• Title/Summary/Keyword: Minimum Temperature

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Development of Prediction Model on Fruit Width Using Climatic Environmental Factors in 'Fuji' Apple (기후 환경 요인을 이용한 사과 '후지'의 과실 횡경 예측 모델 개발)

  • Han, Hyun Hee;Han, Jeom Hwa;Jeong, Jae Hoon;Ryu, Suhyun;Kwon, YongHee
    • Journal of Bio-Environment Control
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    • v.26 no.4
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    • pp.346-352
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    • 2017
  • In this study, we analyzed environmental factors including annual fruit growth and meteorological conditions in Suwon area from 2000 to 2014 to develop and verify a fruit width prediction model in 'Fuji' apple. The 15-year average of full bloom data was April 28 and that of fruit development period was 181 days. The fruit growth until 36 days after full bloom followed single sigmoid curve. The environmental factors affecting fruit width were BIO2, precipitation in September, the average of daily maximum and minimum temperature in April, minimum temperature in August, and growing degree days (GDD) in April. Among them, the model was constructed by combining BIO2 and precipitation in September, which are not cross-correlated with each other or, with other factors. And then, the final model was selected as 19.33095 + (5.76242 ${\times}$ BIO2) - (0.01891 ${\times}$ September precipitation) + (2.63046 ${\times}$ minimum temperature in April) which was the most suitable model with AICc of 92.61 and the adjusted $R^2$ value of 0.53. The model was compared with the observed values f rom 2000 to 2014. As a result, the mean difference between the measured and predicted values of 'Fuji' apple fruit width was ${\pm}2.9mm$ and the standard deviation was 3.54.

Climate Change Impact on the Flowering Season of Japanese Cherry (Prunus serrulata var. spontanea) in Korea during 1941-2100 (기후변화에 따른 벚꽃 개화일의 시공간 변이)

  • Yun Jin-I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.2
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    • pp.68-76
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    • 2006
  • A thermal time-based two-step phenological model was used to project flowering dates of Japanese cherry in South Korea from 1941 to 2100. The model consists of two sequential periods: the rest period described by chilling requirement and the forcing period described by heating requirement. Daily maximum and minimum temperature are used to calculate daily chill units until a pre-determined chilling requirement for rest release is met. After the projected rest release date, daily heat units (growing degree days) are accumulated until a pre-determined heating requirement for flowering is achieved. Model calculations using daily temperature data at 18 synoptic stations during 1955-2004 were compared with the observed blooming dates and resulted in 3.9 days mean absolute error, 5.1 days root mean squared error, and a correlation coefficient of 0.86. Considering that the phonology observation has never been fully standardized in Korea, this result seems reasonable. Gridded data sets of daily maximum and minimum temperature with a 270 m grid spacing were prepared for the climatological years 1941-1970 and 1971-2000 from observations at 56 synoptic stations by using a spatial interpolation scheme for correcting urban heat island effect as well as elevation effect. A 25km-resolution temperature data set covering the Korean Peninsula, prepared by the Meteorological Research Institute of Korea Meteorological Administration under the condition of Inter-governmental Panel on Climate Change-Special Report on Emission Scenarios A2, was converted to 270 m gridded data for the climatological years 2011-2040, 2041-2070 and 2071-2100. The model was run by the gridded daily maximum and minimum temperature data sets, each representing a climatological normal year for 1941-1970, 1971-2000, 2011-2040, 2041-2070, and 2071-2100. According to the model calculation, the spatially averaged flowering date for the 1971-2000 normal is shorter than that for 1941-1970 by 5.2 days. Compared with the current normal (1971-2000), flowering of Japanese cherry is expected to be earlier by 9, 21, and 29 days in the future normal years 2011-2040, 2041-2070, and 2071-2100, respectively. Southern coastal areas might experience springs with incomplete or even no Japanese cherry flowering caused by insufficient chilling for breaking bud dormancy.

Phonology and Minimum Temperature as Dual Determinants of Late Frost Risk at Vineyards (발아시기 정밀추정에 의한 포도 만상해 경보방법 개선)

  • Jung, Jea-Eun;Yun, Jin-I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.1
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    • pp.28-35
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    • 2006
  • An accurate prediction of budburst in grapevines is indispensable for vineyard frost warning system operations in spring because cold tolerance depends heavily on phonology. However, existing frost warning systems utilize only daily minimum temperature forecasts since there is no way to estimate the site-specific phonology of grapevines. A budburst estimation model based on thermal time was used to project budburst dates of two grapevine cultivars (Kyoho and Campbell Early), and advisories were issued depending on phonology as well as temperature. A 'warning' is issued if two conditions are met: the forecasted daily minimum temperature falls below $-1.5^{\circ}C$ and the estimated phonology is within the budburst period. A 'watch' is issued for a temperature range of -1.5 to $+1.5^{\circ}C$ with the same phonology condition. Validation experiments were done at 8 vineyards in Anseong in spring 2005, and the results showed a good agreement with the observations. This method was applied to the climatological normal year (1971-2000) to determine sites with high frost risk at a 30 m grid cell resolution. Among 608,585 grid cells constituting Anseong, 1,059 cells were identified as high risk for growing Kyoho and 2,788 cells for Campbell Early.

Forecasting of Daily Minimum Temperature during Pear Blooming Season in Naju Area using a Topoclimate-based Spatial Interpolation Model (공간기후모형을 이용한 나주지역 배 개화기 일 최저기온 예보)

  • Han, J.H.;Lee, B.L.;Cho, K.S.;Choi, J.J.;Choi, J.H.;Jang, H.I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.9 no.3
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    • pp.209-215
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    • 2007
  • To improve the accuracy of frost warning system for pear orchard in a complex terrain in Naju area, the daily minimum temperature forecasted by Korea Meteorological Administration (KMA) was interpolated using a regional climate model based on topoclimatic estimation and optimum scale interpolation from 2004 to 2005. Based on the validation experiments done for three pear orchards in the spring of 2004, the results showed a good agreement between the observed and predicted values, resulting in improved predictability compared to the forecast from Korea Meteorological Administration. The differences between the observed and the predicted temperatures were $-2.1{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the valley, $-1.6{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the riverside and $-1.1{\sim}3.5^{\circ}C$ (on average $0.6^{\circ}C$) in the hills. Notably, the errors have been reduced significantly for the valley and riverside areas that are more affected by the cold air drainage and more susceptible to frost damage than hills.

Estimation of Daily Maximum/Minimum Temperature Distribution over the Korean Peninsula by Using Spatial Statistical Technique (공간통계기법을 이용한 전국 일 최고/최저기온 공간변이의 추정)

  • 신만용;윤일진;서애숙
    • Korean Journal of Remote Sensing
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    • v.15 no.1
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    • pp.9-20
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    • 1999
  • The use of climatic information is essential in the industial society. More specialized weather servies are required to perform better industrial acivities including agriculture. Especially, crop models require daily weather data of crop growing area or cropping zones, where routine weather observations are rare. Estimates of the spatial distribution of daily climates might complement the low density of standard weather observation stations. This study was conducted to estimate the spatial distribution of daily minimum and maximum temperatures in Korean Peninsula. A topoclimatological technique was first applied to produce reasonable estimates of monthly climatic normals based on 1km $\times$ 1km grid cell over study area. Harmonic analysis method was then adopted to convert the monthly climatic normals into daily climatic normals. The daily temperatures for each grid cell were derived from a spatial interpolation procedure based on inverse-distance weighting of the observed deviation from the climatic normals at the nearest 4 standard weather stations. Data collected from more than 300 automatic weather systems were then used to validate the final estimates on several dates in 1997. Final step to confirm accuracy of the estimated temperature fields was comparing the distribution pattern with the brightness temperature fields derived from NOAA/AVHRR. Results show that differences between the estimated and the observed temperatures at 20 randomly selected automatic weather systems(AWS) range from -3.$0^{\circ}C$ to + 2.5$^{\circ}C$ in daily maximum, and from -1.8$^{\circ}C$ to + 2.2$^{\circ}C$ in daily minimum temperature. The estimation errors, RMSE, calculated from the data collected at about 300 AWS range from $1.5^{\circ}C$ to 2.5$^{\circ}C$ for daily maximum/minimum temperatures.

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Analysis of Agricultural Climatology in Cheju Island I. Distribution of Daily Minimum Temperature in Winter Season Estimated from a Topoclimatological Method (제주도의 농업기후 분석 I. 지형기후 추정법과 동계 일최저기온 분포)

  • 윤진일;유근배;이민영;정귀원
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.3
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    • pp.261-269
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    • 1989
  • Agricultural activities in Chejudo require more specialized weather services in this region. The meteorological information available from the Korea Meteorological Service (KMS) is limited in its areal coverage because the KMS stations are located along the narrow band of coastal area. topoclimatological technique which makes use of empirical relationships between the topography and the weather can be applied to produce reasonable estimates of the climatic variables such as air temperature and precipitation over remote land area where routine observations are rare. Presentation of these estimates in a from of fine-mesh grid map can also be helpful to upgrade the quality of weather services in this region. Altitude values of the 250 m grid points were read from a 1: 25000 topographic map and the mean altitude, the mean slope, and the aspect of the slope were determined for each 1 km$^2$ land area from these altitude data. Daily minimum air temperature data were collected from 18 points in Chejudo during the winter period from November 1987 to February 1988. The data were grouped into 3 sets based on synoptic pressure pattern. Departures from the KMS observations were regressed to the topographical variables to delineate empirical relationships between the local minimum temperature under specific pressure patterns and the site topography. The selected regression equations were used to calculate the daily minimum temperature for each 1 km$^2$ land area under the specific pressure patterns. The outputs were presented in a fine-mesh grid map with a 6-level contour capability.

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The Development of Refrigerator Using the Thermoelectric semiconductor (열전반도체를 이용한 냉장고의 개발)

  • Chung, Yong-Ho;Lee, Woo-Sun;Lee, Young-Jin;Kim, Sang-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.50-53
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    • 2001
  • The thermoelectric refrigeration technologies have no moving parts. compressor, or piping required. In this study, the basic capacity of thermoelectric devices and development on some thermoelectric refrigerator were reviewed and basic technical concepts related with many kinds of thermoelectric materials were discussed. Especially the result of performance test on thermoelectric refrigerator whose minimum temperature of $-2^{\circ}C$ was introduced briefly.

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Interpolating Monthly Normals of Daily Minimum Temperature over South Korea Based on Urban Heat Island Correction (도시효과를 고려한 일최저기온의 월별 평년값 분포)

  • 최재연
    • Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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    • pp.81-84
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    • 2002
  • 우리나라를 포함한 동아시아 지역의 기온상승, 특히 일최저기온 상승은 상당부분 도시화에 기인한 것으로 보고되었다(Hulme et al., 1994). 따라서 도시화 영향을 효과적으로 제거하여야 한반도에서 진행되는 온난화의 경향을 파악할 수 있으며 궁극적으로 장기 기후변화에 대한 예측과 대응이 가능하다 할 것이다(백과 권, 1994).(중략)

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A Special-day Load Forecasting with the Characteristics of Temperature based on Fuzzy Linear Regression (온도 특성을 고려한 퍼지 선형 회귀 분석 모델 기반 특수일 전력 수요 예측)

  • Yi, Kyoung-Jin;Baek, Young-Sik;Song, Kyung-Bin;Kim, Moon-Young
    • Proceedings of the KIEE Conference
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    • pp.432-434
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    • 2001
  • This paper proposes a special-day load forecasting method with the characteristics of temperature based on fuzzy linear regression. We can obtain a linear regression model from the relation between daily peak load and daily maximum or minimum temperature. Simulation results show that the proposed method can improve an accuracy of a special-day load forecasting.

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