• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.879-881
• /
• 2003

Sea level variations and sea surface circulations in the Korean seas were observed by Topex/Poseidon altimeter data from 1993 through 1997. In sea level variations, the West and South Sea showed relatively high variations with comparison to the East Sea. Then, the northern and southern area in the West Sea showed the range of 20${\sim}$30cm and 18${\sim}$24cm, and the northern west of Jeju island and the southern west of Tsushima island in the South Sea showed the range of 15${\sim}$20cm and 10${\sim}$15cm, respectively. High variations in the West Sea was results to the inflow in sea surface of Yellow Sea Warm Current (YSWC) and bottom topography. Sea level variations in the South Sea was due to two branch currents(Jeju Warm Current and East Korea Warm Current) originated from Kuroshio Current (KC). In sea surface circulations, there existed remarkably three eddies circulations in the East Sea that are mainly connected with North Korea Cold Current (NKCC), East Korea Warm Current (EKWC) and Tushima Warm Current(TWC). Their eddies are caused basically to the influence of currents in sea surface circulations; Cyclone (0.03 cm/sec) in the Wonsan bay off shore with NKCC, and anticyclone (0.06 cm/sec) in the southwestern area of Ulleung island with EKWC, and cyclone (0.01 cm/sec) in the northeastern area of Tushima island with TWC, respectively.

• Journal of the Korean association of regional geographers
• /
• v.11 no.5
• /
• pp.383-390
• /
• 2005

The purpose of this study is to show distribution pattern of comfortable Indoor-Temperature in South Korea based on 10-days normal data(June 3rd, July 2nd, August 1st). Comfortable Indoor-Temperature values and Heat flow equation values for the 68 stations are constructed to show how man tend to feel in various areas. In the early summer, comfortable Indoor-Temperature is very low in Taegwallong regions and the Southern interior regions due to the influence of the orographic effects or the altitude. In the hot summer, All regions except Taegwallong and Central interior regions have been the high value. These are largely derived from the low Clo-values due to the stable weather with the highest insolation, humidity and strong radiation heat by the North Pacific Anticyclone appears in Eastern Asia.

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.5
• /
• pp.697-711
• /
• 2004

Severe haze, mist, and fog phenomena occurred in the central part of Korea during 15~25 May 2003 resulted in poor visibility and air quality. When these phenomena occurred, Korean peninsula was under the effects of anticyclone. The atmosphere was stable, and wind speed was so weak. Under this meteorological conditions, air quality was worse and worse. The characteristics of aerosol in Seoul, Incheon, and Gosan (Jeju) during this period are investigated from the $PM_{10}$. TSP concentrations and aerosol number concentrations. Concentrations of $PM_{10}$ and TSP measured at KMA increased upto 176 and 230 J.${\mu}g/m^3$ on 22 May 2003, respectively. Aerosol number concentrations of size range from 0.82 to 6.06 ${\mu}m$ increased in Seoul on 17, 19, and 21~24 May 2003, and the concentrations of $NO_2$ and $SO_2$had maximum value of 0.165 ppm at Gwanak Mt. and 0.036 ppm at Guro-dong on 23 May 2003, respectively. Result from analysis on heavy metal elements showed high concentrations of Zn, Pb, Cr, Ni, Cu, and Cd during 20~24 May 2003. This event is examined by comprehensive analyses of synoptic weather conditions, satellite images, concentrations of suspended particles and air pollutants, and heavy metal elements.

• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.1
• /
• pp.14-28
• /
• 2007

This study presented the selection of ozone ($O_3$) potential factors and designed and assessed its potential prediction model using multiple-linear regression equations in Ulsan area during the springtime from April to June, $2000{\sim}2004$. $O_3$ potential factors were selected by analyzing the relationship between meterological parameters and surface $O_3$ concentrations. In addition, cluster analysis (e.g., average linkage and K-means clustering techniques) was performed to identify three major synoptic patterns (e.g., $P1{\sim}P3$) for an $O_3$ potential prediction model. P1 is characterized by a presence of a low-pressure system over northeastern Korea, the Ulsan was influenced by the northwesterly synoptic flow leading to a retarded sea breeze development. P2 is characterized by a weakening high-pressure system over Korea, and P3 is clearly associated with a migratory anticyclone. The stepwise linear regression was performed to develop models for prediction of the highest 1-h $O_3$ occurring in the Ulsan. The results of the models were rather satisfactory, and the high $O_3$ simulation accuracy for $P1{\sim}P3$ synoptic patterns was found to be 79, 85, and 95%, respectively ($2000{\sim}2004$). The $O_3$ potential prediction model for $P1{\sim}P3$ using the predicted meteorological data in 2005 showed good high $O_3$ prediction performance with 78, 75, and 70%, respectively. Therefore the regression models can be a useful tool for forecasting of local $O_3$ concentration.

• Journal of the Korean earth science society
• /
• v.33 no.1
• /
• pp.49-58
• /
• 2012

Through a statistical change-point analysis, this study found that Korea landfalling tropical cyclone (TC) frequency has increased rapidly since 1981. This increase is due to the following phenomenon. When anomalous cyclone is developed in the East Asian continent, anomalous anticyclone is reinforced in the western Pacific, which is related to the eastward shift of western North Pacific high, and thus anomalous southerly is formed to Korea from low-latitudes. This anomalous southerly plays an important role as steering flow in moving TCs toward Korea. To examine the cause of the development of anomalous cyclone in the East Asian continent, this study analyzed the water equivalent of accumulated snow depth during the preceding spring (March to May). As a result, less snow depth is observed in most regions of the East Asian continent than before 1981. Therefore, anomalous cyclone in the East Asian continent in summer can be reinforced by the land heating from the preceding spring and then the steering flow of anomalous southerly that moves TCs toward Korea can be also developed to Korea from low-latitudes in summer.

• Journal of Environmental Science International
• /
• v.24 no.11
• /
• pp.1371-1384
• /
• 2015

This study analyzes the characteristics of Western North Pacific (WNP) tropical cyclone (TC) activity and large-scale environments according to the Western Pacific (WP) teleconnection pattern in summer. In the positive WP phase, an anomalous cyclone and an anomalous anticyclone develop in the low and middle latitudes of the East Asia, respectively. As a result, southeasterlies are reinforced in the northeast area of the East Asia including Korea and Japan which facilitates the movement of TC to this area, whereas northwesterlies are reinforced in the southwest area of the East Asia including South China and Indochina Peninsula which blocks the movement of TC to this area. Due to the spatial distribution of this reinforced pressure system, TCs develop, move, and turn more to the northeast of WNP than those in the negative WP phase. Consequently, the characteristics of this TC activity in the positive WP phase are associated with the location of upper tropospheric jet further to the northeast. Meanwhile, TCs in the negative WP phase mainly move to the west from Philippines toward south China and Indochina Peninsula. Furthermore, due to the terrain effect caused by the high passage frequency of TCs in the mainland China, the intensity of TCs are weaker than those in the positive WP phase.

• Journal of Environmental Science International
• /
• v.18 no.11
• /
• pp.1271-1281
• /
• 2009

The heavy snowfall event over the eastern part of Seoul, Korea on Mar. 04, 2008 has been abruptly occurred after the frontal system with the heavy snowfall event had been past over the Korean peninsula on Mar. 03, 2008. Therefore, this heavy snowfall event couldn't be predicted well by any means of theoretical knowledges and models. After the cold front passed by, the cold air mass was flown over the peninsula immediately and became clear expectedly except the eastern part and southwestern part of peninsula with some large amount of snowfall. Even though the wide and intense massive cold anticyclone was expanded and enhanced by the lowest tropospheric baroclinicity over the Yellow Sea, but the intrusion and eastward movement of cold air to Seoul was too slow than normally predicted. Using the data of numerical model, satellite and radar images, three dimensional analysis Products(KLAPS : Korea Local Analysis and Prediction System) of the environmental conditions of this event such as temperature, equivalent potential temperature, wind, vertical circulation, divergence, moisture flux divergence and relative vorticity could be analyzed precisely. Through the analysis of this event, the formation and westward advection of lower cyclonic circulation with continuously horizontal movement of air into the eastern part of Seoul by the analyses of KLAPS fields have been affected by occurring the heavy snowfall event. As the predictability of abrupt snowfall event was very hard and dependent on not only the synoptic atmospheric circulation but also for mesoscale atmospheric circulation, the forecaster can be predicted well this event which may be occurred and developed within the very short time period using sequential satellite images and KLAPS products.

• Atmosphere
• /
• v.25 no.3
• /
• pp.435-447
• /
• 2015

This study explores the synoptic characteristics of cold days over South Korea and their relationship with large-scale climate variability. The cold day, which is different from cold surge, is defined when daily-mean surface air temperature, averaged over 11 KMA stations, is colder than 1-percentile temperature in each year by considering its long-term trend over 1960~2012. Such event is detected by quantile regression and the related synoptic patterns are identified in reanalysis data. Composite geopotential height anomalies at 500 hPa show that cold days are often preceded by positive anomalies in high latitudes and negative anomalies in midlatitudes on the west of Korea. While the formers are quasi-stationary and quasi-barotropic, and often qualified as blocking highs, the latters are associated with transient cyclones. At cold days, the north-south dipole in geopotential height anomalies becomes west-east dipole in the lower troposphere as high-latitude anticyclone expands equatorward to the Northern China and mid-latitude cyclone moves eastward and rapidly develops over the East Sea. The resulting northerlies cause cold days in Korea. By performing composite analyses of large-scale climate indices, it is further found that the occurrence of these cold days are preferable when the Arctic Oscillation is in its negative phase and/or East Asian monsoon circulation and Siberian high are anomalously strong.

• Journal of the Korean earth science society
• /
• v.30 no.3
• /
• pp.282-293
• /
• 2009

This study examines the effects of the Madden-Julian oscillation (MJO) or the Intraseasonal Oscillation (ISO) on precipitation, temperature and circulation anomalies over East Asia according to the eight different MJO phases during the winter and summer seasons. A nonlinear response appears the wintertime precipitation pattern during the phase of 3 (where the MJO center is located over the Eastern Indian Ocean) and 8 (where the MJO center is located over the Western Hemisphere) over the Korean Peninsula. That is, for these phases, the positive precipitation anomalies appear for the MJO intensity less than 2 standard deviations while the negative precipitation anomalies appear in the case of the MJO intensity greater than 2 standard deviations. The negative precipitation anomaly in the latter case is duandard d stronger anomalous anticyclone formed over the Korean Peninsula and cold and dry advection by northerly winds. The response of precipitation and circulation to the boreal summer ISO is also investigated.

• Journal of the Korean earth science society
• /
• v.30 no.5
• /
• pp.529-549
• /
• 2009

In 2007, just after the recession of the Changma, anomalously long rainy period (from July 30 to August 15) occurred in Korea. To identify the cause of the sustained rainy period, we performed synoptic analysis and the associated air motions. The behavior of each air parcel trajectory associated with atmospheric motion was then investigated. As a result, three particular phenomena occurring at latitudes lower than $40^{\circ}N$ were discovered. First, a mass of relatively cold air, referred to as E, made a deep intrusion from $20^{\circ}N$ to $60^{\circ}N$. Second, this intrusion was accompanied by another mass of air called dE. It was colder and drier than E and originated from the mid-troposphere over the tropical ocean. Third, dE and E rotated clockwise three times over a period of 17 days over the Northwestern Pacific and blocked the westerly waves imbedded in the zonal flow from propagating. Two additional phenomena were observed at latitudes higher than $40^{\circ}N$. First, the cold core system, while approaching from the west with low geopotential values at its center, was stagnated over Shanxi China. It enhanced the northward intrusion of dE and E, and then diminished. The subsequent low system showed similar evolution as the first one. Second, a warm core anticyclone was formed over Lake Baikal, blocking the westerlies for 13 days and contributed to the persistent northward incursion of warm moist air. Moreover, a horizontally extended intrusion of upper level clouds from the tropics to $50^{\circ}N$, which may be interpreted as a tropical plume, was found around the end of the period (from August 12 to 15, 2007) with successive tropical nights over Korea.