• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.330-330
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• 2022

우리나라에서 발생하는 기상 재해 현상은 주로 태풍, 집중호우, 장마 등 인명 및 경제적인 피해가 크며, 단기간에 국지적으로 나타난다. 현재 재해 감시 및 예보는 주로 종관기상관측체계를 이용하고 있다. 하지만, 우리나라의 복잡한 지형, 인구 밀집 지형, 관측 시기가 일정하지 않은 지형과 같은 조건에서 미계측 자료 및 지역이 다수 존재 때문에 강수의 공간 분포와 강도에 대한 정밀한 정보를 제공하지 못하는 실정이다. 최근 광범위한 관측영역과 공간 분해능의 개선, 자료추출 알고리즘의 개발로 전세계적으로 위성영상 기반 기상관측 자료의 활용성이 증대되고 있다. 본 연구에서는 한반도 지역의 지상 관측데이터와 전지구 격자형 위성 강우자료를 비교하여 한반도의 적용성을 분석하고자 한다. 다양한 위성영상 기반 기상자료인 Climate Hazards Groups InfraRed Precipitation with Station (CHIRPS), Precipitation Estimation From Remotely Sensed Information Using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR), Global Precipitation Climatology Centre (GPCC), Precipitation Estimation From Remotely Sensed Information Using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS) 4개의 강우위성영상을 수집하여, 1991년부터 2020년까지 30년 데이터를 활용하였다. 강수량 변동성 비교를 위하여 기상청의 종관기상관측장비 (Automated Synoptic Observation System, ASOS), 자동기상관측시설 (Automatic Weather System, AWS) 데이터와 상관 분석을 수행하고, 강우위성영상의 국내 적합성을 판단하고자 한다.

• 대기
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• 제34권2호
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• pp.107-121
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• 2024

In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

• 대기
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• 제22권1호
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• pp.117-128
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• 2012

Does snow depth initialization have a quantitative impact on sub-seasonal to seasonal prediction skill? To answer this question, a snow depth initialization technique for seasonal forecast system has been implemented and the impact of the initialization on the seasonal forecast of surface air temperature during the wintertime is examined. Since the snow depth observation can not be directly used in the model simulation due to the large systematic bias and much smaller model variability, an anomaly rescaling method to the snow depth initialization is applied. Snow depth in the model is initialized by adding a rescaled snow depth observation anomaly to the model snow depth climatology. A suite of seasonal forecast is performed for each year in recent 12 years (1999-2010) with and without the snow depth initialization to evaluate the performance of the developed technique. The results show that the seasonal forecast of surface air temperature over East Asian region sensitively depends on the initial snow depth anomaly over the region. However, the sensitivity shows large differences for different timing of the initialization and forecast lead time. Especially, the snow depth anomaly initialized in the late winter (Mar. 1) is the most effective in modulating the surface air temperature anomaly after one month. The real predictability gained by the snow depth initialization is also examined from the comparison with observation. The gain of the real predictability is generally small except for the forecasting experiment in the early winter (Nov. 1), which shows some skillful forecasts. Implications of these results and future directions for further development are discussed.

• 대기
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• 제28권1호
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• pp.15-24
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• 2018

Sea ice plays an important role in modulating surface conditions at high and mid-latitudes. It reacts rapidly to climate change, therefore, it is a good indicator for capturing these changes from the Arctic climate. While many models have been used to study the predictability of climate variables, their performance in predicting sea ice was not well assessed. This study examines the predictability of the Arctic sea ice extent from ensemble prediction systems. The analysis is focused on verification of predictability in each model compared to the observation and prediction in particular, on lead time in Sub-seasonal to Seasonal (S2S) scales. The S2S database now provides quasi-real time ensemble forecasts and hindcasts up to about 60 days from 11 centers: BoM, CMA, ECCC, ECMWF, HMCR, ISAC-CNR, JMA, KMA, Meteo France, NCEP and UKMO. For multi model comparison, only models coupled with sea ice model were selected. Predictability is quantified by the climatology, bias, trends and correlation skill score computed from hindcasts over the period 1999 to 2009. Most of models are able to reproduce characteristics of the sea ice, but they have bias with seasonal dependence and lead time. All models show decreasing sea ice extent trends with a maximum magnitude in warm season. The Arctic sea ice extent can be skillfully predicted up 6 weeks ahead in S2S scales. But trend-independent skill is small and statistically significant for lead time over 6 weeks only in summer.

• 대기
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• 제28권1호
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• pp.85-97
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• 2018

This study evaluates the performance of the Weather Research and Forecasting (WRF) model in reproducing the present-day (1981~2005) precipitation over Far East Asia and South Korea. The WRF model is configured with 25-km horizontal resolution within the context of the COordinated Regional climate Downscaling Experiment (CORDEX) - East Asia Phase 2. The initial and lateral boundary forcing for the WRF simulation are derived from European Centre for Medium-Range Weather Forecast Interim reanalysis. According to our results, WRF model shows a reasonable performance to reproduce the features of precipitation, such as seasonal climatology, annual and inter-annual variabilities, seasonal march of monsoon rainfall and extreme precipitation. In spite of such model's ability to simulate major features of precipitation, systematic biases are found in the downscaled simulation in some sub-regions and seasons. In particular, the WRF model systematically tends to overestimate (underestimate) precipitation over Far East Asia (South Korea), and relatively large biases are evident during the summer season. In terms of inter-annual variability, WRF shows an overall smaller (larger) standard deviation in the Far East Asia (South Korea) compared to observation. In addition, WRF overestimates the frequency and amount of weak precipitation, but underestimates those of heavy precipitation. Also, the number of wet days, the precipitation intensity above the 95 percentile, and consecutive wet days (consecutive dry days) are overestimated (underestimated) over eastern (western) part of South Korea. The results of this study can be used as reference data when providing information about projections of fine-scale climate change over East Asia.

• 대기
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• 제29권4호
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• pp.343-353
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• 2019

The seasonal climatology of atmospheric rivers (ARs) and their effects on the seasonal precipitation and temperature in Korea are examined using the AR chronology obtained by a methodology based on the vertically integrated water vapor transport (IVT) in conjunction with a fine-scale gridded analysis of station precipitation and temperature. ARs are found to affect Korea most heavily in the warm season with minimal impacts in winter. This contrasts the AR effects in the western North America and the Western Europe that are affected most in winters. Significant portions of precipitation in Korea are associated with AR landfalls for all seasons; over 35% (25%) of the summer (winter) rainfall in the southern part of the Korean peninsula. The percentage of AR precipitation over Korea decreases rapidly towards the north. AR landfalls are also associated with heavier-than-normal precipitation events for all seasons. AR landfalls are associated with above-normal temperatures in Korea; the warm anomalies increase towards the north. The warm anomalies during AR landfalls are primarily related to the reduction in cold episodes as the AR landfalls in Korea are accompanied by anomalous southerlies/southwesterlies.

• Asian-Australasian Journal of Animal Sciences
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• 제15권3호
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• pp.340-345
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• 2002

In this experiment, oocytes were collected from goat ovaries available in slaughterhouse by follicle puncture method. Morphologically culturable type of oocytes which having compact, multilayered cumulus granulosa cell complex and evenly granulated cytoplasm, was separated under a stereozoom microscope. Oocytes were washed thoroughly in maturation medium containing TCM-199, $1{\mu}g/ml$ estradiol-$17{\beta}$, 0.5 ${\mu}g/ml$ FSH, $100{\mu}g/ml$ LH, 3 mg/ml BSA and 10% estrus goat serum. Washed oocytes were cultured into maturation medium on granulosa cell monolayer. Culture plate was then kept into $CO_2$ incubator at $38{\pm}1^{\circ}C$, maximum humidity and 5% $CO_2$ for 18 h. After maturation the oocytes were washed thoroughly with maturation medium containing polyvinyl alcohol (PVA) without serum and BSA and further cultured for 12 h for secretory proteins of oocytes. PVA medium was collected, pooled and concentrated by 5000 cut off centrisart. Secretory proteins were separated on 12.5% SDS-PAGE. A total number of 3.41 oocytes per ovary were obtained and 2.17 culturable oocytes per ovary were cultured into maturation medium. After 18 h of maturation, 4,567 oocytes (1.82 oocytes per ovary) were further cultured into serum and BSA free PVA medium for its secretory proteins. Four secretory proteins of oocytes with approximately molecular weight of 45, 55, 65 and 95 kDa were obtained on SDS-PAGE in silver staining and three proteins with approximately molecular weight of 45, 55 and 65 kDa in Coomassie brilliant blue staining. In conclusion, four secretory proteins with approximately molecular weight of 45, 55, 65 and 95 kDa was obtained from in vitro cultured oocytes of goats.

• 한국음향학회지
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• 제34권6호
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• pp.455-462
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• 2015

동해에는 주변 수온보다 온도가 높은 난수성 소용돌이가 자주 발생되는 것으로 알려져 있다. 이러한 난수성 소용돌이의 발생은 음속구조의 변화를 야기해 음전달특성을 변화시키게 되며, 특히 원거리 음전달에 큰 영향을 줄 것으로 예상된다. 본 논문에서는 난수성 소용돌이가 확인되는 2007년 3월 23일의 수온자료를 재분석한 자료를 이용하여 난수성 소용돌이가 원거리 음전달에 미치는 영향을 분석하였다. 연구를 위해 포물선 방정식 모델을 이용해 음파 전달손실과 평균 직접 신호초과 거리를 이용한 탐지거리 성능분포분석을 수행하였다. 분석결과 난수성 소용돌이의 존재는 난수성 소용돌이가 존재하지 않을 때와는 매우 다른 음전달 특성을 보여주고 있으며, 특히 난수성 소용돌이의 경계는 음전달의 제한적인 요소가 될 수 있기 때문에 원거리 음전달에 불리할 것으로 판단된다. 이러한 난수성 소용돌이에 의한 원거리 음전달의 제한은 해저 심도가 낮을수록 더 커지는 것을 확인하였다.

• 대기
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• 제19권2호
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• pp.127-143
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• 2009

This study investigates characteristics of wintertime simulation conducted by METRI AGCM utilizing new radiation parameterization scheme. New radiation scheme is based on the method of Chou et al., and is utilized in the METRI AGCM recently. In order to analyze characteristics of seasonal simulation in boreal winter, hindcast dataset from 1979 to 2005 is produced in two experiments - control run (CTRL) and new model's run (RADI). Also, changes in performance skill and predictability due to implementation of new radiation scheme are examined. In the wintertime simulation, the RADI experiment tends to reduce warm bias in the upper troposphere probably due to intensification of longwave radiative cooling over the whole troposphere. The radiative cooling effect is related to weakening of longitudinal temperature gradient, leading to weaker tropospheric jet in the upper troposphere. In addition, changes in vertical thermodynamic structure have an influence on reduction of tropical precipitation. Moreover, the RADI case is less sensitive to variation of tropical sea surface temperature than the CTRL case, even though the RADI case simulates the mean climate pattern well. It implies that the RADI run does not have significant improvement in seasonal prediction point of view.

• 한국농림기상학회지
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• 제13권1호
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• pp.20-27
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• 2011

북한지역에 대해 좌표내장 수치기후지도를 제작하기 위한 선결조건으로서 국지 소기후 추정모형의 최소 공간적용단위인 표준유역(Hydrologic Unit)이 설정되어야 한다. Arc Hydro 기반의 유역추출 알고리즘을 ASTER GDEM에 적용하고, 북한의 5대강(예성강, 대동강, 청천강, 압록강, 두만강) 및 산경도에 나타난 산맥체계에 의해 보완함으로써 신뢰성 높은 북한지역 표준유역도를 제작하였다. 이 표준유역도에 의하면 북한지역은 21개의 대권역, 93개의 중권역, 885개의 소유역으로 구성된다. 기존 남한 표준유역도 840개와 결합하고 각각 소기후모형을 적용할 경우 한반도 전역을 1,725개의 소기후구로 하는 상세 농업기후지대구분이 가능해진다.