In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tid...In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.展开更多
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) n...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.展开更多
In this paper, through the nonlinear response of rock strain and stress, we have analized the physical mechanism of loading and unloading response ratio of the well level to the earth tides,the respouse of an aquife...In this paper, through the nonlinear response of rock strain and stress, we have analized the physical mechanism of loading and unloading response ratio of the well level to the earth tides,the respouse of an aquifer of confined well to bulk strain tide and showed two methods of the calculation of loading and unloading response ratio of the well level to the earth tides. We took the example of the Yu 01 well, which is near the epicenter of Heze M S 5.9 earthquake, calculated the response rate and loading and unloading response ratio of two kinds of the earth tides of it. The response rate and response ratio before the earthquake had the variation of increase.展开更多
The latest Intergovernmental Panel on Climate Change (IPCC) report shows that sea-level rise, which has been accelerated since the 19th century resulting to the global warming, threatens coastal areas with high popula...The latest Intergovernmental Panel on Climate Change (IPCC) report shows that sea-level rise, which has been accelerated since the 19th century resulting to the global warming, threatens coastal areas with high population growth. A Global Sea Level Observing System (GLOSS) assessment highlighted the lack of data in Africa, and in Côte d’Ivoire in particular. In order to estimate the evolutionary trend of sea level along the Ivorian coast, and to draw up preventive plans to protect properties and populations, we digitized 65 years of historical tidegrams recorded in the Ebrie Lagoon, using the “Surfer” and “Nunieau” software, then processed them using “T-Tide” and “U-Tide” software. The average levels were calculated using the Demerliac filter from complete daily (day and night) recordings for providing a usable database of 31 years of hourly lagoon data from 1979 to 2015. Our results show that a mean water level in lagoon is 1.04 m. The evolutionary trend in sea level, estimated in the lagoon via the Vridi canal, during the rainy season is the most significant at 2.93 mm/year. This is followed by the dry season, with a trend of 2.89 mm/year. The flood season trend is 2.78 mm/year. This suggests that marine water inflows dominate continental inflows. Our results highlight the vulnerability of Côte d’Ivoire’s coasts to the risk of marine submersion.展开更多
A nonlinear two-dimension dynamic model of storm surge (SS) and astronomical tide(AT) was used to investigate the effects of SS and AT on expected sea level rise (SLR) at principalcoastal stations in the Shanghai regi...A nonlinear two-dimension dynamic model of storm surge (SS) and astronomical tide(AT) was used to investigate the effects of SS and AT on expected sea level rise (SLR) at principalcoastal stations in the Shanghai region and to estimate numerically the probable maximum water lerel for2010 - 2050. Evidence suggests tha SLR causes reduction of SS; that its influence on SS depends on theintensity and path of a tropical cyclone and the station locality; tha the SLR’s effects on AT vary periodi-cally, with the peried being the same as tha of the AT’s: and that as the SLR increment grows, its impactincreases; below mean sea level (MSL) the effect is positive at rising tide and negative at ebb tide, andvice versa for the effect above MSL. Study of the probable maximum water level (by assuming SLR, SSalong favorable tropical cyclone’s path, its possible maximum intensity and effectivee spring AT at a rangeof set paths of Cyclones 5612, 8114, 9417) showed that the probable maximum water level is 740, 745,and 751 cm in the years 2010, 2030, and 2050, respetively, over the target region.展开更多
In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The ca...In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The calculated values were consistent with the predicted ones (the observed values in the case of calm) in the Tidal Table. On the basis of the modelling of the tide, the sea level and current fields under the effects of strong wind were simulated. The calculated results were also quite satisfactory.展开更多
海平面变化是全球气候和环境变化的重要指标之一,本文基于中国首套全球海洋气候数据集(Climate Data Records,CDRs)中的海平面高度异常(Sea Level Anomaly,SLA)数据、长期验潮站观测数据以及GNSS数据对北欧海的海平面变化进行了详细的...海平面变化是全球气候和环境变化的重要指标之一,本文基于中国首套全球海洋气候数据集(Climate Data Records,CDRs)中的海平面高度异常(Sea Level Anomaly,SLA)数据、长期验潮站观测数据以及GNSS数据对北欧海的海平面变化进行了详细的分析。首先利用1993-2019年的SLA数据分析了北欧海海平面变化的空间分布、主要周期;然后联合长期验潮站观测数据、GNSS数据分析了北欧海部分站点的绝对海平面变化,并与SLA数据获得的绝对海平面变化进行比对。结果表明:1993-2019年北欧海海平面变化具有显著的区域性差异,挪威海和格陵兰海北部海平面变化振幅最大,整体变化速率约为2.47±0.54 mm/a,每年春季(2-4月)为季节性低海平面期,秋季(9-11月)为季节性高海平面期;联合验潮站观测数据和GNSS数据可以很好地校正验潮站地壳垂直运动的影响,其中NY-ALESUN和ANDENES站经GNSS数据校正后的海平面变化趋势与同期基于CDRs数据的绝对海平面变化差异最小。展开更多
基金The National Key Fundamental Research and Development Program ("973" Program) of China under contract No. 2010CB429001
文摘In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.
文摘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.
文摘In this paper, through the nonlinear response of rock strain and stress, we have analized the physical mechanism of loading and unloading response ratio of the well level to the earth tides,the respouse of an aquifer of confined well to bulk strain tide and showed two methods of the calculation of loading and unloading response ratio of the well level to the earth tides. We took the example of the Yu 01 well, which is near the epicenter of Heze M S 5.9 earthquake, calculated the response rate and loading and unloading response ratio of two kinds of the earth tides of it. The response rate and response ratio before the earthquake had the variation of increase.
文摘The latest Intergovernmental Panel on Climate Change (IPCC) report shows that sea-level rise, which has been accelerated since the 19th century resulting to the global warming, threatens coastal areas with high population growth. A Global Sea Level Observing System (GLOSS) assessment highlighted the lack of data in Africa, and in Côte d’Ivoire in particular. In order to estimate the evolutionary trend of sea level along the Ivorian coast, and to draw up preventive plans to protect properties and populations, we digitized 65 years of historical tidegrams recorded in the Ebrie Lagoon, using the “Surfer” and “Nunieau” software, then processed them using “T-Tide” and “U-Tide” software. The average levels were calculated using the Demerliac filter from complete daily (day and night) recordings for providing a usable database of 31 years of hourly lagoon data from 1979 to 2015. Our results show that a mean water level in lagoon is 1.04 m. The evolutionary trend in sea level, estimated in the lagoon via the Vridi canal, during the rainy season is the most significant at 2.93 mm/year. This is followed by the dry season, with a trend of 2.89 mm/year. The flood season trend is 2.78 mm/year. This suggests that marine water inflows dominate continental inflows. Our results highlight the vulnerability of Côte d’Ivoire’s coasts to the risk of marine submersion.
文摘A nonlinear two-dimension dynamic model of storm surge (SS) and astronomical tide(AT) was used to investigate the effects of SS and AT on expected sea level rise (SLR) at principalcoastal stations in the Shanghai region and to estimate numerically the probable maximum water lerel for2010 - 2050. Evidence suggests tha SLR causes reduction of SS; that its influence on SS depends on theintensity and path of a tropical cyclone and the station locality; tha the SLR’s effects on AT vary periodi-cally, with the peried being the same as tha of the AT’s: and that as the SLR increment grows, its impactincreases; below mean sea level (MSL) the effect is positive at rising tide and negative at ebb tide, andvice versa for the effect above MSL. Study of the probable maximum water level (by assuming SLR, SSalong favorable tropical cyclone’s path, its possible maximum intensity and effectivee spring AT at a rangeof set paths of Cyclones 5612, 8114, 9417) showed that the probable maximum water level is 740, 745,and 751 cm in the years 2010, 2030, and 2050, respetively, over the target region.
文摘In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The calculated values were consistent with the predicted ones (the observed values in the case of calm) in the Tidal Table. On the basis of the modelling of the tide, the sea level and current fields under the effects of strong wind were simulated. The calculated results were also quite satisfactory.
