scholarly journals The mechanism of after-runner storm surge along the Northern coast of Vietnam

2017 ◽  
Vol 17 (4B) ◽  
pp. 208-216
Author(s):  
Nguyen Ba Thuy
Keyword(s):  
Wind Field ◽  
Pressure Field ◽  
Research Result ◽  
Wrf Model ◽  
Coupled Model ◽  
Storm Surges ◽  
Observation Data ◽  
Northern Coast ◽  
Before And After ◽  
Coast Of Vietnam

In this study, the mechanism of sea level rise along the Northern coast of Vietnam after the landfall of the Typhoon Kalmaegi (September/2014) at Quang Ninh province was analyzed based on the observation data and the results of a coupled model of surge, wave and tide (called SuWAT), by using asymmetric and symmetric wind and pressure fields. For the asymmetric wind and pressure field, the Weather Research and Forecasting (WRF) model was used, while for the symmetric wind and pressure field, a parametric wind and pressure model was used. In the case using wind fields from the WRF model, the case that did not consider the effect of tail wind field after the typhoon landfall was also conducted in order to assess the role of the wind field before and after the typhoon landfall on the surge. The results showed that the case using wind and pressure field from the WRF model showed better agreement with observation data, because the WRF model well simulated the wind and pressure field before and after the typhoon landfall. The strong tail wind mainly caused the high surge in the area. This research result will be useful in warning and forecasting storm surges in the area.

scholarly journals Verification of the Reliability of Offshore Wind Resource Prediction Using an Atmosphere–Ocean Coupled Model

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 254
Author(s):  
Minhyeop Kang ◽  
Kyungnam Ko ◽  
Minyeong Kim
Keyword(s):  
Wind Speed ◽  
Energy Production ◽  
Prediction Models ◽  
Wrf Model ◽  
Coupled Model ◽  
Sea Surface ◽  
Offshore Wind ◽  
Wind Effect ◽  
Observation Data ◽  
Wind Resource

An atmosphere–ocean coupled model is proposed as an optimal numerical prediction method for the offshore wind resource. Meteorological prediction models are mainly used for wind speed prediction, with active studies using atmospheric models. Seawater mixing occurring at sea due to solar radiation and wind intensity can significantly change the sea surface temperature (SST), an important variable for predicting wind resources and energy production, considering its wind effect, within a short time. This study used the weather research forecasting and ocean mixed layer (WRF-OML) model, an atmosphere–ocean coupled model, to reflect time-dependent SST and sea surface fluxes. Results are compared with those of the WRF model, another atmospheric model, and verified through comparison with observation data of a meteorological mast (met-mast) at sea. At a height of 94 m, the wind speed predicted had a bias and root mean square error of 1.09 m/s and 2.88 m/s for the WRF model, and −0.07 m/s and 2.45 m/s for the WRF-OML model, respectively. Thus, the WRF-OML model has a higher reliability. In comparing to the met-mast observation data, the annual energy production (AEP) estimation based on the predicted wind speed showed an overestimation of 15.3% and underestimation of 5.9% from the WRF and WRF-OML models, respectively.

scholarly journals Fusion of Simulated and Observational Temperature Data in the Beijing-Tianjin-Hebei Region Based on High-Accuracy Surface Modeling

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Yu Liu ◽  
Tianxiang Yue ◽  
Yimeng Jiao ◽  
Yapeng Zhao ◽  
Zhengyi Bao
Keyword(s):  
Wrf Model ◽  
Absolute Error ◽  
High Accuracy ◽  
Surface Modeling ◽  
Temperature Fields ◽  
Observation Data ◽  
Human Society ◽  
Fusion Data ◽  
Before And After ◽  
Temperature Records

Temperature changes have a major impact on all aspects of human society and have attracted global attention. The scarcity of observation data and the inaccuracy of the models make obtaining accurate temperature distributions a challenge. This study introduces high-accuracy surface modeling (HASM) combined with temperature simulations from the Weather Research and Forecasting (WRF) model and temperature records from observation stations to investigate the spatiotemporal characteristics of temperature in the Beijing-Tianjin-Hebei region during the period of 1956–2005. Leave-one-out cross-validation is applied to verify the temperature fields before and after the fusion of the models. The results indicate that the WRF model has a limited ability to simulate temperature conditions, but the overall deviation across the region is relatively large. The fusion results of the HASM decrease the mean absolute error (MAE) and the root-mean-square error (RMSE) by half in most instances, and the correlation between the fusion data and observation data is approximately 0.01–0.03 higher than that with the WRF simulation data. Based on the fusion data, obvious warming trends are observed during 1976–2005. In general, temperatures in spring, summer, and autumn increase rapidly from 1996 to 2005 but from 1976 to 1995 in winter. The substantial fluctuations in the interannual temperature during 1996–2005 in summer, autumn, and winter may be related to the frequent occurrence of extreme weather. The spatial distribution of temperature change differs in each season during 1956–1995. A dramatic increase in temperature occurs in the western part of the study area during 1996–2005 but with no seasonal difference.

Tendencias de los Sistemas de Información Geográfica. Alcances y limitaciones

2019 ◽  
pp. 8-13
Author(s):  
Erika Alarcón-Ruiz ◽  
Luis Daniel Ordoñez-Pacheco
Keyword(s):  
Information System ◽  
Global Positioning System ◽  
Information Technologies ◽  
Research Result ◽  
Observation Data ◽  
Positioning System ◽  
Global Positioning ◽  
It Support ◽  
Sistemas De Informacion ◽  
Geographical Characteristics

The synergy that exists between geography, computer science and advances in information technologies has allowed the consolidation of geographic science from an integral perspective and allowing the correlation of basic elements for the analysis of the territory in an applied science called Geomatics. The research result in this field are linked to the collection and analysis of observation data, which are collected through satellites, ground stations, ocean buoys, the global positioning system (GPS), aerial sensors (photogrammetry), Weather balloons and traditional techniques for measuring and describing land. To process this data, Geographic Information System (GIS) has been developed, involving aspects of hardware and software with applications that are as diverse and varied as the users themselves. Also, presents an analysis of the main SIG's, its main features and applications , because despite having a scientific structure and IT support that allows one effective land management in rural or urban type, yet there is a wide area of opportunity solving and Previ or endo the emergence of conflicts interactions between human activities and geographical characteristics.

scholarly journals Mangrove Forest Landcover Changes in Coastal Vietnam: A Case Study from 1973 to 2020 in Thanh Hoa and Nghe An Provinces

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 637
Author(s):  
Huong Thi Thuy Nguyen ◽  
Giles E. S. Hardy ◽  
Tuat Van Le ◽  
Huy Quoc Nguyen ◽  
Hoang Huy Nguyen ◽  
...  
Keyword(s):  
Mangrove Forest ◽  
Monsoon Season ◽  
Coastal Development ◽  
Northern Coast ◽  
Mangrove Forests ◽  
Visual Interpretation ◽  
Mangrove Restoration ◽  
Coast Of Vietnam ◽  
Landsat Satellite

Mangrove forests can ameliorate the impacts of typhoons and storms, but their extent is threatened by coastal development. The northern coast of Vietnam is especially vulnerable as typhoons frequently hit it during the monsoon season. However, temporal change information in mangrove cover distribution in this region is incomplete. Therefore, this study was undertaken to detect change in the spatial distribution of mangroves in Thanh Hoa and Nghe An provinces and identify reasons for the cover change. Landsat satellite images from 1973 to 2020 were analyzed using the NDVI method combined with visual interpretation to detect mangrove area change. Six LULC classes were categorized: mangrove forest, other forests, aquaculture, other land use, mudflat, and water. The mangrove cover in Nghe An province was estimated to be 66.5 ha in 1973 and increased to 323.0 ha in 2020. Mangrove cover in Thanh Hoa province was 366.1 ha in 1973, decreased to 61.7 ha in 1995, and rose to 791.1 ha in 2020. Aquaculture was the main reason for the loss of mangroves in both provinces. Overall, the percentage of mangrove loss from aquaculture was 42.5% for Nghe An province and 60.1% for Thanh Hoa province. Mangrove restoration efforts have contributed significantly to mangrove cover, with more than 1300 ha being planted by 2020. This study reveals that improving mangrove restoration success remains a challenge for these provinces, and further refinement of engineering techniques is needed to improve restoration outcomes.

scholarly journals Stock Market Reaction to COVID-19: Evidence in Customer Goods Sector with the Implication for Open Innovation

2020 ◽  
Vol 6 (4) ◽  
pp. 99
Author(s):  
Zaky Machmuddah ◽  
St. Dwiarso Utomo ◽  
Entot Suhartono ◽  
Shujahat Ali ◽  
Wajahat Ali Ghulam
Keyword(s):  
Stock Prices ◽  
Stock Price ◽  
Practical Implication ◽  
Efficient Market Hypothesis ◽  
Future Research ◽  
Observation Data ◽  
Economic Sectors ◽  
Significant Difference ◽  
Before And After ◽  
Long Term Impact

The coronavirus pandemic has spread all over the world, affecting both the health and economic sectors. The aim of this research was to observe stock prices of customer goods before and after the COVID-19 pandemic using event study and the comparison test. The sample included data of daily closing stock prices and volume of stock trade during the three months before (−90 days) and after (+90 days) the occurrence of the COVID-19 pandemic ongoing, totaling 2670 observation data both before and after the COVID-19 pandemic, for a total of 5340. The research findings indicate a significant difference between the daily closing stock price and volume of stock trade before and after the COVID-19 pandemic. The current research has both theoretical and practical implications: the findings strengthen the efficient market hypothesis, which states that the more complete the provided information, the more efficient the market. The practical implication is that investors should be careful when choosing to invest. Investors should choose customer goods sector companies that provide products that are much needed by customers, for example, pharmacy, food, beverages, etc. Future research is needed to investigate the long-term impact of the pandemic on the economy.

scholarly journals Lively Social Space, Well-Being Activity, and Urban Design: Findings From a Low-Cost Community-Led Public Space Intervention

2016 ◽  
Vol 49 (6) ◽  
pp. 685-716 ◽  
Author(s):  
Jamie Anderson ◽  
Kai Ruggeri ◽  
Koen Steemers ◽  
Felicia Huppert
Keyword(s):  
Public Space ◽  
Urban Design ◽  
Design Research ◽  
Local Community ◽  
Social Space ◽  
Low Cost ◽  
Well Being ◽  
Observation Data ◽  
Before And After ◽  
The Impact

Empirical urban design research emphasizes the support in vitality of public space use. We examine the extent to which a public space intervention promoted liveliness and three key behaviors that enhance well-being (“connect,” “be active,” and “take notice”). The exploratory study combined directly observed behaviors with self-reported, before and after community-led physical improvements to a public space in central Manchester (the United Kingdom). Observation data ( n = 22,956) and surveys (subsample = 212) were collected over two 3-week periods. The intervention brought significant and substantial increases in liveliness of the space and well-being activities. None of these activities showed increases in a control space during the same periods. The findings demonstrate the feasibility of the research methods, and the impact of improved quality of outdoor neighborhood space on liveliness and well-being activities. The local community also played a key role in conceiving of and delivering an effective and affordable intervention. The findings have implications for researchers, policy makers, and communities alike.

scholarly journals Modeling Study on the Asymmetry of Positive and Negative Storm Surges along the Southeastern Coast of China

2021 ◽  
Vol 9 (5) ◽  
pp. 458
Author(s):  
Dongdong Chu ◽  
Haibo Niu ◽  
Wenli Qiao ◽  
Xiaohui Jiao ◽  
Xilin Zhang ◽  
...  
Keyword(s):  
Storm Surge ◽  
Pressure Field ◽  
Three Dimensional ◽  
Storm Surges ◽  
Ocean Model ◽  
Central Pressure ◽  
Linear Interaction ◽  
Southeastern Coast ◽  
Zhoushan Archipelago ◽  
Wind Intensity

In this paper, a three-dimensional storm surge model was developed based on the Finite Volume Community Ocean Model (FVCOM) by the hindcasts of four typhoon-induced storm surges (Chan-hom, Mireille, Herb, and Winnie). After model validation, a series of sensitivity experiments were conducted to explore the effects of key parameters in the wind and pressure field (forward speed, radius of maximum wind (RMW), inflow angle, and central pressure), typhoon path, wind intensity, and topography on the storm surge and surge asymmetry between sea level rise (positive surge) and fall (negative surge) along the southeastern coast of China (SCC). The model results show that lower central pressure and larger RMW could lead to stronger surge asymmetry. A larger inflow angle results in a stronger surge asymmetry. In addition, the path of Chan-hom is the most dangerous path type for the Zhoushan Archipelago area, and that of Winnie follows next. The model results also indicate that the non-linear interaction between wind field and pressure field tends to weaken the peak surge elevation. The effect of topography on storm surges indicates that the peak surge elevation and its occurrence time, as well as the surge asymmetry, increase with a decreasing slope along the SCC.

scholarly journals Assessment of Extreme Storm Surges over the Changjiang River Estuary from a Wave–Current Coupled Model

2021 ◽  
Vol 9 (11) ◽  
pp. 1222
Author(s):  
Yutao Chi ◽  
Zengrui Rong
Keyword(s):  
Return Period ◽  
River Estuary ◽  
Coupled Model ◽  
Storm Surges ◽  
Distribution Model ◽  
Changjiang River ◽  
Changjiang River Estuary ◽  
The Changjiang River ◽  
The Changjiang River Estuary ◽  
The Impact

Disastrous storm surges and waves caused by typhoons are major marine dynamic disasters affecting the east China coast and the Changjiang River Estuary, especially when they occur coincidentally. In this study, a high-resolution wave–current coupled model consisting of ADCIRC (Advanced Circulation) and SWAN (Simulating Waves Nearshore) was established and validated. The model shows reasonable skills in reproducing the surge levels and waves. The storm surges and associated waves are then simulated for 98 typhoons affecting the Changjiang River Estuary over the past 32 years (1987–2018). Two different wind fields, the ERA reanalysis and the ERA-based synthetic wind with a theoretical typhoon model, were adopted to discern the potential uncertainties associated with winds. Model results forced by the ERA reanalysis show comparative skills with the synthetic winds, but differences may be relatively large in specific stations. The extreme surge levels with a 50-year return period are then presented based on the coupled model results and the Gumbel distribution model. Higher risk is presented in Hangzhou Bay and the nearshore region along the coast of Zhejiang. Comparative runs with and without wave effects were conducted to discern the impact of waves on the extreme surge levels. The wave setup contributes to 2–12.5% of the 50-year extreme surge level. Furthermore, the joint exceedance probabilities of high surge levels and high wave height were evaluated with the Gumbel–logistic statistic model. Given the same joint return period, the nearshore region along the coast of Zhejiang is more vulnerable with high surges and large waves than the Changjiang River Estuary with large waves and moderate surges.

scholarly journals EFEKTIVITAS MODEL PEMBELAJARAN JIGSAW PADA KETERAMPILAN MENULIS BAHASA PERANCIS

2020 ◽  
Vol 20 (1) ◽  
pp. 121-131
Author(s):  
Tri Indri Hardini ◽  
Iim Siti Karimah ◽  
Adelya Erliani
Keyword(s):  
Research Result ◽  
Writing Skills ◽  
Posttest Score ◽  
Education Students ◽  
Writing Ability ◽  
Argumentative Text ◽  
Before And After ◽  
French Education ◽  
Positive Impression ◽  
Test Result

This research aims to describe student’s writing ability before and after using Jigsaw model, the effectiveness of Jigsaw model in improving writing skills, and the opinion of students. This study applies descriptive quantitative method in form of pre-experimental design. Instruments that are used in the form of tests and questionnaires. The sample of this research is 32 characteristics writing skill of 6th  semester French Education students. Based on the research result, the researcher can conclude that the students have been able to write the argumentative text nicely. The test result showed that the average test score after using the Jigsaw model is 8.9. It means, the average posttest score is higher than the average pretest score, up to 1.7%. Meanwhile, the results of the questionnaire show that students like writing but they find so much difficulty in making a writing or a text, and most students give a positive impression for the Jigsaw model.

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