Maintenance dredging in a macrotidal estuary: Modelling and assessment of its variability with hydro-meteorological forcing

2021 ◽  
pp. 107366
Author(s):  
J.P. Lemoine ◽  
P. Le Hir
Keyword(s):  
Meteorological Forcing ◽  
Macrotidal Estuary ◽  
Maintenance Dredging

scholarly journals Measuring compound flood potential from river discharge and storm surge extremes at the global scale

2020 ◽  
Vol 20 (2) ◽  
pp. 489-504 ◽  
Author(s):  
Anaïs Couasnon ◽  
Dirk Eilander ◽  
Sanne Muis ◽  
Ted I. E. Veldkamp ◽  
Ivan D. Haigh ◽  
...  
Keyword(s):  
Storm Surge ◽  
River Discharge ◽  
Flood Hazard ◽  
Joint Probability ◽  
Global Scale ◽  
Statistical Dependence ◽  
Dependence Structure ◽  
Meteorological Forcing ◽  
Continental Scale ◽  
Bivariate Dependence

Abstract. The interaction between physical drivers from oceanographic, hydrological, and meteorological processes in coastal areas can result in compound flooding. Compound flood events, like Cyclone Idai and Hurricane Harvey, have revealed the devastating consequences of the co-occurrence of coastal and river floods. A number of studies have recently investigated the likelihood of compound flooding at the continental scale based on simulated variables of flood drivers, such as storm surge, precipitation, and river discharges. At the global scale, this has only been performed based on observations, thereby excluding a large extent of the global coastline. The purpose of this study is to fill this gap and identify regions with a high compound flooding potential from river discharge and storm surge extremes in river mouths globally. To do so, we use daily time series of river discharge and storm surge from state-of-the-art global models driven with consistent meteorological forcing from reanalysis datasets. We measure the compound flood potential by analysing both variables with respect to their timing, joint statistical dependence, and joint return period. Our analysis indicates many regions that deviate from statistical independence and could not be identified in previous global studies based on observations alone, such as Madagascar, northern Morocco, Vietnam, and Taiwan. We report possible causal mechanisms for the observed spatial patterns based on existing literature. Finally, we provide preliminary insights on the implications of the bivariate dependence behaviour on the flood hazard characterisation using Madagascar as a case study. Our global and local analyses show that the dependence structure between flood drivers can be complex and can significantly impact the joint probability of discharge and storm surge extremes. These emphasise the need to refine global flood risk assessments and emergency planning to account for these potential interactions.

scholarly journals Impact on Ultrafine Particles Concentration and Turbulent Fluxes of SARS-CoV-2 Lockdown in a Suburban Area in Italy

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 407
Author(s):  
Antonio Donateo ◽  
Adelaide Dinoi ◽  
Gianluca Pappaccogli
Keyword(s):  
Ultrafine Particles ◽  
Particle Number ◽  
Ultrafine Particle ◽  
Turbulent Fluxes ◽  
Number Concentration ◽  
Suburban Area ◽  
Observation Site ◽  
Meteorological Forcing ◽  
Restrictive Measures ◽  
Measurement Area

In order to slow the spread of SARS-CoV-2, governments have implemented several restrictive measures (lockdown, stay-in-place, and quarantine policies). These provisions have drastically changed the routines of residents, altering environmental conditions in the affected areas. In this context, our work analyzes the effects of the reduced emissions during the COVID-19 period on the ultrafine particles number concentration and their turbulent fluxes in a suburban area. COVID-19 restrictions did not significantly reduce anthropogenic related PM10 and PM2.5 levels, with an equal decrement of about 14%. The ultrafine particle number concentration during the lockdown period decreased by 64% in our measurement area, essentially due to the lower traffic activity. The effect of the restriction measures and the reduction of vehicles traffic was predominant in reducing concentration rather than meteorological forcing. During the lockdown in 2020, a decrease of 61% in ultrafine particle positive fluxes can be observed. At the same time, negative fluxes decreased by 59% and our observation site behaved, essentially, as a sink of ultrafine particles. Due to this behavior, we can conclude that the principal particle sources during the lockdown were far away from the measurement site.

Implementation of Self-Organizing Maps (SOM) to analyses of environmental parameters and phytoplankton biomass in a macrotidal estuary and artificial lake

2012 ◽  
Vol 93 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Roksana Jahan ◽  
Hyu Chang Choi ◽  
Young Seuk Park ◽  
Young Cheol Park ◽  
Ji Ho Seo ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Algal Blooms ◽  
Suspended Solids ◽  
Inorganic Nitrogen ◽  
Environmental Parameters ◽  
Ecological Data ◽  
Self Organizing Maps ◽  
Macrotidal Estuary ◽  
Phytoplankton Communities ◽  
Self Organizing

Self-Organizing Maps (SOM) have been used for patterning and visualizing ten environmental parameters and phytoplankton biomass in a mactrotidal (>10 m) Gyeonggi Bay and artificial Shihwa Lake during 1986–2004. SOM segregated study areas into four groups and ten subgroups. Two strikingly alternative states are frequently observed: the first is a diverse non-eutrophic state designated by three groups (SOM 1–3), and the second is a eutrophic state (SOM 4: Shihwa Lake and Upper Gyeonggi Bay; summer season) characterized by enhanced nutrients (3 mg l−1 dissolved inorganic nitrogen, 0.1 mg l−1 PO4) that act as a signal and response to that signal as algal blooms (24 µg chlorophyll-a l−1). Bloom potential in response to nitrification is affiliated with high temperature (r = 0.26), low salinity (r = −0.40) and suspended solids (r = –0.27). Moreover, strong stratification in the Shihwa Lake has accelerated harmful algal blooms and hypoxia. The non-eutrophic states (SOM 1–3) are characterized by macro-tidal estuaries exhibiting a tolerance to pollution with nitrogen-containing nutrients and retarding any tendency toward stratification. SOM 1 (winter) is more distinct from SOM 4 due to higher suspended solids (>50 mg l−1) caused by resuspension that induces light limitation and low chlorophyll-a (<5 µg l−1). In addition, eutrophication-induced shifts in phytoplankton communities are noticed during all the seasons in Gyeonggi Bay. Overall, SOM showed high performance for visualization and abstraction of ecological data and could serve as an efficient ecological map that can specify blooming regions and provide a comprehensive view on the eutrophication process in a macrotidal estuary.

scholarly journals Turbidity maximum formation in a well-mixed macrotidal estuary: The role of tidal pumping

2014 ◽  
Vol 119 (11) ◽  
pp. 7705-7724 ◽  
Author(s):  
Qian Yu ◽  
Yunwei Wang ◽  
Jianhua Gao ◽  
Shu Gao ◽  
Burg Flemming
Keyword(s):  
Turbidity Maximum ◽  
Tidal Pumping ◽  
Macrotidal Estuary

High-resolution simulations of a macrotidal estuary using SUNTANS

2009 ◽  
Vol 28 (1-3) ◽  
pp. 167-192 ◽  
Author(s):  
B. Wang ◽  
O.B. Fringer ◽  
S.N. Giddings ◽  
D.A. Fong
Keyword(s):  
High Resolution ◽  
Macrotidal Estuary
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