• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1298-1300
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• 2003

Based on the Leaf Area Index (LAI) data derived from remote sensing information and eco-climate data, the responses of regional ecosystem variations in seasonal and interannual scales to the East Asian monsoon are studied in this paper. It is found that the vegetation ecosystems of eastern China are remarkably correlated with the East Asian monsoon in seasonal and interannual scales. In the seasonal timescale, the obvious variations of the vegetation ecosystems occur with the development of the East Asian monsoon from the south in the spring to the north in the autumn. In the interannual scale, high LAI appears in the strong East Asian monsoon year, whereas low LAI is related to the weak East Asian monsoon year. These further lead to the characteristic of 'onsoon-driven ecosystem' in the eastern China monsoon region, which can be revealed by LAI.

• 한국환경과학회지
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• 제23권10호
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• pp.1719-1729
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• 2014

This study is carried out in order to bridge the gap to understand the relationships between South Asian and East Asian monsoon systems by comparing the summer (June-September) precipitation of Nepal and South Korea. Summer monsoon precipitation data from Nepal and South Korea during 30 years (1981-2010) are used in this research to investigate the association. NCEP/NCAR reanalysis data are also used to see the nature of large scale phenomena. Statistical applications are used to analyze these data. The analyzed results show that summer monsoon precipitation is higher over Nepal ($1513.98{\pm}159.29mm\;y^{-1}$) than that of South Korea ($907.80{\pm}204.71mm\;y^{-1}$) and the wettest period in both the countries is July. However, the coefficient of variation shows that amplitude of interannual variation of summer monsoon over South Korea (22.55%) is larger in comparison to that of Nepal (10.52%). Summer monsoon precipitation of Nepal is found to be significantly correlated to that of South Korea with a correlation coefficient of 0.52 (99% confidence level). Large-scale circulations are studied to further investigate the relationship between the two countries. wind and specific humidity at 850 hPa show a strong westerly from Arabian Sea to BOB and from BOB, wind moves towards Nepal in a northwestward direction during the positive rainfall years. In case of East Asia, strong northward displacement of wind can be observed from Pacific to South Korea and strong anticyclone over the northwestern Pacific Ocean. However, during the negative rainfall years, in the South Asian region we can find weak westerly from the Arabian Sea to BOB, wind is blowing in a southerly direction from Nepal and Bangladesh to BOB.

• 한국물환경학회지
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• 제29권5호
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• pp.598-609
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• 2013

Spatial and temporal distribution of environmental factors and epilithic diatom communities in major rivers (30 rivers and 58 sampling points) of the Korean peninsula were surveyed each one time before (May) and after the monsoon (October) 2012. The stream of the east harbor (EAST), the south harbor (SOUTH), and the west harbor (WEST) was sampled in order. Over the survey, a total of 284 taxa were classified, and the number of diatom species in each harbor did not show significant changes after the monsoon, but a biomass significantly decreased. Results also showed that EAST deterioration of water quality and chlorophyll-a after the monsoon, was opposite to SOUTH. Five major dominant species including Nitzschia inconspicua, which contained higher biomass over the survey, were common species which widely distributed in brackish water. Indicator Species Analysis showed that a large number of clean water species in EAST and polluted water species in SOUTH and WEST were emerged respectively. In sum, the Asian monsoon significantly decreased a biomass of epilithic diatoms and water qualities over the harbors (lower stream) in the Korean peninsula, but did not change the major species indicating water quality.

• 대기
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• 제18권1호
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• pp.55-70
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• 2008

The global time slice approach is a transient experiment using high resolution atmosphere-only model with boundary condition from the low resolution globally coupled ocean-atmosphere model. The present study employs this "time slice concept" using ECHAM4 atmosphere-only model at a horizontal resolution of T106 with the lower boundary forcing obtained from a lower-resolution (T42) greenhouse gas + aerosol forcing experiment performed using the ECHO-G/S (ECHAM4/HOPE-G) coupled model. In order to assess the impact of horizontal resolution on simulated East Asian summer monsoon climate, the differences in climate response between the time slice experiments of the present and that of IPCC SRES AR4 participating 21 models including coarser (T30) coupled model are compared. The higher resolution model from time slice experiment in the present climate show successful performance in simulating the northward migration and the location of the maximum rainfall during the rainy season over East Asia, although its rainfall amount was somewhat weak compared to the observation. Based on the present climate simulation, the possible change of East Asian summer monsoon rainfall in the future climate by the IPCC SRES A1B scenario, tends to be increased especially over the eastern part of Japan during July and September. The increase of the precipitation over this region seems to be related with the weakening of northwestern part of North Pacific High and the formation of anticyclonic flow over the south of Yangtze River in the future climate.

• 한국지구과학회지
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• 제23권4호
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• pp.369-379
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• 2002

저온 습윤한 1993년 여름철과 고온 건조한 1994년 여름철과 관련된 동아시아에서 대조적인 여름철 몬순순환의 특성을 상, 하층 대류권의 대기순환 특성과 함께 전구 해수온도 및 적도 대류성 강수장을 분석함으로써 조사하였다. 1993년의 경우, 동아시아, 중앙 북태평양 및 미국 서부지역에서 500hpa 면과 200hpa 면의 음의 지위고도 편차가 나타났지만, 1994년의 경우, 이들 지역들에서 양의 편차를 보였다. 1993년의 아열대 제트류는 평년보다 다소 남쪽에 치우쳐져 한반도 북쪽에 위치하였다. 서태평양 아열대 고기압이 남쪽으로 이동하여 동아시아지역에는 평년보다 많은 여름철 강수와 낮은 여름철 기온이 나타났다. 이는 오오츠크해로부터 동해로 저온 습윤한 기단의 확장에 때문으로 판단된다. 대조적으로 1994년의 아열대 제트류는 평년보다 다소 북쪽에 위치하였고, 서태평양 아열대 고기압의 갑작스런 북상은 동아시아 여름철 강수대의 북상을 동반하였다. 따라서, 아시아 여름철 강수 및 기온 편차는 1993년과 반대 양상을 보였다. 적도 태평양상의 해수온 편차에서는, 1993년은 엘니뇨가, 1994년은 라니냐가 각각 나타났다. 오스트레일리아 고기압과 마스카렝 고기압의 북서 연변을 따른 하층 적도 횡단류와 관련된 서태평양과 인도양에서 이상적인 대류성 강수는 이들 대조적인 동아시아 여름철의 대규모 대기순환에 영향을 준 것으로 판단된다. 또한, 동아시아 여름몬순지역에서 평균된 200 hPa 면의 동서바람편차는 한반도 여름 기온편차와 음의 상관을 보였다.

• 대기
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• 제31권5호
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• pp.563-576
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• 2021

The performance of East Asian summer monsoon is assessed for GC2 and GC3.1, which are climate change models of the current and next climate prediction system in the Korea Meteorological Administration (KMA), GloSea5 and GloSea6. The most pronounced characteristics of GC models are strong monsoon trough and the weakening of the Western North Pacific Subtropical High (WNPSH). These are related to the weakening of the southwesterly wind and resulting weak monsoon band toward the Korean Peninsula. The GC3.1 is known to have improved the model configuration version compared to GC2, such as cloud physics and ocean parameters. We can confirm that the overall improvements of GC3.1 against GC2, especially in pressure, 850 hPa wind fields, and vertical wind shear. Also, the precipitation band stagnant in the south of 30°N in late spring is improved, therefore the biases of rainy onset and withdrawal on the Korean Peninsula are reduced by 2~4 pentad. We also investigate the impact of initialization in comparison with GloSea5 hindcast. Compared with GCs, hindcast results show better simulation within 1 month lead time, especially in pressure and 850 hPa wind fields, which can be expected to the improvement of WNPSH. Therefore, it is expected that the simulation performance of WNPSH will be improved in the result of applying the initialization of GloSea6.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.24-24
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• 2023

This presentation highlights the IAHR book, recently published last April, of which the author is the editor-in-chief, on the historical water projects and traditional water technologies of international interest in the Asian region, addressing information on past water projects (mostly before the 20th century) in the regions that are technically and culturally of interest and educationally valuable. The book explores historical water projects in these regions, presenting technologies used at the time, including calculation and forecasting methods, measurement, material, labor, methodologies, and even water culture. Through this book, it is expected that the old Asian wisdom of "reviewing the old and learning the new" would be realized to a certain extent in modern planning and practice of water projects. The book comprises a lead article that the presenter authored and five Parts representing China, Japan, Korea, South Asia, and Southeast Asia, respectively, followed by an invited one from Uzbekistan. Throughout the book, it is found that historically the Asian monsoon, affecting the Indian subcontinent and Southeast and East Asian regions, induced rice cultivation. It fundamentally needs proper irrigation systems, including reservoirs (dams) and canals, water wheels, and even rain gauges. Flood risks have been more common in Asia than Europe under this climate condition, as recognized in history. To utilize and sometimes overcome these climate conditions, people built and managed many historical and grandiose water projects and invented and used localized but sophisticated water-related technologies in the Asian region.

• 대기
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• 제30권3호
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• pp.293-309
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• 2020

There are lots of indices that define the intensity of East Asian summer monsoon (EASM) in climate systems. This paper assesses the prediction skill for EASM indices in a Global Seasonal Forecasting System (GloSea5) that is currently operating at KMA. Total 5 different types of EASM indices (WNPMI, EAMI, WYI, GUOI, and SAHI) are selected to investigate how well GloSea5 reproduces them using hindcasts with 12 ensemble members with 1~3 lead months. Each index from GloSea5 is compared to that from ERA-Interim. Hindcast results for the period 1991~2010 show the highest prediction skill for WNPMI which is defined as the difference between the zonal winds at 850 hPa over East China Sea and South China Sea. WYI, defined as the difference between the zonal winds of upper and lower level over the Indian Ocean far from East Asia, is comparatively well captured by GloSea5. Though the prediction skill for EAMI which is defined by using meridional winds over areas of East Asia and Korea directly affected by EASM is comparatively low, it seems that EAMI is useful for predicting the variability of precipitation by EASM over East Asia. The regressed atmospheric fields with EASM index and the correlation with precipitation also show that GloSea5 best predicts the synoptic environment of East Asia for WNPMI among 5 EASM indices. Note that the result in this study is limited to interpret only for GloSea5 since the prediction skill for EASM index depends greatly on climate forecast model systems.

• 대기
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• 제15권2호
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• pp.91-99
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• 2005

This study compares the summer monsoon circulations during a heavy rainfall period over the Korean peninsular from 11 to 18 July 2004, simulated by three widely used regional models; WRF, MM5, and RSM. An identical model setup is carried out for all the experiments, except for the physical option differences in the RSM. The three models with a nominal resolution of about 50 km over Korea are nested by NCEP-DOE reanalysis data. Another RSM experiment with the same cumulus parameterization scheme as in the WRF and MM5 is designed to investigate the importance of the representation of subgrid-scale parameterized convection in reproducing monsoonal circulations in East Asia. All thee models are found to be capable of reproducing the general distribution of monsoonal precipitation, extending northeastward from south China across the Korean peninsula, to northern Japan. The results from the WRF and MM5 are similar in terms of accumulated precipitation, but a slightly better performance in the WRF than in the MM5. The RSM improves the bias for precipitation as compared to those from the WRF and MM5, but the pattern correlation is degraded due to overestimation of precipitation in northern China. In the comparison of simulated synoptic scale features, the RSM is found to reproduce the large-scale features well compared to the results from the MM5 and WRF. On the other hand, the simulated precipitation from the RSM with the convection scheme used in the MM5 and WRF is closer to that from the WRF and MM5 simulations, indicating the significant dependency of simulated precipitation in East Asia on the cumulus parameterization scheme.

• 대기
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• 제15권2호
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• pp.75-90
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• 2005

이 연구에서는 지면-대기 모수화 방안 (BATS1e)이 접합된 미국 국립기상연구센터 (NCAR)에서 개발한 지역기후모델(RegCM2)을 이용하여 지면피복의 변화가 동아시아 여름몬순에 미치는 영향에 대해서 조사하였다. 지면피복 변화의 영향을 분석하기 위하여 두 종류의 지면피복 자료를 이용하였다. 하나는 NCAR에서 제공하는 지면피복 자료 (CTL 실험)이고 다른 하나는 최근의 기상위성자료로부터 직접 분류한 고해상도 지면피복분류 자료(LCV 실험)이다. CTL 실험에서는 중국 중부지역과 몽고지역의 지면온도가 각각 약 $1-3^{\circ}C$ 높고 낮게 모의되었다. 또한 모의 영역 북부지역에서는 강수가 과다하게 모의된 반면 모의영역 남부 바다지역의 강수는 과소하게 모의되었다. 지면피복 변화에 의한 알베도, 거칠기 길이 및 최소기공저항계수와 같은 지면의 생물리적 요소들의 변화는 지면-대기 상호작용을 변경시켰다. 즉, 지면피복이 낙엽활엽수림에서 농지와 관계농지로 변경된 LCV 실험의 중국 중부지역에서는 잠열 속과 풍속이 현저하게 증가되었다. 그 결과 CTL 실험에서 나타났던 중국 중부지역에서의 온난편차가 LCV 실험에서는 대부분 완화되었다. 중국 중부지역에서의 강한 기온 하강은 태평양과 대륙사이의 기압 차를 약화시키고 있다. 남동에서 북서방향으로의 기압경도력이 약화됨에 따라 중국 남부와 남중국해로부터 북동쪽으로의 수증기 수송도 약화되었다. 이러한 수증기 수송의 변화는 모의 영역 북부지역에서의 과다한 강수 모의와 남중국해에서의 과소한 강수모의를 동시에 크게 완화시켰다. 그러나 지면피복의 변화는 특히 7월과 8월에 한반도와 일본 열도 지역에서의 강수를 크게 증기시키고 있다.