scholarly journals A Novel Method for Regional Short-Term Forecasting of Water Level

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 820
Author(s):  
Zejie Tu ◽  
Xingguo Gao ◽  
Jun Xu ◽  
Weikang Sun ◽  
Yuewen Sun ◽  
...  
Keyword(s):  
Water Level ◽  
Rhode Island ◽  
Short Term Memory ◽  
Spatial Distance ◽  
Background Information ◽  
Residual Water ◽  
Short Term ◽  
Model Residuals ◽  
Meteorological Features ◽  
Residual Water Level

The water level forecasting system represented by the hydrodynamic model relies too much on the input data and the forecast value of the boundary, therefore introducing uncertainty in the prediction results. Tide tables ignore the effect of the residual water level, which is usually significant. Therefore, to solve this problem, a water level forecasting method for the regional short-term (3 h) is proposed in this study. First, a simplified MIKE21 flow model (FM) was established to construct the regional major astronomical tides after subdividing the model residuals into stationary constituents (surplus astronomical tides, simulation deviation) and nonstationary constituents (residual water level). Harmonic analysis (HA) and long short-term memory (LSTM) were adopted to forecast these model residuals, respectively. Finally, according to different spatial background information, the prediction for each composition was corrected by the inverse distance weighting (IDW) algorithm and its improved IDW interpolation algorithm based on signal energy and the spatial distance (IDWSE) from adjacent observation stations to nonmeasured locations. The developed method was applied to Narragansett Bay in Rhode Island. Compared with the assimilation model, the root-mean-square error (RMSE) of the proposed method decreased from 12.3 to 5.0 cm, and R2 increased from 0.932 to 0.988. The possibility of adding meteorological features into the LSTM network was further explored as an extension of the prediction of the residual water level. The results show that the accuracy was limited to a moderate level, which is related to the difficulty presented by using only wind features to completely characterize the regional dynamic energy equilibrium process.

scholarly journals Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping

2019 ◽  
Vol 23 (6) ◽  
pp. 2779-2794 ◽  
Author(s):  
Huayang Cai ◽  
Hubert H. G. Savenije ◽  
Erwan Garel ◽  
Xianyi Zhang ◽  
Leicheng Guo ◽  
...  
Keyword(s):  
Water Level ◽  
River Discharge ◽  
Yangtze River ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
Residual Water ◽  
The Yangtze River ◽  
The Yangtze River Estuary ◽  
Seasonal Behaviour ◽  
Residual Water Level

Abstract. As a tide propagates into the estuary, river discharge affects tidal damping, primarily via a friction term, attenuating tidal motion by increasing the quadratic velocity in the numerator, while reducing the effective friction by increasing the water depth in the denominator. For the first time, we demonstrate a third effect of river discharge that may lead to the weakening of the channel convergence (i.e. landward reduction of channel width and/or depth). In this study, monthly averaged tidal water levels (2003–2014) at six gauging stations along the Yangtze River estuary are used to understand the seasonal behaviour of tidal damping and residual water level slope. Observations show that there is a critical value of river discharge, beyond which the tidal damping is reduced with increasing river discharge. This phenomenon is clearly observed in the upstream part of the Yangtze River estuary (between the Maanshan and Wuhu reaches), which suggests an important cumulative effect of residual water level on tide–river dynamics. To understand the underlying mechanism, an analytical model has been used to quantify the seasonal behaviour of tide–river dynamics and the corresponding residual water level slope under various external forcing conditions. It is shown that a critical position along the estuary is where there is maximum tidal damping (approximately corresponding to a maximum residual water level slope), upstream of which tidal damping is reduced in the landward direction. Moreover, contrary to the common assumption that larger river discharge leads to heavier damping, we demonstrate that beyond a critical value tidal damping is slightly reduced with increasing river discharge, owing to the cumulative effect of the residual water level on the effective friction and channel convergence. Our contribution describes the seasonal patterns of tide–river dynamics in detail, which will, hopefully, enhance our understanding of the nonlinear tide–river interplay and guide effective and sustainable water management in the Yangtze River estuary and other estuaries with substantial freshwater discharge.

scholarly journals Storm Surge Prediction Based on Long Short-Term Memory Neural Network in the East China Sea

2021 ◽  
Vol 12 (1) ◽  
pp. 181
Author(s):  
Kuo Chen ◽  
Cuiping Kuang ◽  
Lei Wang ◽  
Ke Chen ◽  
Xuejian Han ◽  
...  
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
Yangtze River ◽  
Short Term Memory ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
The East China Sea ◽  
Short Term ◽  
The Yangtze River Estuary ◽  
Long Short Term Memory

As an area frequently suffering from storm surge, the Yangtze River Estuary in the East China Sea requires fast and accurate prediction of water level for disaster prevention and mitigation. Due to storm surge process being affected by the long-term and short-term correlation of multiple factors, this study attempts to introduce a data-driven idea into the water level prediction during storm surge. By collecting the observed meteorological data and water level data of 12 typhoons from 1986 to 2016 at the Lusi tidal station of Jiangsu Province, China near the north branch of the Yangtze River Estuary, a Long Short-Term Memory (LSTM) neural network model was constructed by using multi-factor time series to predict the water level during the storm surge period. This study concludes that the LSTM model performs precisely for 1 h prediction of water level during the storm surge period and it can provide a 15 h prediction of water level within a limited error, and the prediction performance of the LSTM model is visibly superior to the four traditional ML models by 41% in terms of Accuracy Coefficient.

Impact of River-Tide Dynamics on the Temporal-Spatial Distribution of Residual Water Level in the Pearl River Channel Networks

2018 ◽  
Vol 41 (7) ◽  
pp. 1885-1903 ◽  
Author(s):  
Huayang Cai ◽  
Qingshu Yang ◽  
Zihao Zhang ◽  
Xiaojuan Guo ◽  
Feng Liu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Water Level ◽  
River Channel ◽  
Pearl River ◽  
Residual Water ◽  
Channel Networks ◽  
The Pearl River ◽  
Residual Water Level

scholarly journals The Effect of Tropical Cyclone Nicholas (11–20 February 2008) on Sea Level Anomalies in Indonesian Waters

2020 ◽  
Vol 8 (11) ◽  
pp. 948
Author(s):  
Nining Sari Ningsih ◽  
Farrah Hanifah ◽  
Tika Sekar Tanjung ◽  
Laela Fitri Yani ◽  
Muchamad Al Azhar
Keyword(s):  
Tropical Cyclone ◽  
Water Level ◽  
Sea Level ◽  
Atmospheric Pressure ◽  
Water Levels ◽  
Western Coast ◽  
Residual Water ◽  
Southern Coast ◽  
Sea Levels ◽  
Residual Water Level

As reported extensively in both electronic and print media in Indonesia, high wave and anomalously high sea level phenomena occurred in February 2008 in Indonesian waters, mainly along the western coast of Sumatra and the southern coasts of Java-Bali. Tropical Cyclone (TC) Nicholas, occurring in northwestern coastal waters of Australia between 11 and 20 February 2008, might have contributed to the existence of these phenomena in the Indonesian region. This study focused on investigating the effect of TC Nicholas on the increases in sea levels in the Indonesian waters by analyzing residual water levels (non-astronomic tide). In this regard, a storm tide event (the sum of the astronomical tide and storm surge generated by the TC Nicholas) was simulated in this region using the Regional Ocean Modeling System (ROMS). The residual water levels were obtained by removing the tidal part (astronomic tide) from the ROMS simulated total water levels. In addition, to confirm possible influences of TC Nicholas, a lagged correlation analysis was applied between atmospheric pressure at the center of TC Nicholas and residual water level oscillations in the Indonesian waters. It was found that the residual water levels showed a strong correlation with the atmospheric pressure at the center of TC Nicholas in some areas of the Indonesian seas, such as the western coast of Sumatra, the southern coast of Java, Lesser Sunda Islands, and the southern coast of Papua. The increased sea levels on the western coast of Sumatra are up to 16 cm, with TC Nicholas leading the residual water level by 4.18 days (TL: time lag). Meanwhile, they are up to 20 cm (TL = 5.75 days), 21 cm (TL = 1.12 days), and 38 cm (TL = 3.96 days) on the southern coast of Java, the Lesser Sunda Islands, and the southern coast of Papua, respectively. The results of this study could be used as an initial assessment to investigate the most vulnerable Indonesian coastal areas to the impact of the TC and they might be significantly beneficial for designing both a proper disaster risk reduction program and investment policies in the region, particularly in the context of flood risk reduction and adaptation.

Water Thickness Gaging in a Bellows Tube Using Special UT Shoes & an Immersion Ultrasonic System

2006 ◽  
Vol 321-323 ◽  
pp. 468-471
Author(s):  
Kil Mo Koo ◽  
Sang Baik Kim ◽  
In Chul Lim ◽  
Chul Moo Sim ◽  
Yong Moo Cheong ◽  
...  
Keyword(s):  
Water Level ◽  
Complex Structure ◽  
Residual Water ◽  
Ultrasonic Technique ◽  
Considerable Depth ◽  
Residual Water Level

In this experiment, a residual water level gaging in a bellows tube is implemented by appling the immersion ultrasonic technique. The bellows tube is located in a complex structure. Since it is located at considerable depth implemented, it is difficult to approach it from the outside working area, which has a residual water level after a drainage of the water in it, because a structure like the bellows has a peak and mold shape.

Comparison between the skew surge and residual water level along the coastline of China

2021 ◽  
Vol 598 ◽  
pp. 126299
Author(s):  
Jianlong Feng ◽  
Danqing Li ◽  
Delei Li ◽  
Jing Zhang ◽  
Liang Zhao
Keyword(s):  
Water Level ◽  
Residual Water ◽  
Residual Water Level
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