• Energy Research

Circulation of sea breeze is a well-known and important mesoscale system, boosted by different properties of reception and storage of solar heat between land and sea during one day, and its effect on waves, currents, and transport of atmospheric contaminants, among others, has been proven. The aim of this work is to characterize sea breeze in three coastal zones of the Colombian Caribbean, in the north of South America: Riohacha, Barranquilla, and Santa Marta, through the analysis of data from the Instituto de Hidrologia, Meteorologia y Estudios Ambientales (Hydrology, Meteorology and Environmental Studies Institute) of Colombia during the period 1981-2008, and a detail analysis in the city of Santa Marta with data from the station of the Jorge Tadeo Lozano University of Bogota in the period January 1 st to December 31, 2010. Gustavsson´s method was used to identify the marine breeze cycle, its duration, frequency, and hourly pattern; hodograph representation and spectral analysis were performed according to the periodogram modified by the Welch method. It was established that the marine breeze signal in the Colombian Caribbean coast is stronger during the dry season (December-March), when it reaches the highest gradients of sea-land temperature and with a predominantly diurnal component. In the city of Santa Marta and central Caribbean, the sea breeze is stronger and more defined compared to those of the cities of Riohacha at the northeast, and Barranquilla at the southwest, reaching an estimated medium value of 4 m s –1 in March, and minimum values of 2 m s –1 in August. In Barranquilla, the sea breeze signal reaches 2.5 m s –1 , while in Riohacha it reaches 1.5 m s –1 , both in the dry season (December-March). According to the results, the strong signal in the city of Santa Marta is related to the gradient of 3 oC between the sea-land temperature in the dry season, while in Barranquilla is 1.2 oC, and in Riohacha it is less than 1oC. Despite having observed a sea-land temperature gradient close to 2.5 oC in July in the city of Riohacha, the hodograph is not well defined, and the signal magnitude is not strong, which could be related to the presence of strong synoptic winds almost the whole year, the desert landscape of the zone, and its geographical position. This the first scientific work related to marine breeze in this region of the Caribbean, and its results constitute an important base for studying the effect that such breezes may have on the spectrum of waves, upwelling, and especially in the transport of contaminants, given that Santa Marta is one of the most important harbors of mineral coal in Colombia, and one of the main touristic destinations in the northern Colombian coast.

Abstract Colombia's exclusive location surrounded by the warm tropical waters of the Caribbean Sea and the eastern equatorial Pacific Ocean make it a suitable region for ocean thermal energy conversion (OTEC). These are systems that can produce significant amounts of renewable electricity. From the assessment of the temperature gradient and the bathymetric, environmental and socio-economical characteristics, the maritime area around the island of San Andres (in the northwestern Caribbean Sea) was found to be ideal for an OTEC facility since sea surface temperature varies only slightly during annual and interannual timescales. The thermal difference encountered from the surface to a depth of 1000 m is always around 22°–24 °C and cold waters are available for intake at around 450–750 m, within a short horizontal distance from the coast (less than 2.5 km). At these depths, the 20 °C thermal gradient required for OTEC operations is achieved. Furthermore, winds, waves and surface currents around the island are of relatively weak intensity. Presently, energy sources based entirely on Diesel generators are inducing negative impacts on the sustainable development of the region and on the fragile marine ecosystem. An environmentally friendly 10 MW OTEC facility could be part of future energy and water management solutions for the island. It would cover nearly 50% of total electricity demands and provide important additional advantages such as chilled soil agriculture, aquaculture, freshwater, mariculture and seawater air conditioning.

Ce travail analyse les impacts côtiers de l'effet combiné des vagues extrêmes et des extrêmes du niveau de la mer, y compris les surtensions et l'élévation projetée du niveau moyen de la mer à Bocagrande, Carthagène (Colombie). Les vagues extrêmes sont évaluées à partir d'une réanalyse des vagues qui se propagent des eaux profondes à la plage en tenant compte des processus hydrodynamiques et en tenant compte de l'interaction entre les vagues et l'élévation côtière dans la zone d'étude. Tout d'abord, nous considérons le niveau actuel de la mer, les ondes de tempête et les vagues affectant la zone. Ensuite, nous analysons l'effet de l'élévation du niveau de la mer selon un scénario de changement climatique modéré (RCP4.5) pour le XXIe siècle (années 2025, 2050, 2075 et 2100). Le scénario le plus pessimiste (année 2100) donne un pourcentage de zone inondée de 97,2%, révélant ainsi la menace majeure que représente l'élévation du niveau de la mer pour les zones côtières de la mer des Caraïbes. Este trabajo analiza los impactos costeros del efecto combinado de las olas extremas y los extremos del nivel del mar, incluidas las marejadas y el aumento medio proyectado del nivel del mar en Bocagrande, Cartagena (Colombia). Las olas extremas se evalúan a partir de un reanálisis de olas que se propagan desde aguas profundas hasta la playa considerando los procesos hidrodinámicos y teniendo en cuenta la interacción entre las olas y la elevación costera dentro del área de estudio. En primer lugar, consideramos el nivel actual del mar, las marejadas ciclónicas y las olas que afectan a la zona. A continuación, analizamos el efecto de la subida del nivel del mar según un escenario de cambio climático moderado (RCP4.5) para el siglo XXI (años 2025, 2050, 2075 y 2100). El escenario más pesimista (año 2100) arroja un porcentaje de área inundada del 97.2%, revelando así la mayor amenaza que representa el aumento del nivel del mar para las zonas costeras del Mar Caribe. This work analyzes the coastal impacts of the combined effect of extreme waves and sea level extremes, including surges and projected mean sea level rise in Bocagrande, Cartagena (Colombia). Extreme waves are assessed from a wave reanalysis that are propagated from deep waters to the beach considering the hydrodynamic processes and taking into account the interaction between waves and the coastal elevation within the study area. First, we consider present sea level, storm surges and waves affecting the area. Next, we analyze the effect of sea level rise according to a moderate (RCP4.5) climate change scenario for the 21st century (years 2025, 2050, 2075 and 2100). The most pessimistic scenario (year 2100) yields a percentage of flooded area of 97.2%, thus revealing the major threat that represents sea level rise for coastal areas in the Caribbean Sea. يحلل هذا العمل الآثار الساحلية للتأثير المشترك للأمواج الشديدة والظواهر المتطرفة لمستوى سطح البحر، بما في ذلك الطفرات والمتوسط المتوقع لارتفاع مستوى سطح البحر في بوكاغراندي، قرطاجنة (كولومبيا). يتم تقييم الأمواج الشديدة من خلال إعادة تحليل الأمواج التي تنتشر من المياه العميقة إلى الشاطئ مع مراعاة العمليات الهيدروديناميكية ومراعاة التفاعل بين الأمواج والارتفاع الساحلي داخل منطقة الدراسة. أولاً، نعتبر أن مستوى سطح البحر الحالي والعواصف والأمواج تؤثر على المنطقة. بعد ذلك، نقوم بتحليل تأثير ارتفاع مستوى سطح البحر وفقًا لسيناريو معتدل (RCP4.5) لتغير المناخ للقرن الحادي والعشرين (السنوات 2025 و 2050 و 2075 و 2100). ينتج عن السيناريو الأكثر تشاؤماً (عام 2100) نسبة مئوية من المساحة المغمورة تبلغ 97.2 ٪، مما يكشف عن التهديد الرئيسي الذي يمثل ارتفاع مستوى سطح البحر للمناطق الساحلية في البحر الكاريبي.

Abstract. The main object of the present work was to study the role of morphodynamic changes in the flooding of a dissipative beach with microtidal regime, considering the simultaneous and individual effects of erosion and flooding in scenarios of long-term mean sea level rise. For this analysis, we selected a sector of the Colombian Caribbean coast with great touristic, historical, economic, cultural and social importance, namely, Cartagena de Indias; specifically, the beach of Bocagrande. By simultaneously considering erosion and flood processes associated with highly energetic waves, the study facilitates the construction of more precise models for assessing threats to coastal zones. SWAN and XBeach nested models were carried out in order to predict morphological changes and flooding during selected cold fronts and hurricanes that affected Cartagena de Indias; those numerical models were calibrated using field campaigns data (pre- and post-storm). The results of this research indicate that flooding on microtidal dissipative beaches under extreme wave conditions should be approached by considering morphodynamics, because ignoring them can underestimate flooding by ~15%. The erosion and flood effects are intensified by sea level rise, resulting in the most unfavorable condition when extreme events are contemporaneous with high tides.