• Korean Journal of Remote Sensing
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• v.39 no.4
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• pp.441-458
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• 2023

Tropical cyclones frequently occur in the Southwest Pacific Ocean and are considered one of the driving forces for coastal alterations. Therefore, this study investigates the frequency and intensity of tropical cyclonesfrom 2000 to 2021 and their influence on the surface winds and wave conditions around the atoll nation Tuvalu. Cyclone best-track and ERA5 single-level reanalysis data are utilized to analyze the condition of the surface winds, significant wave heights, mean wave direction, and mean wave period. Additionally, the scatterometer-derived wind information was employed to compare wind conditions with the ERA5 data. On average, nine cyclones per year originated here, and the frequency increased to 11 cyclones during the last three years while the intensity decreased by 25 m/s (maximum sustained wind speed). Besides, a total of 14 cyclones were observed around Tuvalu during the period from 2015 to 2021, which showed an increase of 3 cyclones compared to the preceding period of 2001 to 2007. During cyclones, the significant wave height reached the highest 4.8 m near Tuvalu, and the waves propagated in the east-southeast direction during most of the cyclone events (52%). In addition, prolonged swells with a mean wave period of 7 to 11 seconds were generated in the vicinity of Tuvalu, for which coastal alteration can occur. After this preliminary analysis, it was found that the waves generated by cyclones have a crucial impact in altering the coastal area of Tuvalu. In the future, remotely sensed high-resolution satellite data with this wave information will be used to find out the degree of alterations that happened in the coastal area of Tuvalu before and after the cyclone events.

• Korean Journal of Remote Sensing
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• v.39 no.1
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• pp.23-45
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• 2023

Tuvalu is a small reef islands country in the Pacific Ocean. Its coastal regions are very much dynamic due to the profound effects of tropical cyclones and sea level rise (SLR). However, research works on coastline dynamics of Tuvalu mainly cover its capital, Funafuti. Therefore, this review summarizes the extent of long-term coastal changes in different islets of Funafuti and on overall Tuvalu. In Funafuti, highly accreting areas are Te Afualiku, Fuafatu, Motugie, and Amatuku, and highly eroding areas are Fuagea and Tefala with the fully disappeared islet of Vasafua after 2005. However, in spite of different causes and supposition of scientists on disappearing these lands the accretion is more dominant than erosion which resulted in 7.3% net increase of land areas of Tuvalu over 117 years till 2015. Severe tropical cyclones mainly caused accretion of land areas by forming coral rubble rampart formation and further reworks and erosion to small sandy islands whereas frequent low-energy cyclones mainly caused erosion. Though, till now severe erosion of coastal areas are not evident by global SLR, islets of Funafuti experienced remarkable shoreline increase as formation of 30-40 m wide rubble rampart formation along 19 km in 1971 by tropical cyclone Bebe and net increase of area of 3.45 ha by tropical cyclone Pam in 2015. In spite of such overall accretion of coastal areas several scientists suspect drowning of its areas in future because of high SLR (~5.1±0.7 mm/year) at Funafuti which supposedly will not work as a breakwater anymore. Thus, protection measures should be taken to prevent coastline erosion as well as land reclamation activities should be done following the global examples.

• Journal of the Korean Geographical Society
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• v.51 no.2
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• pp.185-200
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• 2016

The discipline of Geography is broadly concerned with the interconnections between people and the environment. Particularly, this unique human-environment relationship often can be typically reflected from, and well illustrated by, the dynamics of microstates' island environment. While Tuvaluans living on vulnerable, low-lying atolls in the Pacific are not primarily responsible for contributing to climate change, yet they are experiencing its dreadful effects. Population pressure, caused by the differences in population size, distribution, and composition, has been constantly affected by resource unavailability and environmental instability on the islands. It also represents one of our challenges in understanding the complex influence of population dynamics on the living environment. What can be learned from Tuvalu in the context of population geography and environmental geography as well as its relationship with other Pacific island microstates? What are Tuvaluans' migration responses to their atolls' environmental crisis as well as the carrying capacity scenarios related to overpopulation? What are the current living experiences and settlement situations of Tuvaluan internal and external migrants both at home and abroad? This research examines the contemporary migration literature in the context of Tuvalu's population geography, while analyzing Tuvaluan migration patterns, discourses and perspectives in relation to environmental change.

• Journal of the Korean Professional Engineers Association
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• v.43 no.1
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• pp.26-31
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• 2010

The changes of climate and earth environment caused by Global Warming has seriously occurred recently. For instance, the water in the Chad Lake in Africa has continuously disappeared and Tuvalu in the South Pacific is facing a serious natural disaster with that the entire country is sinking under the sea. These natural disasters become a serious risk threatening the existence of the human-race. Therefore, we needs a fundamental measure to prevent Global Warming. That is a natural phenomenon that makes the earth warmer by 6 types a greenhouse gas including $CO_2So$ we look for an answer from the 'Green Growth' movement.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.356-363
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• 2016

To suggest more efficient fishing operation, it was analyzed using five years (2011~2015) catch data of six Korean-flagged tuna purse seiners (with 1000 mt of haul capacity) operating in the western and central Pacific Ocean. In terms of annual total catch, it presented a two-year cycle of variation on catch, showing that catches of 2012, 2014 and 2015 were high, whereas those of 2011 and 2013 were low. The proportions on fishing effort of associated set were around 21.9~30.8% having 21.5~45.0% of total catch. In this study, there was no significant difference between catches of unassociated set and associated set. When considered having good fishing conditions, fishing activities were concentrated in the areas of Papua New Guinea (PNG) and Kiribati, while it showed that fishing ground spreaded out to the areas of not only PNG and Kiribati but also Federated States of Micronesia (FSM), Tuvalu and Solomon islands. The average number of fishing days was 271 with a range of 246~285. As restriction on fishing operation such as reduction of fishing days and higher fishing fee are expected to strengthen, the result of this study will be helpful to select more efficient fishing methods for purse seine fishery based on fishing conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.746-752
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• 2022

Kiribati, a South Pacific island, and its surrounding countries are gradually submerging to rising sea levels. The sea level continues to change according to the degree of thermal expansion of glaciers and seawater that decreases with increase in temperature. Global warming affects both the amount and volume of seawater, thus increasing sea level. Tidal phenomena occur twice a day to the attraction of celestial bodies such as the moon and the sun. The moon changes the angle of orbiting surface with the Earth equator every 18.6 years, and the magnitude of the tidal force changes depending on the distance between the Earth equator and the moon orbital surface. The University of Hawaii Sea Level Center selected Tarawa, Christmas, Kanton of Kiribati,, Lautoka, Suva of Fiji,Funafuti of Tuvalu, Nuk1u'alofa of Tonga, and Port Vila of Vanuatu. When comparing tide levels for each year for 19 years, the focus was on checking the change in sleep to Tide levels, and rising sea levels was the effect of Tide levels. The highest astronomical tides (HAT) and lowest astronomical tides (LAT) were identified as Tarawa 297.0, 50.8 cm, Christmas 123.8, 19.9 cm, Kanton 173.7, 39.9 cm, Lautoka 240.7, 11.3 cm, Funafuti 328.6, 98.4 cm, Nuk1u'alofa 188.8, 15.5 cm, Port Vila 161.5, -0.5cm, respectively. The Sea level rising speed was Tarawa 3.1 mm/year, Christmas -1.0 mm/year, Kanton 1.6 mm/year, Lautoka 3.1 mm/year, Suva 7.4 mm/year, Funafuti 1.4 mm/year, Nuk1u'alofa 4.2 mm/year, and Port Vila -1.2 mm/year, respectively

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.72-81
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• 2021

Gravity-driven membrane (GDM) filtration system based on the nanofiber membrane was investigated. This system can be operated with little energy demand due to a gravitational pressure-driven filtration and biological fouling control strategy. Moreover, the optimal module configuration based on the high permeance of nanofiber membrane can provide a significantly high water productivity. In order to evaluate its applicability potential, the pilot-scale (3000-5000 L/day) systems with nanofiber membranes were operated in developing countries (Kiribati and Tuvalu). Our results showed that the 14-92 L/(m²×h) of the permeate flux was determined indicating a stabilized water productivity. In addition, the permeate water indicated a high removal rate (more than 99.99%) of turbidity and bacteria. Consequently, the system can provide a stabilized water production with safe permeate water quality during long-term operation. These findings exemplify an effective approach to decentralized drinking water treatment for developing countries.