• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.759-768
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• 2019

This study was conducted to estimate the mean annual extreme minimum temperature raster and predict the potential distribution of the invasive plant, Ipomoea triloba, on the Korean peninsula. We collected annual extreme minimum temperature and mean coldest month minimum temperature data from 129 weather stations on the Korean peninsula from 1990-2019 and used this data to create a linear regression model. The min temperature of the coldest month raster from Worldclim V2 were used to estimate a 30 second spatial resolution, mean annual extreme minimum temperature raster of the Korean peninsula using a regression model. We created three climatic rasters of the Korean peninsula for use with the Proto3 species distribution model and input the estimated mean annual extreme minimum temperature raster, a Köppen-Geiger climate class raster from Beck et al. (2018), and we also used the mean annual precipitation from Worldclim V2. The potential distribution of I. triloba was estimated using the Proto3 model with 117 occurrence points. As a result, the estimated area for a potential distribution of I. triloba was found to be 50.7% (111,969 ㎢) of the Korean peninsula.

• Atmosphere
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• v.33 no.5
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• pp.477-492
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• 2023

Based on the new climate normals (1991~2020), annual mean, maximum and minimum temperature is 12.5℃, 18.2℃, and 7.7℃, respectively while annual precipitation is 1,331.7 mm, the annual mean wind speed is 2.0 m s^-1, and the relative humidity is 67.8% in the Republic of Korea. Compared to 1981~2010 normal, annual mean temperature increased by 0.2℃, maximum and minimum temperatures increased by 0.3℃, while the amount of precipitation (0.7%) and relative humidity (1.1%) decreased. There was no distinct change in annual mean wind speed. The spatial range of the annual mean temperature in the new normals is large from 7.1 to 16.9℃. Annual precipitation showed a high regional variability, ranging from 787.3 to 2,030.0 mm. The annual mean relative humidity decreased at most weather stations due to the rise in temperature, and the annual mean wind speed did not show any distinct difference between the new and old normals. With the addition of a warmer decade (2011~2020), temperatures all increased consistently and in particular, the increase in the maximum temperature, which had not significantly changed in previous decades, was evident. The increasing trend of annual and summer precipitation by the 2010s has disappeared in the new normals. Among extreme climate indices, MxT30 (Daily maximum temperature ≥ 33℃ days), MnT25 (Daily minimum temperature ≥ 25℃ days), and PH30 (1 hour maximum precipitation ≥ 30 mm days) increased while MnT-10 (Daily minimum temperature < -10℃ days) and W13.9 (Daily maximum wind speed ≥ 13.9 m/s days) decreased at a statistically significant level. It is thought that a detailed study on the different trends of climate elements and extreme climate indices by region should be conducted in the future.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.711-721
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• 2004

The aim of this study is to clarify whether frequency and/or severity of extreme climate events have changed significantly in Korea during recent years. Using the best available daily data, spatial and temporal aspects of ten climate change indicators are investigated on an annual and seasonal basis for the periods of 1954-1999. A systematic increase in the $90^{th}$ percentile of daily minimum temperatures at most of the analyzed areas has been observed. This increase is accompanied by a similar reduction in the number of frost days and a significant lengthening of the thermal growing season. Although the intra-annual extreme temperature range is based on only two observations, it provides a very robust and significant measure of declining extreme temperature variability. The five precipitation-related indicators show no distinct changing patterns for spatial and temporal distribution except for the regional series of maximum consecutive dry days. Interestingly, the regional series of consecutive dry days have increased significantly while the daily rainfall intensity index and the fraction of annual total precipitation due to events exceeding the $95^{th}$ percentile for 1901-1990 normals have insignificantly increased.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.77-96
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• 2017

This study was carried out to clarify the climatic factors of the freezing injury for the judgement on the adaptation areas of evergreen broad-leaved trees. We surveyed and analyzed the climatic factors of the freezing injury to Machilus thunbergii Siebold & Zucc. on the streets with the analyzation of planting grounds, soil conditions and the surrounding buildings. This study showed that only the minimum air temperature factor out of the other climate elements, which were the annual precipitation; the average annual temperature; the average monthly temperature of january; the average monthly minimum temperature of January; the average temperature of the coldest month; the warmth index and the coldness index, was matched up with the previous theories and reports on the freezing damages on the evergreen broad leaved trees and Machilus thunbergii Siebold & Zucc. The freezing injury of Machilus thunbergii Siebold & Zucc was occurred when the mean minimum temperature of the coldest month(TMC) in winter season fell down below $-4.1^{\circ}C$ and the temperature fell down below $-9.2^{\circ}C$. The freezing damage on Machilus thunbergii Siebold & Zucc surrounded by high buildings were less than those surrounded by low buildings or at non buildings.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.69-74
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• 2015

To analyze quantitatively environmental characteristics of cultivation area of citrus, Satsuma mandarin (Citrus unshiu Marc.), we made digital maps of environmental elements such as topography and climate. Elevation, degree of slope, and slope aspect were selected as elements of topological environment, and the annual mean air temperature, annual total precipitation, mean air temperature on January, extreme value of daily minimum air temperature, and the number of days below $-5^{\circ}C$ were selected as elements of climatic environments. The grid values of 8 environmental elements were extracted by shape of citrus farm area and analyzed distribution patterns. We can determine 3 agroclimatic criteria for growing Satsuma mandarin as over $14.5^{\circ}C$ of annual mean air temperature, over $-10.0^{\circ}C$ of extreme value of daily minimum air temperature, and less 5 days of below $-5^{\circ}C$ of daily minimum air temperature.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.124-131
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• 2008

To investigate main air temperature factors correlated to difference of fruit characteristics according to cultivating areas, fruit and air temperature characteristics of eight cultivating areas of 'Fuyu' persimmon were analyzed by principle components and multiple regression analysis. The first principal components extracted from 16 air temperature factors was annual mean temperature, mean temperature during October, annual mean minimum extreme temperature, mean temperature during growing period, and so forth. The second principal components was mean temperature during May and June and so forth. And cumulative contribution was 91.4%. The five of eight cultivating area had clearly the difference of main factors or the correlated direction among cultivating areas. In multiple regression analysis between the extracted main factors and fruit characteristics, fruit hight were highly correlated with mean temperature during growing period ($X_8$) and cumulative temperature ($X_6$), and the regression equation was $Y=150.55-5.375X_8+ 0.014X_6(r^2=0.843)$. Also this regression equation was affected by mean minimum temperature during growing period, cumulative temperature, and mean temperature during August. Fruit diameter was negatively correlated with mean temperature during growing period, flesh browning rate and Hunter a value of peel color were positively correlated with mean minimum temperature during growing period and annual minimum air temperature, respectively.

• Journal of the Korean earth science society
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• v.27 no.2
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• pp.188-197
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• 2006

The characteristics of variability of temperature and precipitation in Jeju were investigated using data observed in Jeju station for from 1924 to 2004. Annual mean temperature change for the last 81 years is $0.02^{\circ}C$ increase per year. After 1980, the increase is $0.05^{\circ}C$ per year, larger than the former. The increase of the minimum temperature is larger than that of the maximum temperature in Jeju and has resulted in the increase of mean temperature. The frequency of climate extreme occurrence of temperature and rainfall was also investigated. The temporal variation of frequency of the extremely higher temperature has increased in the 1980's with global warming. The appearance of the extremely lower minimum temperature has decreased during the summers and winters. The facts that the frequencies of rainy days has decreased and heavy rainfall days of more than 80 mm per day in precipitation has increased indicate the increase of rainfall intensity.

• Journal of the Korean Geographical Society
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• v.43 no.5
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• pp.681-700
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• 2008

In this study, the spatial and temporal patterns of changes in means and extreme events of temperature and precipitation across the Republic of Korea over the last 35 years (1973-2007) are examined. Over the study period, meteorological winter (December-February) mean minimum (maximum) temperature has increased by $+0.54^{\circ}C$/decade ($+0.6^{\circ}C$/decade), while there have been no significant changes in meteorological summer (June-August) mean temperatures. According to analyses of upper or lower $10^{th}$ percentile-based extreme temperature indices, the annual frequency of cool nights (days) has decreased by -9.2 days/decade (-3.3 days/decade), while the annual frequency of warm nights (days) has increased by +4.9 days/decade (+6.8 days/decade). In contrast, the increase rates of summer warm nights (+8.0 days/$^{\circ}C$) and days (+6.6 days/$^{\circ}C$) relative to changes in summer means minimum and maximum temperatures means are greater than the decreasing rates of winter nights (-5.2 days/$^{\circ}C$) and days (-4.3 days/$^{\circ}C$) relative to changes in winter temperatures. These results demonstrate that seasonal and diurnal asymmetric changes in extreme temperature events have occurred. Moreover, annual total precipitation has increased by 85.5 mm/decade particularly in July and August, which led to the shift of a bimodal behavior of summer precipitation into a multi-modal structure. These changes have resulted from the intensification of heavy rainfall events above 40mm in recent decades, and spatially the statistically-significant increases in these heavy rainfall events are observed around the Taebaek mountain region.

• Journal of People, Plants, and Environment
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• v.24 no.5
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• pp.519-527
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• 2021

Background and objective: This study was conducted to establish a Plant Hardiness Zone (PHZ) map, investigate the effect of global warming on changes in PHZ, and elucidate the difference in the distribution of evergreen trees between the central and southern region within hardiness Zone 7b in Korea. Methods: Mean annual extreme minimum temperature (EMT) and related temperature fluctuation data for 40 years (1981 to 2020) in each of the meteorological observation points were extracted from the Open MET Data Portal of the Korea Meteorological Administration. Using EMT data from 60 meteorological observation points, PHZs were classified according to temperature range in the USDA Plant Hardiness Zone Map. Changes in PHZs for each decade related to the effects of global warming were analyzed. Temperature fluctuation before and after the day of EMT were analyzed for 4 areas of Seoul, Suwon, Suncheon, and Jinju falling under Zone 7b. For statistical analysis, descriptive statistics and ANOVA were performed using the IBM SPSS 22 Statistics software package. Results: Plant hardiness zones in Korea ranged from 6a to 9b. Over four decades, changes to warmer PHZ occurred in 10 areas, especially in colder ones. Based on the analysis of daily temperature fluctuation, the duration of sub-zero temperatures was at least 2 days in Seoul and Suwon, while daily maximum temperatures were above zero in Suncheon and Jinju before and after EMT day. Conclusion: It was found that the duration of sub-zero temperatures in a given area is an important factor affecting the distribution of evergreen trees in PHZ 7b.

• Journal of the Korean Geographical Society
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• v.47 no.2
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• pp.208-225
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• 2012

The spatial characteristics of changes in extreme temperature indices for 2070-2099 relative to 1971-2000 in the Republic of Korea were investigated using daily maximum (Tmax) and minimum (Tmin) temperature data from a regional climate model (HadGEM3-RA) based on the IPCC RCP4.5/8.5 at 12.5km grid spacing and observations. Six temperature-based indices were selected to consider the frequency and intensity of extreme temperature events. For validation during the reference period (1971-2000), the simulated Tmax and Tmin distributions reasonably reproduce annual and seasonal characteristics not only for the relative probability but also the variation range. In the future (2070-2099), the occurrence of summer days (SD) and tropical nights (TR) is projected to be more frequent in the entire region while the occurrence of ice days (ID) and frost days (FD) is likely to decrease. The increase of averaged Tmax above 95th percentile (TX95) and Tmin below 5th percentile (TN5) is also projected. These changes are more pronounced under RCP8.5 scenario than RCP4.5. The changes in extreme temperature indices except for FD show significant correlations with altitude, and the changes in ID, TR, and TN5 also show significant correlations with latitude. The mountainous regions are projected to be more influenced by an increase of low extreme temperature than low altitude while the southern coast is likely to be more influenced by an increase of tropical nights.