• Journal of the Korean earth science society
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• v.28 no.7
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• pp.947-956
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• 2007

In this article, the extratropical transition (ET) of tropical cyclone (TC) was investigated based on the case study covering the latest three TCs (Shanshaa Yaki, and Soulik) associated with ET evolution (onset and completion) using the objective 37 diagnostics of Evans and Hart (2003) and Hart (2003). At 500-hPa level, on an onset of ET, all three TCs entered the baroclinic zone. In a vertical cross-section analysis, three TCs before and at an onset of ET kept warm and humid throughout all levels around the TC center. However, these TCs after ET onset became relatively cold and dry over the western part of TC as the typical characteristics of ET concept model. Although our case study was not sufficient, it is concluded that the diagnostics of the ET onset and atmospheric structure change associated with Evans and Hart (2003) and Hart (2003) will be useful in ET operational forecast.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.58-60
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• 2020

겨울철 온대저기압은 그 세력이 강하여 해양사고의 주요 원인이 되는 등 선박의 안전 운항에 있어서 매우 중요하다. 이 연구에서는 겨울철(2019년 12월~2020년 2월)의 기상 데이터를 이용하여 제1태평양 한대전선대 부근의 온대저기압에 대하여 분석하였다. 분석 결과는 다음과 같다. 3개월 동안에 제1태평양 한대전선대 부근에서 발생한 온대저기압은 41개이고, 그 중 8개가 현저히 발달하였다. 발생 위치 별 온대저기압은 일본 동쪽 태평양이 가장 많았고(16개), 그 다음은 우리나라 주변, 동중국해, 일본 남쪽 해상 순이었다. 이동경로는 크게 5개로 구분할 수 있는데, 공통적으로 북동진하는 패턴을 보였다.

• Journal of the Korean earth science society
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• v.29 no.7
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• pp.567-578
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• 2008

The extratropically transitioning cyclones have been shown to have a large effect on weather system in the midlatitues and cause sometimes the severe weather phenomena. However, both operational forecasting and research aspect of ET remain a significant challenge. Because it is difficult to distinguish ET stage due to obscure configuration of the cyclone itself. Furthermore, any definition of ET should not only be precise enough to satisfy the needs of the operational and research communities. Therefore, the "operational deterministic process for ET" was proposed and has been used to diagnose both structure and subsequent process of ET in 2007. In this study, it has been examined the maximum wind and SST in the 1st step, satellite image in the 2nd step, sounding in the 3rd step, surface weather chart analysis in the final step. This operational manual has allowed better monitoring and understanding of the changes in the structure as ET occurs.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.447-452
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• 2020

Extratropical cyclone in winter season is very important in safe operation of ships because it is a major cause of marine accidents due to its strong power. In this study, we used meteorological data, to analyze extratropical cyclones occurring near the 1st Pacific polar front from December 2019 to February 2020. The analysis results are as follows. During those three months, we recorded 41 extratropical cyclones, 8 of which were remarkably developed. The central pressure of the strongest cyclone was 947hPa. The highest number of cyclones were generated in the East P acific Ocean around J apan (16), followed by the areas around Korea, the East China Sea, and the southern Sea of J apan. The cyclones followed five major tracks with a common northeast pattern. We thus concluded that the optimal route for a ship encountering an extratropical cyclone in the North P acific in winter would be south of the cyclone's center traveling eastbound and north of the center traveling westbound.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.195-207
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• 2020

In Korea, specific thermal elements such as annual mean temperature (AMT) 13℃, 14℃, and Kira's coldness index (CI) -10℃, have been suggested about the northernmost distribution of the warm-temperate evergreen broad-leaved forest zone. We reviewed the relationship between three thermal elements and the actual distribution of evergreen broad-leaved woody plants or its communities. Thiessen and Kriging method using point-data calibrated by seasonal lapse rate according to altitude were utilized for the spatial distribution pattern analysis. Several phytoclimatic maps were also produced in order to compare different thermal values. We identified that the AMT 13℃ was the best thermal element to demarcate the northern limit of the warm-temperate forest zone. Its area was estimated ca. 20,334 ㎢ and larger than those of other thermal elements. We concluded that an indirectly fabricated index i.e. CI -10℃ is useless and it was enough for a direct value of AMT 13℃ to represent the northern-limit distribution of warm-temperate forest zone, at least in Korea. Further researches on the reciprocity between floristic regions and phytoclimate zones are raised.

• Korean Journal of Environment and Ecology
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• v.25 no.1
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• pp.47-56
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• 2011

The research was conducted to find optimal habitats of warm-temperate evergreen broad-leaved trees, and to investigate climate factors to determine their distribution using classification tree (CT) analysis. The warm-temperate evergreen broad-leaved trees model (EG-model) constructed by CT analysis showed that Mean minimum temperature of the coldest month (TMC) is a major climate factor in determining distribution of warm-temperate evergreen broad-leaved trees. The areas above the $-5.95^{\circ}C$ of TMC revealed the optimal habitats of the trees. The coldest month mean temperature (CMT) equitable to $-5.95^{\circ}C$ of TMC is $-1.7^{\circ}C$, which is lower than $-1^{\circ}C$ of CMT of warm-temperate evergreen broad-leaved trees. Suitable habitats were defined for warm-temperate evergreen broad-leaved trees in Korea. These habitats were classified into two areas according to the value of TMC. One area with more than$-5.95^{\circ}C$ of TMC was favorable to trees if the summer precipitation (PRS) is above 826.5mm; the other one with less than $-5.95^{\circ}C$ of TMC was favorable if PRS is above 1219mm. These favorable conditions of habitats were similar to those of warm-temperate evergreen broad-leaved trees in Japan. We figured out from these results that distribution of warm-temperate evergreen broad-leaved trees were expanded to inland areas of southern parts of Korean peninsula, and ares with the higher latitude. Finally, the northern limits of warm-temperate evergreen broad-leaved trees might be adjusted accordingly.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.2
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• pp.45-53
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• 2006

The objectives of this study are to determine the primary yield components responsible for yield differences in a subtropical environment of the Hunan province China and in a temperature environment of Honam province Korea. Field experiments were conducted in a subtropical environment in Hunan province China during 2002 and in a temperate environment in Honam province Korea during 2003. Seven rice cultivars were grown under optimum crop management in each experiment field. Yield, yield components and plant dry matter were determined at maturation. The highest yield (567 kg/10a) was produced at Honam province by Jinyou 207, a Chinese cultivar, The maximum yield at Hunan province was 453 kg/10a by Sanyou 63. On the average across cultivars, Honam produced 23% greater yields than Hunan. Sink size (spikelets per $m^2$) was responsible far these yield differences. Panicle number per $m^2$ was much greater at Honam.

• Journal of Korean Society of Forest Science
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• v.88 no.3
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• pp.379-388
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• 1999

As a first step for delineating the provenance regions of the forest trees in Korea, horizontal zones have been deduced primarily from the various climatic factors such as annual mean temperature, extremely low temperature, relative humidity, annual gum of possible growing days, duration of sunshine and dry index. The basic concept to the delineation of the provenance regions was based on the ecological regions, which was likely to be more practical than that on the basis of the typical provenance regions at the species level. Primary classification of the regions has been based on the forest zones(sub-tropical, warm-temperate, mid-temperate and cool-temperate) as a broad geographic region. Further classification has been carried out using cluster analyses among the basic regions within forest zone. On the basis of clustering, a total of 19 regions including 3 from sub-tropical, 6 from warm-temperate, 8 from mid-temperate and 2 from cool-temperate was horizontally delineated. Of the mean values of 6 climate factors at the broad geographic region level, three factors such as annual mean temperature, extremely low temperature, annual growing days showed directional tendencies from subtropical to cool-temperate, while the others didn't. The values of relative humidity, duration of sunshine and dry index varied among the provenance regions within forest zone. These three factors might he more sensitive by the micro-environment condition than by the macro-environment condition. Present study aimed to delineate the primary provenance regions for tentative application to forest practices. These will be stepwise revised through the supplement using accumulated information regard to genecological data.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.590-600
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• 2011

The research was carried out for prediction of the potential habitats of warm-temperate evergreen broad-leaved trees under the current climate(1961~1990) and three climate change scenario(2081~2100) (CCCMA-A2, CSIRO-A2 and HADCM3-A2) using classification tree(CT) model. Presence/absence records of warm-temperate evergreen broad-leaved trees were extracted from actual distribution data as response variables, and four climatic variables (warmth index, WI; minimum temperature of the coldest month, TMC; summer precipitation, PRS; and winter precipitation, PRW) were used as predictor variables. Potential habitats(PH) was predicted 28,230$km^2$ under the current climate and 77,140~89,285$km^2$ under the three climate change scenarios. The PH masked by land use(PHLU) was predicted 8,274$km^2$ and the proportion of PHLU within PH was 29.3% under the current climate. The PH masked by land use(PHLU) was predicted 35,177~45,170$km^2$ and increased 26.9~36.9% under the three climate change scenarios. The expansion of warm-temperate evergreen broad-leaved trees by climate change progressed habitat fragmentation by restriction of land use. The habitats increase of warm-temperate evergreen broad-leaved trees had been expected competitive with warm-temperate deciduous broadleaf forest and suggested the expand and northward shift of warm-temperate evergreen broad-leaved forest zone.

• Korean Journal of Environment and Ecology
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• v.16 no.3
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• pp.309-320
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• 2002

In order to understand the condition of mostly-degraded evergreen broad-leaved forests(EBLF) and to make a restoration plan of EBLF in the Korean warm temperate, the distribution of EBLF and forest vegetation types have been investigated and the categories of degraded levels have been set. The coverage of the EBLF in the Korean peninsula was approximately 10,285ha based on the existing literature review and the actual vegetation map. Forest vegetation types have been investigated at thirty-two area of the south coast and inland in the warm temperate region. As a result, The forest vegetation was classified as 52 types; 26 types of EBLF, 13 types of semi-evergreen broad-leaved forests, 9 types of deciduous broad-leaved forests, 4 types of evergreen coniferous forests. The categories of degraded levels were divided into 8 levels and 14 sub-levels according to the importance percentage(I.P.) and the number of warm temperate species.