• Journal of the Korean earth science society
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• v.42 no.3
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• pp.296-310
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• 2021

El Niño is a typical ocean and atmospheric interaction phenomenon that causes climate variability on a global scale, so it has been used as a very important teaching and learning material in the field of earth science. This study summarized the distribution and dynamics of the equatorial current system. The variability of the equatorial current system during the El Niño period and the associated misconceptions were also investigated. The North Equatorial Current, South Equatorial Current, and Equatorial Under Current significantly weaken during El Niño years. However, the variability of the North Equatorial Counter Current (NECC) during the El Niño period cannot be generalized because the NECC shows southward movement with weakening in the northern area and strengthening in the southern area, along its central axis. In the western Pacific, the NECC is further south during El Niño years, and thus, it has an eastward flow in the equatorial western Pacific. Our analysis of a mass media science article, a secondary school exam, and a survey for incumbent teachers confirmed disparate ideas about the equatorial current system's variability during El Niño periods. This is likely due to inaccurate interpretations of the existing El Niño schematic diagram and insufficient understanding of the equatorial current and wave dynamics.

• Ocean and Polar Research
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• v.26 no.2
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• pp.341-349
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• 2004

Hyrdography and deep currents were measured from 1997 to 1999 to investigate deep-sea environments in the KODOS (Korea Deep Ocean Study) area of the northeastern tropical Pacific. KODOS area is located meridionally from the North Equatorial Current to the boundary between the North Equatorial Current and the Equatorial Counter Current. Strong thermocline exists between 10 m and 120 m depths at the study area. Since that strong thermocline does hardly allow vertical mixing between surface and lower layer waters, vertical distributions of temperature, salinity, dissolved oxygen and nutrients drastically change near the thermocline. Salinity-minimum layer, which indicate the North Pacific Intermediate Water (NPIW) and the Antartic Intermediate Water (AAIW), vertically occupies vertically at the depths from 500 m down to 1400 m. The NPIW and the AAIW horizontally occur to the north and to the south of $7^{\circ}N$, respectively. The near-bottom water shows the physical characteristics of $1.05^{\circ}C$ and 34.70 psu at the depths of 10 m to 110 m above the bottom (approximately 4000-5000 m), which was originated from the Antarctic Circumpolar Water. It flows northeastwards for 2 to 4 months at the study area, and its mean velocity was 3.1-3.7 cm/s. Meanwhile, reverse (southwestward) currents appear for about 15 days with the average of 1.0-6.1 cm/s every 1 to 6 months. Dominant direction of the bottom currents obtained from the data for more than 6 months is northeastward with the average speeds of 1.7-2.1 cm/s. Therefore, it seems that deep waters from the Antarctica flow northwards passing through the KODOS area in the northeastern tropical Pacific.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.190-199
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• 2008

To investigate hydrographic structure and characteristics of the tropical ocean in the eastern and the western Pacific, CTD(Conductivity-Temperature-Depth) data along $131^{\circ}W$ and $137^{\circ}-142^{\circ}E$ in July-August 2005 were analyzed. Sea surface temperature along $131.5^{\circ}W$ in summer is highest in the Equatorial Counter Current(ECC) because of the high-temperature water greater than $28^{\circ}C$ moving through the ECC from the western Pacific to the eastern Pacific in spring and summer. Based on the evidence of the presence of low salinity and high dissolved oxygen water in the North Equatorial Current(NEC), we suggested that the low salinity water moved from the Gulf of Panama to the east of Philippine along the North Equatorial Current(NEC). The South Equatorial Current(SEC) had the most saline water from surface to deep layer because the saline water from the Subtropical South Pacific Ocean moved to the north. The salinity minimum layer was observed at 500-1500 m depth along $131.5^{\circ}W$. The water mass with the salinity minimum layer in the north of $5^{\circ}N$ came from the North Pacific Intermediate Water(NPIW) and that in the south of $5^{\circ}N$ came from the Antarctic Intermediate Water(AAIW), which was more saline than the NPIW. Cyclonic cold eddy with a diameter of about 200km was found in $4-6^{\circ}N$. Sea surface temperature along $131.5^{\circ}W$ in the eastern Pacific was lower than along $137^{\circ}-142^{\circ}E$ in the western Pacific; on the other hand, sea surface salinity in the eastern Pacific was higher than in the western Pacific. Subsurface saline water from the Subtropical South Pacific Ocean was less saline in the eastern Pacific than in the western Pacific. Salinity and density(${\sigma}_{\theta}$) of the salinity minimum layer south of $14^{\circ}N$ was higher in the eastern Pacific than in the western Pacific.