• Korean Journal of Agricultural and Forest Meteorology
• /
• v.3 no.1
• /
• pp.55-70
• /
• 2001

It was unusual crop weather for 1998 and 1999 compared with normal in Korea. The consecutive days of the optimum ripening period for rice plant that had daily mean temperature 21~23$^{\circ}C$ for 40 days after flowering, increased with long anomalies in 1998~99. The air temperature during ripening period was much higher than the optimum temperature and lower sunshine hour than norm in the local adaptability tests of newly developed rice lines during those years. In response of rice cultivation to warming and cloudy weather during crop season, the yield shall be decreased. Most scientists agree that the rate of heating is accelerating and temperature change could become increasingly disruptive. Weather patterns should also become more erratic. Agrometeorologists could be analyzed yearly variations of temperature, sunshine hour and rainfall pattern focused on transient agroclimate change for last a decade. Rice agronomists could be established taking advantage of real time agricultural meteorology information system for fertilization, irrigation, pest control and harvest. Also they could be analyzed the characteristics of flowering response of the recommended and newly bred rice cultivars for suitable cropping plan such as cultural patterns and sowing or transplanting date. Rice breeders should be deeply considered introducing the characteristics of basic vegetative type of flowering response like Togil rices as prospective rice cultivars corresponding to global warming because of the rices needed higher temperature at ripening stage than japonica rices, photoperiod-sensitive and thermo-sensitive ecotypes.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.11 no.3
• /
• pp.118-122
• /
• 2009

Net Radiation ($R_N$) is the major driving force for biophysical and biogeochemical processes in the terrestrial ecosystems, which is one of the most critical variables in both measurement and modeling. Despite its importance, there are only 10 weather stations conducting $R_N$ measurements among the 544 stations operated by Korea Meteorological Administration (KMA; KMA, 2008). The measurement of incoming shortwave radiation ($R_S{\downarrow}$) is, however, conducted at 22 stations while that of sunshine duration is conducted at all the manned stations. In this context, the recent research for estimating $R_N$ using $R_S{\downarrow}$ in Korean peninsula by Kwon (2009) is of great worth. The author used a linear regression and the radiation balance methods. We generally agree with the author that, in terms of simplicity and practicality, both methods show reliable applicability for estimating $R_N$. We noted, however, that the author's experimental method and analysis need some clarification and improvement, that are addressed in the following perspectives: (1) the use of daily integrated data for regression, (2) the use of measured albedo, (3) the use of linear coefficients for whole year data, (4) methodological improvement, (5) the use of sunshine duration, and (6) the error assessment.

• Current Research on Agriculture and Life Sciences
• /
• v.32 no.3
• /
• pp.135-143
• /
• 2014

The variability and temporal trends of the annual and seasonal minimum and maximum temperature, rainfall, relative humidity, wind speed, sunshine hours, and runoff were analyzed for 5 major rivers in Korea from 1960 to 2010. A simple regression and non-parametric methods (Mann-Kendall test and Sen's estimator) were used in this study. The analysis results show that the minimum temperature ($T_{min}$) had a higher increasing trend than the maximum temperature ($T_{max}$), and the average temperature increased by about $0.03^{\circ}C\;yr.^{-1}$. The relative humidity and wind speed decreased by $0.02%\;yr^{-1}$ and $0.01m\;s^{-1}yr^{-1}$, respectively. With the exception of the Han River basin, the regression analysis and Mann-Kendall and Sen results failed to detect trends for the runoff and rainfall over the study period. Rapid land use changes were linked to the increase in the runoff in the Han River basin. The sensitivity of the evapotranspiration and ultimately the runoff to the meteorological variables was in the order of relative humidity > sunshine duration > wind speed > $T_{max}$ > $T_{min}$. Future studies should investigate the interaction of the variables analyzed herein, and their relative contributions to the runoff trends.

• Solar Energy
• /
• v.14 no.2
• /
• pp.17-28
• /
• 1994

It is necessary to estimate enpirical constants in order to predict the monthly mean daily global radiation on a horizontal surface in the developing areas for alternative energy. Therefore many different equations have propoed to evaluate them for certain areas. In this work a new corrlation has been made to predict the solar radiation for any areas over Korea by cululating the regression models taking into account latitude, percentage of possible sunshine, and cloud cover. From the results, the single linear equation proposed by using percentage of possible sunshine method shows reliable results for estimating the global rdiation with average annual deviation of -4 to +2% from measured values.

• Journal of the Korean Solar Energy Society
• /
• v.36 no.1
• /
• pp.1-9
• /
• 2016

To well design the solar energy system, the correlation to calculate and predict solar irradiation is basically needed. So, this study was performed to reveal the relationships between the solar irradiation and four meteorological observation data(dry-bulb temperature, relative humidity, duration of sunshine, and amount of cloud) that didn't show from previous any other researches. And then, we finally proposed the various order non-linear correlation from the measured solar irradiation and four meteorological measurement data using MINITAB. To show the deviation and accuracy of the solar irradiation between measured and calculated, this study compared for the daily total solar insolation. From those results, the calculation error could well predicted about maximum 97% for the daily total solar insolation. But, the coefficients of the proposed correlations didn't show any relationships. So, needs more studies to make the proper one correlation for the country.

• Journal of Climate Change Research
• /
• v.6 no.4
• /
• pp.283-290
• /
• 2015

This study was carried out a trend analysis for analyzing change of meteorological elements in the main producing areas of Chinese cabbage, radish, pepper, garlic and onion. As meteorological elements, we selected air temperature (maximum, minimum), precipitation and duration of sunshine. We used monthly data of meteorological elements obtained from the main producing areas of vegetables for 30 years from 1981 to 2010. Mann-Kendall test used for significance test of trend and Sen's estimator of slope for computing the variance of meteorological elements. The study results showed that air temperature tended to increase, but duration of sunshine tended to decrease in most regions.

• Journal of Korean Society of Rural Planning
• /
• v.27 no.2
• /
• pp.69-76
• /
• 2021

This study focuses on the relationship between ginseng production per area and meteorological factors. Four areas of major ginseng production are considered in the study. Chungcheongnam-do and Gyengsangbuk-do are selected as the original major production places and Gyeonggi-do and Kangwon-do are selected as the new major places. The meteorological factors applied for study are the average temperature, accumulated precipitation, and integrated sunshine hours. With the data collected across four areas, we used a panel data analysis. From the results of Hausman test, the fixed effects model allowing to control individual area effect is preferable to the random effects model. Based on the results of the fixed effects model, the accumulated precipitation statistically and significantly affect the decreases in ginseng production. Changes in the average temperature negatively affect ginseng production, but the value is not statistically significant. The integrated sunshine positively affect ginseng production, but the value is not statistically significant.

• Korean Journal of Agricultural Science
• /
• v.2 no.1
• /
• pp.111-123
• /
• 1975

6 years data on the plant growth and grain yield of 13 rice varieties were investigated to define the relations between meteological conditions and plant growth of rice including grain yield. The results obtained are summarized as follows; 1. Variation of average temperature by years showed great number at early and middle July, middle August and early November, however smallest figure at late June and late July. And that of sunshine hours by years were least at late June and late July, and largest at middle July. 2. Among rice yield components variation of panicle number per hill by years was biggest and that of 1000 grain weight least. Rate of variation of plant growth and rice yield was different by rice varieties. 3. Direct effects on rice yield was greatest at maturing ratio and next at 1000 grain weight. The effects of yield factor on the rice yield wers different by years. 4. Higher temperature and longer sunshine delayed the miaxmum tillering stage but shortened the days from seeding to heading. 5. A significant negative correlation was recognized between the number of panicles per hill and average temperature of 11 to 40 days after transplanting, and number of grains per panicle was correlated with the average temperature of 11 to 70 days after transplanting. High temperature before heading time showed atime decreased maturing ratio. 6. Accumulated temperature was highly correlated with 1000 grain weight in all season. Highest positive correltaion was recognized between grain yield of rice and average temperature of 61 to 70 days after transplanting but correlations between rice yield and average temperature after heading stage were negative. 7. Highly significant correlations were confirmed between maturing ratio and sunshine hours of 31 to 50 days as well as 61 to 70 days after transplanting, and maturing ratio was highly correlated with accumulated hours of sunshine. Correlation between rice yield and hours of sunshine was significant at 51 to 60 days after transplanting.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.264-273
• /
• 2020

'Ilpum', a Korean short-grain mid-late maturing rice cultivar, was developed in 1990, more than 30 years ago. Despite its age, it has been the most widely grown cultivar in the Gyeongbuk province of South Korea for more than 25 years, making it the most important rice cultivar for the people of the Gyeongbuk province. The aim of this study was to analyze the relationship between the rice yield of "Ilpum', the main rice cultivar in the Gyeongbuk province, and climate elements in the Daegu (southern plain area) and the Andong (inland mountainous area) regions in Gyeongbuk, South Korea. The rice yield over the past five years increased by about 13% and 24%, compared to that produced in the late 1990s in Daegu and the early 2000s in the Andong region, respectively. The number of panicles per hill and the grain ripening rate significantly affected rice yield in the 'Ilpum' cultivars in the Daegu region. The faster heading was a factor in the increase in 'Ilpum' rice yield in the Andong region. The air temperature has been rising and sunshine duration has been increasing from the late 1990s to present in both regions. Rice yield was evaluated to understand the effect of climate factors. The rice yields increased owing to the long sunshine duration during the grain-filling stage in both regions. In Andong, increasing the maximum temperature during the vegetative stage increased rice yield. Rising air temperature during the reproductive stage also increased rice yield. In particular, long sunshine hours throughout the whole rice growing period increased the rice yield of this cultivar in the Andong region.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.2 no.3
• /
• pp.95-102
• /
• 2000

The northward shift of the cultivation region of winter barley has been considered because of consecutive warm winters from the middle of 1980's. There was 1.02$^{\circ}C$ rise in mean air temperature during winter barley cropping season from 1975 to 1998. During this period, the maximum air temperature affected the mean air temperature rise rather than the minimum air temperature. The amount of mean precipitation was 513.3 mm during winter barley cropping season from 1975 to 1998 and was least in 1992. Sunshine hours has increased little by little in the all regions except rural regions. The air temperature during winter barley cropping season from 1987 to 1999 in which the winter was warm was higher than the normal air temperature(1961~1990). On the other hand, the air temperature during winter barley cropping season from 1974 through 1986 was similar to the normal air temperature. The amount of mean precipitation during winter barley cropping season from 1987 through 1999 was similar to the normal precipitation except April. During this period, the amount of mean precipitation of April was lower by 26 mm than the normal year(1961~1990). Sunshine hours during winter barley cropping season from 1987 to 1999 decreased generally in comparison with a normal year. Considering the air temperature rise during wintering from 1987 to 1998, it might be possible to extend the cropping area of winter barley northward.