• 대기
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• 제30권4호
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• pp.319-333
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• 2020

Aircraft observations constitute one of the major sources of temperature observations which provide three-dimensional information. But it is well known that the aircraft temperature data have warm bias against sonde observation data, and therefore, the correction of aircraft temperature bias is important to improve the model performance. In this study, the algorithm of the bias correction modified from operational KMA (Korea Meteorological Administration) global model is adopted in the preprocessing of aircraft observations, and the effect of the bias correction of aircraft temperature is investigated by conducting the two experiments. The assimilation with the bias correction showed better consistency in the analysis-forecast cycle in terms of the differences between observations (radiosonde and GPSRO (Global Positioning System Radio Occultation)) and 6h forecast. This resulted in an improved forecasting skill level of the mid-level temperature and geopotential height in terms of the root-mean-square error. It was noted that the benefits of the correction of aircraft temperature bias was the upper-level temperature in the midlatitudes, and this affected various parameters (winds, geopotential height) via the model dynamics.

• Journal of Ecology and Environment
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• 제45권4호
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• pp.182-189
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• 2021

Background: Organism body size is a basic characteristic in ecology; it is related to temperature according to temperature-size rule. Butterflies are affected in various aspects by climate change because they are sensitive to temperature. Therefore, this study was conducted to understand the effect of an increase in temperature due to global warming on the wing of butterflies. Results: A total of 671 butterflies belonging to 9 species were collected from 1990 to 2016 in Seoul (336 specimens) and Mokpo (335 specimens). Consequently, as the mean temperature increased, the wing length of the species increased. However, there are exceptions that the Parnassius stubbendorfii, Pieridae canidia, and Pieris rapae wing length of Seoul increased, but the butterfly wing length of Mokpo decreased. Conclusions: The positive correlations between the butterfly wing length and mean temperature showed that the change of mean temperature for about 26 years affects the wing length of butterfly species. The exception is deemed to have been influenced by the limited research environment, and further studies are needed. We would expect that it can be provided as basic data for studying effect of climate change.

• 한국안전학회지
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• 제25권2호
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• pp.12-17
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• 2010

Numerical simulations were performed for the prediction of the flame structure during the interaction between hydrogen and hydrocarbon flames. A counterflow flow geometry was introduced to establish the interacting two flames. Methane was used as a representative hydrocarbon fuel in this study. A well-known numerical code for the counterflow flame, OPPDIF, was used for the simulations. The detailed chemistry was adopted to predict the flame structure reasonably. The interaction of two one-dimensional premixed flames established in counterflow burner was investigated with the global strain rate and velocity ratio. It was found that the maximum temperature located near the methane flame surface while the heat release rate of methane was lower than hydrogen flame. The flame thickness become narrow with increasing the velocity ratio while the global strain rate was fixed. The local strain rate and heat release rate at the methane flame surface were correlated with the global strain rate, while those at the hydrogen flame were not correlated with the global strain rate. However, the maximum temperature of the interacting flames was correlated with the global strain rate.

• 한국가스학회지
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• 제8권2호
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• pp.42-47
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• 2004

변형률이 대향류 화염의 구조에 미치는 영향을 조사하기 위해, 무중력상태에서의 축대칭 메탄-공기 대향류화염의 시뮬레이션을 수행하였다. 질소와 메탄의 혼합물인 연료 중 메탄의 몰분율 Xm= 20, 50, $80\%$와 각 몰분율당 변형률 ag= 20, 60, 90 $s^{-1}$에 대한 화염형태와 온도 및 축방항 속도의 분포를 비교하였다. 온도와 축방항 속도 분포가 1차원 화염코드인 OPPDIF의 결과와 잘 일치하였다. 또 축대칭 시물레이션을 통해, 변형률이 증가하면 화염이 반경방향으로 늘어나 화염의 반경은 증가하고 두께가 감소함을 확인하였다.

• 대기
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• 제17권2호
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• pp.185-193
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• 2007

This study investigates urbanization effect in warming trend of surface air temperature over Korea. The data used in this study consist of the daily minimum and maximum temperatures during the period of 32 years(1968-1999) from 16 stations of KMA. To calculate magnitude and trend of urbanization effect, stations were classified into urban and rural stations using population statistics. Urban stations were defined as those with population densities greater than 1000 persons per kilometer squared in 1995. The others were defined as rural stations. The urban stations were also subdivided into two groups according to their population totals. For estimates of urban effect magnitude, temperature change was calculated by comparing 16-year mean values between 1968-83 and 1984-99. Then, the difference between each urban station and every rural station was calculated. During the analysis period of 32 years, maximum temperature increase is $1.22^{\circ}C$. In the total temperature increase, urban effect is estimated by 28.7%. For minimum temperature, it becomes larger by about 10% than that in maximum temperature. Therefore, urban effect in an increasing trend of minimum temperature is 38.9% in the change of $1.13^{\circ}C$.

• Journal of Ecology and Environment
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• 제33권3호
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• pp.195-204
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• 2010

In the study, the effects of elevated $CO_2$ and temperature on the photosynthetic characteristics, chlorophyll content, nitrogen content, carbon content, and C/N ratio of Phytolacca insularis and Phytolacca americana were examined under control (ambient $CO_2+$ ambient temperature) and treatment (elevated $CO_2+$ elevated temperature) for 2 years (2008 and 2009). The photosynthetic rate, transpiration rate and water use efficiency of two plant species were higher under the treatment than the under the control. The stomatal conductance of P. insularis was higher under the control, but that of P. americana was not significantly affected by $CO_2$ and temperature under the treatment. The chlorophyll contents of two species were decreased about 72.5% and 20%, respectively, by elevated $CO_2$ and temperature. The nitrogen contents of two species were not significantly altered by increase in $CO_2$ and temperature. The carbon contents of the two species were higher under the treatment than under the control. The C/N ratio of P. insularis was higher under the treatment but that of P. americana was not significantly affected by $CO_2$ and temperature. These results demonstrated that the physiological responses of P. insularis native plants might be more sensitively influenced by a $CO_2$-mediated global warming situation than those of the P. americana invasive plants.

• 대한지리학회지
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• 제41권1호
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• pp.94-105
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• 2006

본 연구에서는 우리나라의 여름과 겨울철의 이상기온 출현 빈도의 변화와 그에 영향을 미치는 요인과의 관계를 파악하고자 하였다. 우리나라의 대부분 관측 지점에서는 여름철 이상고온 출현 빈도의 증가와 겨울철 이상저온 출현 빈도의 감소 경향이 뚜렷하다. 이러한 이상기온 출현 빈도의 변화는 대기 순환 지수 중 겨울철 이상기온 출현에 영향을 미치는 겨울 몬순 지수와 시베리아 고기압 강도 지수 및 북극 진동 지수, 그리고 여름철 이상저온 출현에 영향을 미치는 오호츠크해 고기압 강도 지수와 북태평양 지수 등의 변화 경향과 유사하다. 이 지수들은 이상기온의 변화에 영향을 미치는 요인 중 최근의 지구 온난화 경향을 반영하며 우리나라 전 지역의 이상기온 출현 빈도와 관계가 뚜렷하다.

• 대기
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• 제24권3호
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• pp.403-417
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• 2014

Future changes in seasonal mean temperature and precipitation over East Asia under anthropogenic global warming are investigated by comparing the historical run for 1979~2005 and the Representative Concentration Pathway (RCP) 4.5 run for 2006~2100 with 20 coupled models which participated in the phase five of Coupled Model Inter-comparison Project (CMIP5). Although an increase in future temperature over the East Asian monsoon region has been commonly accepted, the prediction of future precipitation under global warming still has considerable uncertainties with a large inter-model spread. Thus, we select best five models, based on the evaluation of models' performance in present climate for boreal summer and winter seasons, to reduce uncertainties in future projection. Overall, the CMIP5 models better simulate climatological temperature and precipitation over East Asia than the phase 3 of CMIP and the five best models' multi-model ensemble (B5MME) has better performance than all 20 models' multi-model ensemble (MME). Under anthropogenic global warming, significant increases are expected in both temperature and land-ocean thermal contrast over the entire East Asia region during both seasons for near and long term future. The contrast of future precipitation in winter between land and ocean will decrease over East Asia whereas that in summer particularly over the Korean Peninsula, associated with the Changma, will increase. Taking into account model validation and uncertainty estimation, this study has made an effort on providing a more reliable range of future change for temperature and precipitation particularly over the Korean Peninsula than previous studies.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
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• pp.313-335
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• 1998

If the atmospheric concentrations of greenhouse gases double, the annual temperature increase in mean surface temperature relative to 1990 will be about 2.0 to $2.5^{\circ}C$ and the annual precipitation increase about $15{\%}$ by 2100 in Korea. When the temperature rises $2^{\circ}C$, the annual temperature will be $13^{\circ}C,\;15^{\circ}C,\;and\;16^{\circ}C$ in Western Central, Yeongnam Basin, and Southern Coastal respectively. Consequently the crop period could be prolonged $10{\~}29$ days. In the case of gradual global warming, annual crops could be adapted to the changed environment by breeding, and the perennial crops should be shifted to ether area. If global warming happens suddenly over the threshold of atmospheric greenhouse gases concentration, then we shall have disturbance of ecosystem. When $2^{\circ}C$ higher than present, the optimum flowering date of rice plant delayed about 10 days, so it may not possible to adopt the fate with present japonica rices, therefore, the recommended characteristics of rice varieties are longer basic vegetative period, more late maturing and higher ripening temperature. Barley and wheat crops could be shifted to northern coastal areas and apple production areas should be shifted to those areas under $13.5^{\circ}C$ in annual mean temperature at global warming. Ideotypes of crops under climate changes should have such ecological characteristics that are indispensable to accomplish the sustainable agriculture under increased $CO_{2}$ and temperature condition as the diversification of genetic resources from yield-oriented to biomass-oriented characteristics with the higher potentials of $CO_{2}$ absorption and Primary production. In addition, a heat-tolerance, a pest resistance, an environmental adaptability and a production stability should be also incorporated collectively into our integrated agroecosystem.

• 인간식물환경학회지
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• 제24권5호
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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.