• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.865-881
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• 2010

To evaluate influence of the future climate change on water environment, it is necessary to use a rainfall-runoff model, or a basin model allowing us to simultaneously simulate water quality factors such as sediment and nutrient material. Thus, SWAT is selected as a watershed-based model and Nakdong river basin is chosen as a target basin for this study. To apply climate change scenarios as input data to SWAT, Australian model (CSIRO: Mk3.0, CSMK) and Canadian models (CCCma: CGCM3-T47, CT47) of GCMs are used. Each GCMs which have A2, B1, and A1B scenarios effectively represent the climate characteristics of the Korean peninsula. For detecting climate change in Nakdong river basin, precipitation and temperature, increasing rate of these were analyzed in each scenarios. By simulation results, flow and increasing rate of these were analyzed at particular points which are important in the object basin. Flow and variation of flow in the scenarios for present and future climate changes were compared and analyzed by years, seasons, divided into mid terms. In most of the points temperature and flow rate are increased, because climate change is expected to have a significant effect on rising water temperature and flow rate of river and lake, further on the basis of this study result should set enhancing up water control project of hydraulic structures caused by increasing outer discharge of the Nakdong River Basin due to climate change.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.297-304
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• 2020

BACKGROUND: Emission of nitrous oxide (N2O) from the soil is expected to depend on the types of nitrogen fertilizer used. Biochar has recently been proposed as a potential mitigation of climate change by reducing the N2O emission. Although laboratory studies reported that biochar applications could reduce N2O emission, the number of field-based studies is still limited. Therefore, a field experiment was conducted to investigate the effect of biochar on N2O emission when different nitrogen fertilizers were applied in corn cultivated field. METHODS AND RESULTS: The field experiment consisted of six treatments: urea fertilizer without biochar (U), ammonium sulfate fertilizer without biochar (A), oil cake fertilizer without biochar (O), urea fertilizer with biochar (U+B), ammonium sulfate fertilizer with biochar (A+B), and oil cake fertilizer with biochar (O+B). Biochar was applied at a rate of 10 t/ha. Greenhouse gas fluxes were measured during growing seasons using static vented chambers. The cumulative N2O emissions were 0.99 kg/ha in the U, 1.23 kg/ha in the A, 3.25 kg/ha in the O, 1.19 kg/ha in the U+B, 0.86 kg/ha in the A+B, and 1.55 kg/ha in the O+B. CONCLUSION: It was found that N2O emission was related to application of both nitrogen fertilizer type and biochar. In particular, the N2O reduction effect was the highest in the corn field incorporated with biochar when oil cake was applied to the soil.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.1-34
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• 1974

These experiments pertain to various factors influencing the quantitative characters of cocoon crops in summer and early autumn seasons. Initially, in order to establish the possible ways of the silkworm rearing more than three times a year in Korea, the author attempted to get further information about the various factors affecting the cocoon crop in every silkworm rearing season. The trials were conducted eleven times a year at four places for three years. The field trial was conducted with 19 typical sericultural farmers who had been surveyed. At the same time the author statistically analyzed the various factors in close relation to tile cocoon crop in autumn season. The effect of guidance on 40 sericultural farmers was analyzed, comparing higher level farmers with lower level farmers ; and the author surveyed 758 non-guided farmers near the guided farmers during both spring and autumn seasons. In addition, another trial on the seasonal change of leaf quality was attempted with artificial diets prepared with leaves grown in each season. It was found that related factors to cocoon crops in summer and early autumn seasons appeared to be leaf quality, and temperature for young and grown larvae. A 2$^4$ factorial experiment was designed in summer season, and another design with one more level of varied temperature or hard leaf added to a 24 factorial experiment was conducted in early autumn. The experimental results can be summarized： 1. Study on the cocoon crops in the different rearing seasons 1) It was shown that earlier brushing of silkworm generally produced the most abundant cocoon crop in spring season, and earlier or later than the conventional brushing season, especially earlier brushing was unfavorable for the abundant cocoon crop in autumn season. 2) The cocoon crop was affected by the rearing season, and decreases in order of sire with spring, autumn, late autumn, summer and early autumn seasons. 3) It was Proved that ordinary rearing and branch rearing were possibles 4 times a year ; in the 1st, 3rd, 8th, and 10th brushing season. But the 11th brushing season was more favorable for the most abundant cocoon crop of branch rearing, instead of the 10th brushing season with ordinary rearing. 2. Study on the main factors affecting the cocoon crop in autumn season 1) Accumulated pathogens were a lethal factor leading to a bad cocoon crop through neglect of disinfection of rearing room and instruments. 2) Additional factors leading to a poor cocoon crop were unfavorable for rearing temperature and humidity, dense population, poor choice of moderately ripened leaf, and poor feeding techniques. However, it seemed that there was no relationship between the cocoon crop and management of farm. 3) The percentage of cocoon shell seemed to be mostly affected by leaf quality, and secondarily affected by the accumulation of pathogens. 3. Study on the effect of guidance on rearing techniques 1) The guided farms produced an average yearly yield of 29.0kg of cocoons, which varied from 32.3kg to 25.817g of cocoon yield per box in spring versus autumn, respectively. Those figures indicated an annual average increase of 26% of cocoon yield over yields of non-guided farmers. An increase of 20% of cocoon yield in spring and 35% of cocoon yield in autumn were responsible. 2) On guided farms 77.1 and 83.7% of total cocoon yields in the spring and autumn seasons, respectively, exceeded 3rd grade. This amounted to increases of 14.1 and 11.3% in cocoon yield and quality over those of non-guided farms. 3) The average annual cocoon yield on guided farms was 28.9kg per box, based on a range of 31.2kg to 26.9kg per box in spring and autumn seasons, respectively. This represented an 8% increase in cocoon yield on farms one year after guidance, as opposed to non-guided farms. This yield increase was due to 3 and 16% cocoon yield increases in spring and autumn crops. 4) Guidance had no effect on higher level farms, but was responsible for 19% of the increases in production on lower level farms. 4. Study on the seasonal change of leaf quality 1) In tests with grown larvae, leaves of tile spring crop incorporated in artificial diets produced the best cocoon crop; followed by leaves of the late autumn, summer, autumn, and early autumn crops. 2) The cocoon crop for young larvae as well as for grown larvae varied with the season of leaf used. 5. Study on factors affecting the cocoon crops in summer and early autumn A. Early autumn season 1) Survival rate and cocoon yield were significantly decreased at high rearing temperatures for young larvae 2) Survival rate, cocoon yield, and cocoon quality were adversely affected by high rearing temperatures for grown larvae. Therefore increases of cocoon quantity and improvement of cocoon quality are dependent on maintaining optimum temperatures. 3) Decreases in individual cocoon weight and longer larval periods resulted with feeding of soft leaf and hard leaf to young larvae, but the survival rate, cocoon yield and weight of cocoon shell were not influenced. 4) Cocoon yield and cocoon quality were influenced by feeding of hard leaf to grown larvae, but survival rate was not influenced by the feeding of soft leaf and hard leaf. 5) When grown larvae were inevitably raised at varied temperatures, application of varied temperature in the raising of both young and grown larvae was desirable. Further research concerning this matter must be considered. B. Summer season 1) Cocoon yield and single cocoon weight were decreased at high temperatures for young larvae and survival rate was also affected. 2) Cocoon yield, survival rate. and cocoon quality were considerably decreased at high rearing temperatures for grown larval stages.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.207-221
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• 2012

Air temperature in Korea has increased by $1.5^{\circ}C$ over the last 100 years, which is nearly twice the global average rate during the same period. Moreover, it is projected that such change in temperature will continue in the 21st century. The objective of this study was to evaluate the potential impacts of future climate change on the rice production and adaptation methods in Korea. Climate data for the baseline (1971~2000) and the three future climate (2011~2040, 2041~2070, and 2071~2100) at fifty six sites in South Korea under IPCC SRES A1B scenario were used as the input to the rice crop model ORYZA2000. Six experimental schemes were carried out to evaluate the combined effects of climatic warming, $CO_2$ fertilization, and cropping season on rice production. We found that the average production in 2071~2100 would decrease by 23%, 27%, and 29% for early, middle, and middle-late rice maturing type, respectively, when cropping seasons were fixed. In contrast, predicted yield reduction was ~0%, 6%, and 7%, for early, middle, and middle-late rice maturing type, respectively, when cropping seasons were changed. Analysis of variation suggested that climatic warming, $CO_2$ fertilization, cropping season, and rice maturing type contributed 60, 10, 12, and 2% of rice yield, respectively. In addition, regression analysis suggested 14~46 and 53~86% of variations in rice yield were explained by grain number and filled grain ratio, respectively, when cropping season was fixed. On the other hand, 46~78 and 22~53% of variations were explained respectively with changing cropping season. It was projected that sterility caused by high temperature would have no effect on rice yield. As a result, rice yield reduction in the future climate in Korea would resulted from low filled grain ratio due to high growing temperature during grain-filling period because the $CO_2$ fertilization was insufficient to negate the negative effect of climatic warming. However, adjusting cropping seasons to future climate change may alleviate the rice production reduction by minimizing negative effect of climatic warming without altering positive effect of $CO_2$ fertilization, which improves weather condition during the grain-filling period.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.364-371
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• 2014

BACKGROUND: To evaluate the impact of rapid temperature change at spring and the early summer seasons in climate change, we have investigated the physiological response and yield of onion in a greenhouse with thermostat control system. METHODS AND RESULTS: Seedlings of onion(cv. Sunshine) were planted on October 30, 2012 and harvested on May 30, 2013. The used treatments(March-April-May) for a rapid temperature change were T0(control): $6.0-10.4-17.2^{\circ}C$, T1: $6.0-5.4(-5)-17.2^{\circ}C$, T2: $6.0-10.4-22.2(+5)^{\circ}C$ and T3: $6.0-5.4(-5)-22.2(+5)^{\circ}C$. Total yields of bulb within the temperature change as high temperature treatment T2 and control treatment T0 were increased significantly(p<0.05), as compared to the low temperature treatment T1. Low temperature conditions significantly (p<0.05) reduced plant height, SPAD reading, crude protein and fiber etc., as compared to the TO and T2. CONCLUSION: The rapid temperature changes were highly affected by low temperature than high temperature. These results suggest that rapid climate change of future could need systematic standard model for physiological characteristics and yields of onion.

• Journal of Climate Change Research
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• v.2 no.1
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• pp.33-42
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• 2011

It was analyzed climatic data in Gimje, Buan, Iksan and Jeonju in Jeonbuk Province between 1930s and 1990s. The data source of Gimje and Iksan in 1930s were Namseon Agricultural Experimental Station. Those in 1990s was Honam Agricultural Research Institute, Rural Development Administration. The data source of Jeonju of 1930s and 1990s was Jeonju Weather Station, Korea Meteorological Administration. Weather Station of Gimje and Buan were located at the agricultural area in rural paddy field. That of Iksan was located at the agricultural area in suburban paddy field. That of Jeonju was located at the downtown area. As compared to mean air temperature between 1930s and 1990s, it was increased by $0.2^{\circ}C$ in agricultural area, $0.6^{\circ}C$ in Iksan city and $1.4^{\circ}C$ in Jeonju city. On the while, increased temperature was the higher in winter than other seasons. Annual precipitation was increased by 128.1 mm in agricultural area and 169.3 mm in Jeonju city. And it was remarkable in summer season.

• Ocean Science Journal
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• v.43 no.4
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• pp.175-182
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• 2008

Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.3
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• pp.264-272
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• 2012

A study on the IR(InfraRed) signature of a naval ship has been performed using well known IR signature analysis software, ShipIR/NTCS. Variations of the IR signature radiated from skins of a naval ship have been investigated according to the monthly averaged marine climate conditions. An unclassified destroyer model with and without applying the washdown system was applied to compare the influence on the signature under the background changes. The marine background models were created from the observed data by a buoy of Korea Meterological Administration(KMA). The sensitivity of the ship signature against the climate variables such as air temperature, sea temperature, relative humidity has been studied as well. The seasons which show extreme(max, min) skin signature change by whether the washdown is applied or not. The sensitivities of the air temperature and the sea temperature for a dry-ship reversed by applying the washdown on the ship surfaces.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.179-184
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• 2012

This research on building Integrated Photovoltaic System replacing windows and doors with amorphous silicon thin film PV windows and doors installing same exact mount on Mock-up. The windows and doors should be installed in different angle and bearing so that we can analyse the amount of electricity from them. The objective of the research is to evaluate and investigate the relationship between factors(intensity of solar radiation, PV window surface temperature, incidence angle, and sky conditions) that affects performance of PV window and performance. The range and method of this research is to establish monitoring system and analysis the data from the monitoring system to evaluate the performance of PV windows that have thin film of solar battery. We should evaluate the insolation according to the position of PV window, output, and surface temperature according to months and seasons so that we can figure out the relationship between these. And we should investigate the relationship between performance and efficiency according to incidence angle and sky condition so that we can figure out the correlation between factors and performance.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.439-447
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• 1992

Eight healthy Holstein bulls, 4-6 years old were used to study the effect of season of the year on the biophysical characteristics of semen. Semen was collected twice a week by AV (artificial vagina) over one-year period. The analyses revealed that all the basic seminal traits studied were differed significantly due to season, except the ejaculate volume and consistency and the percentage of swollen spermatozoa in a hypo-osmotic fructose-citrate solution. Ejaculates collected during hot summer season had significantly lower sperm motility, concentration and total counts, and higher percentage of dead spermatozoa than those collected during winter time. Warm spring had moderate semen quality. The temperature-humidity index was calculated and it was associated (p < 0.01) negatively with the ejaculate pH, sperm concentration and total counts, and positively with the % of dead sperms. Ejaculate volume, percentage of swollen spermatozoa, individual motilities did not correlate significantly with the change in temperature-humidity index values. The total live, motile spermatozoa per ejaculate during both the winter and spring seasons showed significant increase of about 37% and 32% respectively over the summer season. Also, rectal temperatures of the bulls were elevated during the hot summer season, while the values of blood hemoglobin and packed-cell volume were decreased.