• 대한지리학회지
• /
• 제32권1호
• /
• pp.31-46
• /
• 1997

본 연구는 남한의 동계 일강수량 데이터를 기초로 매일매일의 분포도를 작성하여, 강수의 공간적 분포 유형을 분류하였다. 그리고 강수의 공간적 분포유형과 그 종관적 특성과의 대응관계를, 먼저 기압배치형을 중심으로, 그리고 강수분포형을 중심으로 살펴보았다. 또한 지상일기도로 볼 때 유사한 특성을 지닌 울릉도형과 울릉도${\cdot}호남 동시 출현형의 차이를 알아보기 위해 850hPa, 700hPa, 500hPa면의 기압장, 기온장의 특성을 분석하였다. 그 결과 울릉도지역은 강수계급에 관계없이 높은 출현빈도를 보이고, 동해안은 5mm 이상에서, 호남지역은 1~5mm구간에서 더 높은 출현빈도를 나타냈다. 동계강수분포형은 12개로 분류할 수 있으며, 이들 분포형은 뚜렷한 계절 변화를 보인다. 울릉도형과 울릉도${\cdot}$호남 동시 출현형 간의 강수분포의 차이는 풍향, 풍속보다는 상층 한기의 이류 양상과 관련이 깊다.

• 대기
• /
• 제25권1호
• /
• pp.31-49
• /
• 2015

From the hourly data of 75 Korean weather stations over a 12-year period (2001~2012), this study has chosen three cases (January 12, 2006; January 11, 2008; and February 22, 2009) of multiple freezing rains and investigated the atmospheric circulations that seemed to cause the events. As a result, the receding high pressure type (2006), prevailing high pressure type (2008), and warm front type (2009) are confirmed as synoptic patterns. In all three cases, freezing rain was found in regions with a strong ascending current near the end point of a low-level jet that carried the warm humid air from low latitudes. The strong ascending current resulted from lower-level convergence and upper-level divergence. In 2006 and 2009, the melting process was confirmed. In 2008, the supercooled warm rain process (SWRP) was confirmed. In contrast to existing SWRP theory, it was found that the cool air produced at the middle atmosphere and near the earth's surface led to the formation of freezing rain. The sources of this cool air were supposed to be the evaporative latent heat and the cold advection coming from the northeast. On the other hand, a special case was detected, in which the freezing rain occurred when both the soil surface temperature and surface air temperature were above $0^{\circ}C$. The thickness distributions related to freezing rain in Korea were found to be similar to those in North America. A P-type nomogram was considered for freezing rain forecasting; however, it was not relevant enough to Korea, and few modifications were needed.

• 대기
• /
• 제25권4호
• /
• pp.611-622
• /
• 2015

Heavy rainfall ($>30mm\;hr^{-1}$) over the Korean Peninsula is examined in order to understand thermo-dynamic characteristics of the atmosphere, using radiosonde observational data from seven upper-air observation stations during the last 17 years (1997~2013). A total of 82 heavy rainfall cases during the summer season (June-August) were selected for this study. The average values of thermo-dynamic indices of heavy rainfall events are Total Precipitable Water (TPW) = 60 mm, Convective Available Potential Energy (CAPE) = $850J\;kg^{-1}$, Convective Inhibition (CIN) = $15J\;kg^{-1}$, Storm Relative Helicity (SRH) = $160m^2s^{-2}$, and 0~3 km bulk wind shear = $5s^{-1}$. About 34% of the cases were associated with a Changma front; this pattern is more significant than other synoptic pressure patterns such as troughs (22%), migratory cyclones (15%), edges of high-pressure (12%), typhoons (11%), and low-pressure originating from Changma fronts (6%). The spatial distribution of thermo-dynamic conditions (CAPE and SRH) is similar to the range of thunderstorms over the United States, but extreme conditions (supercell thunderstorms and tornadoes) did not appear in the Korean Peninsula. Synoptic conditions, vertical buoyancy (CAPE, CIN), and wind parameters (SRH, shear) are shown to discriminate among the environments of the three types. The first type occurred with high CAPE and low wind shear by the edge of the high pressure pattern, but Second type is related to Changma front and typhoon, exhibiting low CAPE and high wind shear. The last type exhibited characteristics intermediate between the first and second types, such as moderate CAPE and wind shear near the migratory cyclone and trough.

• 한국지역지리학회지
• /
• 제11권4호
• /
• pp.429-439
• /
• 2005

본 연구는 한국에 있어서 동계한발의 지역적 출현빈도 분포특성과 한발시 해면기압장 및 500hPa면의 종관기후학적 특성을 평년과 비교 분석한 연구이다. 한국의 동계한발의 출현빈도 분포는 월별 지역적 강수변동률의 분포를 반영하여 1 12월은 강수변동률이 높은 한국의 동부가 높고 강수변동률이 낮은 서부가 낮아서 동고 서저유형, 2월은 북고 남저유형을 나타내고 있다. 해면기압 및 500hPa면 고도편차 분포에서 1, 2월의 한발시 한반도 주변 및 시베리아 고기압 지역은 양의 편차, 알류샨 저기압 지역 및 북태평양 서안은 음의 편차를 나타내므로 서고 동저형의 기압배치가 탁월하여 남동쪽으로부터 온난습윤한 공기의 유입이 차단될 때 한발이 출현한다. 따라서 이 때 한반도 주변은 동서풍의 풍속은 강하다. 12월의 한발 시에는 한반도를 포함한 동아시아의 중위도 전역이 양의 편차를 나타내어 남쪽으로부터 온난습윤한 공기의 유입이 적을 뿐만 아니라 저기압 통과의 빈도가 적음을 반영하고 있다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_4호
• /
• pp.197-206
• /
• 2001

The long-range transport mechanisms of Asian dust were analyzed based on the synoptic weather system and numerical simulation by using NCEP/NCAR reanalysis and TOMS data during the periods of 1996-2001. We classified the whole weather types of eastern Asia during spring and created the representative weather types during the yellow sand events using cluster analysis and weather charts for the last 6 years(1996~2001). These long-range transport mechanisms were related to various pressure patterns including high and low, trough and ridge, and upper-level fronts. Case studies of the yellow sand events have performed by the simulation of MM5 with meteorological elements such as the horizontal wind of u and v component, potential temperature, potential vorticity, and vertical circulation during the episodic days(2~8 March 2001). In addition, the origin of the long-range transport was examined with the estimation of backward trajectory using HYSPLIT4 Model. In this paper, we concluded that three weather types at 1000 hPa, 850 hPa, 500 hPa, and 300 hPa levels were classified respectively. The dominant features were the extending continental outflow from China to Korea at 1000 hPa and 850 hPa levels, the deep trough passage and cold advection at 500 hPa and 300 hPa levels during the yellow sand events. And also, we confirmed the existence of pola $r_tropical jets in the upper-level, the behavior of potential vorticity over Korea, the estimation of potential vorticity through vertical cross section, and the transport of yellow sand through backward trajectories.es.

• International Journal of Computer Science & Network Security
• /
• 제21권5호
• /
• pp.23-30
• /
• 2021

In recent years, hazardous flash flooding has caused deaths and damage to infrastructure in Saudi Arabia. In this paper, our aim is to assess patterns and trends in climate means and extremes affecting flash flood hazards and water resources in Saudi Arabia for the purpose to improve risk assessment for forecast capacity. We would like to examine temperature, precipitation climatology and trend magnitudes at surface stations in Saudi Arabia. Based on the assessment climate patterns maps and trends are accurately used to identify synoptic situations and tele-connections associated with flash flood risk. We also study local and regional changes in hydro-meteorological extremes over recent decades through new applications of statistical methods to weather station data and remote sensing based precipitation products; and develop remote sensing based high-resolution precipitation products that can aid to develop flash flood guidance system for the flood-prone areas. A dataset of extreme events has been developed using the multi-decadal station data, the statistical analysis has been performed to identify tele-connection indices, pressure and sea surface temperature patterns most predictive to heavy rainfall. It has been combined with time trends in extreme value occurrence to improve the potential for predicting and rapidly detecting storms. A methodology and algorithms has been developed for providing a well-calibrated precipitation product that can be used in the early warning systems for elevated risk of floods.

• 한국대기환경학회지
• /
• 제28권2호
• /
• pp.142-158
• /
• 2012

This paper investigates the physical and chemical characteristics of long-range transport (LRT) process of air pollutants by employing the MM5-CMAQ and its comparison with local emission dominant (LED) case over northeast Asia. We first classified high air pollution days into LRT and LED cases based on the synoptic meteorological variables of vorticity and geostrophic wind speed/direction at a geopotential level of over 850hPa. LRT cases are further categorized into three types of transport patterns (LRT-I-III) according to the air mass pathways from source regions. LRT-I-III are originated from northern, central, and southern China, respectively, identified by back trajectory analysis. Three LRT-I-III groups have different and unique locations of high pressure and transport pathways. The chemical characteristics showed that the simulated spatial distributions varied in terms of locations of maximum concentrations and the temporal variation of surface concentrations. The primary air pollutants such as $NO_x$, $PM_{10}$ and $SO_2$ of all of three LRT cases are well transported into Korea peninsula with different concentration levels. Of LRT cases, LRT-II has the greatest effect on air quality of Korea peninsula, followed by LRT-I and LRT-III. In comparison with LRT, the LED case shows relatively higher air pollution concentrations in general, but showed a variety of different air quality levels following the emission strength pattern. These widely varying patterns are impling the case dependent multi-directional approach for the development of indicators of long-range transport process over northeast Asia.

• 한국지구과학회지
• /
• 제41권5호
• /
• pp.447-458
• /
• 2020

본 연구에서는 K-means 군집 분석을 통하여 최근 5년간(2014-2018) 한반도 남동 지역의 고농도 미세먼지 발생에 영향을 미치는 주요 종관 기상 패턴을 분류하였다. 또한 고농도 미세먼지 사례일의 발생과 관련된 지역적 차이를 살펴보기 위하여 NCEP (National Centers for Environmental Prediction)/FNL (Final Operational Global Analysis) 재해석 기상자료를 이용하여 부산, 울산, 경남 지역의 미세먼지 발생 특성과 관련된 종관 규모 기상의 특성에 대한 비교 연구도 수행하였다. 한반도 남동 지역의 고농도 미세먼지 사례일과 관련된 종관 기상 패턴은 총 5개(C1-C5)로 분류된다. 각 군집의 발생빈도는 24.8% (C1), 21.3% (C2), 20.4% (C3), 17.3% (C4), 16.2% (C5)이다. 기상 패턴 분석을 통하여 제시된 남동 지역의 고농도 미세먼지를 유발하는 요인에는 지역 외부에서 장·단거리 수송(C1, C3, C5)에 의한 영향과 지역내 배출(C2, C4)에 의한 것임을 알 수 있었다. 또한 고농도 미세먼지 발생일에 대해 부산, 울산, 경남 세 지역의 기상장을 분석하였을 때, 500 hPa 지위 고도 및 풍속 등의 기상학적 특성이 지역별로 다르게 나타났다. 그리고 고기압의 작은 위치 변화가 각 지역의 미세먼지 발원과 장거리 이동 경향성에 영향을 미치고 있었다.

• 한국대기환경학회지
• /
• 제32권3호
• /
• pp.256-271
• /
• 2016

The source and transport of the severe Asian dust event (ADE) recently observed in the Korean peninsula were analyzed based on observations (surface weather charts and satellite data) and modeling study (WRF-CMAQ modeling systems). The ADE occurred on 20-21 March 2010 in South Korea with very high $PM_{10}$ concentrations (up to approximately $3,000{\mu}g/m^3$ in Daegu and Jeju). The dominant meteorological conditions affecting the dust outbreak and transport processes were found to be associated with the two synoptic features: (1) strong airflows (i.e., westerlies) induced by a strong pressure gradient resulting from a dense isobar pattern (west-high and east-low) between Tuva Republic and Mongolia and (2) a rapid movement of the strong westerlies merged with airflows generated near Gobi Desert and Inner Mongolia. The merged strong westerlies with a low pressure played a pivotal role in the huge amount of AD and its transport height of 5-8 km. The time and location of dust emissions calculated in the source regions were similar to those observed in the weather charts and satellite image. The ADE simulation mostly showed agreement in the patterns and the concentration levels of modeled dust (including $PM_{10}$) with those of the observations.

• 한국환경과학회지
• /
• 제7권2호
• /
• pp.177-184
• /
• 1998

1981년부터 1990년까지 10년간 발생한 274개의 호우사례를 분류하여,한반도에서 호우시에 나타나는 강수량의 공간분포를 여섯 종류로 나누고 각각의 정관적 특성을 분석하였다. 첫때, 강하게 발달한 지표 저기압에 연관되어 발생하는 호우보다 상, 하층 제트를 동반한 채 발달중인 저기압에 연관되어 발생하는 호우가 많다. 둘째, 재부분의 호우역은 하층 제트의 위치와 방향 그리고 지표 온나전선의 위치에 연관되어 있다. 셋째, 500hPa 면의 저기압 중심이나 기압골의 위치가 서쪽으로 멀어질수록 한반도에어 호우는 고위도에서 발생하는 경향이 있다. 넷째, 한반도에 호우를 초래하는 500hPa의 저기압 중심은 하계몬순의 발달을 따라 서쪽으로 자리잡는 경향이 있으나 해마다 차이가 있다.차이가 있다.