• Title/Summary/Keyword: ERA5-Land

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Evaluation of bias and uncertainty in snow depth reanalysis data over South Korea (한반도 적설심 재분석자료의 오차 및 불확실성 평가)

  • Jeon, Hyunho;Lee, Seulchan;Lee, Yangwon;Kim, Jinsoo;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.56 no.9
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    • pp.543-551
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    • 2023
  • Snow is an essential climate factor that affects the climate system and surface energy balance, and it also has a crucial role in water balance by providing solid water stored during the winter for spring runoff and groundwater recharge. In this study, statistical analysis of Local Data Assimilation and Prediction System (LDAPS), Modern.-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), and ERA5-Land snow depth data were used to evaluate the applicability in South Korea. The statistical analysis between the Automated Synoptic Observing System (ASOS) ground observation data provided by the Korea Meteorological Administration (KMA) and the reanalysis data showed that LDAPS and ERA5-Land were highly correlated with a correlation coefficient of more than 0.69, but LDAPS showed a large error with an RMSE of 0.79 m. In the case of MERRA-2, the correlation coefficient was lower at 0.17 because the constant value was estimated continuously for some periods, which did not adequately simulate the increase and decrease trend between data. The statistical analysis of LDAPS and ASOS showed high and low performance in the nearby Gangwon Province, where the average snowfall is relatively high, and in the southern region, where the average snowfall is low, respectively. Finally, the error variance between the four independent snow depth data used in this study was calculated through triple collocation (TC), and a merged snow depth data was produced through weighting factors. The reanalyzed data showed the highest error variance in the order of LDAPS, MERRA-2, and ERA5-Land, and LDAPS was given a lower weighting factor due to its higher error variance. In addition, the spatial distribution of ERA5-Land snow depth data showed less variability, so the TC-merged snow depth data showed a similar spatial distribution to MERRA-2, which has a low spatial resolution. Considering the correlation, error, and uncertainty of the data, the ERA5-Land data is suitable for snow-related analysis in South Korea. In addition, it is expected that LDAPS data, which is highly correlated with other data but tends to be overestimated, can be actively utilized for high-resolution representation of regional and climatic diversity if appropriate corrections are performed.

Historical Review on the Characteristics of Specialized and Mixed Land Uses of Korean Zoning System - From Chosun Planning Ordinace of 1934 to City Planning Law of 1962 (우리나라 용도지역제의 용도순화 및 용도혼합 특성에 관한 역사적 고찰 - 조선시가지계획령에서 도시계획법에 이르기까지 -)

  • Jun, Chae-Eun;Choi, Mack Joong
    • Journal of Korea Planning Association
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    • v.53 no.6
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    • pp.5-18
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    • 2018
  • While the zoning system has been developed based on the rationale of separated and specialized land uses to prevent negative externalities in the modern industrial era, the emergence of office-based new industries in the post-industrial era rather encourages mixed land uses to create agglomeration economies. This study aims to find historical basis to justify the reform of zoning system to promote both specialized and mixed land uses. When the zoning system was first introduced in Japanese colonial period by Chosun Planning Ordinance enacted in 1934, Special District within Manufacturing Area, and later within Residential, Commercial, and Mixed Areas respectively was institutionalized for specialized land uses, though it was not actually designated. When City Planning Law was enacted in 1962, Special District was substituted by Exclusive Areas (Exclusive Residential Area, Exclusive Manufacturing Area). Meanwhile Undesignated Area was designated for mixed land uses by Chosun Planning Ordinance, and later it was converted mostly into Mixed Area and partially into Green Area. Finally Mixed Area was substituted by Semi-Areas (Semi-Residential Area, Semi-Manufacturing Area) by City Planning Law in 1962. These demonstrate that Korean zoning system needs to revive the tradition that clearly promoted both specialized and mixed land uses.

Understanding Physical Mechanism of 2022 European Heat Wave (2022년 발생한 기록적인 유럽 폭염 발생의 역학적 원인 규명 연구)

  • Ju Heon Kim;Gun-Hwan Yang;Hyun-Joon Sung;Jung Hyun Park;Eunkyo Seo
    • Atmosphere
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    • v.33 no.3
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    • pp.307-317
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    • 2023
  • This study investigates the physical mechanisms that contributed to the 2022 European record-breaking heatwave throughout May-August (MJJA). The European climate has experienced surface warming and drying in the recent decade (1979~2022) which influences the development of the 2022 European heatwave. Since its spatial pattern resembles the 2003 European heatwave which is a well-known case developed by the strong coupling of near-surface conditions to land surface processes, the 2022 heatwave is compared with the 2003 case. Understanding heatwave development is carried out by the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis version 5 (ERA5) and daily maximum surface temperature released by NCEP (National Centers for Environmental Prediction) CPC (Climate Prediction Center). The results suggest that the persistent high pressure along with clear sky tends to increase the downward shortwave radiation which leads to enhanced sensible heat flux with the land surface dryness. Terrestrial Coupling Index (TCI), a process-based multivariate metric, is employed to quantitatively measure segmented feedback processes, separately for the land, atmosphere, and two-legged couplings, which appears to the development of the 2022 heatwave, can be viewed as an expression of the recent trends, amplified by internal land-atmosphere interactions.

Analysis of the impact of the land surface resolution on soil moisture and fire simulation (지면 모델 격자 크기에 따른 토양수분과 화재 모의 영향 분석)

  • Hocheol Seo;Eunjee Lee;Randal D. Koster;Yeonjoo Kim
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.69-69
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    • 2023
  • 격자 기반의 지면모형을 구동하기에 앞서 사용자의 목적에 따른 모델의 정확도와 모델의 구동 시간의 적절한 균형을 이루는 지면 모델의 격자 크기의 설정은 중요하다. 특히, 격자 크기에 따라 화재 모의 결과 영향이 매우 클 수 있지만, 이에 관한 연구들을 거의 이루어지지 않았다. 화재 모의는 탄소 순환뿐만 아니라 물 순환에도 직접적인 영향을 미치기 때문에 이를 위한 적절한 격자 크기 설정은 중요하다. 본 연구에서는 지면모형인 NCAR Community Land Model version 5(CLM 5)-biogeochemistry (BGC) 모형과 2000년부터 2019년의 The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) 기상자료 이용하여서 지면 모델 격자 크기(1.9°×2.5°, 0.47°×0.63°, 0.25°×0.25°)에 따른 전 지구 규모의 화재 시뮬레이션 결과들을 분석하였다. 연평균 화재면적은 격자 크기가 제일 큰 1.9°×2.5° 격자의 시뮬레이션에서 연평균 450M ha로 가장 작게 나타났으며 격자의 크기가 작아질수록 화재의 크기는 증가하는 것으로 나타났다. 지면 모델의 격자가 작아짐에 따라 토양 입자의 분포가 세분화되고 이에 따라 투수 계수값이 증가하며 높은 토양수분의 분포들을 줄어들고 낮은 토양수분의 분포는 증가함을 확인하였다. 토양수분이 줄어듦에 따라 화재 연소성 정도를 나타내는 변수의 값이 증가하고 이에 따라 화재 발생빈도 및 화재 확산이 증가하여 지면 모델의 화재면적을 더 증가시키는 요인이 됨을 확인하였다. 이 연구를 바탕으로 하여 화재 모의의 불확실성 요소를 이해하고, 격자 크기에 따라 화재 모의 관련 매개변수의 수정이 필요할 것으로 판단된다.

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Assessment of Noah land surface model-based soil moisture using GRACE-observed TWSA and TWSC (GRACE 관측 TWSA와 TWSC를 활용한 Noah 지면모형기반 토양수분 평가)

  • Chun, Jong Ahn;Kim, Seon Tae;Lee, Woo-Seop;Kim, Daeha
    • Journal of Korea Water Resources Association
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    • v.53 no.4
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    • pp.285-291
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    • 2020
  • The Noah 3.3 Land Surface Model (LSM) was used to estimate the global soil moisture in this study and these soil moisture datasets were assessed against satellite-based and reanalysis soil moisture products. The Noah 3.3 LSM simulated soil moistures in four soil layers and root-zone soil moistures defined as a depth-weighted average in the first three soil layers (i.e., up to 1.0 m deep). The Noah LSM soil moisture products were then compared with a satellite-based soil moisture dataset (European Space Agency Climate Change Initiatives (ESA CCI) SM v04.4) and reanalysis soil moisture datasets (ERA-interim). In addition, the five major basins (Yangtze, Mekong, Mississippi, Murray-Darling, Amazon) were selected for the assesment with the Gravity Recovery and Climate Experiment (GRACE)-based Total Water Storage Anomaly (TWSA) and TWS Change (TWSC). The results revealed that high anomaly correlations were found in most of the Asia-Pacific regions including East Asia, South Asia, Australia, and Noth and South America. While the anomaly correlations in the Murray-Darling basin were somewhat low, relatively higher anomaly correlations in the other basins were found. It is concluded that this study can be useful for the development of soil moisture based drought indices and subsequently can be helpful to reduce damages from drought by timely providing an efficacious strategy.

Changes in Layout Structure and Space in the Vicinity of Jongno in Hanseong-bu(漢城府) in the Early 20th Century (20세기 초 한성부 종로 주변 시전의 배치구조와 공간 변화)

  • Jeong, Su-In;Han, Dong-Soo
    • Journal of architectural history
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    • v.30 no.5
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    • pp.17-28
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    • 2021
  • The Sijeon (Licensed Markets) legally permitted by the government along the Jongno and the Namdaemunro Avenues played a central commercial role in Hanyang. However, after the opening of the port in the late Joseon era, the Licensed Markets suffered a blow and declined due to the introduction of a new product of civilization and the appearance of foreign merchants. Although the Licensed Markets, which have been maintained without major changes for a long time, have played a major role in the urban spatial structure, the exact location has not been still determined, and researches until now has remained limited for such that. In this study, based on the 1912 land survey records, the location of the Licensed Markets pre-and post- 1910 is identified, and the spatial change of the dismantling process is investigated.

A Study on the Roadiside Forest in Jungeup-Gun, Chunbuk-Do -ase Study on the Roadside Forest from Wonpyung to Kamgok- (전북 정읍지역 도로 주변림에 관한 연구 -김재 원평에서 정읍 감곡 사이의 지방도 사례로-)

  • 박재철
    • Journal of the Korean Institute of Landscape Architecture
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    • v.22 no.1
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    • pp.53-63
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    • 1994
  • There are lots of forests around the Korean rural village. This study was conducted to investigate the state of the forests by the 15 forests case study of the Kamgok region in Chon-guk-Do province, Korea. The results are as follows. 1. The forests lose mostly original form by the construction of road and forest clearing for the land development business. And almostly the form of the forests is a trapezoid or roundness. 2. The forests were remained on account of the Korean cemetery customs which is burying underground. 3. The conservation of the forests becomes more difficult because of the continuous development pressure. 4. Because the scale of the forests is so small, they aren't named as the natural resort forest by the forest law. So it will be the better alternative that they are conserved and used by inducing the concept of the village resort forest. 5. Because the owenership of the forests exists in a person or a family, the forests will be destructed continuously by the cemetery development. 6. The vegetation of the upper trees in the forests is the simple forests of Pinus densiflora, Pinus rigida and bamboo. The height of upper tree is average 10-12m. And average root diameter is 13-29cm. The age of the tree is average 50 years old. The state of the forests is mostly fine. 7. It is clarified that the price of the forest land is 3-5 times expensive than the other cultivated land. 8. The forests were made by the forefathers for the purpose of the practical use and were reforested in the era 1960s, 1970s.

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Evaluation of near-realtime weekly root-zone Soil Moisture Index (SMI) for the extreme climate monitoring web-service across East Asia (동아시아 이상기후 감시 서비스를 위한 지면모형 기반 준실시간 토양수분지수평가)

  • Chun, Jong Ahn;Lee, Eunjeong;Kim, Daeha;Kim, Seon Tae;Lee, Woo-Seop
    • Journal of Korea Water Resources Association
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    • v.53 no.6
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    • pp.409-416
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    • 2020
  • An extreme climate monitoring is essential to the reduction of socioeconomic damages from extreme events. The objective of this study was to produce the near-realtime weekly root-zone Soil Moisture Index (SMI) on the basis of soil moisture using the Noah 3.3 Land Surface Model (LSM) for potentially monitoring extreme drought events. The Yangtze basin was selected to evaluate the Noah LSM performance for the East Asia region (15-60°N, 70-150°E) and the evapotranspiration (ET) and sensible heat flux (SH) were compared with ET and SH from FluxNet and with ET from FluxCom, Global Land Evaporation Amsterdam Model (GLEAM), ERA-5, and Generalized Complementary Relationship (GCR). For the ET, the coefficients of determination (R2) were higher than 0.96, while the R2 value for the SH was 0.71 with slightly lower than those. A time series of the weekly root-zone SMI revealed that the regions with Extreme drought had been expanded from the northern part of East China to the entire East China between July to October 2019. The trend analysis of the number of extreme drought events showed that extreme drought events in spring had reduced in South Korea over the past 20 years, while those in fall had a tendency to increase. It is concluded that this study can be useful to reduce the socioeconomic damages resulted from climate extremes by comprehensively characterizing extreme drought events.

Calculation of Soil Moisture and Evaporation on the Korean Peninsula using NASA LIS(Land Information System) (NASA LIS(Land Information System)을 이용한 한반도의 토양수분·증발산량 산출)

  • PARK, Gwang-Ha;YU, Wan-Sik;HWANG, Eui-Ho;JUNG, Kwan-Sue
    • Journal of the Korean Association of Geographic Information Studies
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    • v.23 no.4
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    • pp.83-100
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    • 2020
  • This study evaluated the accuracy of soil moisture and evapotranspiration by calculating the hydrological parameters in Korean peninsula using Land Information System(LIS) developed by US NASA. We used Noah-MP surface model to calculate hydrological parameters, and used MERRA2(Modern-Era Retrospective analysis for Research and Applications, Version 2) for hydrological forcing data. And, International Geosphere-Biosphere Program(IGBP) and University of Maryland(UMD) land cover maps were applied to compare the output accuracy, and Automated Synoptic Observing System(ASOS) of KMA was used as ground observation data. In order to evaluate the accuracy of the output data, the correlation coefficient(CC), BIAS, and efficiency factor (NSE, Nash-Sutcliffe Efficiency) were analyzed with soil moisture and evapotranspiration by ASOS ground observation data. As a result, the correlation coefficient of soil moisture using IGBP was 0.56 on average, and evapotranspiration was about 0.71. On the other hand, soil moisture using UMD was 0.68 on average and evapotranspiration was about 0.72, and the correlation coefficient by UMD was evaluated as high accuracy compared to the results by using IGBP. The correlation coefficient of soil moisture was an average of 0.68 and evapotranspiration was an average of 0.72 when MERRA2 was used as hydrological forcing data. On the other hand, the soil moisture applied with ASOS was an average of 0.66, and evapotranspiration was an average of 0.72. It is judged that the ASOS point data was reanalyzed as 0.65°× 0.5°grids, which is the same spatial resolution with MERRA2, resulting in differences in accuracy depending on the region.

Survey on Residents' Awareness of Housing Environment in Old Housing Districts Created by the Land Readjustment Project in the Modern Age - Focused on Uam-Dong in Cheongju City - (근대기 토지구획정리사업지구 내 노후 주거지의 주거환경에 대한 거주자의 인식 조사 - 청주시 우암동을 대상으로 -)

  • Kim, Mi-Yeon;Oh, Deog-Seong;Won, Se-Yong
    • Journal of the Korean Institute of Rural Architecture
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    • v.21 no.1
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    • pp.1-8
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    • 2019
  • This study is about the research of living environment in residential areas created by the land readjustment projects in the modern era, and recently lifted from Residential Environment Improvement district at the same time. The five criteria for evaluating the residential area are safety, health, convenience, comfort, and sustainability. The level of resident satisfaction in general is as follows. [completely dissatisfy as 5.30%, dissatisfy as 16.29%, neutral as 49.62%, satisfy as 16.29% and completely satisfy as 6.82%]. The results of the five survey items on the residential areas show that residents are aware of the area not as an old residential area to be demolished, but as a comparatively excellent residential area, namely very different results from the designation criteria of the redevelopment area designated by the Urban and Residential Environment Improvement Act. If the road conditions and the deterioration of the buildings are judged to be designated as the redevelopment area and to be removed these settlements, the residential areas with social sustainability could demolished. Based on this study, it is necessary to conduct the research to find out the reason for deriving the results of each evaluation item in the succeeding study. These studies are needed to rediscover, to develop and manage the value of many old residential areas scattered in the city centers of local areas.