• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.435-456
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• 2006

This study examines the long-term spatial patterns and recent trends of seasonal onsets and durations defined by daily temperatures in South Korea for the period 1973-2004. Spatially, spring and winter onset dates show approximately 44 day and 63 day maximum difference respectively between south and north (Seongsanpo to Daegwallryeong) attributable to the impacts of latitudes and altitudes. In contrast, summer onset, which is more affected by proximity to oceans and altitudes than by latitudes, begins earlier in interior low elevated areas than in the coastal areas but earliest at higher latitudes than Jeiu Island. Five climatic types regarding the seasonal cycles in South Korea are spatially clustered according to the combination of longer seasonal durations. As a reflection of recent climate changes on seasonal cycles in South Korea, winter duration was shortened by 10 days during the post-1988 period due to a late winter onset of 4 days and an early spring onset of 6 days. The winter reduction began in the southern regions of the Korean Peninsula in the mid-1980s and spread northward during the 1990s period, ultimately appearing everywhere. In urbanized cities, where much of the surface is covered with asphalt or concrete, the winter reduction was intensified and summer duration was locally incremented. The reduced winter duration in recent decades shows significant teleconnections with variations of geopotential height (925hPa) in the eastern Arctic region ($0-90^{\circ}E$, $65-85^{\circ}N$) during the cold season. The reduction in winter duration in South Korea agrees with results in overall global warming trends as a climate change signal.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.30-42
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• 2016

Climate change are known to have had enormous impacts on plant phenology and thus to have damage on other species which are interacted within ecosystem. In Korea, however, it is difficult to analyze the relationship between climate and phenology due to the limitation of measurement data of plant phenological records. In this study, to be effective analysis of SOG(start of growing season), we used phenological transition dates by using satellite data. Then, we identified the most influential variable in variation of SOG throughout the relationship between SOG and temperature factors. As a result, there is a strong correlation between the SOG and April temperature, TSOGmin($3^{\circ}C$, 12days). This study is expected to be used for predicting plant phenological change using climate change scenario data.

• Journal of Embryo Transfer
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• v.1 no.1
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• pp.59-68
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• 1986

산양의 발정주기의 생리와 조절에 관한 최근 연구 보고들과 한국 재래산양의 대한 이들 연구 결과를 모아 고찰하였다. 온대지역에서 산양의 번식계절은 분명하나 한국재래산양의 경우는 비번식계절이 비교적 짧거나 계절적 무발정율이 낮은 편이며, 비번식계절에는 기능적 황체가 유지되지 않는다. 한국재래산양의 발정주기와 발정지속기간은 타품종과 비슷하며, 발정지속기간의 반복력은 매우 낮으며, 발정주기중의 progesterone과 estradiol-17$\beta$의 소장을 규명하였다. 한국재래산양의 경우 황체기에 PGF2 1-3mg을 투여하면 항체퇴행을 유기할 수 있으나 주기중의 투여시기에 따라 투여후 발정개시 시간에 차이가 있었다. 그리고 pro-gesterone priming후 PGF$\alpha$를 투여함으로써 효과적인 발정동기화를 이룰 수 있었다. 분만후 1개월경과 유상후 12일경에 발정이 재귀되었으며, 첫 발정 후 80%의 산양에서 5-7일의 단발정주기를 나타냈으며, 대부분의 과배란유기 산양에서도 단발정주기를 나타냈는데 이는 황체의 조기퇴행 때문이었다. 초발정후 3-5일에 GnRH를 연속 주사하면 단발정주기의 발생율이 유의적으로 감소되었다.

• Journal of Animal Environmental Science
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• v.15 no.2
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• pp.139-146
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• 2009

This study was carried out to investigate the reproductive and weaned performances in sow farms, which located in Boryeong city, Chungnam. Data surveyed a total of 10,394 litters of sow recorded from April, 2007 to March, 2008 were collected and analyzed. The results obtained were as follows; 1. The average of number of sow and farrowing rate were 314.10 sows and 78.77%, respectively. And then, there was not significant difference among seasons in number of sows, but significant difference among season was found in farrowing rate (p<0.05). 2. The average of litter size at farrowing and at initial sucking were 11.04 and 10.22 pigs, respectively. The significant differences were not all found in litter size among seasons. 3. The number of pigs, age and growth rate at weaning were 9.23 pigs, 25.77 days and 91.48%, respectively. The significant differences among seasons were not found in number of pigs and age at weaning. However, there was significant difference in growth rate at weaning (P<0.05). 4. The average of farrowing rate of sows per year, pigs from sow per year (PSY), and body weight at marketing were 2.25 times, 20.75 pigs, and 110.46 kg, respectively. The significant differences among seasons were not found in farrowing rate per year and weight at marketing, but that was found only in PSY (p<0.05), respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.208-217
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• 2023

Accurate estimation of dormancy breaking and first bloom dates is crucial for effective fire blight control by disease model such as Maryblyt in apple orchards. The duration from dormancy breaking to first bloom in apple trees was influenced by daily minimum temperatures during the dormant period. The purpose of this study is to investigate the relationship between minimum temperatures during this period and the time taken for flowering to commence. Webcam data from eight apple orchards, equipped by the National Institute of Horticultural and Herbal Science, were observed from 2019 to 2023 to determine the dates of starting bloom (B1). Additionally, the dormancy breaking dates for these eight sites were estimated using an apple chill day model, with a value of -100.5 DD, based on collected weather data. Two regressions were performed to analyze the relationships: the first regression between the number of days under 0℃ (X₁) and the time from calculated dormancy breaking to observed first bloom (Y), resulting in Y = 0.87 × X₁ + 40.76 with R² = 0.84. The second regression examined the starting date of breaking dormancy (X₂) and the duration from dormancy breaking to observed first bloom (Y), resulting in Y = -1.07 × X₂ + 143.62 with R² = 0.92. These findings suggest that apple anti-chill days are significantly affected by minimum temperatures during the period from dormancy breaking to flowering, indicating their importance in fire blight control measures.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.20-38
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• 2014

Vegetation phenology is the most important indicator of ecosystem response to climate change. Therefore it is necessary to continuously monitor forest phenology. This paper analyzes the phenological characteristics of forests in South Korea using the MODIS vegetation index with error from clouds or other sources removed using the HANTS algorithm. After using the HANTS algorithm to reduce the noise of the satellite-based vegetation index data, we were able to confirm that phenological transition dates varied strongly with altitudinal gradients. The dates of the start of the growing season, end of the growing season and the length of the growing season were estimated to vary by +0.71day/100m, -1.33day/100m and -2.04day/100m in needleleaf forests, +1.50day/100m, -1.54day/100m and -3.04day/100m in broadleaf forests, +1.39day/100m, -2.04day/100m and -3.43day/100m in mixed forests. We found a linear pattern of variation in response to altitudinal gradients that was related to air temperature. We also found that broadleaf forests are more sensitive to temperature changes compared to needleleaf forests.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.380-387
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• 2013

The objective of this study is to investigate the effect of elevated $CO_2$ and temperature on the phenology and reproductive ecological characteristics of Bupleurum latissimum. We measured characteristics of 4-year-old B. latissimum grown under control (ambient $CO_2$+ambient temperature, 340~370 ppm) and treatment (elevated $CO_2$+elevated temperature, 690~770 ppm) conditions in a glass house. The period of flowering, fruit appearance and fruit maturing was earlier by 4, 1, 2 days, respectively, under elevated $CO_2$ and temperature. The comparative weight of a single ripe fruit, all ripe fruits and total ripe and unripe fruits was higher per control than treated plants. However the other characteristics, such as no. of peduncle, matured fruits, total fruits per plant and fruit setting rate per plant of B. latissimum were not significantly affected by elevated $CO_2$ and temperature. The germination rate of B. latissimum was higher in control than in treatment plants. These results showed that the phenology of B. latissimuin might be well suited to an earlier growing season, and the response of reproductive characteristics of B. latissimuin is negatively influenced by global warming.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.549-556
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• 2011

We investigated the plant phenology on the threatened species for climate change in the summit area of Mt. Deogyusan which is a representative sub-alpine zone in Korea. We had performed the monitoring survey of plant phenology on 38 species including 20 trees and 18 herbs from May 2009 to November 2010. The investigated phenological charateristics were five dates for leafing, flowering, floral abscission, autumn leaf colors and leaf abscission on each plant species in sub-alpine region. The climate data were measured from November 2009 to December 2010. The range of temperature was from 30.4 to -$20.3^{\circ}C$ at Hyangjeokbong to Jungbong region, and the relative humidity was 100% to 3.4%. The leafing dates in 2010 were similar to 2009 or were 6-20 days delayed in most of the investigated species except Veratrum oxysepalum and Sanguisorba hakusanensis which showed 8 days earlier leafing dates in 2010. The biggest difference among phenological characters was found in flowering dates. The flowering dates of early Spring blooming species such as Heloniopsis koreana, Rhododendron yedoense for. poukhanense and Viola orientalis showed 13-20 days earlier in 2010, and the several summer flowering species as Viburnum opulus var. calvescens, Smilacina japonica and Bupleurum longeradiatum showed 6-10 days delay in 2010. The dates for floral abscission and autumn leaf colors in 2010 were delayed about 10-18 days, and leaf abscission dates were similar to 2009. The effects of climate change on the phenology for the threatened species in sub-alpine zones of Korea are occuring especially on flowering, floral abscission and autumn leaf colors.

• (The)Study of the Eastern Classic
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• no.67
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• pp.345-378
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• 2017

In the scriptures of "$Ch{\bar{u}}n-qi{\bar{u}}$(春秋)", the expression method of '$Ch{\bar{u}}n-w{\acute{a}}ng-zh{\bar{e}}ng-yu{\grave{e}}$(春王正月 : It's spring. It's the first month regulated by the king.)' was used as Jì-yuè-fǎ(紀月法 : the rules to determine the first month(正月)), the month of winter solstice was regarded as the first month of a year, and three years since then were named as $Ch{\bar{u}}n$(春 : spring). With regard to this "$Ch{\bar{u}}n-qi{\bar{u}}$"Wáng-lì("春秋"王曆 : the calendar regulated by the king of $Zh{\bar{o}}u$(周) dynasty in "$Ch{\bar{u}}n-qi{\bar{u}}$"), depending on whether Confucius(孔子) changed and recorded the names of the months and the season or not, there were three different arguments; the theory that 'Confucius changed the names of both the months and the season'(孔子改月 改時說), the view that 'Confucius changed the name of the season, not the names of the months'(孔子不改月 改時說), and then the theory that 'Confucius changed neither the names of the months nor the name of the season'(孔子不改月 不改時) since Song(宋) dynasty. The first view was taken by $Hh{\acute{u}}-{\bar{a}}n-gu{\acute{o}}$(胡安國) and $C{\grave{a}}i-ch{\acute{e}}n$(蔡沈), and the second theory was mentioned by Chéng-yí(程?) and Zhū-zǐ(朱子). The advocates of the third view had become remarkable since Ming(明) dynasty, and one of representatives was Wàng-yáng-míng(王陽明). All of them based their arguments on ancient scriptures and Confucian legal books, and there were cases of taking the same records as the support for different opinions. Confucius' so-called 'Chūn-qiū-bǐ-fǎ(春秋筆法 : the method to describe historical facts by making clear discrimination between right and wrong)' and '$Sh{\grave{u}}-{\acute{e}}r-b{\grave{u}}-zu{\grave{o}}$(述而不作 : the attitude to succeed virtuous men's achievements and only explain and describe them not creating and adding new contents)' could come from thoughts of $Z{\bar{u}}n-w{\acute{a}}ng$(尊王 : to respect the king with the virtues of benevolence, righteousness, propriety, wisdom and sincerity). Therefore, even though Confucius is assumed to have been the writer of "$Ch{\bar{u}}n-qi{\bar{u}}$(春秋)", whether he actually changed and recorded the names of the months and the season in the calendar used in "$Ch{\bar{u}}n-qi{\bar{u}}$" is doubtful. These theories on Confucius's intervention in the calendar of "$Ch{\bar{u}}n-qi{\bar{u}}$" hadn't been discussed as conflicting in reality until Tang(唐) dynasty.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.172-177
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• 2011

The study sought to determine the efficient management of Korean aucha perch by estimating the potential yield (PY), which means the maximum sustainable yield (MSY) based on the optimal stock, in the mid-upper region of the Seomjin River watershed from August 2008 to April 2009. The stock assessment was conducted by the swept area method and PY was estimated by a modified fisheries management system based on the allowable biological catch. Also, the yield-per-recruit analysis (Beverton and Holt, 1957) was used to review the efficient management of resource, Coreoperca herzi. The age at first capture ($t_c$) was 1.464 age and converted body length was 7.8 cm. Concerning current fishing intensities, the instantaneous coefficient of fishing mortality (F) was estimated to be 0.061 $year^{-1}$; yield-per-recruit analysis estimated the current yield per recruit as 4.124 g with F and $t_c$. The fishing mortality of Allowable Biological Catch ($F_{ABC}$) based on the current $t_c$ and F was estimated to be 0.401 $year^{-1}$, therefore, the optimum fishing intensities could be achieved at the higher fishing intensity for Coreoperca herzi. The calculated annual stock of Coreoperca herzi was 3,048 kg, the potential yield was estimated to be 861 kg with $t_c$ and $F_{ABC}$ at the fixed current level. Using yield-per-recruit analysis, if F and $t_c$ were set at 0.643 $year^{-1}$ and 3 age, respectively, the yield per recruit would be predicted to increase 3.4-fold, from 4.12 g to 13.84 g.