• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.361-370
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• 1982

The effects of climatic factors on organisms lire variable and complex, and it, however, can be interpreted in terms of those on the distribution and those on the population densities. The distribution of an organism may largely be determined by the temperatures, except some temporal organisms which are depended on the air mass movements. Population density of an organism is determined by various climatic factors, such as previous winter temperature, temperature of growing season and rainfall. The start of growing season of the rice plants has been shifted to earlier since last decade in Korea. This may mean that the overall climatic condition during the growing season might be considerably different from those in past years, and such a difference in climatic conditions might have close relation with the recent status of the diseases and insect pests through direct effects on the physiology and population dynamics of the organisms, as well as through on the biotic associations of the pest organisms. The white back planthopper and brown planthopper have become the key insect pests in Korea in recent years. They are migratory and have high reproductive pontentials and more generations than average residential insects. The synchronization of the migrants and physiological condition of the rice plants seems to be the important factors in relation to the recent outbreaks of these insects; the high reproductive rate can be obtained with the growth stage of rice being 30-50 days after transplanting. The modication of the microclimate associated with high plant density and some other introduced new cultural techniques also have some relation with the outbreak. The key diseases of the rice are the blast disease, sheath blight and the bacterial leaf blight. For the rice blast, the seedling blast and leaf blast during the early growing season and the neck blast, have become more serious, the former may be related to hotbed nursery and the later may be related to the high humidity in early August, and synchronization of the heading time which has been shifted to early part from middle or late part of August. In general, for the rice diseases, the development of the new races have been the most serious which are largely resulted from the introduction of the new varieties, but it also seems to be related with the prolonged periods of the favorable condition associated with the shifted growing seasons. In general, the diseases and insect pest problems have become much more variable and complex, and control measures should be based on the thorough knowledge of the ecology of the pest organisms, that is, effects of various environmental factors on the disease cycle; spore release, spore deposition, infection, colonization and sporulation of the disease organisms, and those on the development, reproductive potentials, dispersal, age specific responses of the insects. The well organized real-time pest management systems, such as alfalfa weevil management system developed at the Purdue University in U.S., is the prime importance for the implementation of the pest management principles.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.151-158
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• 1997

This study was carried out to identify how soybean seed oil is influenced by climatic factors and to investigate how genotypes differ in their responses. Twelve lines selected were studied in 13 environments of North Carolina. Responses of oil concentration and total seed oil to climatic variables were investigated using a linear regression model. The best response models were determined. There were wide climatic effects in oil concentration and total seed oil. The lowest oil concentration environment was characterized by the most HTD and the smallest VADTRg and the lowest total oil environment was distinguished by the largest VADTRa and the smallest VMnDT. For oil concentration, most lines except for NC107 responded negatively to MxDT, HTD, ADT, and ADTRg, although they had different degrees of sensitivities, indication that warmer temperature may result in decreased oil concentration. All lines responded positively to VMnDT, VADTRg, and ADRa, although they had different degrees of sensitivities, suggesting that larger variation in minimum daily temperature and average daily temperature range and more average daily rain may result in increased oil concentration. Eleven lines had best response models with 1 to 3 variables. However, although NC109 did not show a significant sensitivity to any variable, it had the best response model with 2 significant variables, demonstrating that an interaction between 2 variables might be more critical in determining oil concentration than one variable.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.99-106
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• 2011

Here we reported an analyzing result for the relationship between climatic variables and rice(c.v. Odaebyeo and Ilpumbyeo) yield characteristics (including some growth characteristics) based on a long-term observed data at GARES and at KMA for rice and weather, respectively. Most of crop parameters investigated, such as heading date, culm height, panicle number $m^{-2}$, grain number $panicle^{-1}$ ripening rate, 1,000 grain weight and yield were strongly affected by wind velocity and relative humidity, as well as by daily mean air temperature, precipitation, sunshine hours and daily variations in air temperature depending on variety and crop developmental stages. Air velocity and relative humidity had not been studied as climatic variables affecting on the characteristics of rice growth and yield, however, they turned out to affect all the characteristics of rice investigated, especially ripening rate and yield, as much as any other climatic variables in this study. Air velocity appeared to affect highly the culm height and yield of Odaebyeo and ilpumbyeo. Relative humidity appeared to affect highly grain number and ripening rate of Odaebyeo and yield of Ilpumbyeo. Consequently Rice yield revealed to increase in the climatic conditions of high air velocity and low relative humidity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.105-113
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• 2001

This study was conducted to reveal the effects of local climatic conditions on the vegetative growth in a mature stand of Korean white pine based on climatic estimates. For this, the annual increments of stand variables such as DBH, height, basal area and volume were measured and estimated for seven years from 1974 to 1980. The local climatic conditions in the study site were also estimated by both a topoclimatological method and a spatial statistical technique. The local climatic conditions were then correlated with and regressed on the growth factors to reveal the relationships between the climatic estimates and the growth. It is found that relatively high temperatures had positive effects on the diameter growth. The yearly diameter growth increased when each of mean, maximum, and minimum temperature during the growing season was high. Height growth showed positively significant correlation with three climatic variables. The most important variable influencing height growth was the average of maximum temperature for 10 months from January to October. It means that the higher the average of maximum temperature for 10 months from January to October is, the more height growth of Korean white pine increases. Other climatic variables related to height growth were average of minimum temperature for 3 months in the early growing season and mean relative humidity for the growing season. Six climatic variables related to temperature had effects on basal area increment and all of them were positively correlated with basal area increment. Especially, temperatures from January to March were important factors affecting the basal area increment. In volume increment, high correlation was also recognized with most of temperature variables. This tendency was the same as the results in diameter and hight increments. This means that the volume growth increases when temperatures during the growing season are relatively high.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.3
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• pp.205-214
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• 2016

The objective of this study was to construct a forage rye (FR) dry matter yield (DMY) estimation model based on climate data by locations in South Korea. The data set (n = 549) during 29 years were used. Six optimal climatic variables were selected through stepwise multiple regression analysis with DMY as the response variable. Subsequently, via general linear model, the final model including the six climatic variables and cultivated locations as dummy variables was constructed as follows: DMY = 104.166SGD + 1.454AAT + 147.863MTJ + 59.183PAT150 - 4.693SRF + 45.106SRD - 5230.001 + Location, where SGD was spring growing days, AAT was autumnal accumulated temperature, MTJ was mean temperature in January, PAT150 was period to accumulated temperature 150, SRF was spring rainfall, and SRD was spring rainfall days. The model constructed in this research could explain 24.4 % of the variations in DMY of FR. The homoscedasticity and the assumption that the mean of the residuals were equal to zero was satisfied. The goodness-of-fit of the model was proper based on most scatters of the predicted DMY values fell within the 95% confidence interval.

• Journal of the Ergonomics Society of Korea
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• v.17 no.3
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• pp.41-59
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• 1998

Thermal comfort aspect of a locally-cooled target space in warm and humid environments(typically in the rainy summer season) was studied in view of PPD index. First. theoretical analyses were conducted to examine the effect of the governing parameters(such as air temperature, relative humidity and air velocity, etc.) using a computer model. Secondly, experimental investigations were also performed in a climatic room designed to simulate corresponding thermal conditions of outdoor environments. During the tests, temporal variation of PPD was recorded as functions of climatic variables(outdoor and indoor temperatures, relative humidity and air velocity) for the given human factors(metabolic heat generation and clothing). From both theoretical and experimental investigations, air temperature and air velocity were found to be the most dominant parameters affecting PPD of the target space. Results were summarized as: 1. Relative humidity of the locally-cooled target space tends to approach that of outdoor's as the space is subjected to an ON-OFF mode of cooling, since moisture potential of the two rooms reaches an equalized state as a result of moisture diffusion. 2. It was recognized that changes in relative humidity did not show any significance in view of thermal comfort as was reported in the previous studies, while variations of both temperature and air velocity caused relatively large changes in the degree of thermal comfort. 3. In-door environment should be evaluated in terms of PPD instead of relative humidity commonly recognized as an important climatic variable particularly in warm and humid environments.

• Korean Journal of Plant Resources
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• v.2 no.2
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• pp.298-305
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• 1989

This study was carried out to understand the immigration period, climatic conditions for mass immigration and bionomical characters ofthe brown pLanthopper(BPH) in Hae NamThe results are as follows ; (1) The Periods of first immigraion and mass immigration of BPH , were from the late June to early JuLy and from earlyto mid JuLy in HaeNam, that were faster about 15-30days than in inland of ChonnanThe climatic factors that related closely to mass immigration wereas follows ; temp.: $20{\;}~{\;}25^{\circ}C$, humidity : 86 ~ 95 % , wind direcion : SW, wind velocity: 1.0 ~ 2.9gm/sec. (2)The population of immigranted BPH was in the field much more overthe mountain near coast than other places . Biotype composition showed that biotype I was on the decrease and biotype II, III were on the increase (3)The bionomical characters were variable, for climatic conditions,that egg stage, nymphal stage and adult stafe of immigranted BPHwere 9-12days, 13-16days and 12-36days respectively, that hatchability(%) and emergence rate ( % ) were higher than 80%. The adult Longevity in female and macropterous BPH showed Longerthan that of male and brachypterous respectively. (4) The distance of nymphs and brachypterous adults move by walking was within 16cm over the water surface, by hopping was within 20cm horizontally.

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.908-913
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• 2010

This study analyzed the impact of climatic and topographic factors on tree radial growth of Pinus densiflora and Quercus spp. in central regions of Korea. To find the relationship between annual tree radial growth and climatic factors, we took the core samples from individual trees and measured the tree radial width. On the assumption that the tree radial growth is related to the tree age, we estimated the radial growth by the tree age as an independent variable. Also, we estimated the standard growth, defined as the radial growth of trees aged 30. As results, we found the spatial auto-correlation in the radial growth of the red pine. Moreover, we also found the relationships between climatic and topographic and the standard growth using the GAM (Generalized Additive Model). Increase of temperature has negative impacts on the radial growth of Pinus densiflora, while it has positive impacts on the radial growth of Quercus spp.. On the other hands, increase of precipitation has negative impacts on the radial growth of both species. Lastly, we predicted the spatial distribution changes of Pinus densiflora and Quercus spp. using the temperature increase scenario and the Geographic Information System (GIS) based forest type map. We could predict that Pinus densiflora is more vulnerable than Quercus spp. to climate change so that the habitats of Pinus densiflora will be gradually changed to the habitats of Quercus spp. in eastern coastal and southern regions of Korea after 60 years.

• Korean Journal of Hydrosciences
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• v.6
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• pp.39-49
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• 1995

The surface hydrology of large land areas is susceptible to several preferred stable states with transitions between stable states induced by stochastic fluctuation. This comes about due to the close couping of land surface and atmospheric interaction. An interesting and important issue is the duration of residence in each mode. Mean transition times between the stable modes are analyzed for different model parameters or climatic types. In an example situation of this differential equation exhibits a bimodal probability distribution of soil moisture states. Uncertainty analysis regarding the model parameters is performed using a Monte-Carlo simulation method. The method developed in this research may reveal some important characteristics of soil moisture or precipitation over a large area, in particular, those relating to abrupt change in soil moisture or preciptation having extremely variable duration.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1755-1763
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• 2015

The objective of this study is to empirically analyze the relationship between sea temperature and jellyfish blooms. Ever since the 2000s, jellyfish population has been dramatically increased, which brought negative influence on the national health and the fisheries activities. Jellyfish blooms have been recognized as an effect of climate change, but there has been no empirical evidence to support such relationship. In this paper, the relationship between sea temperature and jellyfish blooms has been analyzed by using the regional jellyfish monitoring data and coastal stationary observing data of National Institute of Fisheries Science. Since the dependant variable carries left censoring issues, we used the panel tobit model. Our results indicate that there are statistically significant positive relationship between sea temperature and jellyfish blooms.