Random walk method for modeling water exchange: An application to coastal zone environmental management

Lv, Xiangcui; Liu, Bo; Yuan, Daoxian; Feng, Huan; Teo, Fang Yenn

doi:10.1016/j.jher.2015.07.001

Cited by 11 publications

(4 citation statements)

References 18 publications

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“…Simple and straightforward step simulations are important in data modeling [82]. Maps generated for spatio-temporal analysis provide a clearer picture of the regions that required attention under current climate change [83].…”

Section: Development Of Php Programsmentioning

confidence: 99%

Sequential Data Processing for IMERG Satellite Rainfall Comparison and Improvement Using LSTM and ADAM Optimizer

et al. 2023

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This study introduces a systematic methodology whereby different technologies were utilized to download, pre-process, and interactively compare the rainfall datasets from the Integrated Multi-Satellite Retrievals for Global Precipitation Mission (IMERG) satellite and rain gauges. To efficiently handle the large volume of data, we developed automated shell scripts for downloading IMERG data and storing it, along with rain gauge data, in a relational database system. Hypertext pre-processor (pHp) programs were built to visualize the result for better analysis. In this study, the performance of IMERG estimations over the east coast of Peninsular Malaysia for the duration of 10 years (2011–2020) against rain gauge observation data is evaluated. Moreover, this study aimed to improve the daily IMERG estimations with long short-term memory (LSTM) developed with Python. Findings show that the LSTM with Adaptive Moment Estimation (ADAM) optimizer trained against the mean square error (MSE) loss enhances the accuracy of satellite estimations. At the point-to-pixel scale, the correlation between satellite estimations and ground observations was increased by about 15%. The bias was reduced by 81–118%, MAE was reduced by 18–59%, the root-mean-square error (RMSE) was reduced by 1–66%, and the Kling–Gupta efficiency (KGE) was increased by approximately 200%. The approach developed in this study establishes a comprehensive and scalable data processing and analysis pipeline that can be applied to diverse datasets and regions encountering similar domain-specific challenges.

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Section: Development Of Php Programsmentioning

confidence: 99%

Sequential Data Processing for IMERG Satellite Rainfall Comparison and Improvement Using LSTM and ADAM Optimizer

et al. 2023

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“…Among all weather parameters, air temperature is generally considered to be the most influential on the overall climate pattern of an area, as it significantly impacts (accelerates) the hydrological cycle by expediting the movement of water vapors from land to atmosphere (via increased evapotranspiration), and also influences the other components of weather system including the air pressure gradient and wind circulation, evaporating potential of atmosphere, air moisture availability, cloud cover, and the precipitation characteristics [6]. During the last century, the mean global air temperature has increased by about 0.74 °C [7,8], whereas regionally, the mean…”

Section: Introductionmentioning

confidence: 99%

Investigation of Causes and Characteristics of Monsoon Extremes in Pakistan: A Case Study for Summer Monsoon 2022

H. Shah,

Qureshi,

Yassin

et al. 2023

TJIEM

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Apart from the long-term changes in the normal weather patterns, the occurrence of short-lived extreme meteorological events has also emerged as a major consequential aspect of global climate change. Pakistan being listed among the most susceptible nations to the changing global climate patterns has witnessed an increasing frequency of extreme summer monsoon rainfall events during the past decades. This study was conducted to comprehensively investigate the major meteorological factors that lead to the extreme summer monsoon precipitation in Pakistan in 2022. The results obtained from the study showed that in April 2022, Balochistan observed 1.5 to 6 °C, Sindh observed 2 to 4 °C, while Punjab and KPK observed 3 to 5.5 °C above normal temperatures (1961-2010). In May, Sindh and Balochistan observed 1 to 3.5 °C above normal temperature, consequently causing intense low-pressure conditions over the area. In April 2022, about 1 to 2.5 mb below normal air pressure was found in Sindh and Balochistan, while in May, about 1 to 3 mb below normal pressure was found over the area. The summer monsoon 2022 analysis showed that in July, about 0.2 to 4 mb above normal vapor pressure was found in Sindh and Balochistan, while Punjab reported 1 to 5 mb above normal vapor pressure. In August, Balochistan and Sindh recorded 1 to 5 mb, while Punjab recorded 1.5 to 5 mb above normal vapor pressure. Further, the extreme monsoon precipitation was more concentrated in Sindh and Balochistan, as compared to the other provinces. In July 2022, Sindh received 307 %, Balochistan received 450 %, while Punjab received 116% above normal rainfall. In August, Sindh received the highest rainfall (+726% above normal) followed by Balochistan with the rainfall departure as +590%. Conclusively, it was established that the unusual pre-monsoon heating over the arid plains in Sindh, Balochistan and southern Punjab resulted in the development of intense trough over the area, that pulled excess moisture from the Indian ocean, causing high vapor pressures

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“…The strength of water exchange is influenced by the local hydrodynamic condition, which is determined by the upstream freshwater runoff and downstream sea tide. Many parameters are proposed to quantify the ability of water exchange, including the flushing time, turnover time, exchange rate, and so forth (He et al, 2021; Lv et al, 2016; Montano‐Ley & Federico Soto‐Jimenez, 2019). The freshwater runoff has a vital impact on the water exchange, and the flushing time and turnover time tend to be large with small water exchange in the dry seasons (Liu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Combined effects of runoff increase and sea level rise on the water exchange and saltwater intrusion for an estuary bay in non‐flood season

Zhou

Zhang

et al. 2022

Hydrological Processes

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Estuary bays are vulnerable to salinization effects due to relative sea level rise and modification in upland hydrology owing to a variety of factors. Much research has evaluated the one‐sided effect of runoff discharge or sea level on the water exchange and saltwater intrusion for an estuary, while their combined effects have not been evaluated, especially for an estuary bay with narrow river mouth. Taking the Wanquan Estuary Bay (WEB), China, as study case, this paper has revealed the long‐term significant increasing trend of freshwater runoff in non‐flood season during years 1956–2017 using the Man‐Kendall trend analysis, robust principle component regression and Theil–Sen's estimator. A 3‐D hydrodynamic‐salinity‐tracer numerical model is built and calibrated based on the finite‐volume community ocean model, and the effects of runoff increase and sea level rise on the water exchange and saltwater intrusion are investigated. This paper shows the following: (1) The freshwater runoff during non‐flood season in WEB shows significant long‐term increasing trend, and the mean changing magnitude is 0.4546 m3/s/a. (2) The increased runoff accelerates the water exchange, and reduces the turn‐over time and saltwater intrusion in the WEB. The sea level rise reduces the water exchange and increase the saltwater intrusion. (3) For the estuary bay with narrow river mouth, the salinity distributions show more vertical stratification characteristics. The freshwater runoff has power relationships with the average turnover time and salinity, and the sea level has linear relationships. (4) The water exchange and salinity of an estuary bay is more vulnerable to the changed runoff than the sea level rise, while the impacts of sea level rise would increase for estuaries with wide river mouth. This paper provides support for the freshwater exploitation and utilization in estuary bay under the background of climate change and sea level rise.

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Random walk method for modeling water exchange: An application to coastal zone environmental management

Cited by 11 publications

References 18 publications

Sequential Data Processing for IMERG Satellite Rainfall Comparison and Improvement Using LSTM and ADAM Optimizer

Sequential Data Processing for IMERG Satellite Rainfall Comparison and Improvement Using LSTM and ADAM Optimizer

Investigation of Causes and Characteristics of Monsoon Extremes in Pakistan: A Case Study for Summer Monsoon 2022

Combined effects of runoff increase and sea level rise on the water exchange and saltwater intrusion for an estuary bay in non‐flood season

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