• Journal of Environmental Science International
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• v.30 no.1
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• pp.29-43
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• 2021

This study analyzed the status of climate-change indicator plants native to the main islands of the Korean peninsula, while elucidating their distribution characteristics. Information on flora from over 129 island locations, comprising more than 100 species of native plants, was collected, compiled into a database, and utilized as raw data. The distribution of 193 climate-change indicator plants was confirmed. The distribution area of broadleaf evergreen trees and ferns, including Mallotus japonicus and Cyrtomium falcatum, was relatively wide. In contrast, the distribution of common northern plants such as Corydalis turtschaninovii and Malus baccata was limited. If global warming persists, northern plant distribution is expected to decrease rapidly in the Korean Peninsula island region, while the northern limit line of the southern plants is expected to migrate further northward. During this process, it is likely that the plant congregation structure and species diversity within the island region will change dynamically. In this study, comparative analyses between species and regions were conducted by assessing the relative frequency of their occurrence, and six types of botanical geographic distribution patterns were noted.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.599-609
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• 2015

A total of 19 species of three genera Dinophysis, Histioneis, and Parahistioneis of the family Dinophysaceae are reported here from samples obtained using a 20-µm mesh net from June 2006 to December 2014 around Jeju Island including the East China Sea, and 16 of these species are new to Korean waters. A checklist of the three genera of dinoflagellates reported from coastal and oceanic Korean waters is presented. Short descriptions and synonyms are given for each species. The dinoflagellates of the family Dinophysaceae belong to mostly marine species, and include many tropical and/or subtropical species. Recently, the composition of dinoflagellate species has changed around Jeju Island as well as in Korean waters due to global warming and climate change. Tropical and subtropical dinoflagellates occur frequently in the coastal waters of Jeju Island, which reflects the ecosystem shift around the sea adjacent to Jeju Island from a temperate to a subtropical / tropical region.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1129-1135
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• 2011

Recently, In Korea region becoming subtropical climate, freezing index values have been increasing in winter. The climate condition in Korean became polarized. Since freezing index is increased recently, track heaving from frost is often occurred, which is ignored in past couple of years. Methods to prevent frost-heaving are circumfusion of calcium chloride and replacement of gravel ballast in usual. The effects of those methods are minimal, incontinuous, and not eco-friendly. Therefore, maintenances are performed repeatedly every year. This study discussed utilizing the waste-tire-chips and insulators in the small structures(bridge and box etc) for prevention of frost-heaving. In order to prove effect of waste-tire-chips, laboratory and field tests were conducted with CBR and measurement of frost-heaving amount to prove and verify effect of insulators.

• Journal of Climate Change Research
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• v.2 no.4
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• pp.269-281
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• 2011

In this review, numerical model results from global and regional climate models are introduced to regional detailed climate changes over East Asia and Korea. In particular, regional climate change scenarios in this region, which are created by several research groups in Korea based on Special Report on Emissions Scenarios (SRES) of IPCC 4th assessment report are introduced and characteristics of the scenarios are investigated. Despite slight differences in intensity, all scenarios reveal prominent warming over the Korean peninsula in future climate. Changes in precipitation amount vary with given scenarios and periods, but the frequency and intensity of heavy precipitation generally tend to increase in all scenarios. South Korea except for mountainous regions is expected to change into subtropical climate in future, which accompanies distinct changes in ecosystems and seasons.

• Ocean and Polar Research
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• v.33 no.spc3
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• pp.371-383
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• 2011

To investigate the physical characteristics and variations of oceanic parameters in the tropical central North Pacific, oceanographic surveys were carried out in summer of 2006 and 2007. The survey periods were classified by Oceanic Ni$\tilde{n}$o Index as a weak El Ni$\tilde{n}$o in 2006 and a medium La Ni$\tilde{n}$a in 2007. The survey instruments were used to acquire data on CTD (Conductivity Temperature and Depth), XBT (Expendable Bathythermograph), and TSG (Thermosalinograph). The dominant temporal variation of surface temperature was diurnal. The diurnal variation in 2007, when the La Ni$\tilde{n}$a weather pattern was in place, was stronger than that in 2006. Surface salinity in 2006 was affected by a northwestward branch of North Equatorial Current, which implies that the El Ni$\tilde{n}$o affects surface properties in the North Equatorial Current region. Two salinity minimum layers existed at stations east of Chuuk in both year's observations. The climatological vertical salinity section along $180^{\circ}E$ shows that the two salinity minimum layers exist in $2^{\circ}N{\sim}12^{\circ}N$ region, consistent with our observations. Analysis of isopycnal lines over the salinity section implies that the upper salinity minimum layer is from intrusion of the upper part of North Pacific Intermediate Water into the lower part of South Pacific Subtropical Surface Water and the lower salinity minimum layer is from Antarctic Intermediate Water.

• Journal of Climate Change Research
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• v.34 no.15
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• pp.6335-6353
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• 2021

This study examines the temporal evolution of the extratropically forced tropical response in an idealized aquaplanet model under equinox condition. We apply a surface thermal forcing in the northern extratropics that oscillates periodically in time. It is shown that tropical precipitation is unaltered by sufficiently high-frequency extratropical forcing. This sensitivity to the extratropical forcing periodicity arises from the critical time required for sea surface temperature (SST) adjustment. Low-frequency extratropical forcing grants sufficient time for atmospheric transient eddies to diffuse moist static energy to perturb the midlatitude SSTs outside the forcing region, as demonstrated by a one-dimensional energy balance model with a fixed diffusivity. As the transient eddies weaken in the subtropics, a further equatorward advection is accomplished by the Hadley circulation. The essential role of Hadley cell advection in connecting the subtropical signal to the equatorial region is supported by an idealized thermodynamical-advective model. Associated with the SST changes in the tropics is a meridional shift of the intertropical convergence zone. Since the time needed for SST adjustment increases with increasing mixed layer depth, the critical forcing period at which the extratropical forcing can affect the tropics scales linearly with the mixed layer depth. Our results highlight the important role of decadal-and-longer extratropical climate variability in shaping the tropical climate system. We also raise the possibility that the transient behavior of a tropical response forced by extratropical variability may be strongly dependent on cloud radiative effects.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.287-298
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• 2020

It is predicted that future climate warming will occur, and the subtropical climate zone currently confined to the south coast of Korea will gradually rise north. The shift of climate zone implies a change in area for cultivating crops. This study aimed to evaluate the current and future status of climate zones based on the high-resolution climate data of South Korea to prepare adaptation measures for cultivating crops under changing agricultural climate conditions. First, the climatic maps of South and North Korea were produced by using the high-resolution monthly maximum and minimum daily temperature and monthly cumulative precipitation produced during the past 30 years (1981-2010) covering South and North Korea. Then the climate zones of the Korean Peninsula were classified based on the Köppen climate classification. Second, the changes in climate zones were predicted by using the corrected monthly climate data of the Korean Peninsula (grid resolution 30-270m) based on the RCP8.5 scenario of the Korea Meteorological Administration. Köppen climate classification was applied based on the RCP8.5 scenario, the temperature and precipitation of the Korean Peninsula would continue to increase and the climate would become simpler. It was predicted that the temperate climate, appearing in the southern region of Korea, would be gradually expanded and the most of the Korean Peninsula, excluding some areas of Hamgkyeong and Pyeongan provinces in North Korea, would be classified as a temperate climate zone between 2071 and 2100. The subarctic climate would retreat to the north and the Korean Peninsula would become warmer and wetter in general.

• Ocean and Polar Research
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• v.38 no.2
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• pp.89-102
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• 2016

In this study, we evaluated the model performance with respect to Sea Surface Temperature (SST) and Net Heat Flux (NHF) by considering the characteristics of seasonal temperature variation and contributing factors and by analyzing heat budget terms in the Northwestern Pacific and East Asian Marginal Seas ($110^{\circ}E-160^{\circ}E$, $15^{\circ}N-60^{\circ}N$) using the HadGEM2-AO historical run. Annual mean SST of the HadGEM2-AO is about $0.065^{\circ}C$ higher than observations (EN3_v2a) from 1950 to 2000. Since 1960, the model has simulated well the long-term variation of SST and the increasing rate of SST in the model ($0.014^{\circ}C/year$) is comparable with observations ($0.013^{\circ}C/year$). Heat loss from the ocean to the atmosphere was simulated slightly higher in the HadGEM2-AO than that in the reanalysis data on the East Asian Marginal Seas and the Kuroshio region. We investigated the causes of temperature variation by calculating the heat budget equation in the two representative regions. In the central part of the Kuroshio axis ($125^{\circ}E-130^{\circ}E$, $25^{\circ}N-30^{\circ}N$: Region A), both heat loss in the upper mixed layer by surface heat flux and vertical heat advection mainly cause the decrease of heat storage in autumn and winter. Release of latent heat flux through the heat convergence brought about by the Kuroshio contributes to the large surface net heat flux. Positive heat storage rate is mainly determined by horizontal heat advection from March to April and surface net heat flux from May to July. In the central part of the subtropical gyre ($155^{\circ}E-160^{\circ}E$, $22^{\circ}N-27^{\circ}N$: Region B), unlike Region A, vertical heat advection predominantly causes the decrease of heat storage in autumn and winter. In spring and summer, surface heat flux contributes to the increase of heat storage in Region B and the period is two times longer than the period for Region A. In this season, shoaling of the mixed layer depth plays an important role in the increase of SST.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.141-155
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• 1988

We have large areas of forests in our country where various types of trees can grow. Since Japan geographically locates on a wide region with the extention of 3,000 km south and north, the climate varies from subtropical to subarctical one. Many mountains additionally make the climatic condition more complicated. Thus, we are able to see many kinds of trees in our forest areas. We have also frequent rainfalls through whole season and the precipitation reaches approximately 1,500 mm per year in many forests areas. In some rainy regions, it sometimes account for more than 2,000 mm. The condition is so advantageous for the growth of weeds and shrubs that it makes them very strong competitors with plantation trees in our forestries. It, therefore, may be said that the most important problem in Japanese forestries is to combat with undesirable vegetations continuously and to keep trees from weeds.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.732-739
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• 2014

This research was performed to investigate the effect of recent climate changes on wood decay hazard index (Scheffer index) in Korea. The index was determined using a climate data of 58 different locations obtained from the website of Korea Meteorological Administration (KMA), and the wood decay hazard index was determined at the intervals of 10 years. Most of regions in Korea except Juju island showed wood decay hazard index values between 35 and 65, considered to be moderate decay hazard zones. But in recent 10 years (2003~2012), the wood decay hazard index was rapidly increased, resulting in showing many high decay hazard regions. The trend may be explained by the in crease of temperature and precipitation. The recent climate change of Korea turning into the weather of subtropical region may explain the increase of wood decay hazard index.