• Journal of Ecology and Environment
• /
• 제38권3호
• /
• pp.375-381
• /
• 2015

We investigated the influence of summer rainfall on Pectinatella magnifica colonies in lotic ecosystems. Of the examined substrate materials, branches and aquatic macrophytes supported more colonies of P. magnifica than that by stones or artificial materials. The influence of rainfall on P. magnifica colonies differed in accordance with the type of substrate material at each study site. In the Geum River, little difference was noted in the number of P. magnifica colonies on branches before ($mean{\pm}SE$, $24{\pm}7.3$ individuals) and after rainfall ($20{\pm}8.4$ ind.); other substrate types supported fewer colonies of P. magnifica after rainfall. In contrast, in the Miryang River, rainfall had minimal effect on the number of P. magnifica colonies supported by macrophytes ($13{\pm}3.8$ and $12{\pm}4.3$ ind., respectively). Artificial material was more abundant in the Banbyeon Stream where it was able to support more colonies of P. magnifica. We found that the structure of different substrates sustains P. magnifica following rainfall. In the Miryang River, free-floating and submerged plants with a relatively heterogeneous substrate surface were the dominant macrophytes, whereas in the Geum River, simple macrophytes (i.e., emergent plants) were dominant. Therefore, we conclude that the substrate type on which P. magnifica grows plays an important role in resisting physical disturbances such as rainfall.

• 한국환경과학회지
• /
• 제2권3호
• /
• pp.179-191
• /
• 1993

This paper aims to know the characteristics of occurrence of the anomaly level and variability of the monthly precipitation in Kyeongnam, Korea. For this study, it was investigated 주e distribution of the annual and cont비y mean precipitation, the precipitation variability and its annual change, and the characteristics of occurrence of the anomaly level in Kyeongnam area the results were summarized as follows : 1) she mean of annual total precipitation averaged over Kyeongnam area is 1433.3mm. I'he spatial distribution of the annual total precipitation shows that in Kyeongnam area, the high rainfall area locates in the southwest area and south coast and the low rainfall area in an inland area. 2) Monthly mean precipitation in llyeongnam area was the highest in July(266.4mm) 각lowed by August(238.0mm), June(210.2mm) in descending order. In summer season, rainfall was concentrated and accounted for 49.9 percent of the annual total precipitation. Because convergence of the warm and humid southwest current which was influenced by Changma and typhoon took place well in this area. 3) The patterns of annual change of precipitaion variability can be divided into two types; One is a coast type and the other an inland type. The variability of precipitation generally appears low in spring and summer season and high in autumn and winter season. This is in accord with the large and small of precipitation. 4) The high frequency of anomaly level was N( Normal)-level and the next was LN( Low Informal) -level and 25(Extremely Subnormal)-level was not appeared in all stations. The occurrence frequency of N level was high in high rainfall area and distinguish성 in spring and summer season but the low rainfall area was not. hey Words : anomaly level, variability, precipitation, coast type, inland type.

• 한국물환경학회지
• /
• 제36권1호
• /
• pp.1-13
• /
• 2020

The purpose of this study was to investigate the thermal and chemical stratification in Lake Paldang 2013-2018 weekly using Schmidt's stability index (SSI) and the index of chemical stratification (IC-i). The annual average for SSI was 19.1 g cm/㎠ with the maximum value of 45.3 g cm/㎠ in the summer and the minimum value of 4.8 g cm/㎠ in fall-winter showing seasonal differences as well as increased vertical mixing in the summer. The lake stability increased higher in 2016 as compared with the other period. The most influential factors of thermal stratification were temperature and heavy rainfall. Especially, high water temperature and a prolonged residence duration caused by reduced rainfall and inflows could result in an increase of the stratification period. While decreasing inflow and outflow at the end of the rainfall, the thermal stratification was restrengthened within 7-14 days, and then stabilized rapidly before the rainfall. IC-DO increased with high air temperature in the spring and fall-winter. However increasing sunshine duration and residence time and decreasing rate of outflow caused an increase of IC-DO in the summer. Rainfall (less than 800 mm/year) and discharge (less than 200 CMS) significantly declined in 2015 resulting in IC-DO (0.77) increased more than three times over the other years and bottom water hypoxia occurred. The SSI and IC-i used in this study could be applied to other lakes to understand changes in stratification and mixing dynamics.

• 대한원격탐사학회지
• /
• 제25권6호
• /
• pp.465-474
• /
• 2009

Convective/stratiform radar echo classification schemes by Steiner et al. (1995) and Biggerstaff and Listemaa (2000) are examined on a monsoonal front during the summer monsoon-Changma period, which is organized as a cloud cluster with mesoscale convective complex. Target radar is S-band with wavelength of 10cm, spatial resolution of 1km, elevation angle interval of 0.5-1.0 degree, and minimum elevation angle of 0.19 degree at Jindo over the Korean Peninsula. For verification of rainfall amount retrieved from the echo classification, ground-based rain gauge observations (Automatic Weather Stations) are examined, converting the radar echo grid data to the station values using the inverse distance weighted method. Improvement from the echo classification is evaluated based on the correlation coefficient and the scattered diagram. Additionally, an optimal use method was designed to produce combined rainfalls from the radar echo and Tropical Rainfall Measuring Mission Precipitation Radar (TRMM/PR) data. Optimal values for the radar rain and TRMM/PR rain are inversely weighted according to the error variance statistics for each single station. It is noted how the rainfall distribution during the summer monsoon frontal system is improved from the classification of convective/stratiform echo and the use of the optimal use technique.

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

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2009년도 학술발표회 초록집
• /
• pp.1147-1151
• /
• 2009

In this study, we address the problem of producing probability forecasts of summer seasonal rainfall, on the basis of Hindcast experiments from a ensemble of GCMs(cwb, gcps, gdaps, metri, msc_gem, msc_gm2, msc_gm3, msc_sef and ncep). An advanced Hierarchical Bayesian weighting scheme is developed and used to combine nine GCMs seasonal hindcast ensembles. Hindcast period is 23 years from 1981 to 2003. The simplest approach for combining GCM forecasts is to weight each model equally, and this approach is referred to as pooled ensemble. This study proposes a more complex approach which weights the models spatially and seasonally based on past model performance for rainfall. The Bayesian approach to multi-model combination of GCMs determines the relative weights of each GCM with climatology as the prior. The weights are chosen to maximize the likelihood score of the posterior probabilities. The individual GCM ensembles, simple poolings of three and six models, and the optimally combined multimodel ensemble are compared.

• 대기
• /
• 제30권4호
• /
• pp.421-437
• /
• 2020

The effects of the terminal fall velocity-diameter relationship for raindrops, which is prescribed based on the measurement, on the simulated surface precipitation over Korea during summer season were investigated in our study. Two rainfall cases, 1-month summer precipitation and mesoscale rainfall, have been simulated using the Weather Research and Forecasting (WRF) model. The selected cloud microphysics parameterizations are WRF Single-Moment 5-class (WSM5) and WRF Single-Moment 6-class (WSM6) in the WRF model. The measured terminal fall-diameter relationship for raindrops by Gunn and Kinzer (1949) was applied in both WSM5 and WSM6. The sensitivity experiments with WSM5 and WSM6, applying the measured fall-diameter relationship, presents the different responses in simulated precipitation amount for the 1-month summer precipitation case. Precipitation increases with WSM5, thus enhancing the precipitation statistical skills. However, precipitation decreases with WSM6 leading to the deterioration of precipitation statistical skills. For the mesoscale rainfall case, precipitation increases with both WSM5 and WSM6, which further enhances the positive bias in precipitation amount.

• 한국농공학회지
• /
• 제31권4호
• /
• pp.72-80
• /
• 1989

Various analyses were made to investigate the stochastic structure of the daily rainfall in Korea. Records of daily rainfall amounts from 1951 to 1984 at Chinju Metesrological Station were used for this study. Obtained results are as follows : 1. Time series of the daily rainfall at Chinju were positively, serially correlated for the lag as large as one day. 2. Rainfall events, defined as a sequence of consecutive wet days separated by one or more dry days, showed a seasonal variation in the occurrence frequency. 3. The marginal distribution of event characteristics of each month showed significant dif- ferences each other. Events occurred in summer had longer duration and higher magnitude with higher intensity than those of events occurred in winter. 4. There were significant positive correlations among four event characteristics ; dura- tion, magnitude, average intensity, and maximum intensity. 5. Correlations among the daily rainfall amounts within an event were not significant in general. 6. There were no consistant significancy in identity or difference between the distribu- tions of daily rainfall amounts for different days within events. 7. Above mentioned characteristics of daily rainfall time series must be considered in building a stochastic model of daily rainfall.

• 한국산림과학회지
• /
• 제35권1호
• /
• pp.36-38
• /
• 1977

물오리나무와 소나무의 혼효림으로 구성된 혼효림(混淆林)에서 1975면(年) 1년간(年間) 강우량(降雨量)에서 수관차단(樹冠遮斷)과 유출특성(流出特性)을 조사분석(調査分析)한 결과(結果)는 다음과 같았다. 1. 강우량(降雨量) 1072.7mm에 대해 수관차단율(樹冠遮斷率)은 192.3%이고 그 량(量)은 년강우량(年降雨量) 1072.7mm 중(中) 20.7mm이었다. 2. 강우량(降雨量)이 적은 봄과 초여름에는 수관(樹冠)에 의한 차단율(遮斷率)추은 20~50%이고 강우기(降雨期)인 여름에는 15% 이내(以內)로 되었다. 3. 매(每) 강우량(降雨量)이 10mm 전후(前後)일 경우에는 강우량(降雨量)이 약 50%가 수관(樹冠)에 의해 차단(遮斷)되고 20mm가 넘을 경우는 약 20% 정도가 차단되는 경향이 있었다. 4. 년간(年間) 평균(平均) 유출율(流出率)은 24.9%이고 유출량(流出量)은 $1000m^2$당 2,666.4l이었으며 강우량(降雨量)과 유출량(流出量)과의 관계(關係)는 그림 1과 같았다.

• 한국농공학회지
• /
• 제45권3호
• /
• pp.29-40
• /
• 2003

The objective of the paper is to compute the half-month rainfall-runoff erosivity factor for revised universal soil loss equation (RUSLE). RUSLE is being used to develop soil conservation programs and identify optimum management practices. Rainfall-runoff erosivity factor (R) is a key input parameter to RUSLE. Rainfall-runoff erosivity factor has been calculated for twenty six stations from the nationwide rainfall data from 1973 to 2002 in south Korea. The average annual Rainfall-runoff erosivity factor at the analyzed stations Is between 3,130 and 10,476 (MJ/ha)ㆍ(mm/h). According to the computation of the half-month Rainfall-runoff erosivity factor for locations, 66-85% of the average annual R value has occurred during the summer months, June-August. The half-month R values from this study can be used for RUSLE.