scholarly journals REFINE OF REGIONAL OCEAN TIDE MODEL USING GPS DATA

2018 ◽  
Vol XLII-3 ◽  
pp. 1685-1688
Author(s):  
F. Wang ◽  
P. Zhang ◽  
Z. Sun ◽  
Z. Jiang ◽  
Q. Zhang
Keyword(s):  
High Precision ◽  
Global Ocean ◽  
Ocean Tide ◽  
Gps Tracking ◽  
Inversion Method ◽  
Observation Data ◽  
Ocean Tide Model ◽  
Tide Model ◽  
Loading Effects ◽  
Ocean Tide Models

Due to lack of regional data constraints, all global ocean tide models are not accuracy enough in offshore areas around China, also the displacements predicted by different models are not consistency. The ocean tide loading effects have become a major source of error in the high precision GPS positioning. It is important for high precision GPS applications to build an appropriate regional ocean tide model. We first process the four offshore GPS tracking station’s observation data which located in Guangdong province of China by using PPP aproach to get the time series. Then use the spectral inversion method to acquire eigenvalues of the Ocean Tidal Loading. We get the estimated value of not only ~12hour period tide wave (M2, S2, N2, K2) but also ~24hour period tide wave (O1, K1, P1, Q1) which has not been got in presious studies. The contrast test shows that GPS estimation value of M2, K1 is consistent with the result of five famous glocal ocean load tide models, but S2, N2, K2, O1, P1, Q1 is obviously larger.

scholarly journals Research Article. Towards a tidal loading model for the Argentine-German Geodetic Observatory (La Plata)

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
A. Richter ◽  
L. Müller ◽  
E. Marderwald ◽  
L. Mendoza ◽  
E. Kruse ◽  
...  
Keyword(s):  
Earth Tides ◽  
Global Ocean ◽  
Ocean Tide ◽  
Observation Data ◽  
Additional Contribution ◽  
La Plata ◽  
Ocean Tide Model ◽  
Tide Model ◽  
Loading Effects ◽  
Tidal Loading

AbstractWe present a regionalized model of ocean tidal loading effects for the Argentine-German Geodetic Observatory in La Plata. It provides the amplitudes and phases of gravity variations and vertical deformation for nine tidal constituents to be applied as corrections to the observatory’s future geodetic observation data. This model combines a global ocean tide model with a model of the tides in the Río de la Plata estuary. A comparison with conventional predictions based only on the global ocean tide model reveals the importance of the incorporation of the regional tide model. Tidal loading at the observatory is dominated by the tides in the Atlantic Ocean. An additional contribution of local tidal loading in channels and groundwater is examined. The magnitude of the tidal loading is also reviewed in the context of the effects of solid earth tides, atmospheric loading and non-tidal loads.

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>

scholarly journals On the Resonance and Shelf/Open-Ocean Coupling of the Global Diurnal Tides

2013 ◽  
Vol 43 (7) ◽  
pp. 1301-1324 ◽  
Author(s):  
Aaron W. Skiba ◽  
Libo Zeng ◽  
Brian K. Arbic ◽  
Malte Müller ◽  
William J. Godwin
Keyword(s):  
Sea Of Okhotsk ◽  
Open Ocean ◽  
Ice Age ◽  
Global Ocean ◽  
Ocean Tide ◽  
Free Oscillations ◽  
Tidal Forcing ◽  
Tide Model ◽  
Ocean Tide Models ◽  
Diurnal Tides

Abstract The resonance of diurnal tidal elevations is investigated with a forward ocean tide model run in a realistic near-global domain and a synthesis of free oscillations (normal modes) computed for realistic global ocean geometries and ocean physics. As a prelude to performing the forward ocean tide simulations, the topographic wave drag, which is now commonly employed in forward ocean tide models, is tuned specifically for diurnal tides. The synthesis of global free oscillations predicts reasonably well the forward ocean diurnal tide model sensitivity to changes in the frequency, zonal structure, and meridional structure of the astronomical diurnal tidal forcing. Three global free oscillations that are important for understanding diurnal tides as a superposition of forced-damped, resonant, free oscillations are identified. An admittance analysis of the frequency sweep experiments demonstrates that some coastal locations such as the Sea of Okhotsk are resonant to diurnal tidal forcing. As in earlier work done with semidiurnal tides, a series of simulations are performed in which regions possessing significant coastal diurnal tides are blocked out. The largest perturbations to the open-ocean diurnal tides take place in Blocked Sea of Okhotsk experiments. Lesser but still significant perturbations also arise from the blocking out of other regions of large diurnal tidal elevations or dissipation. Interpretation of the results is made more complex, however, by the fact that substantial perturbations also arise from blocking out regions where neither tidal elevations nor dissipation are large. The “blocking” experiments are relevant to understanding tides of the ice age, during which lower sea levels entail a reduced area of continental shelves.

scholarly journals EFFECTS OF OCEAN TIDE MODELS ON GNSS-ESTIMATED ZTD AND PWV IN TURKEY

2015 ◽  
Vol XL-1-W5 ◽  
pp. 255-258
Author(s):  
G. Gurbuz ◽  
S. Jin ◽  
C. Mekik
Keyword(s):  
Water Vapour ◽  
Weather Prediction ◽  
Precipitable Water ◽  
Ocean Tide ◽  
Tropospheric Delay ◽  
Precipitable Water Vapour ◽  
Ocean Tide Model ◽  
Tide Model ◽  
Gnss Data ◽  
Ocean Tide Models

Global Navigation Satellite System (GNSS) observations can precisely estimate the total zenith tropospheric delay (ZTD) and precipitable water vapour (PWV) for weather prediction and atmospheric research as a continuous and all-weather technique. However, apart from GNSS technique itself, estimations of ZTD and PWV are subject to effects of geophysical models with large uncertainties, particularly imprecise ocean tide models in Turkey. In this paper, GNSS data from Jan. 1<sup>st</sup> to Dec. 31<sup>st</sup> of 2014 are processed at 4 co-located GNSS stations (GISM, DIYB, GANM, and ADAN) with radiosonde from Turkish Met-Office along with several nearby IGS stations. The GAMIT/GLOBK software has been used to process GNSS data of 30-second sample using the Vienna Mapping Function and 10° elevation cut-off angle. Also tidal and non-tidal atmospheric pressure loadings (ATML) at the observation level are also applied in GAMIT/GLOBK. Several widely used ocean tide models are used to evaluate their effects on GNSS-estimated ZTD and PWV estimation, such as IERS recommended FES2004, NAO99b from a barotropic hydrodynamic model, CSR4.0 obtained from TOPEX/Poseidon altimetry with the model FES94.1 as the reference model and GOT00 which is again long wavelength adjustments of FES94.1 using TOPEX/Poseidon data at 0.5 by 0.5 degree grid. The ZTD and PWV computed from radiosonde profile observations are regarded as reference values for the comparison and validation. In the processing phase, five different strategies are taken without ocean tide model and with four aforementioned ocean tide models, respectively, which are used to evaluate ocean tide models effects on GNSS-estimated ZTD and PWV estimation through comparing with co-located Radiosonde. Results showed that ocean tide models have greatly affected the estimation of the ZTD in centimeter level and thus the precipitable water vapour in millimeter level, respectively at stations near coasts. The ocean tide model FES2004 that is the product of assimilation of the altimetric data of ERS2, TOPEX/POSEIDON and the data of a global tide gauge network, gave the most accurate results when compared to radiosonde with ±1.99 mm in PWV at stations near coastline. While other ocean tides models agree each other at millimeter level in PWV. However, at inland GNSS stations, ocean tide models have less effects on GNSS-estimated ZTD and PWV, e.g., with ±1.0 mm in ZTD and ±0.1 mm in PWV.

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