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

• 수완나부미
• /
• 제9권2호
• /
• pp.167-173
• /
• 2017

• 한국제4기학회지
• /
• 제20권1호
• /
• pp.9-27
• /
• 2006

이 연구는 동아시아 (중국, 한국, 그리고 일본) 여름몬순과 그 변동성을 MME (multi-model ensemble)을 이용하여 IPCC AR4 (Intergovernmental Panel on Climate Change Fourth Assessment Report) 실험의22개 접합 기후모델 결과 자료로 분석하였다. 결과자료들은 사용 가능한 모든 모델의 평균값을 이용하였다. 여름 몬순 기간 동안 최대 강수를 가지는 연주기는 모델에 의해 모의되었으나 장마(Meiyu-Changma-Baiu) 강수밴드의 이동(북쪽)과 연관되어 7월에 나타나는 최소값은 모의하지 못했다. MME 강수 패턴은 북태평양아열대 고기압과 장마전선대의 위치와 연관된 강수의 공간적 분포를 잘 나타내었다. 그러나 중국, 한반도, 그리고 일본의 동해와 인근 해역의 강수는 과소 예측되었다. 마지막으로 $CO_2$ 농도 배증시나리오의 복사 강제에 대한 미래예측을 분석하였다. MME는 $CO_2$ 농도가 배증될 때 동아시아지역에서 강수는 평균 7.8%로 나타났고, $5{\sim}10%$의 변화폭을 보였다. 그러나 이러한 강수의 증가는 통계적으로 한반도와 일본, 그리고 인근 북중국 지역에서만 중요한 의미를 가진다. 강수 예측에서 나타난 변화는 아열대 고기압의 강도 변화에 비례하는 것으로 나타났다. 그리고 봄에서 초가을까지 여름 몬순의 지속기간이 길어짐을 확인하였다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2023년도 학술발표회
• /
• pp.24-24
• /
• 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
• /
• 제25권2호
• /
• pp.295-308
• /
• 2015

Based on the CMIP5 historical simulation datasets, we assessed the performance of state-of-the-art climate models in respect to the relationship between interannual variabilities of the North Pacific synoptic eddy (NPSE) and East Asian winter monsoon (EAWM). Observation (ERA-Interim) shows a high negative correlation (-0.73) between the interannual variabilities of East Asian winter monsoon (EAWM) intensity and North Pacific synoptic eddy (NPSE) activity during the period of 1979~2005. Namely, a stronger (weaker) EAWM is related to a weaker (stronger) synoptic eddy activities over the North Pacific. This strong reverse relationship can be well explained by latitudinal distributions of the surface temperature anomalies over East Asian continent, which leads the variation of local baroclinicity and significantly weakens the baroclinic wave activities over the northern latitudes of $40^{\circ}N$. This feature is supported by the distribution of the meridional heat flux (${\overline{{\nu}^{\prime}{\theta}^{\prime}}}$) anomalies, which have negative (positive) values along the latitudes $40{\sim}50^{\circ}N$ for strong(weak) EAWM years. In this study, the historical simulations by 11 CMIP5 climate models (BCC-CSM1.1, CanESM2, GFDL-ESM2G, GFDL-ESM2M, HadGEM2-AO, HadGEM2-CC, IPSL-CM5A-LR, MPI-ESM-LR, MPI-ESM-MR, MRI-CGCM3, and NorESM1-M) are analyzed for DJF of 1979~2005. Correlation coefficient between the two phenomena is -0.59, which is comparable to that of observation. Model-to-model variation in this relationship is relatively large as the range of correlation coefficient is between -0.76 (HadGEM2-CC and HadGEM2-AO) and -0.33 (MRI-CGCM3). But, these reverse relationships are shown in all models without any exception. We found that the multi-model ensemble is qualitatively similar to the observation in reasoning (that is, latitudinal distribution of surface temperature anomalies, variation of local baroclinicity and meridional heat flux by synoptic eddies) of the reverse relationship. However, the uncertainty for weak EAWM is much larger than strong EAWM. In conclusion, we suggest that CMIP5 models as an ensemble have a good performance in the simulation of EAWM, NPSE, and their relationship.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2002년도 춘계학술대회 논문집
• /
• pp.73-74
• /
• 2002

Active upwelling air motion in every summer over the Tibetan plateau is an essential process controlling activities of asian summer monsoon which affects water cycle and precipitation in eastern Asia. Large heating rate of surface air on the high plateau with average height of 4000m is considered to cause such large scale upwelling over the plateau. (omitted)

• 한국농림기상학회지
• /
• 제7권4호
• /
• pp.240-249
• /
• 2005

일반적으로 인도양 동쪽 해수면 온도는 따뜻하고, 서쪽 해수면 온도는 차갑다. 이러한 인도양 동/서쪽의 해수면 온도 변화는 인도 해양 다이폴 현상(Indian Ocean Dipole Mode, IODM)이 그 원인이다. 다이폴의 양의 위상은 서쪽 인도양에 양의 SST 아노말 리가 나타나고, 남동 인도양에는 음의 SST 아노말리가 나타나고 음의 위상은 이와 반대의 SST 아노말리가 나타난다. 반면 태평양의 경우, 일반적으로 서쪽 해수면 온도는 따뜻하고, 동쪽 해수면 온도는 차갑다. 중앙/동(서) 태평양 해양의 양(음)의 SST 아노말리가 현상이 나타날 때는 엘니뇨 시기이다. 이와 반대의 SST 아노말리 현상은 라니냐 시기이다 이러한 태평양의 대기-해양간의 상호작용으로 나타나는 현상을 엘니뇨 난방진동(El Nino Southern Oscillation, ENSO)이라 한다. 본 연구에서는 IODM과 ENSO현상에 따른 동아시아 몬순 변동성을 분석하기 위해 관측자료와 NCAR MCA모델 자료를 사용하였다 IODM과 ENSO 현상과 관련된 SST 아노말리 5가지 실험을 수행하였다. IDO모드는 최고의 값이 나타난 이후 약 $3\~4$계절의 시간 지연을 가지고 동아시아의 여름 몬순 활동에 영향을 주는 반면, ENSO는 동아시아 여름 몬순과 같은 계절에 영향을 준다. IODM 음(양의)위상과 태평양에서의 엘니뇨(라니냐) 현상은 한국과 일본지역에서 몬순 활동을 강화(억제)하는 역할을 한다. 반면 중국 지역에서는 IDOM과 몬순 변동성과는 별다른 연관성이 없는 것으로 나타났다. 그러나 엘니뇨(라니냐)일 때, 중국 지역에서 몬순 활동은 억제(강화)되는 경향을 보였다. IODM은 북태평양 아열대 고기압이 강화 할 때 나타나고, ENSO는 북서 태평양 알류산 저기압의 영향으로 나타난다. 따라서 태평양으로부터 동아시아 쪽으로의 수분 공급은 아열대 고기압과 알류산 저기압의 강화/약화에 의해 결정된다.

• 한국제4기학회지
• /
• 제21권2호
• /
• pp.45-48
• /
• 2007

• 대기
• /
• 제25권2호
• /
• pp.323-337
• /
• 2015

This study explores the 6-month lead prediction skill of several climate indices that influence on East Asian climate in the GloSea5 hindcast experiment. Such indices include Nino3.4, Indian Ocean Diploe (IOD), Arctic Oscillation (AO), various summer and winter Asian monsoon indices. The model's prediction skill of these indices is evaluated by computing the anomaly correlation coefficient (ACC) and mean squared skill score (MSSS) for ensemble mean values over the period of 1996~2009. In general, climate indices that have low seasonal variability are predicted well. For example, in terms of ACC, Nino3.4 index is predicted well at least 6 months in advance. The IOD index is also well predicted in late summer and autumn. This contrasts with the prediction skill of AO index which shows essentially no skill beyond a few months except in February and August. Both summer and winter Asian monsoon indices are also poorly predicted. An exception is the Western North Pacific Monsoon (WNPM) index that exhibits a prediction skill up to 4- to 6-month lead time. However, when MSSS is considered, most climate indices, except Nino3.4 index, show a negligible prediction skill, indicating that conditional bias is significant in the model. These results are only weakly sensitive to the number of ensemble members.

• Asian Journal of Atmospheric Environment
• /
• 제9권1호
• /
• pp.48-56
• /
• 2015

The trajectory analysis of boundary layer ozone data at four regional sites in the East Asian outflow regions in Japan was carried out together with boundary layer ozone data observed at Mt. Tai and Mt. Huang in the source region of central eastern China during the monsoon onset in May-June 2003 and 2004. At all sites, the influences of anthropogenic emissions from East Asia have been found. During May and June 2004, the evidences of direct pollution transport from central eastern China to Hedo, an outflow site in Okinawa Island were observed. Ozone mixing ratios associated with air masses from central eastern China averaged 45 ppb while those associated with clean air masses from the Pacific were only 14 ppb, which resulted in averaged 31 ppb increase of ozone mixing ratios during the pollution episodes from central eastern China at Cape Hedo. Using transport time analysis and averaging all ozone episodes transported from central eastern China, the ozone dilution rate of 5.4 ppb per day was roughly estimated during air masses transported from source to outflow regions at Hedo. In the regions nearby Japanese mainland, however ozone increases by long-range transports were more related to both domestic and East Asian sources as a whole.