise was estimated using the tidal data from 9 stations selected by an anomaly coherency analysis. The results indicated that the sea level has risen by 0.28 cm yr-1 around the Korean Peninsula over the past two decades. The extent of such a rise is about two times higher than that of the global increase (0.1-0.2 cm yr-1). However, because most global warming effects occurred mainly over mid- and high-latitudes, this level of change appears to be realistic. According to the spectral analysis (at a spectral window of k=2, k is the number of subdivisions), the decadal band of sea level variability is computed at 30% of the energy. Its spectral peak is found at 12.8 years. In the interannual band, the predominant sea level variability is in the 1.4-1.9-year band, with a sharp peak at 1.6 years. A secondary peak, although marginal, has a period of 2.2 years. Based on our estimates of sea level height from Topex/Poseidon, the quasi-biennial periodicity of 1.6 years is the representative interannual sea level variability in the seas adjacent to Korea. Trends vary greatly according to the geographical location, from a maximum of 1.0 cm yr-1 (the southern sector of the East sea) to a minimum of 0.17 cm yr-1 (the northern sector of the East sea). This is fairly consistent with the qualitative description already given with reference to the global map. As an analogue to the pattern seen in Korea, that of the Yellow sea reveals practically the same trend as that of the adjacent seas (0.56 cm yr-1). However, in the case of TOPEX/POSEIDON (T/P) data, there is no clear evidence of a linkage between the interannual sea level variability around the Korean Peninsula and ENSO.

关键词： sea level tidal station altimetry TOPEX/POSEIDON ENSO

A prediction of sea level rising amplitude in 2030 and defensive countermeasures in the Zhujiang delta

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Science China Earth Sciences 2001年第5期44卷 446-454页

作者：黄镇国张伟强吴厚水陈特固范锦春江沛霖黎子浩黄本胜 Guangzhou Institute of Geography Guangzhou China South China sea Institute of Oceanology Chinese Academy of Sciences Guangzhou China Zhujiang River Water Resources Commission Guangzhou China Water Conservancy and Hydroelectric Power Resources Institute of Guangdong Province Guangzhou China

By analysing comprehensively the factors such as theoretical sealevel, abnormal fluctuation of sea level, rising amplitude of floodtide water level and land deformation, a rising amplitude of 22-33 cm of relative sea level by the year of 2030 is forecasted in the Zhujiang Delta. From the forecasted amplitude of 30 cm, using hydraulic and hydrometric models the scope influenced by sea level rise is delimited and the reappearing periods of floodtide water level, protecting ability of embankments, design parameters of water conservancy project, drain waterlogging, saline intrusion, resource of mud beach and comprehensive prevention measures are discussed.

关键词： sea level prevention Zhujiang Delta

Inferring the global mean sea level from a global tide gauge network

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Acta Oceanologica Sinica 2011年第4期30卷 102-106页

作者： TAI Chang-Kou National Oceanic and Atmospheric Administration National Environmental StelliteData and Information ServiceMaryland 20746USA

An attempt is made to infer the global mean sea level（GMSL） from a global tide gauge network and frame the problem in terms of the limitations of the network. The network,owing to its limited number of gauges and poor geographical distribution complicated further by unknown vertical land movements,is ill suited for measuring the GMSL. Yet it remains the only available source for deciphering the sea level rise over the last 100 a. The poor sampling characteristics of the tide gauge network have necessitated the usage of statistical inference. A linear optimal estimator based on the Gauss-Markov theorem seems well suited for the job. This still leaves a great deal of freedom in choosing the estimator. GMSL is poorly correlated with tide gauge measurements because the small uniform rise and fall of sea level are masked by the far larger regional signals. On the other hand,a regional mean sea level（RMSL） is much better correlated with the corresponding regional tide gauge measurements. Since the GMSL is simply the sum of RMSLs,the problem is transformed to one of estimating the RMSLs from regional tide gauge measurements. Specifically for the annual heating and cooling cycle,we separate the global ocean into 10-latitude bands and compute for each 10-latitude band the estimator that predicts its RMSL from tide gauges within. In the future,the statistical correlations are to be computed using satellite altimetry. However,as a first attempt,we have used numerical model outputs instead to isolate the problem so as not to get distracted by altimetry or tide gauge errors. That is,model outputs for sea level at tide gauge locations of the GLOSS network are taken as tide gauge measurements,and the RMSLs are computed from the model outputs. The results show an estimation error of approximately 2 mm versus an error of 2.7 cm if we simply average the tide gauge measurements to estimate the GMSL,caused by the much larger regional seasonal cycle and mesoscale variation plaguing the

关键词： sea level remote sensing global warming