• Journal of the Korean earth science society
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• v.29 no.5
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• pp.428-436
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• 2008

This study observed the upper tropospheric ozone enhancement in the northern Atlantic for the Aerosols99 campaign in January-February 1999. To find the origin of this air, we have analyzed the horizontal and vertical fields of Isentropic Potential Vorticity (IPV) and Relative Humidity (RH). The arch-shaped IPV is greater than 1.5 pvus indicating stratospheric air stretches equatorward. These arch-shaped regions are connected with regions of RH less than 20%. The vertical fields of IPV and RH show the folding layer penetrating into the upper troposphere. These features support the idea that the upper tropospheric ozone enhancement originated from the stratosphere. Additionally, we have investigated the climatological frequency of stratospheric intrusion over the tropical north Atlantic using IPV and RH. The total frequency between the equator and $30^{\circ}N$ over the tropical north Atlantic exhibits a maximum in northern winter. It suggests that the stratospheric intrusion plays an important role in enhancing ozone in the upper troposphere over the tropical north Atlantic in winter and early spring. Although the tropospheric ozone residual method assumed zonally invariant stratospheric ozone, stratospheric zonal ozone variance could be caused by stratospheric intrusions. This implies that stratospheric intrusion influences ozone variance over the Atlantic in boreal winter and spring, and the intrusion is a possible source for the tropical north Atlantic paradox.

• Proceedings of the Korean Quaternary Association Conference
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• 2004.11a
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• pp.37-43
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• 2004

The response of the CCCma coupled climate model to the imposition of LGM conditions is investigated. The global mean SAT and SST decrease by about $10^{\circ}C$ and $5.6^{\circ}C$ in the coupled model. Tropical SST decreases by $6.5^{\circ}C$, whereas CLIMAP reconstructions suggest that the tropics cool by only about $1.7^{\circ}C$, although the larger tropical cooling is consistent with the more recent proxy estimates. With the incorporation of a full ocean component, the coupled model gives a realistic spatial SST pattern, capturing features associated with ocean dynamics that are seen in the CLIMAP reconstructions. The larger decrease of the surface temperature in the model is associated with a reduction in global precipitation rate (about 15%). The tropical Pacific warm pool retreats to the west and a mean La $Ni\tilde{n}a$-like response is simulated with less precipitation over the central Pacific and more in the western tropical Pacific. The more arid ocean climate in the LGM results in an increase in SSS almost everywhere. This is particularly the case in the Arctic Ocean where large SSS increase is due to a decrease in river discharge to the Arctic Ocean associated with the accumulation of snow over the ice sheet, but in the North Atlantic by contrast SSS decreases markedly. This remarkable reduction of SSS in the North Atlantic is attributed to an increase in fresh water supply by an increase in discharges from the Mississippi and Amazon rivers and an increase in P-E over the North Atlantic ocean itself. The discharges increase in association with the wetter LGM climate south of the Laurentide ice sheet and in South America. The fresh water capping of the northern North Atlantic results in a marked reduction of deep convection and consequently a marked weakening of the North Atlantic overturning circulation. In the LGM, the maximum overturning stream function associated with the NADW formation decreases by about 60% relative to the control run, while in the Southern Ocean, oceanic convection is stronger in the LGM due to reduced stratification associated with an increase in SSS and a decrease in SST and the overturning stream function associated with the formation of AABW and the outflow increases substantially.

• Korean Journal of Remote Sensing
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• v.22 no.1
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• pp.1-10
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• 2006

During the northern burning season, biomass burning is found north of the equator, while satellite estimates from the residual-type method such as the CCD method show higher ozone south of the equator. This discrepancy is called the tropical Atlantic paradox (Thompson et ai., 2000). We use satellite and ground-based measurements to investigate the paradox. When the background tropospheric ozone over the Pacific Ocean from TOMS measurements is subtracted from the latitudinal total ozone distribution (e.g. TOMS-Pacific method), the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD method. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the TOMS-Pacific method. It suggests that the complicated CCD method can be replaced by the simple TOMS-Pacific method. However, the tropical Atlantic paradox exists in the results of both the CCD and TOMS-Pacific methods during the northern buming season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and TOMS-Pacific methods by using the SAGE measurements (e.g. TOMS-SAGE method) and the SHADOZ ozonesoundings (e.g. TOMS-Sonde method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the TOMS-SAGE and TOMS-Sonde methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and TOMS-Pacific methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.

• Atmosphere
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• v.34 no.2
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• pp.97-106
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• 2024

The seasonal forecast skill of tropical cyclones (TCs) in the Northern Hemisphere from the Korea Meteorological Administration (KMA) Global Seasonal Forecast System version 6 (GloSea6) hindcast has been verified for the period 1993 to 2016. The operational climate prediction system at KMA was upgraded from GloSea5 to GloSea6 in 2022, therefore further validation was warranted for the seasonal predictability and variability of this new system for TC forecasts. In this study, we examine the frequency, track density, duration, and strength of TCs in the North Indian Ocean, the western North Pacific, the eastern North Pacific, and the North Atlantic against the best track data. This methodology follows a previous study covering the period 1996 to 2009 published in 2020. GloSea6 indicates a higher frequency of TC generation compared to observations in the western North Pacific and the eastern North Pacific, suggesting the possibility of more TC generation than GloSea5. Additionally, GloSea6 exhibits better interannual variability of TC frequency, which shows relatively good correlation with observations in the North Atlantic and the western North Pacific. Regarding TC intensity, GloSea6 still underestimates the minimum surface pressures and maximum wind speeds from TCs, as is common among most climate models due to lower horizontal resolutions. However, GloSea6 is likely capable of simulating slightly stronger TCs than GloSea5, partly attributed to more frequent 6-hourly outputs compared to the previous daily outputs.

• Proceedings of the KSRS Conference
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• v.1
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• pp.253-256
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• 2006

When the background tropospheric ozone column over the Pacific Ocean is subtracted from the latitudinal total ozone distribution, the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the T-P method. It suggests that the CCD method can be replaced by the simple T-P method. However, the tropical Atlantic paradox exists in the results of both the CCD and T-P methods during the northern burning season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and T-P methods by using the SAGE measurements (e.g. TSA method) and the SHADOZ ozonesoundings (e.g. T-S method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the T-SA and T-S methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and T-P methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.

• Proceedings of the KSRS Conference
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• v.1
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• pp.308-311
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• 2006

This study compared between tropospheric column ozone by applying the SAM method to TOMS and OMI data for northern summer. Tropospheric ozone from the SAM represents a peak over the tropical Atlantic, where it is related with biomass burning. This feature is also seen in the distribution of the model and CO. Additionally, enhancement of the SAM ozone over the Middle East, and South and North America agrees well with the model and CO distribution. However, the SAM results show more ozone than the model results over the northern hemisphere, especially the ocean (e.g. the North Pacific and the North Atlantic). The tropospheric ozone distribution from OMI data shows more ozone than that from TOMS data. This can be caused by different viewing angle, sampling frequency, and a-priori ozone profiles between OMI and TOMS. The correlation between the SAM tropospheric ozone and CO is better than that between the model and CO in the tropics. However, that correlation is reversed in the midlatitude.

• Atmosphere
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• v.30 no.3
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• pp.209-220
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• 2020

Seasonal predictability and variability of tropical storms (TCs) simulated in the Global Seasonal Forecast System version 5 (GloSea5) of the Korea Meteorological Administration (KMA) is assessed in Northern Hemisphere in 1996~2009. In the KMA, the GloSea5-Global Atmosphere version 3.0 (GloSea5-GA3) that was previously operated was switched to the GloSea5-Global Coupled version 2.0 (GloSea5-GC2) with data assimilation system since May 2016. In this study, frequency, track, duration, and strength of the TCs in the North Indian Ocean, Western Pacific, Eastern Pacific, and North Atlantic regions derived from the GloSea5-GC2 and GloSea5-GA3 are examined against the best track data during the research period. In general, the GloSea5 shows a good skill for the prediction of seasonally averaged number of the TCs in the Eastern and Western Pacific regions, but underestimation of those in the North Atlantic region. Both the GloSea5-GA3 and GC2 are not able to predict the recurvature of the TCs in the North Western Pacific Ocean (NWPO), which implies that there is no skill for the prediction of landfalls in the Korean peninsula. The GloSea5-GC2 has higher skills for predictability and variability of the TCs than the GloSea5-GA3, although continuous improvements in the operational system for seasonal forecast are still necessary to simulate TCs more realistically in the future.

• ALGAE
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• v.27 no.2
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• pp.95-108
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• 2012

Using genetic sequencing (COI-5P, LSU, $rbc$L) to elucidate their phylogenetic positions and then morphological characters to distinguish each from existing species, three procumbent species, including two novel species, from warm temperate Northern Hemisphere waters are added to the recently resurrected genus $Halopeltis$ J. Agardh: $H.$ $adnata$ (Okamura) comb. nov. from Korea, $H.$ $pellucida$ sp. nov. from Bermuda and $H.$ $willisii$ sp. nov. from North Carolina, USA. Prior to these reports, the genus was confined to the Southern Hemisphere and tropical equatorial waters of the Northern Hemisphere although the latter records lack molecular confirmation. These three additional species join the six known species presently residing in $Halopeltis$.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.7-11
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• 2002

This study introduces the first method that determines tropospheric ozone column directly from a space-based instrument. This method is based on the physical differences in the Total Ozone Mapping Spectrometer (TOMS) measurement as a function of its scan-angle geometry. Tropospheric ozone in September-October exhibits a broad enhancement over South America, the southern Atlantic Ocean, and western South Africa and a minimum over the central Pacific Ocean. Tropical tropospheric ozone south of the equator is higher than north of the equator in September-October, the southern burning season. Conversely, ozone north of the equator is higher in March, the northern burning season. Overall, the ozone over the southern tropics during September-October is significantly higher than over the northern tropics. Abnormally high tropospheric ozone occurs over the western Pacific Ocean during the El Nino season when the ozone amounts are as high as the ozone over the Africa.

• Journal of the Korean Institute of Navigation
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• v.11 no.1
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• pp.107-144
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• 1987

In cold season, ice accretion on ship, drift ice, NW winter monsoon, developed extratropical cyclones and associated cold fronts, in warm season, tropical cyclones and dense sea fogs, are encountered very frequently in the North Pacific, especially in the northwest part of it. The two areas, namely, the northwest part of the North Pacific and Burmuda Triangle in the North Atlantic are generally known as most dangerous areas in the world because its high incidence of sea cascualities. In recent years, the small fisherboats operating in the northern seas were frequently sunk in a group as they encountered ice accretion or drift ice. And ocean going vessels were also sunk frequently due to strong winds and very high seas in winter monsoon or developed cyclones and cold fronts. The purpose of this paper is to analyze the real state of heavy weather conditions such as ice accretion on ship drift, ice, typhoons and sea fogs, and also to analyse the effect of these heavy weather phenomena on the vessels at sea, thus helping mariners operate in such heavy weather conditions.