scholarly journals Ocean-tide parameters from the simultaneous long-period analysis of the orbits of Starlette and Stella

1997 ◽  
Vol 15 (2) ◽  
pp. 263-271 ◽  
Author(s):  
N. M. Harwood ◽  
G. G. Swinerd
Keyword(s):  
Ocean Tide ◽  
Ocean Tides ◽  
Orbital Inclination ◽  
Period Analysis ◽  
Analysis Techniques ◽  
Long Period ◽  
Simultaneous Fitting ◽  
One Year ◽  
Ocean Tide Models ◽  
Right Ascension

Abstract. The orbits of two geodetic satellites, Starlette and Stella, have been analysed in order to determine ocean-tide parameters. The orbit of Starlette has been determined over a three-year period and Stella over a one-year period. Long-period analysis techniques have been used to determine the evolutions of the orbital inclination, eccentricity and right ascension of the ascending node for each satellite due to ocean tides. The ocean-tide parameters have been determined in a simultaneous fitting of the theoretical orbital variations to the observed variations. The results are compared with ocean-tide models.

scholarly journals Evaluation of global ocean tide models based on tidal gravity observations in China

2020 ◽  
Author(s):  
Hongbo Tan ◽  
Chongyong Shen ◽  
Guiju Wu
Keyword(s):  
High Precision ◽  
Earth Tide ◽  
Global Ocean ◽  
Ocean Tide ◽  
Ocean Tides ◽  
Ocean Tide Model ◽  
Tidal Forces ◽  
The Earth ◽  
Gravity Observation ◽  
Ocean Tide Models

<p>Solid Earth is affected by tidal cycles triggered by the gravity attraction of the celestial bodies. However, about 70% the Earth is covered with seawater which is also affected by the tidal forces. In the coastal areas, the ocean tide loading (OTL) can reach up to 10% of the earth tide, 90% for tilt, and 25% for strain (Farrell, 1972). Since 2007, a high-precision continuous gravity observation network in China has been established with 78 stations. The long-term high-precision tidal data of the network can be used to validate, verifying and even improve the ocean tide model (OTM).</p><p>In this paper, tidal parameters of each station were extracted using the harmonic analysis method after a careful editing of the data. 8 OTMs were used for calculating the OTL. The results show that the Root-Mean-Square of the tidal residuals (M<sub>0</sub>) vary between 0.078-1.77 μgal, and the average errors as function of the distance from the sea for near(0-60km), middle(60-1000km) and far(>1000km) stations are 0.76, 0.30 and 0.21 μgal. The total final gravity residuals (Tx) of the 8 major constituents (M<sub>2</sub>, S<sub>2</sub>, N<sub>2</sub>, K<sub>2</sub>, K<sub>1</sub>, O<sub>1</sub>, P<sub>1</sub>, Q<sub>1</sub>) for the best OTM has amplitude ranging from 0.14 to 3.45 μgal. The average efficiency for O<sub>1</sub> is 77.0%, while 73.1%, 59.6% and 62.6% for K<sub>1</sub>, M<sub>2</sub> and Tx. FES2014b provides the best corrections for O<sub>1</sub> at 12 stations, while SCHW provides the best for K<sub>1 </sub><sub>,</sub>M<sub>2</sub>and Tx at 12,8and 9 stations. For the 11 costal stations, there is not an obvious best OTM. The models of DTU10, EOT11a and TPXO8 look a litter better than FES2014b, HAMTIDE and SCHW. For the 17 middle distance stations, SCHW is the best OTM obviously. For the 7 far distance stations, FES2014b and SCHW model are the best models. But the correction efficiency is worse than the near and middle stations’.</p><p>The outcome is mixed: none of the recent OTMs performs the best for all tidal waves at all stations. Surprisingly, the Schwiderski’s model although is 40 years old with a coarse resolution of 1° x 1° is performing relative well with respect to the more recent OTM. Similar results are obtained in Southeast Asia (Francis and van Dam, 2014). It could be due to systematic errors in the surroundings seas affecting all the ocean tides models. It's difficult to detect, but invert the gravity attraction and loading effect to map the ocean tides in the vicinity of China would be one way.</p>

Impact of sea level variations on hydrographic survey around Taiwan

2020 ◽  
Author(s):  
Wen-Hau Lan ◽  
Chung-Yen Kuo ◽  
Sheng-Fong Lin ◽  
Chien-Hsing Lu
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Temporal Changes ◽  
Altimeter Data ◽  
Ocean Tide ◽  
Ocean Tides ◽  
Sea Level Anomalies ◽  
Sea Level Variations ◽  
Ocean Tide Models ◽  
And Sea Level

<p>Taiwan is an island entirely surrounded by oceans, so living and economics are significantly influenced by the oceans. The electronic navigational chart system is extremely important for improving the safety of marine navigation and ocean depth is the essential data for electronic charts. Sea surface variations affected by ocean tide and sea level change are the main error sources in hydrographic surveys since the traditional tidal correction only using tide gauge stations, ignoring geographically non-uniform ocean tides and sea level anomalies around Taiwan. In this research, we evaluate two factors impacting the accuracy of hydrographic surveys, including ocean tides and seasonal sea level variations, using tide gauge records, satellite altimeter data and ocean tide models around Taiwan, and also analyze the accuracy of the ocean tide models around Taiwan. In addition, sea level anomalies are strongly influenced by climate changes in recent years. An understanding of seasonal sea level cycle and its spatial and temporal changes are importance because its temporal changes can result in the variation of the frequency and magnitude of coastal hazards. Therefore, we will apply the Ensemble Empirical Mode Decomposition to sea level data to assess the stability of the long-term seasonal sea level fluctuations with time.</p>

scholarly journals Improving Stage–Discharge Relation in The Mekong River Estuary by Remotely Sensed Long-Period Ocean Tides

2020 ◽  
Vol 12 (21) ◽  
pp. 3648
Author(s):  
Hongrui Peng ◽  
Hok Sum Fok ◽  
Junyi Gong ◽  
Lei Wang
Keyword(s):  
Time Series ◽  
Water Level ◽  
Water Discharge ◽  
Remotely Sensed ◽  
Tidal Height ◽  
Global Ocean ◽  
Ocean Tide ◽  
Ocean Tides ◽  
Long Period ◽  
Short Period

Ocean tidal backwater reshapes the stage–discharge relation in the fluvial-to-marine transition zone at estuaries, rendering the cautious use of these data for hydrological studies. While a qualitative explanation is traditionally provided by examining a scatter plot of water discharge against water level, a quantitative assessment of long-period ocean tidal effect on the stage–discharge relation has been rarely investigated. This study analyzes the relationship among water level, water discharge, and ocean tidal height via their standardized forms in the Mekong Delta. We found that semiannual and annual components of ocean tides contribute significantly to the discrepancy between standardized water level and standardized water discharge time series. This reveals that the long-period ocean tides are the significant factors influencing the stage–discharge relation in the river delta, implying a potential of improving the relation as long as proper long-period ocean tidal components are taken into consideration. By isolating the short-period signals (i.e., less than 15 days) from land surface hydrology and ocean tides, better consistent stage–discharge relations are obtained, in terms of improving the Pearson correlation coefficient (PCC) from ~0.4 to ~0.8 and from ~0.6 to ~0.9 for the stations closest to the estuary and at the Mekong Delta entrance, respectively. By incorporating the long-period ocean tidal height time series generated from a remotely sensed global ocean tide model into the stage–discharge relation, further refined stage–discharge relations are obtained with the PCC higher than 0.9 for all employed stations, suggesting the improvement of daily averaged water level and water discharge while ignoring the short-period intratidal variability. The remotely sensed global ocean tide model, OSU12, which contains annual and semiannual ocean tide components, is capable of generating accurate tidal height time series necessary for the partial recovery of the stage–discharge relation.

scholarly journals Regional Evaluation of Minor Tidal Constituents for Improved Estimation of Ocean Tides

2021 ◽  
Vol 13 (16) ◽  
pp. 3310
Author(s):  
Michael G. Hart-Davis ◽  
Denise Dettmering ◽  
Roman Sulzbach ◽  
Maik Thomas ◽  
Christian Schwatke ◽  
...  
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Sea Surface ◽  
Global Ocean ◽  
Ocean Tide ◽  
Ocean Tides ◽  
Tidal Constituents ◽  
Ocean Tide Models ◽  
Tidal Correction

Satellite altimetry observations have provided a significant contribution to the understanding of global sea surface processes, particularly allowing for advances in the accuracy of ocean tide estimations. Currently, almost three decades of satellite altimetry are available which can be used to improve the understanding of ocean tides by allowing for the estimation of an increased number of minor tidal constituents. As ocean tide models continue to improve, especially in the coastal region, these minor tides become increasingly important. Generally, admittance theory is used by most global ocean tide models to infer several minor tides from the major tides when creating the tidal correction for satellite altimetry. In this paper, regional studies are conducted to compare the use of admittance theory to direct estimations of minor tides from the EOT20 model to identify which minor tides should be directly estimated and which should be inferred. The results of these two approaches are compared to two global tide models (TiME and FES2014) and in situ tide gauge observations. The analysis showed that of the eight tidal constituents studied, half should be inferred (2N2, ϵ2, MSF and T2), while the remaining four tides (J1, L2, μ2 and ν2) should be directly estimated to optimise the ocean tidal correction. Furthermore, for certain minor tides, the other two tide models produced better results than the EOT model, suggesting that improvements can be made to the tidal correction made by EOT when incorporating tides from the two other tide models. Following on from this, a new approach of merging tidal constituents from different tide models to produce the ocean tidal correction for satellite altimetry that benefits from the strengths of the respective models is presented. This analysis showed that the tidal correction created based on the recommendations of the tide gauge analysis provided the highest reduction of sea-level variance. Additionally, the combination of the EOT20 model with the minor tides of the TiME and FES2014 model did not significantly increase the sea-level variance. As several additional minor tidal constituents are available from the TiME model, this opens the door for further investigations into including these minor tides and optimising the tidal correction for improved studies of the sea surface from satellite altimetry and in other applications, such as gravity field modelling.

scholarly journals CAREGIVERS’ NEEDS IN CARING FOR RELATIVES WITH SCHIZOPHRENIA IN MEDAN INDONESIA: A PHENOMENOLOGICAL STUDY

2017 ◽  
Vol 3 (6) ◽  
pp. 656-661 ◽  
Author(s):  
Jenny Marlindawani Purba
Keyword(s):  
Home Care ◽  
Unmet Needs ◽  
Phenomenological Study ◽  
Family Members ◽  
Optimal Care ◽  
Knowledge And Skills ◽  
Long Period ◽  
Primary Nurse ◽  
Caregiver Needs ◽  
One Year

Background: A caregiver is a primary nurse and has a major role in providing care for people with schizophrenia. Caring for those with schizophrenia for a long period of time is a challenge for families, especially caregivers. Various needs ought to be studied by nurses to assist caregivers in providing optimal care for family members who experience schizophrenia.Objective: This qualitative study aims to explore the needs of caregivers in treating schizophrenia at home.Methods: The method used in this study is the method of purposive sampling with the number of participants as many as 10 people with criteria: 1) have family members diagnosed with schizophrenia, 2) directly involved in home care patients, 3) caring for schizophrenia for more than one year, 4) willing to be a participant by signing informed consent, 4) being able to identify what is needed in treating schizophrenia. Colaizzi is used to analyze interview data.Results: The results of the study found four themes of caregiver needs in caring for schizophrenia patients at home, ly: 1) seeking information about schizophrenia, 2) sought schizophrenic relatives’ recovery, 3) looking for appropriate rehabilitation for relatives with schizophrenias, and 4) utilizing mental health facilities.Conclusions: It is expected that nurses have the knowledge and skills in identifying and helping families, especially caregivers, to meet unmet needs so they can optimize home care.

scholarly journals El restabliment de la Companyia de Jesús a València

2018 ◽  
Vol 11 (11) ◽  
pp. 74
Author(s):  
Francesc Joan Monjo i Dalmau
Keyword(s):  
Society Of Jesus ◽  
Long Period ◽  
The World ◽  
One Year ◽  
Jesuit Order

Resum: L’expulsió de la Companyia de Jesús, decretada per Carles III el 1767, obrí un llarg període de foscor per als jesuïtes hispànics. Tanmateix, el cop de gràcia a l’orde vindria de la mà del papa Climent XIV, que, pressionat per la monarquia espanyola –l’ambaixador del rei hispànic a Roma Moñino recorregué a la coacció i al suborn d’afins al pontífex–, declarà extingida la Companyia el 21 de juliol del 1773. Els jesuïtes suprimits van conrear la propaganda durant més de quaranta anys per tal de revertir la situació. Finalment, el 1814 el papa Pius VII restablí l’orde jesuïta a tot el món mitjançant la butlla Sollicitudo omnium ecclesiarum, i els regulars ignasians van obtenir, un any després, el desitjat permís de Ferran VII per tornar als territoris hispànics. El 18 de juliol del 1816 els jesuïtes prenien possessió de la Casa Professa, ara convertida en col·legi.   Paraules clau: Jesuïtes, restauració, Pius VII, Ferran VII, València   Abstract: The expulsion of the Society of Jesus, decreed by Charles III of Spain in 1767, initiated a long period of darkness for the Hispanic Jesuits. Although the coup de grace to the order would come by the hands of Pope Clement XIV, who was pressured by the Spanish monarchy (the ambassador of the Hispanic king in Rome Moñino resorted to the coercion and subornation of those who were related to the pontiff), declared the Society extinguished on July 21, 1773. The suppressed Jesuits produced propaganda for more than forty years to reverse the situation. Finally, in 1814 Pope Pius VII restored the Jesuit Order around the world through the Bull Sollicitudo omnium ecclesiarum, and one year later the regular Ignatians obtained the desired permission from Ferdinand VII to return to the Hispanic territories. On July 18, 1816, the Jesuits took possession of Casa Professa, now converted into a school.   Keywords: Jesuits, restoration, Pius VII, Ferdinand VII, València.

Synergistic Use of Satellite and In-Situ Current Data to Improve the Characterisation of Seasonal Trends

2009 ◽  
Author(s):  
Liam Harrington-Missin ◽  
Mark Calverley ◽  
Gus Jeans
Keyword(s):  
Current Data ◽  
Seasonal Trend ◽  
Measured Signal ◽  
Geostrophic Current ◽  
Geostrophic Currents ◽  
Current Regime ◽  
Long Period ◽  
In Situ Data ◽  
One Year

The synergistic use of measured in-situ current data and altimetry derived geostrophic current data provides improved seasonal characterisation of the current regime, West of Shetland. In September 2007, considerable downtime was experienced by an offshore operator, West of Shetland, as a result of unexpectedly high currents persisting for a number of days. This downtime was unanticipated following conclusions derived from one year of in-situ measured data, which suggested a most favourable current regime during the months August to October. Ten years of altimetry derived geostrophic currents were utilised in conjunction with approximately 3 years of in-situ data to assess the validity of the reported seasonal trend. The altimetry derived geostrophic currents correlated well with the dominating long period signal extracted from the in-situ data. Seasonal comparison between the altimetry derived geostrophic currents and the total measured signal showed the previously available measurement year had a relatively benign September. Based on the 10 years of satellite data, the inter-annual variability of the current regime West of Shetland does not show any clear seasonal trend.

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