scholarly journals Radioactivity levels in beach sand from the West Coast of Sri Lanka

2013 ◽  
Vol 41 (4) ◽  
pp. 279 ◽  
Author(s):  
P Mahawatte ◽  
KNR Fernando
2020 ◽  
Author(s):  
Iyyappan Suresh ◽  
Jerome Vialard ◽  
Matthieu Lengaigne ◽  
Takeshi Izumo ◽  
Muraleedharan Pillathu Moolayil

<p>Remote wind forcing plays a strong role in the Northern Indian Ocean, where oceanic anomalies can travel long distances within the coastal waveguide. Previous studies for instance emphasized that remote equatorial forcing is the main driver of the sea level and currents intraseasonal variability along the west coast of India (WCI). Until now, the main pathway for this connection between the equatorial and coastal waveguides was thought to occur in the eastern equatorial Indian Ocean, through coastal Kelvin waves that propagate around the Bay of Bengal rim and then around Sri Lanka to the WCI. Using a linear, continuously stratified ocean model, the present study demonstrates that two other mechanisms in fact dominate. First, the equatorial waveguide also intersects the coastal waveguide at the southern tip of India and Sri Lanka, creating a direct connection between the equator and WCI. Rossby waves reflected from the eastern equatorial Indian Ocean boundary indeed have a sufficiently wide meridional scale to induce a pressure signal at the Sri Lankan coast, which eventually propagates to the WCI as a coastal Kelvin wave. Second, local wind variations in the vicinity of Sri Lanka generate strong intraseasonal signals, which also propagate to the WCI along the same path. Sensitivity experiments indicate that these two new mechanisms (direct equatorial connection and local wind variations near Sri Lanka) dominate the WCI intraseasonal sea level variability, with the “classical” pathway around the Bay of Bengal only coming next. Other contributions (Bay of Bengal forcing, local WCI forcing) are much weaker.</p><p>We further show that the direct connection between the equatorial waveguide and WCI is negligible at seasonal timescale, but not at interannual timescales where it contributes to the occurrence of anoxic events. By providing an improved understanding of the mechanisms that control the WCI thermocline and oxycline variability, our results could have socio-economic implications for regional fisheries and ecosystems.</p>


Author(s):  
Yoshimitsu TAJIMA ◽  
Shohei MOCHIZUKI ◽  
Shotaro FUNATAKE ◽  
Wickramaarachchi BANDULA ◽  
Samalakoon LAL ◽  
...  

2016 ◽  
Vol 43 (13) ◽  
pp. 7028-7035 ◽  
Author(s):  
I. Suresh ◽  
J. Vialard ◽  
T. Izumo ◽  
M. Lengaigne ◽  
W. Han ◽  
...  

2017 ◽  
Vol 35 (35) ◽  
pp. 7 ◽  
Author(s):  
Victor Cardenes ◽  
Álvaro Rubio

Abstract: The aesthetical perception of a beach as a recreational place is closely linked to the sand color. This is one of the most perceptible characteristics of a beach. Sand color can be altered after a nourishment work. This type of works is becoming more and more popular since they represent a good tool for preserving beaches from erosion. However, only little (or none) attention has been paid to sand color during nourishment works. Colors of the sands from the Belgian coast were determined in the Cielab space, together with their granulometry and composition. Color coordinates range between 50 and 60 for L*, 0.5 to 4.0 for a*, and 10.5 to 16.5 for b*. The composition shows a dominant quartz fraction, followed by shell fragments and finally rock fragments. Granulometry is rather homogeneous, being the grain distribution for the east part of the coast narrower than for the west coast. This work describes the methodology for performing colorimetric analysis in sand beaches before a nourishment work, together with the main acceptance criteria when choosing the appropriate sand for replacement.Keywords: Sand color, granulometry, nourishment, Cielab.Resumen: La percepción estética de una playa como lugar de recreo está estrechamente ligada al color de la arena. Esta es una de las características más perceptibles de una playa. El color de la arena puede ser alterado después de un trabajo de reposición. Este tipo de obras son cada vez más populares ya que representan una buena herramienta para preservar las playas de la erosión. Sin embargo, se ha prestado poca (o ninguna) atención al color de la arena durante los trabajos de reposición. Los colores de las arenas de la costa belga fueron determinados en el espacio Cielab, junto con su granulometría y composición. Las coordenadas de color varían entre 50 y 60 para L*, 0,5 a 4,0 para a* y 10,5 a 16,5 para b*. La composición muestra una fracción de cuarzo dominante, seguida de fragmentos de conchas y finalmente fragmentos de roca. La granulometría es bastante homogénea, siendo la distribución de grano más estrecha para la parte este de la costa que para la costa oeste. Este trabajo describe la metodología para realizar el análisis colorimétrico en playas de arena antes de un trabajo de reposición, junto con los principales criterios de aceptación al escoger la arena adecuada para el reemplazo.Palabras clave: Color de arena, granulometría, reposición, Cielab.


1987 ◽  
Vol 27 (4) ◽  
pp. 449-454 ◽  
Author(s):  
R. Hewamanna ◽  
R.A.G. Ranawake ◽  
C.M. Samarakoon
Keyword(s):  

2021 ◽  
pp. e00382
Author(s):  
Chamindra L. Vithana ◽  
Prashani A.K. Ulapane ◽  
Rohana Chandrajith ◽  
Leigh A. Sullivan ◽  
Jochen Bundschuh ◽  
...  

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