• Korean Journal of Construction Engineering and Management
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• v.20 no.6
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• pp.126-131
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• 2019

The estimation of available solar energy at particular locations is critical to find and assess suitable locations of PV sites. The amount of PV power generation is however affected by various geographical factors (e.g., weather), which may make it difficult to identify the complex relationship between affecting factors and power outputs and to apply findings from one study to another in different locations. This study thus undertakes a regression analysis using data collected from 172 PV plants spatially distributed in Korea to identify critical weather conditions and estimate the potential power generation of PV systems. Such data also include solar radiation, precipitation, fine dust, humidity, temperature, cloud amount, sunshine duration, and wind speed. The estimated PV power generation is then compared to the actual PV power generation to evaluate prediction performance. As a result, the proposed model achieves a MAPE of 11.696(%) and an R-squred of 0.979. It is also found that the variables, excluding humidity, are all statistically significant in predicting the efficiency of PV power generation. According, this study may facilitate the understanding of what weather conditions can be considered and the estimation of PV power generation for evaluating and determining suitable locations of PV facilities.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.44-54
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• 2001

This study was conducted to estimate microclimate of natural deciduous forest in national forest of Pyungchang, Kangwon province and to investigate the effects of the microclimatic conditions on the periodic annual increment of diameter by site types. In this study, site was first classified by nine types considering both elevation (higher than 1,000 m, 700∼1,000 m, and lower than 700 m) and topographical conditions (ridge, slope and valley). For each of site types, diameter growth was measured by using increment borer and periodic annual increment of diameter was then analyzed. A topoclimatological technique, for estimating microclimatic conditions, which make use of empirical relationships between the topographical factor and the climatic normals in the study area was applied to produce monthly mean, maximum and minimum temperatures, relative humidity, precipitation and hours of sunshine. From these monthly estimtes, 17 weather variables such as warmth index, coldness index, index of aridity etc. which affect the diameter growth were computed for each of site types. The periodic annual increment of diameter was then correlated with and regressed on the 17 weather variables to examine effects of microclimatic conditions on the diameter growth by site types. From the correlation analysis, it was found that the diameter growth by site types was positively correlated with all of 17 weather variables except the warmth index. Especially, the conditions such as high relative humidity and large amount of sunshine hours provide favorable environment for the growth of diameter. On the other hand, it was also found that diameter growth was negatively iufluenced by warmth index. According to the regression analysis, the periodic annual increment of diameter could be well predicted by index of aridity and mean relative humidity for the growing season.

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.247-258
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• 2004

Climatological, hydrological and planktonical research studies, measurements of primary production and photosynthetic efficiency from December 1976 to December 1978 have been carried out in two brackish lakes: Lake Etang de Berre and Lake Etang de Vaine located in the French Mediterranean coast, in the region of Carry-le-Rouet located on the north-west Mediterranean near Marseilles, and in fresh water inflows from 4 Rivers (Touloubre, Durance, Arc, Durancole) to Lake Etang de Berre. Physico-chemical parameters were measured for this study: water temperature, salinity, density, pH, alcalinity, dissolved oxygen (% saturation), phosphate, nitrate, nitrite, silicate etc. Diverse biological parameters were also studied: photosynthetic pigments, phaeopigments, specific composition and biomass of phytoplankton, primary pelagic production etc. Climatical factors were studied: air-temperature, solar-radiation, evaporation, direction (including strength) of winds, precipitation and freshwater volume of the four rivers. The changes in Lake ‘Etang de Berre’ ecosystem depend on the quality of the water in the Durance River, and on the effects of seawater near the entrance of the Caronte Canal. The water quality of the lake varies horizontally and vertically as a result of atmospheric phenomena, maritime currents and tides. The distribution of water temperatures is generally heterogeneous. Southeasterly winds and the Northeasterly Mistral wind are important in the origins of circulated and mixed water masses. These winds are both frequent and strong. They have, as a result, a great effect on the water environment of Lake Etang de Berre. In theory, the annual precipitation in this region is well over eight times the water mass of the lake. The water of the Durance River flows into Lake Etang de Berre through the EDF Canal, amounting to 90% of the precipitation. However, reduction of rainfall in dry seasons has a serious effect on the hydrological characteristics of the lake. The temperature in the winter is partially caused by the low temperature of fresh water, particularly that of the Durance River. The hydrological season of fresh and brackish water is about one month ahead of the hydrological season of sea water in its vicinity. The salinity of Lake Etang de Berre runs approximately 3$\textperthousand$, except at lower levels and near the entrance to the Caronte Canal. However, when the volume of the Durance River water is reduced in the summer and fall, the salinity rises to 15$\textperthousand$. In the lake, the ratio of fresh water to sea water is six to one (6:1). The large quantities of seston conveyed by rivers, particularly the Durance diversion, strongly reduce the transparency in the brackish waters. Although the amount of sunshine is also notable, transparency is slight because of the large amount of seston, carried chiefly by Tripton in the fresh water of the Durance River. Therefore, photosynthesis generally occurs only in the surface layer. The transparency progressively increases from freshwater to open seawater, as mineral particles sink to the bottom (about 1.7kg $m^{-2}a^{-1}$ on the average in brackish lakes). The concentration of dissolved oxygen and the rate of oxygen saturation in seawater (Carry-le-Rouet) ranged from 5.0 to 6.0 $m\ell$ㆍ.$1^{-1}$, and from 95 to 105%, respectively. The amount of dissolved oxygen in Etang de Berre oscillated between 2.9 and 268.3%. The monographs of phosphate, nitrate, nitrite and silicate were published as a part of a study on the ecology of phytoplankton in these environments. Horizontal and vertical distributions of these nutriments were studied in detail. The recent diversion of the Durance River into Lake Etang de Berre has effected a fundamental change in this formerly marine environment, which has had a great impact in its plankton populations. A total of 182 taxa were identified, including 111 Bacillariophyceae, 44 Chlorophyceae, and 15 Cyanophyceae. The most abundant species are small freshwater algae, mainly Chlorophyceae. The average density is about $10^{8}$ cells $1^{-1}$ in Lake Etang de Berre, and about double that amount in Lake Etang de Vaine. Differences in phytoplankton abundance and composition at the various stations or at various depths are slight. Cell biovolume V (equivalent to true biomass), plasma volume VP (‘useful’ biomass) and, simultaneously. the cell surface area S and S/V ratio through the measurement of cell dimensions were computed as the parameters of phytoplankton productivity and metabolism. Pigment concentrations are generally very high on account of phytoplankton blooms by Cyanophyceae, Chlorophyceae and Cryptophyceae. On the other hand, in freshwaters and marine waters, pigment concentrations are comparatively low and stable, showing slight annual variation. The variations of ATP concentration were closely related to those of chlorophyll a and phytoplankton blooms only in marine waters. The carbon uptake rates ranged between 38 and 1091 mg$Cm^{-2}d^{-1}$, with an average surface value of 256 mg; water-column carbon-uptake rates ranged between 240 and 2310 mg$Cm^{-2}d^{-1}$, with an average of 810, representing 290 mg$Cm^{-2}$, per year 45 000 tons per year of photosynthetized carbon for the whole lake. Gross photosynthetic production measured by the method of Ryther was studied over a 2-year period. The values obtained from marine water(Carry-le-Rouet) ranged from 23 to 2 337 mg$Cm^{-2}d^{-1}$, with a weighted average of 319, representing about 110 gCm$^{-2}$ per year. The values in brakish water (Etang de Berre) ranged from 14 to 1778 mg$Cm^{-2}d^{-1}$, with a weighted average of 682, representing 250 mg$Cm^{-2}$ per year and 38 400 tons per year of photosynthesized carbon for the whole lake.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.274-284
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• 2014

Crops and varieties are mostly affected by temperature, the amount of precipitation, and duration of sunshine. This study aims to identify the weather factors that directly influence to apple yield among the series of daily measured weather variables during growing seasons. In order to identify them, 1) a priori natural scientific knowledge with respect to the growth stage of apples and 2) pure statistical approaches to minimize bias due to the subject selection of variables are considered. Each result estimated by the Panel regression using fixed/random effect models is evaluated through suitability (i.e., Akaike information criterion and Bayesian information criterion) and predictability (i.e., mean absolute error, root mean square error, mean absolute percentage). The Panel data of apple yield and weather factors are collected from fifteen major producing areas of apples from 2006 to 2013 in Korea for the case study. The result shows that variable selection using factor analysis, which is one of the statistical approaches applied in the analysis, increases predictability and suitability most. It may imply that all the weather factors are important to predict apple yield if statistical problems, such as multicollinearity and lower degree of freedom due to too many explanatory variables used in the regression, can be controlled effectively. This may be because whole growth stages, such as germination, florescence, fruit setting, fatting, ripening, coloring, and harvesting, are affected by weather.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.253-263
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• 1993

Climatological informations have not been fully utilized by agricultural research and extension workers in Korea due mainly to inaccessbilty to the archived climate data. This study was initiated to improve access to historical climate data gathered from 72 weather stations of Korea Meteorological Administration for agricultural applications by using a microcomputer-based methodology. The climatological elements include daily values of average, maximum and minimum temperature, relative humidity, average and maximum wind speed, wind direction, evaporation, precipitation, sunshine duration and cloud amount. The menu-driven, user-friendly data retrieval system(CLIDAS) provides quick summaries of the data values on a daily, weekly and monthly basis and selective retrieval of weather records meeting certain user specified critical conditions. Growing degree days and potential evapotranspiration data are derived from the daily climatic data, too. Data reports can be output to the computer screen, a printer or ASCII data files. CLIDAS can be run on any IBM compatible machines with Video Graphics Array card. To run the system with the whole database, more than 50 Mb hard disk space should be available. The system can be easily upgraded for further expansion of functions due to the module-structured design.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.359-364
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• 2012

This study were carried out to find bolting response of cultivation in different regions and to isolate FLC (FLOWERING LOCUS C) homologs in Angelica gigas Nakai. The mean temperature of different regions, ordering in altitude, were as follows: 100 m > 350 m > 530 m > 700 m. The largest amount of rainfall was occurred in the region of 350 m while the longest time of sunshine was occurred in the region of 100 m. The content of soil chemical properties in regions showed pH 6.2 ~ 7.4, T-N 0.17 ~ 26, organic mater $1{\sim}32gkg^{-1}$, $P_2O_5$ ${151{\sim}664_{mgkg}}^{-1}$, exchangeable potassium and calcium and magnesium were 0.78 ~ 1.15, 3.9 ~ 10.0, ${0.7{\sim}3.2_{cmol}}^{+kg-1}$. L5 line of A. gigas was occurred in bolting at all regions, but the bolting ratio was 60.0% in 700 m region with non-mulching treatment. Manchu of A. gigas was not occurred in bolting at all regions. The accumulation bolting ratio of L5 line by non-mulching was higher than that of mulching as 90.4% and 72.8% in 100 m region. The MADS-box transcription factor FLC is one of the well-known examples as a strong floral repressor. We decided to isolate FLC homologs from A. gigas as a starting point of flowering mechanism research of this plant. We have isolated two RT-PCR products which showed very high amino acid sequence homology to Arabidopsis FLC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5417-5422
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• 2013

This research was performed in order to improve the goodness of fit of paddy rice production forecasting using MODIS images and to find out appropriate explanatory variables in the forecasting model. The aim of this paper is to review the use of satellite images for the survey of paddy rice production in Korea. Many developed countries, including the United States, Australia, and Japan, have been using satellite images to produce agricultural statistics such as crop production, cultivated acreage, etc. The survey accuracy of crop production by using satellite images, however, is not satisfied in practical use. In this paper, we reviewed several methods to increase the survey accuracy of rice production statistics, gained from satellite images. Rice was selected for this study because its cultivated area and production amount could be more easily identified than other crops by using satellite images. The MODIS images were used because they involved more appropriate images to estimate and analyze rice production. This study estimated yield functions by using the NDVIs, gained from paddy rice yields and annual average isothermal lines, and the meteorological variables such as sunshine hours, rainfall, and temperature during ripening stage. As a result of yield function estimation, the goodness of fit(R-squared) for the models was shown from 0.768 to 0.891. In this study, it is noteworthy academically and practically that vegetation index(NDVIs) identified by annual average isothermal lines and meteorological variables are very useful for estimating yield functions.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.201-209
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• 1982

In 1980, the abnormal low temperature was lasted during the late stage of rice growing season, thus low temperature injury occurred severely. The severity of the injury and nutrition absorption were investigated. The result obtained were summarized as follows: 1. It was considered that the severe low temperature injury of rice was caused by the low temperature and shorts of sunshine in the late growing season of rice, especially, the minimum air temperature which was lasted for a few days below critical reproductive growing temperature in the meiosis stage affected high the injury. 2. The low tmperature injury was lightened in the no nitrogen applied plot, and becoming severe with high nitrogen levels, but the balanced application of NPK lessened the low temperature injury. 3. The low temperature injury was more severe in Indica and Japonica hybrid than in Japonica cultivar, and the injury was shown as sterilizing, degraded spiklets, ill emerging of head and inhibition of nutrition absorption, etc. 4. Under the low temperature condition, $SiO_2$ content of rice plant was significantly reduced according to the increase of nitrogen levels. 5. Under the low temperature condition, the optimum application amount of nitrogen for Milyang 23, was 13, 6 kg/10a, this was approximately 10kg/10a smaller than average in usual year. The highly reduced rice yield was resulted from the cool injury, and the reducing rate of yield was larger in Indica and Japonica hybrid cultivar than in Japonica cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.229-234
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• 1989

In flue-cured tobacco, the relationships between the quality of tobacco leaves (productivity according to quality grade) and specific meteorological factors were noted showing different significances according to different seasons during the growing period of the tobacco plants. The thick leaf high quality was significantly correlated with average temperature in late April, late May, early July and late July. The degree of contribution was greatest in middle May and lowest in late May. In the highest and lowest temperatures, the relations to leaf quality had similar tendency like in the average temperature; the thick leaf low quality showed opposite tendency relative to the high quality in the degrees of correlations and contributions. Amount of precipitation was significantly correlated with the thick leaf high quality in late April, early May, middle May, late June and late July. The degree of positive contribution was shown in order of late April, middle July and early July, and that of negative one was in order of middle June, early June and late June, respectively. Duration of sunshine period was highly associated with thick leaf high quality of tobacco leaves in all of the growing season except for middle April and middle July. The degree of positive contribution was in order of late May, late April, early July and middle July, and that of the negative one was in order of late June, early May, middle June and middle May.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.1
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• pp.65-71
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• 2015

Red Tide phenomenon which happens in the southern coast of Korea gives massive damage to the fishermen who run fish farms and thereby a lot of efforts to prevent damage are made from various angles. In particular, red tide monitoring with satellite imagery can make it possible to obtain the occurrence data of red tide throughout the whole areas of the sea, which helps provide important information for establishing the preventive plans of disasters. In this regard, this study selected the South Sea of Gyeongnam Province with a view to suggesting the monitoring results with regard to the spread and reduction of the Red Tide in the middle of the day by using the GOCI Images of COMS. With this intention, it selected the region in the South Sea of Gyeongnam Province. The study results of analysis on the GOCI image data for the years of 2013(Aug. 12) and 2014 (Sep. 11) are as follows: the pattern of the Red Tide in the region of the South Sea occurred in the southern sea area of Geoje-do in the morning. It gradually spread and showed a gradual decline after reaching the top at 1 PM. In addition, in terms of the tide movement in the middle of the day, Red Tide began in the southern sea area and moved to the west, and moved to the east again at noon. It is judged that additional study on many factors such as the characteristics of the future Red-tide organisms, tidal currents, amount of sunshine, and water temperature is needed, but it is estimated that Red Tide movement monitoring with GOCI images would provide very crucial information for predicting the spread and movement of the Red Tide to protect and manage the Red Tide disasters.