• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.4
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• pp.194-210
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• 2022

The monthly inventory of dissolved inorganic carbon (C_T) and its fluxes were simulated using a box-model for the southeastern Yellow Sea, bordering the northern East China Sea. The monthly C_T data was constructed by combining the observed data representing four seasons with the data adopted from the recent publications. A 2-box-model of the surface and deep layers was used, assuming that the annual C_T inventory was at the steady state and its fluctuations due to the advection in the surface box were negligible. Results of the simulation point out that the monthly C_T inventory variation between the surface and deep box was driven primarily by the mixing flux due to the variation of the mixed layer depth, on the scale of -40~35 mol C m^-2 month^-1. The air to sea CO₂ flux was about 2 mol C m^-2 yr^-1 and was lower than 1/100 of the mixing flux. The biological pump flux estimated magnitude, in the range of 4-5 mol C m^-2 yr^-1, is about half the in situ measurement value reported. The C_T inventory of the water column was maximum in April, when mixing by cooling ceases, and decreases slightly throughout the stratified period. Therefore, the total C_T inventory is larger in the stratified period than that of the mixing period. In order to maintain a steady state, 18 mol C m^-2 yr^-1 (= 216 g C m^-2 yr^-1), the difference between the maximum and minimum monthly CT inventory, should be transported out to the East China Sea. Extrapolating this flux over the entire southern Yellow Sea boundary yields 4 × 10⁹ g C yr^-1. Conceptually this flux is equivalent to the proposed continental shelf pump. Since this flux must go through the vast shelf area of the East China Sea before it joins the open Pacific waters the actual contribution as a continental shelf pump would be significantly lower than reported value. Although errors accompanied the simple box model simulation imposed by the paucity of data and assumptions are considerably large, nevertheless it was possible to constrain the relative contribution among the major fluxes and their range that caused the C_T inventory variations, and was able to suggest recommendations for the future studies.

• Korean Journal of Remote Sensing
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• v.39 no.2
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• pp.207-221
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• 2023

This study suggests deep neural network models for estimating air temperature with Level 1B (L1B) datasets of GEO-KOMPSAT-2A (GK-2A). The temperature at 1.5 m above the ground impact not only daily life but also weather warnings such as cold and heat waves. There are many studies to assume the air temperature from the land surface temperature (LST) retrieved from satellites because the air temperature has a strong relationship with the LST. However, an algorithm of the LST, Level 2 output of GK-2A, works only clear sky pixels. To overcome the cloud effects, we apply a deep neural network (DNN) model to assume the air temperature with L1B calibrated for radiometric and geometrics from raw satellite data and compare the model with a linear regression model between LST and air temperature. The root mean square errors (RMSE) of the air temperature for model outputs are used to evaluate the model. The number of 95 in-situ air temperature data was 2,496,634 and the ratio of datasets paired with LST and L1B show 42.1% and 98.4%. The training years are 2020 and 2021 and 2022 is used to validate. The DNN model is designed with an input layer taking 16 channels and four hidden fully connected layers to assume an air temperature. As a result of the model using 16 bands of L1B, the DNN with RMSE 2.22℃ showed great performance than the baseline model with RMSE 3.55℃ on clear sky conditions and the total RMSE including overcast samples was 3.33℃. It is suggested that the DNN is able to overcome cloud effects. However, it showed different characteristics in seasonal and hourly analysis and needed to append solar information as inputs to make a general DNN model because the summer and winter seasons showed a low coefficient of determinations with high standard deviations.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4296-4311
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• 1977

This study was conducted to derive an Instantaneous Unit Hydrograph for the accurate and reliable unitgraph which can be used to the estimation and control of flood for the development of agricultural water resources and rational design of hydraulic structures. Eight small watersheds were selected as studying basins from Han, Geum, Nakdong, Yeongsan and Inchon River systems which may be considered as a main river systems in Korea. The area of small watersheds are within the range of 85 to 470$\textrm{km}^2$. It is to derive an accurate Instantaneous Unit Hydrograph under the condition of having a short duration of heavy rain and uniform rainfall intensity with the basic and reliable data of rainfall records, pluviographs, records of river stages and of the main river systems mentioned above. Investigation was carried out for the relations between measurable unitgraph and watershed characteristics such as watershed area, A, river length L, and centroid distance of the watershed area, Lca. Especially, this study laid emphasis on the derivation and application of Instantaneous Unit Hydrograph (IUH) by applying Nash's conceptual model and by using an electronic computer. I U H by Nash's conceptual model and I U H by flood routing which can be applied to the ungaged small watersheds were derived and compared with each other to the observed unitgraph. 1 U H for each small watersheds can be solved by using an electronic computer. The results summarized for these studies are as follows; 1. Distribution of uniform rainfall intensity appears in the analysis for the temporal rainfall pattern of selected heavy rainfall event. 2. Mean value of recession constants, Kl, is 0.931 in all watersheds observed. 3. Time to peak discharge, Tp, occurs at the position of 0.02 Tb, base length of hlrdrograph with an indication of lower value than that in larger watersheds. 4. Peak discharge, Qp, in relation to the watershed area, A, and effective rainfall, R, is found to be {{{{ { Q}_{ p} = { 0.895} over { { A}^{0.145 } } }}}} AR having high significance of correlation coefficient, 0.927, between peak discharge, Qp, and effective rainfall, R. Design chart for the peak discharge (refer to Fig. 15) with watershed area and effective rainfall was established by the author. 5. The mean slopes of main streams within the range of 1.46 meters per kilometer to 13.6 meter per kilometer. These indicate higher slopes in the small watersheds than those in larger watersheds. Lengths of main streams are within the range of 9.4 kilometer to 41.75 kilometer, which can be regarded as a short distance. It is remarkable thing that the time of flood concentration was more rapid in the small watersheds than that in the other larger watersheds. 6. Length of main stream, L, in relation to the watershed area, A, is found to be L=2.044A0.48 having a high significance of correlation coefficient, 0.968. 7. Watershed lag, Lg, in hrs in relation to the watershed area, A, and length of main stream, L, was derived as Lg=3.228 A0.904 L-1.293 with a high significance. On the other hand, It was found that watershed lag, Lg, could also be expressed as {{{{Lg=0.247 { ( { LLca} over { SQRT { S} } )}^{ 0.604} }}}} in connection with the product of main stream length and the centroid length of the basin of the watershed area, LLca which could be expressed as a measure of the shape and the size of the watershed with the slopes except watershed area, A. But the latter showed a lower correlation than that of the former in the significance test. Therefore, it can be concluded that watershed lag, Lg, is more closely related with the such watersheds characteristics as watershed area and length of main stream in the small watersheds. Empirical formula for the peak discharge per unit area, qp, ㎥/sec/$\textrm{km}^2$, was derived as qp=10-0.389-0.0424Lg with a high significance, r=0.91. This indicates that the peak discharge per unit area of the unitgraph is in inverse proportion to the watershed lag time. 8. The base length of the unitgraph, Tb, in connection with the watershed lag, Lg, was extra.essed as {{{{ { T}_{ b} =1.14+0.564( { Lg} over {24 } )}}}} which has defined with a high significance. 9. For the derivation of IUH by applying linear conceptual model, the storage constant, K, with the length of main stream, L, and slopes, S, was adopted as {{{{K=0.1197( {L } over { SQRT {S } } )}}}} with a highly significant correlation coefficient, 0.90. Gamma function argument, N, derived with such watershed characteristics as watershed area, A, river length, L, centroid distance of the basin of the watershed area, Lca, and slopes, S, was found to be N=49.2 A1.481L-2.202 Lca-1.297 S-0.112 with a high significance having the F value, 4.83, through analysis of variance. 10. According to the linear conceptual model, Formular established in relation to the time distribution, Peak discharge and time to peak discharge for instantaneous Unit Hydrograph when unit effective rainfall of unitgraph and dimension of watershed area are applied as 10mm, and $\textrm{km}^2$ respectively are as follows; Time distribution of IUH {{{{u(0, t)= { 2.78A} over {K GAMMA (N) } { e}^{-t/k } { (t.K)}^{N-1 } }}}} (㎥/sec) Peak discharge of IUH {{{{ {u(0, t) }_{max } = { 2.78A} over {K GAMMA (N) } { e}^{-(N-1) } { (N-1)}^{N-1 } }}}} (㎥/sec) Time to peak discharge of IUH tp=(N-1)K (hrs) 11. Through mathematical analysis in the recession curve of Hydrograph, It was confirmed that empirical formula of Gamma function argument, N, had connection with recession constant, Kl, peak discharge, QP, and time to peak discharge, tp, as {{{{{ K'} over { { t}_{ p} } = { 1} over {N-1 } - { ln { t} over { { t}_{p } } } over {ln { Q} over { { Q}_{p } } } }}}} where {{{{K'= { 1} over { { lnK}_{1 } } }}}} 12. Linking the two, empirical formulars for storage constant, K, and Gamma function argument, N, into closer relations with each other, derivation of unit hydrograph for the ungaged small watersheds can be established by having formulars for the time distribution and peak discharge of IUH as follows. Time distribution of IUH u(0, t)=23.2 A L-1S1/2 F(N, K, t) (㎥/sec) where {{{{F(N, K, t)= { { e}^{-t/k } { (t/K)}^{N-1 } } over { GAMMA (N) } }}}} Peak discharge of IUH) u(0, t)max=23.2 A L-1S1/2 F(N) (㎥/sec) where {{{{F(N)= { { e}^{-(N-1) } { (N-1)}^{N-1 } } over { GAMMA (N) } }}}} 13. The base length of the Time-Area Diagram for the IUH was given by {{{{C=0.778 { ( { LLca} over { SQRT { S} } )}^{0.423 } }}}} with correlation coefficient, 0.85, which has an indication of the relations to the length of main stream, L, centroid distance of the basin of the watershed area, Lca, and slopes, S. 14. Relative errors in the peak discharge of the IUH by using linear conceptual model and IUH by routing showed to be 2.5 and 16.9 percent respectively to the peak of observed unitgraph. Therefore, it confirmed that the accuracy of IUH using linear conceptual model was approaching more closely to the observed unitgraph than that of the flood routing in the small watersheds.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.329-339
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• 2021

Soybeans (Glycine max), one of major upland crops, require precise management of environmental conditions, such as temperature, water, and soil, during cultivation since they are sensitive to environmental changes. Application of spectral technologies that measure the physiological state of crops remotely has great potential for improving quality and productivity of the soybean by estimating yields, physiological stresses, and diseases. In this study, we developed and validated a soybean growth prediction model using multispectral imagery. We conducted a linear regression analysis between vegetation indices and soybean growth data (fresh weight and LAI) obtained at Miryang fields. The linear regression model was validated at Goesan fields. It was found that the model based on green ratio vegetation index (GRVI) had the greatest performance in prediction of fresh weight at the calibration stage (R²=0.74, RMSE=246 g/m², RE=34.2%). In the validation stage, RMSE and RE of the model were 392 g/m² and 32%, respectively. The errors of the model differed by cropping system, For example, RMSE and RE of model in single crop fields were 315 g/m² and 26%, respectively. On the other hand, the model had greater values of RMSE (381 g/m²) and RE (31%) in double crop fields. As a result of developing models for predicting a fresh weight into two years (2018+2020) with similar accumulated temperature (AT) in three years and a single year (2019) that was different from that AT, the prediction performance of a single year model was better than a two years model. Consequently, compared with those models divided by AT and a three years model, RMSE of a single crop fields were improved by about 29.1%. However, those of double crop fields decreased by about 19.6%. When environmental factors are used along with, spectral data, the reliability of soybean growth prediction can be achieved various environmental conditions.

• Journal of the Korean Society for Library and Information Science
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• v.24
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• pp.289-332
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• 1993

In china, six bibliographies of offical historical books are evaluated at the most important things among the systematically-editing bibliographies. These bibliographies would be usful to study the orign of classical sciences and their development, bibliographic research of Chinese classics, bibliographic judgement on genuine books, titles, authors, volumes. They could be refered to research into graving, correcting, and existence of ancient books. therefore, these bibliographies would be applied to estimation the phase of scientific and cultural development. The study of these bibliographies has been not yet made in Korea. This thesis lays its importance on the background of their appearance, their classification norms, organizing system of their catalogue, and comparison between their difference. 1. Editing and compiling of Chilyak (칠약) by Liu Chin (유흠) and official histories played an important role of entering an apperance of historical book's bibliographies. Chilyak has been lost. However, its classification and compiling system of classical books would be traced by Hansoyemunji(한서예문지) of which basic system is similar to Chilyak. It classified books according to their scientific characteristic. If a few books didn't have their own categories, they were combined by the circles parallel to the books' characteristic. With the books classified under the same scientific characteristic, they were again divided into the scientific schools or structures. It also arranged the same kinds of books according to the chronology. The some books wi th duplicate subjects were classified multiplely by their duplicate subject. 2. Ssu-ma Chon's (사마천) The Historical Records (Saki, 사기) and Pan Ku's (반고) The History of the Former Han Dynasty (Hanso, 한서) has also took effects on appearance of historical books' bibliographies. Covering overall history, Saki was structured by the five parts: The basic annals(본기), the chronological tables (표), the documents (서), the hereditary houses (세가), biographies (열전). The basic annals dealt with kings and courts' affairs according to the chronology. The chronological tables was the records of the annals. The documents described overall the social and cultural systems. The hereditary houses recorded courts' meritorious officials and public figures. The biographies showed exemplars of seventy peoples selected by their social status. Pan Ku(반구)'s The History of the Former Han Dynasty(한서) deserved to be called the prototype for the offical histories after Saki's (사기; The Historical Records) apperance. Although it modelled on Saki, it had set up its own cataloguing system. It was organized by four parts; the basic annals (본기), the chronological tables (표), treatises(지), biographies (열전). The documents in the Hanso(한서) was converted into treatises(지). The hereditary houses and biographies were merged. For the first time, the treatise with The Yemunji could operate function for historical bibliographies. 3. There were six historical bibliographies: Hansoyemunji(한서예문지), Susokyongjeokji (수서경적지), Kudangsokyongjeokji(구당서경적지), Shindangsoyemunji (신당서예문지), Songsayemunji (송사예문지), Myongsayemunji (명사예문지). 1) Modelling on Liu Chin's Chilyak except Chipryak(집략), Hansoyemunji divided the characteristic of the books and documents into six parts: Yukrye(육예), Cheja(제자), Shibu(시부), Pyongsoh(병서), Susul(수술), Pangki(방기). Under six parts, there were thirty eight orders in Hansoyemunji. To its own classification, Hansoyemunji applied the Chilyak's theory of classification that the books or documents were managed according to characteristic of sciences, the difference of schools, the organization of sentences. However the overlapped subjects were deleted and unified into one. The books included into an unsuitable subject were corrected and converted into another. The Hansoyemunji consisted of main preface (Taesoh 대서), minor preface (Sosoh 소서) , the general preface (Chongso 총서). It also recorded the introduction of books and documents, the origin of sciences, the outline of subjects, and the establishment of orders. The books classified by the subject had title, author, and volumes. They were rearranged by titles and the chronological publication year. Sometimes author was the first access point to catalogue the books. If it was necessary for the books to take footnotes, detail notes were formed. The Volume number written consecutively to order and subject could clarify the quantity of books. 2) Refering to Classfication System by Seven Norms (칠분법) and Classification System by Four Norms(사분법), Susokyongjeokji(수서경적지) had accomplished the classification by four norms. In fact, its classification largely imitated Wanhyosoh(완효서)'s Chilrok(칠록), Susokyongjeokji's system of classification consisted of four parts-Kyung(경), Sa(사), Cha(자), Chip(칩). The four parts were divided into 40 orders. Its appendix was again divided into two parts, Buddihism and Taiosm. Under the two parts there were fifteen orders. Totally Susokyongjeokji was made of six parts and fifty five orders. In comparison with Hansoyemunji(한서예문지), it clearly showed the conception of Kyung, Sa, Cha, Chip. Especially it deserved to be paid attention that Hansoyemunji laied history off Chunchu(춘추) and removed history to Sabu(사부). However Chabu(사부) put many contrary subjects such as Cheja(제자), Kiye(기예), Sulsu(술수), Sosol(소설) into the same boundary, which committed errors insufficient theoretical basis. Anothor demerit of Susokyongjeokji was that it dealt with Taiosm scriptures and Buddism scriptures at the appendix because they were considered as quasi-religion. Its compilation of bibliographical facts consisted of main preface(Taesoh 대서), minor preface(Sosoh 소서), general preface (Chongsoh 총서), postscript (Husoh 후서). Its bibliological facts mainly focused on the titles. Its recorded authors' birth date and their position. It wrote the lost and existence of books consecutive to total number of books, which revealed total of the lost books in Su Dynasty. 3) Modelling on the basis of Kokumsorok(고분서록) and Naewaekyongrok(내외경록), Kudangsokyongjeokji(구당서경적지) had four parts and fourty five orders. It was estimated as the important role of establishing basic frame of classification by four norms in classification theory's history. However it had also its own limit. Editing and compling orders of Kudangsokyongjeokji had been not progressively changed. Its orders imitated by and large Susokyongjeokji. In Its system of organizing catalogue, with its minor preface and general preface deleting, Kudangsokyongjeokji by titles after orders sometimes broke out confusion because of unclear boundaries between orders. 4) Shindangsoyemunji(신당서예문지), adding 28,469 books to Kudangsokyongjeokji, recorded 82,384 books which were divided by four parts and fourty four orders. In comparison with Kudangkyongjeokj, Sindangsoyemunji corrected unclear order's norm. It merged the analogical norms four orders (for instance, Kohun 고훈 and Sohakryu 소학류) and seperated the different norms four orders (for example, Hyokyong 효경 and Noneuhryu 논어류, Chamwi 참위 and Kyonghaeryu 경해류, Pyonryon 편년 and Wisaryu 위사류). Recording kings' behaviors and speeches (Kikochuryu 기거주류) in the historical parts induced the concept of specfication category. For the first time, part of Chipbu (집부) set up the order of classification norm for historical and literatural books and documents (Munsaryu 문사류). Its editing and compiling had been more simplified than Kudangsokyongjeokji. Introduction was written at first part of bibliographies. Appendants except bibliographic items such subject, author, title, volume number, total were omitted. 5) Songsayemunji(송사예문지) were edited in the basis of combining Puksong(북송) and Namsong(남송), depending on Sabukuksayemunji(사부국사예문지). Generally Songsayemunji had lost a lot of bibliographical facts of many books. They were duplicated and wrongly classified books because it committed an error of the incorrectly annalistic editing. Particularly Namsong showed more open these defaults. Songsayemunji didin't include the books published since the king Youngchong(영종). Its system of classification was more better controlled. Chamwiryu(참위류) in the part of Kyongbu(경부) was omitted. In the part of history(Sabu 사부), recordings of kings' behaviors and speeches more merged in the annals. Historical abstract documents (Sachoryu 사초류) were seperately arranged. In the part of Chabu(자부), Myongdangkyongmaekryu(명당경맥류) and Euisulryu(의술류) were combined. Ohangryu(오행류) were laied off Shikuryu(시구류). In the part of Chipbu(집부), historical and literatural books (Munsaryu 문사류) were independentely arranged. There were the renamed orders; from Wisa(위사) to Paesa(패사), Chapsa (잡사) to Pyolsa(열사), Chapchonki(잡전기) to Chonki(전기), Ryusoh(류서) to Ryusa(류서). Introduction had only main preface. The books of each subject catalogued by title, the volume number, and author and arranged mainly by authors. Annotations were written consecutively after title and the volume number. In the afternote the number of not-treated books were revealed. Difference from Singdangsohyemunji(신당서예문지) were that the concept and boundary of orders became more clearer. It also wrote the number of books consecutive to main subject. 6) Modelling on Chonkyongdangsomok (경당서목), Myongsayemunji(명사예문지) was compiled in the basis of books and documents published in the Ming Danasty. In classification system, Myongsayemunji partly merged and the seperated some orders for it. It also deleted and renamed some of orders. In case of necessity, combining of orders' norm was occured particulary in the part of Sabu(사부) and Chabu(자부). Therefore these merging of orders norm didn't offer sufficient theretical background. For example, such demerits were seen in the case that historical books edited by annals were combined with offical historical ones which were differently compiled and edited from the former. In the part of Chabu(자부), it broke out another confusion that Pubga(법가), Meongga(명가), Mukga(묵가), Chonghweongka's(종횡가) thoughts were classified in the Chapka(잡가). Scriptures of Taiosim and Buddhism were seperated from each other. There were some deleted books such as Mokrokryu(목록류), Paesaryu(패사류) in the part of history (Sabu 사부) and Chosaryu(초사류) in the part of Chipbu(집부). The some in the each orders had been renamed. Imitating compiling system of Songsayemunji(송사예문지), with reffering to its differ-ence, Myongsayemunji(명사예문지) wrote the review and the change of the books by author. The number of not-treated books didn't appear at the total. It also deleted the total following main subject.