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Coastal and Marine Environments

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Nguyễn Gia Hào

Academic year: 2023

Chia sẻ "Coastal and Marine Environments"

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Questions regarding the use of the book should be directed to the Rights and Permissions Department of INTECHOPEN LIMITED (permissions@intechopen.com). Significance of Mesoscale Warm Core Eddy on the Marine and Coastal Environment of the Bay of Bengal.

Introduction

Later, in the 1980s, a third dam (Beliche) was built, followed by the construction of two more dams (Funcho and Odeleite) in the 1990s, and recently a sixth (Odelouca). However, these dams also suffer from water shortages during the hottest months of the year, which coincide with periods of higher consumption.

Traditional and contemporary decision-making procedures in coastal management processes

In fact, until the 1980s, the construction of works in coastal areas essentially followed the schematic diagram shown in Figure 2. Levels of public action and participation in decision-making on coastal issues.

Figure 5 shows how these systems complement each other for the success of an  intervention located in the coastal zone
Figure 5 shows how these systems complement each other for the success of an intervention located in the coastal zone

Levels of operation and public participation in coastal issues decisions As is clear from the foregoing considerations, the inclusion of different dis-

Prospects for future accommodation in coastal areas

At all stages, different stakeholders should be involved and heard in the decision-making process. For example, many houses are built on stilts along the west coast of the United States.

Figure 12 shows the good performance of an artificial submerged reef taking  advantage of the wave refraction effect
Figure 12 shows the good performance of an artificial submerged reef taking advantage of the wave refraction effect

Conclusions

Information systems used for the integration of knowledge in the coastal management of the Central Region. Potential impacts of mean sea level rise on the hydrodynamics of the Douro River estuary.

Part I: background and preliminaries 1 Introduction

Data sources

Again, most of the results we present are limited to the period ending December 2013. Plots of the monthly mean SST data from Hopkins Marine Station, inside Monterey Bay, and from ICOADS, adjacent to the central California coast, outside the bay, are shown in Figure 3. Finally, we apply singular estimate spectrum analyzes together with long-term estimate spectrum analysis to achieve the data-dependent trend analysis of the data.

In this study, the degree of the local polynomial was set to quadratic. At the level of detail shown in Figure 3, the relative importance of the annual cycle is immediately apparent.

Data representativeness

The goal is to choose α large enough to achieve as smooth as possible without distorting the underlying patterns in the data [22]. In addition, as previously mentioned, there was a large increase in SST in 2014, which is clearly visible in the data inside and outside the bay. Based on a previous comparison of SST data between HMS and Santa Cruz, located at the northern end of Monterey Bay (Figure 1), Breaker [19] concluded that data from HMS are generally representative of SST data collected elsewhere in the bay, consistent with the results presented here.

Spatial anomalies in the SST observations obtained over the offshore domain lead to anomalies in the monthly mean values ​​that are calculated. If the non-buoy data were randomly distributed across the domain, we would find this result encouraging as it suggests some degree of spatial homogeneity in the data.

Long-term trends .1 Background

A trend implies first-order non-stationarity, so removing it can turn the data into a stationary process. This method performed well in obtaining long-term trends, regardless of the degree to which the data were non-linear. One common definition of a trend is a smoothly varying function whose first derivative does not change sign [27].

The number of modes selected is called the window length and determines the resolution of the decomposition. The problem is further reduced in the noise-supported version, i.e. in EEMD, because the slopes of the IMFs tend to be more evenly distributed in the ensemble.

Part II: analyses, results, and discussion 1 Analyses

Ocean processes and time scales .1 Seasonal variability

The green dashed line shows the estimated true trend based on the average of the SSA and EEMD trends. Outside the gulf, SSTs are actually falling, albeit with significant variations along the way, until the end of the record (December 2013). These maxima co-occur with El Nino warming episodes with the addition of the co-occurrence of the first major maximum in the PDO index in or around 1940 (Figure 12).

A smoothed version of the Pacific Decadal Oscillation Index (°C) is shown (dotted curve - black) along with a smoothed version of the SST record from within the bay (dotted curve - green). However, the changes in physical properties associated with the phase change of the BOB are much shorter.

Discussion

Based on these decompositions (Figure 11), significant warming in the bay has occurred only in summer since the 1970s. Of particular note, our decompositions showed that the variance of the BOB, while relatively small compared to the other modes, is much larger within the bay than outside the bay. As a result, we would expect the impact on long-term trends to be greater in the bay.

That this is the case is clearly shown in Figure 9 where the maximum value of the long-term trend within the bay occurs in the early 1990s and thus coincides with one of the two main maxima in the PDO index (Figure 12). Finally, the long-term trend in SST within the bay departs significantly from the trend further offshore over the 94-year period from 1920 to 2014.

Conclusions

The meaning of the warm (cold) core eddy is that it contains a higher (lower) temperature with increased (lower) sea level in the middle. The location of the BoB in the global and regional outlook is shown in Figure 1a. Moreover, the deviation of SST and wind speed values ​​from the fitted line is higher (lower) for the low (high) wind conditions.

This chapter addresses the mesoscale warm core eddies and high-resolution products prominence in the Bay of Bengal. In situ observations are used to analyze and quantify the errors of the AMSR-2 during the WCE over the northern BoB. This study aims to understand the main factors that govern the silting problem in the entrance of the Suez Canal port.

Figure 4 shows the statistical analyses of AMSR-2 SST and wind speed with respect to the in-situ observations
Figure 4 shows the statistical analyses of AMSR-2 SST and wind speed with respect to the in-situ observations

Study site description

The canal supports approximately 8% of the world's shipping traffic with almost 50 ships traveling through the canal every day. It is capable of accommodating ships of up to 150,000 tons fully loaded (Suez Canal Authority personal communication). The results help smooth out bottlenecks and ease the passage of heavily loaded ships along the canal.

As the important geographical location of Port Said Governorate, it has many activities in national and regional development. Consequently, it has valuable resources such as the Mediterranean Sea, Red Sea beaches, lakes, protected areas and historical and archaeological sites.

Remote sensing techniques and results 1 Change detection

Image classification

Unsupervised classification was performed on three image datasets separately using the histogram peak clustering technique to identify dense regions or frequently occurring pixels [13–15]. In general, multispectral classification consists of compressing all the information in a multispectral data set into a single image that shows the main types of surfaces in different colors [16]. Landsat enhanced thematic mapper image classification shows an increased silting problem at the entrance to the Suez Canal port between Figure 3).

Required data for modeling

Extracted shoreline positions

The shoreline positions predicted for modeling were derived from the remote sensing results using the Thematic Map imaging technique. Waves were recorded using a Cassette Acquisition System (CAS); the tide gauge was installed about 1200 m off the west side of the Damietta harbor navigation channel, at a water depth of 12 m. Data provided by the Coastal Research Institute in Alexandria was analyzed to determine wave height, period and direction.

It shows parallel offshore contours with the shoreline trend from 0 to 20 m depth within the coastal zone.

Offshore wave parameters

Bathymetric survey

Results of modeling techniques

MIKE 21 spectral wave

The simulation of shoreline changes, waves, sediment transport and hydrodynamic regime, using Mike 21 HD (Flow Model and Hydrodynamic Module), needs several data sets, which are not changed during all simulation analyses. This data was scanned by AutoCAD 2014 software to be digitized and processed using Civil 3D software to obtain (x, y, z) format and work with the Mike 21 Flow Model. The grid file map was generated from the digital x,y,z file using MIKE 21 to understand the hydrodynamic regime and sediment transport.

The DHI group helped us in this study by giving permission to use the original package of MIKE 21 with a limited license. In order to simulate the growth, transformation of wind-generated waves and swell in offshore coastal areas, MIKE 21 spectral analysis module (SW) was used to obtain two-dimensional wave heights for the study area according to wave bottom interactions and wave structure interactions (foam, breaking, diffraction, [20 wave friction, reflection, breaking) and bottom friction).

MIKE 21 hydrodynamics

The model has coarse triangular mesh at offshore zones and fine triangular mesh at surf zones and study area to get more accurate wave heights with acceptable model run period [21].

MIKE 21 sand transport

Modeling of 10 years of sediment transport during 2008–2018 along the coastal zone of the Suez Canal; (a) accretion along the upstream and entrance, otherwise erosion along the downstream; (b) erosion behind the eastern Jetty; and (c) siltation behind the western jetty. All morphological changes occur due to the coastal drift current, which is created as a result of waves approaching the shoreline at an oblique angle. All morphological changes occur due to the coastal drift current, which is created as a result of waves approaching the shoreline at an oblique angle.

Finally, siltation within the entrance of the Suez Canal can be explained as a result of the movement of waves and currents at the west of Port Said and within the entrance of the Suez Canal. Therefore, if the current comes from shallow depths in the west of the harbor, say in the direction of W-E to deep depths at the entrance of Suez Canal, while carrying sediment load, the velocity gradually decreases near the long western Suez Canal and it starts the sediment load inside the sugary enfigure 5A-CC).

Discussion and conclusion

The ionogram, the record produced by the ionosonde, is a plot of the virtual height of reflection vs. Gallet [13] to produce global maps of the two key ionospheric characteristics related to the maximum electron density in the ionospheric F region. Example of long-term map of MUF over the eastern Mediterranean predicted by SIRM for the Cyprus Ionospheric Forecast Service.

Example of long-term maps of MUF over the Eastern Mediterranean, predicted by SIRM for the Cypriot Ionosphere Forecast Service. GIFINT) [17], one of the space weather pilot projects promoted by the European Space Agency in the Central Mediterranean.

Hình ảnh

Figure 5 shows how these systems complement each other for the success of an  intervention located in the coastal zone
Figure 12 shows the good performance of an artificial submerged reef taking  advantage of the wave refraction effect
Figure 12 shows the good performance of an artificial submerged reef taking  advantage of the wave refraction effect
Figure 4 shows the statistical analyses of AMSR-2 SST and wind speed with respect to the in-situ observations
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