• Korean Journal of Soil Science and Fertilizer
• /
• v.23 no.2
• /
• pp.87-93
• /
• 1990

A statistical model to predict soil temperature from the ambient meteorological factors including mean, maximum and minimum air temperatures, precipitation, wind speed and snow depth combined with Fourier time series expansion was developed with the data measured at the Suwon Meteorolical Service from 1979 to 1988. The stepwise elimination technique was used for statistical analysis. For the yearly oscillation model for soil temperature with 8 terms of Fourier expansion, the mean square error was decreased with soil depth showing 2.30 for the surface temperature, and 1.34-0.42 for 5 to 500-cm soil temperatures. The $r^2$ ranged from 0.913 to 0.988. The number of lag days of air temperature by remainder analysis was 0 day for the soil surface temperature, -1 day for 5 to 30-cm soil temperature, and -2 days for 50-cm soil temperature. The number of lag days for precipitaion, snow depth and wind speed was -1 day for the 0 to 10-cm soil temperatures, and -2 to -3 days for the 30 to 50-cm soil teperatures. For the statistical soil temperature prediction model combined with the yearly oscillation terms and meteorological factors as remainder terms considering the lag days obtained above, the mean square error was 1.64 for the soil surfac temperature, and ranged 1.34-0.42 for 5 to 500cm soil temperatures. The model test with 1978 data independent to model development resulted in good agreement with $r^2$ ranged 0.976 to 0.996. The magnitudes of coeffcicients implied that the soil depth where daily meteorological variables night affect soil temperature was 30 to 50 cm. In the models, solar radiation was not included as a independent variable ; however, in a seperated analysis on relationship between the difference(${\Delta}Tmxs$) of the maximum soil temperature and the maximum air temperature and solar radiation(Rs ; $J\;m^{-2}$) under a corn canopy showed linear relationship as $${\Delta}Tmxs=0.902+1.924{\times}10^{-3}$$ Rs for leaf area index lower than 2 $${\Delta}Tmxs=0.274+8.881{\times}10^{-4}$$ Rs for leaf area index higher than 2.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.56 no.4
• /
• pp.404-412
• /
• 2011

This experiment was conducted to clarify the effect of the temperature for grain filling duration on quality and taste of cooked rice cultivated in different region in Korea. In 2006 and 2007, 4 mid-late maturing group of rice varieties (Nampyeongbyeo, Ilpumbyeo, Junambyeo and Dongjin 1) were cultivated in 28 experimental plots of 27 different regions located in 8 provinces. The taste of cooked rice were positively correlated with 1,000 grain weight but negatively correlated with protein content of brown rice. Mean temperature for 30 days from heading was more closely correlated with grain filling and tastes of cooked rice than those for 40 days. Though, the optimum mean temperature for the best taste of cooked rice for 30 days after heading was 22.1 to $23.1^{\circ}C$ depending on varieties, in general, 1,000 grain weight and cooked rice taste were the highest in the mean temperature of $22.2^{\circ}C$ for 30 days from heading. But grains were poorly ripened in case of the mean temperature lower than $21.0^{\circ}C$ for 30 days after heading. Therefore, for the better taste of cooked rice in Korea, the developing new rice varieties and cultivation method should be focused to adjust the mean temperature within $22-23^{\circ}C$ during the period of 30 days after heading.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.19 no.4
• /
• pp.199-217
• /
• 2016

Influences of seasonal warming and cooling rates on the annual temperature patterns were analyzed based on the meteorological data from 13 weather stations in Busan Metropolitan Area(BMA), Korea during 1997~2014. BMA daily temperature time-series was generalized by Fourier analysis, which mathematically summarizes complex, regularly sampled periodic records, such as air temperature, into a limited number of major wave components. Local monthly warming and cooling rates of BMA were strongly governed by the ocean effect within the city. March($1.121^{\circ}C/month$) and November(-$1.564^{\circ}C/month$) were the two months, when the most rapid warming and cooling rates were observed, respectively during the study period. Geographically, spring warming rates of inland increased more rapidly compared to coastal areas due to weaker ocean effect. As a result, the annual maximum temperature was reached earlier in a location, where the annual temperature range was larger, and therefore its July mean temperature and continentality were higher. Interannual analyses based on average temperature data of all weather stations also showed that the annual maximum temperature tended to occur earlier as the city's July mean temperature increased. Percent area of impervious surfaces, an indicator of urbanization, was another contributor to temperature change rates of the city. Annual mean temperature was positively correlated with percent area of impervious surfaces, and the variations of monthly warming and cooling rates also increased with percent area of impervious surfaces.

• Atmosphere
• /
• v.17 no.4
• /
• pp.471-481
• /
• 2007

Temperature and precipitation, particularly August and summer, in the Korean peninsular are analyzed. The analyzed period is 1973-2007 for the Korean peninsular (that is, 60 meteorological station average). In addition, 100 year record (1908-2007) of temperature and precipitation in Seoul are also analyzed. Results indicate that the temperatures (mean, maximun, and minimum) of August and summer of 2007, both in Korean peninsular and Seoul, are higher than normal. The increasing rate of minimum temperature for the August and summer during the period from 1973 to 2007 shows greater than the mean and maximum temperature both in Korean peninsular and Seoul due to the global warming and urbanization. Number of tropical night days, defined by the days with above $25^{\circ}C$ in minimum temperature, shows increasing trend both in August and summer from 1973 to 2007 due to the combination effect of the global warming and urbanization. The amount of precipitation, both in August and summer, for Korean peninsular and Seoul shows increasing trend from 1973 to 2007, and 1908 to 2007, respectively. Amount of precipitation and rainy days, both August and summer, during 2000s show greater than those of the 1970s both in Korean peninsular and Seoul. Extreme rainy days (greater than 120mm/day, greater than 80mm/day, greater than 30mm in any 1-hour period and greater than 10mm in any 10-minute period) show increasing trend from 1973 to 2007 for both in August and in summer.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.18 no.4
• /
• pp.199-207
• /
• 2016

This study was conducted to develop a forest fire occurrence model using meteorological characteristics for practical forecasting of forest fire danger rate by reflecting the climate change for the time period of 2000yrs. Forest fire in South Korea is highly influenced by humidity, wind speed, temperature, and precipitation. To effectively forecast forest fire occurrence, we developed a forest fire danger rating model using weather factors associated with forest fire in 2000yrs. Forest fire occurrence patterns were investigated statistically to develop a forest fire danger rating index using times series weather data sets collected from 76 meteorological observation centers. The data sets were used for 11 years from 2000 to 2010. Development of the national forest fire occurrence probability model used a logistic regression analysis with forest fire occurrence data and meteorological variables. Nine probability models for individual nine provinces including Jeju Island have been developed. The results of the statistical analysis show that the logistic models (p<0.05) strongly depends on the effective and relative humidity, temperature, wind speed, and rainfall. The results of verification showed that the probability of randomly selected fires ranges from 0.687 to 0.981, which represent a relatively high accuracy of the developed model. These findings may be beneficial to the policy makers in South Korea for the prevention of forest fires.

• Journal of Bio-Environment Control
• /
• v.9 no.1
• /
• pp.60-64
• /
• 2000

This study was conducted to investigate effects of cooling methods on the growth and yield of tomato cv. momotaro in the glasshouse for four years from 1996 to 1999. Cooling methods were fan, fan and fogging, fan and shading(temp. control), fan and shading(radiation control), fan and shading (temp. control) with fogging. Fan, Fogging and Shading(temp. control) were operated automatically when air temperature was over 3$0^{\circ}C$. Amount of fogging was 500m1/min/100m$^2$and Droplets in a fog were 50 microns or smaller. Shading(radiation control) was operated automatically when solar radiation was over 500W/m$^2$. The growth and yield were the least in fan and shading(temp. control) method due to lack of light Intensity. Fogging method must be reconsidered for expensive equipment and maintenance expenses. As the matter stands, It is suggested to be the most considerable cooling method to increase ventilation rate with fan or use fan and shading(radiation control).

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1316-1320
• /
• 2009

최근 한반도지역의 시공간적 수문변화 및 지속시간 연최대강우 추세분석을 위하여 기상청에서 제공 되어지는 관측자료를 이용하여 분석을 실시하였다. 분석을 위하여 서울, 인천, 속초, 부산, 군산등 전국적인 분포를 보이는 60개소의 일강수량, 일평균기온, 일최고 및 최저기온, 일평균풍속, 일습도 자료를 수집하였다. 더불어 지속시간별 연최대강우 추세분석을 위하여 동일기간에 대한 시간자료를 수집하여 분석을 실시하였다. 일자료를 이용한 분석결과 분석기간의 년평균강수량은 1998년 이전 1342.2mm였으나, 1998년 이후는 1,511.6mm로서 최근의 강수량 증가를 확인할 수 있었다. 계절적으로는 비홍수기에 비하여 홍수기에 강수량 증가가 더욱 두드러졌으며, 수계별로는 낙동강과 섬진강의 경우가 한강과 금강등 기타 수계에 비하여 최근의 강수량 증가추세가 상대적으로 뚜렷한 것으로 분석되었다. 내륙과 해안지역의 분석결과에서는 해안지역의 년강수량이 내륙에 비하여 90mm 정도 높게 나타났으며, 지역별로는 동해안지역이 서해안과 남해안에 비하여 변화경향이 크게 나타났다. 일최고강수량 및 집중호우빈도 분석결과 수계별 분석의 경우 한강수계가 다른 수계에 비하여 상대적으로 큰 증가경향을 보였으며, 한편 섬진강수계는 다소 완만한 경향을 나타내고 있었다. 집중호우빈도 분석결과 역시 년강수량과 마찬가지로 동해안지역에서의 변화경향이 크게 나타나고 있었다. 무강수일수는 전국적으로 감소경향을 보이고 있어, 강수발생일당 강수량은 증가하는 경향을 보이고 있었다. 이러한 수문학적 변화경향을 세부적으로 살펴보기 위하여 수계별 대표지점을 선정하여 지속시간별(1hr, 2hr, 3hr, 4hr, 6hr, 12hr) 강우강도 추세분석을 실시하였다. 분석결과 지속시간에 따른 강우강도 역시 증가하는 경향을 나타내는 것을 확인하였으며 짧은 지속시간이 상대적으로 큰 증가경향을 나타내는 것으로 확인하였다. 하지만 정확한 분석을 위하여 보다 많은 관측소에 대한 추가분석이 필요할 것으로 판단되어 진다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.214-214
• /
• 2019

가뭄이 '심함' 단계 이상 도달 시에는 매주 수문분석을 수행하여 가뭄전망을 수행하여야 한다. 이를 위해서는 기상청의 강수량과 기온 등의 기상예측 자료가 필요하다. 현재 기상청에서는 3개월 기상전망으로 월단위 강수량과 평균기온을 매월 제공하고 있다. 1개월 전망에서 4주의 강수량합과 평균기온을 제공하고 있다. 하지만, 향후 4주간을 전망하는 1개월 전망에서는 1주단위의 강수량과 평균기온이 아닌, 4주간의 강수량합과 평균기온을 1주일 단위로 업데이트해 WINS에 제공하고 있다. 1주단위의 강수량과 평균기온을 취득하기 어려워, 평년 일단위 강수량과 평균기온 자료를 사용하여 4주간의 자료를 1주 단위로 분할하는 방법을 사용하였다. 주간단위 수문자료의 처리를 위해 국제표준기구(ISO)에서 제시하는 기준(ISO 8601)에 따랐다. ISO 8601은 월요일부터 일요일까지를 1주로 정의하며 현재 사용하고 있는 날짜체계와 1대1로 대응되도록 하였다. 예를 들면 1981년 2월 22일은 '1981-W07-7' 또는 '1981W077'로 표시한다. 표시된 형식은 1981년 7번째 주 일요일을 뜻한다. 이 기준에 따라 수문자료를 정리할 수 있도록 프로그램을 개발하였다. 주간 단위 잠재증발산량 계산은 월잠재증발산량 프로그램을 1주단위로 계산할 수 있도록 수정 및 보완하여 개발하였다. 수정 및 보완한 부분은 외기복사(外氣輻射)량 계산부분이다. 외기복사량은 지구가 태양을 1년 주기로 공전하므로 특정 위도에서 특정날짜에 따라 복사량이 달라지므로 주간단위의 월요일부터 일요일에 해당하는 날짜의 외기복사량을 각각 계산하고 이를 평균하여 주간단위 대푯값으로 사용하도록 하였다. 계산된 주간단위 외기복사량과 최고 최저기온을 입력하여 Hargreaves식에 의해 잠재증발산량을 계산한다. 융적설을 포함한 주단위 강우-유출 모형의 매개변수를 추정하기 위해 전국 24개 지점의 수문자료를 사용하였다. abcd 모형과 융적설모듈의 초기값 포함 11개 매개변수를 SCE-UA 전역최적화 알고리즘으로 추정하였다. 추정된 유역의 매개변수는 토양배수, 토양심도, 수문지질, 유역특성인자를 사용한 군집분석 결과에 의해 113개 중권역에 할당하였다. 개발된 주간단위 강우-유출 모형은 비교적 단기 가뭄전망을 위해 사용된다. 계산된 유량은 자연유량이며, 전국 취수장 수량, 하수처리장 방류수, 회귀수를 반영하여 지점별 유량을 계산하여 가뭄전망에 사용되고 있다.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.6 no.3
• /
• pp.170-176
• /
• 2004

This study was carried out to establish a spatial decision support system for evaluating climatic aspects of a given geographic location in complex terrains with respect to the quality apple production. Monthly climate data from S6 synoptic stations across South Korea were collected for 1971-2000. A digital elevation model (DEM) with a 10-m cell spacing was used to spatially interpolate daily maximum and minimum temperatures based on relevant topoclimatological models applied to Jangsoo county in Korea. For daily minimum temperature, a spatial interpolation scheme accommodating the potential influences of cold air accumulation and the temperature inversion was used. For daily maximum temperature estimation, a spatial interpolation model loaded with the overheating index was used. Freezing risk in January was estimated under the recurrence intervals of 30 years. Frost risk at bud-burst and blossom was also estimated. Fruit quality was evaluated for soluble solids, anthocyanin content, Hunter L and A values, and LID ratio, which were expressed as empirical functions of temperature based on long-term field observations. AU themes were prepared as ArcGlS Grids with a 10-m cell spacing. Analysis showed that 11 percent of the whole land area of Jangsoo county might be suitable for quality 'Fuji' apple production. A computer program (MAPLE) was written to help utilize the results in decision-making for site-selection of new orchards in this region.

• Journal of Bio-Environment Control
• /
• v.10 no.1
• /
• pp.10-14
• /
• 2001

The cooling effect of a fog cooling system has a close relationship to air flow and relative humidity in the greenhouse. From the VETH chart for cooling design, a cooling efficiency can be improved by means of increasing the air exchange rate and the amount of sprayed water. In the no shading experimental greenhouse by time control, when average air exchange rate was 0.77 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature of the greenhouse was 31$^{\circ}C$ that was almost close to outside temperature and cooling efficiency was 82%. When average air exchange rate was close to temperature of the greenhouse that was no cooling and 70% shading greenhouse environment. When average air exchange rate was 2.59times.min$^{-1}$ , spray water amount was 2,009g and shading rate was 70%, inside relative humidity of the greenhouse was increased was 2,009 g and shading rate was 70%, inside relative humidity of the greenhouse was increased, but temperature was not decreased. When average air exchange rate was 2.33 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature was 31.4 and at that time maximum wind speed at the air inlet of greenhouse was 1.9m.s$^{-1}$ . Since time controller sprayed amount of constant water at a given interval, some of sprayed water remained not to be evaporated, which increased relative humidity and decreased cooling efficiency. Because the shading screen prevented air flow in the greenhouse, it also caused the evaporation efficiency to be decreased. In order to increase cooling efficiency, it was necessary to study on controling by relative humidity and air circulation in the greenhouse.