Automatic Weather System Research Articles

Characteristics of Urban Meteorology in Seoul Metropolitan Area of Korea

The aim of this study is to examine weather modification by urbanization and human activities. The characteristics of the urban heat island (UHI) and precipitation in Seoul metropolitan area of Korea are investigated to demonstrate that cities can change or modify local and nearby weather and climate, and to confirm that cities can initiate convection, change the behavior of convective precipitation, and enhance downstream precipitation. The data used in this study are surface meteorological station data observed in Seoul and its nearby 5 cities for the period of 1960 to 2009, and 162 Automatic Weather System stations data observed in the Seoul metropolitan area from 1998 to 2009. Air temperature and precipitation amount tend to increase with time, and relative humidity decreases because of urbanization. Similar to previous studies for other cities, the average maximum UHI is weakest in summer and is strong in autumn and winter, and the maximum UHI intensity is more frequently observed in the nighttime than in the daytime, decreases with increasing wind speed, and is enhanced for clear skies. Relatively warm regions extend in the east-west direction and relatively cold regions are located near the northern and southern mountains inside Seoul. The satellite cities in the outskirts of Seoul have been rapidly built up in recent years, thus exhibiting increases in near-surface air temperature. The yearly precipitation amount during the last 50 years is increased with time but rainy days are decreased. The heavy rainfall events of more than increases with time. The substantial changes observed in precipitation in Seoul seem to be linked with the accelerated increase in the urban sprawl in recent decades which in turn has induced an intensification of the UHI effect and enhanced downstream precipitation. We also found that the frequency of intense rain showers has increased in Seoul metropolitan area.

최근 4년간(2005~2008) 울릉도와 독도의 강수 및 기온 특성

Characteristics of precipitation and temperature in Ulleung-do and Dok-do were analyzed with hourly accumulated precipitation and mean temperature data obtained from Automatic Weather System(AWS) for latest four years(2005~2008). In Ulleung-do, total annual mean precipitation for this period is 1,574.4 mm, which shows larger amount than 1434.2 mm of whole Korean peninsula for latest 10 years(1999~2008) and 1,236.2 mm at Ulleung-do on common years(1971~2000), shows that the trend of precipitation gradually increases during the recent years. This amount is also 1.4 times larger than the total annual mean precipitation of 660.1 mm in Dok-do. Mean precipitation intensity(mm <TEX>$h^{-1}$</TEX>) at each time of a day in each month at Ulleung-do represents that the maximum values larger than <TEX>$3.0\;mm\;h^{-1}$</TEX> were shown in May and on 0200 LST, whereas these were found in August and 0700 LST with <TEX>$3.1\;mm\;h^{-1}$</TEX> in Dok-do. The difference of the precipitation amount and its intensity between Uleung-do and Dok-do is explained by the topological effect came from each covering area, and this fact is also identified from similar comparison of the precipitation characteristics for the islands in West Sea. The annual mean temperature of <TEX>$14.0^{\circ}C$</TEX> in Dok-do is <TEX>$1.2^{\circ}C$</TEX> higher than that of <TEX>$12.8^{\circ}C$</TEX> in Ulleung-do. Trends of monthly mean temperature in both islands are shown to increase for the observed period.

High-resolution summer rainfall prediction in the JHWC real-time WRF system

The WRF-based real-time forecast system ( http://jhwc.snu.ac.kr/weather ) of the Joint Center for High-impact Weather and Climate Research (JHWC) has been in operation since November 2006; this system has three nested model domains using GFS (Global Forecast System) data for its initial and boundary conditions. In this study, we evaluate the improvement in daily and hourly weather prediction, particularly the prediction of summer rainfall over the Korean Peninsula, in the JHWC WRF (Weather Research and Forecasting) model system by 3DVAR (three-Dimensional Variational) data assimilation using the data obtained from KEOP (Korea Enhanced Observation Program). KEOP was conducted during the period June 15 to July 15, 2007, and the data obtained included GTS (Global Telecommunication System) upper-air sounding, AWS (Automatic Weather System), wind profiler, and radar observation data. Rainfall prediction and its characteristics should be verified by using the precipitation observation and the difference field of each experiment. High-resolution (3 km in domain 3) summer rainfall prediction over the Korean peninsula is substantially influenced by improved synoptic-scale prediction in domains 1 (27 km) and 2 (9 km), in particular by data assimilation using the sounding and wind profiler data. The rainfall prediction in domain 3 was further improved by radar and AWS data assimilation in domain 3. The equitable threat score and bias score of the rainfall predicted in domain 3 indicated improvement for the threshold values of 0.1, 1, and 2.5 mm with data assimilation. For cases of occurrence of heavy rainfall (7 days), the equitable threat score and bias score improved considerably at all threshold values as compared to the entire period of KEOP. Radar and AWS data assimilation improved the temporal and spatial distributions of diurnal rainfall over southern Korea, and AWS data assimilation increased the predicted rainfall amount by approximately 0.3 mm 3hr−1.

위성 및 AWS 자료를 이용한 지표면 피복 조건의 차이가 대구의 도시 열환경에 미치는 영향

The present study explores time and spatial thermal environment for Daegu, which is a city built on a basin area, according to varying land cover conditions of the earth's surface by analyzing data derived from meteorological observation and satellite images. The study has classified land use by utilizing MODIS satellite images and analyzed land surface temperature. Also, by using data acquired from automatic weather system, the study has evaluated the effects of atmospheric heating caused by city pavements by analyzing the sensible heat flux between the city's land surface and the atmosphere. The results are as follows. 1) Classification of land use in the Daegu area shows 46.64% of urban and built-up area, 1.39% of watersides, 35.19% of forest, 11.43% of crops, and 5.37% grasslands. 2) During the weekdays throughout the year, the land surface temperature was high for Dalseogu, Bukgu, and Seogu regions where industrial complexes could be found. Comparatively, lower temperature could be observed in the woodlands. 3) While the land surface temperature displayed the effects of pushing air upwards during the weekdays in urban areas, the reverse was true for forest regions. During the night, the temperature did not exert any significant influence on air movement.

대기예보모형과 진단모형 결합을 통한 복잡지형 바람장 해석능력 평가

A system coupled the prognostic WRF mesoscale model and CALMET diagnostic model has been employed for predicting high-resolution wind field over complex coastal area. WRF has three nested grids down to from during two days from 24 August 2007 to 26 August 2007. CALMET simulation is performed using both initial meteorological field from WRF coarsest results and surface boundary condition that is Shuttle Radar Topography Mission (SRTM) 90m topography and Environmental Geographic Information System (EGIS) 30m landuse during same periods above. Four Automatic Weather System (AWS) and a Sonic Detection And Ranging (SODAR) are used to verify modeled wind fields. Horizontal wind fields in CM_100m is not only more complex but better simulated than WRF_1km results at Backwoon and Geumho in which there are shown stagnation, blocking effects and orographically driven winds. Being increased in horizontal grid spacing, CM_100m is well matched with vertically wind profile compared SODAR. This also mentions the importance of high-resolution surface boundary conditions when horizontal grid spacing is increased to produce detailed wind fields over complex terrain features.

Estimate of Burden of Disease Attributable to Climate Change in South Korea

ISEE-0693 Background and Objective: It has been widely recognized that climate changes are posing for human health. On the other hand, the burden of diseases from climate change has not been studied actively. The aim of this study was to estimate the burden of five infectious diseases attributable to climate change. Methods: The burden of five infectious diseases–leptospirosis, malaria, shigellosis, vibrio vulnificus sepsis, tsutsugamushi fever–due to climate change was estimated by using DALY (Disability Adjusted Life-Year). For the calculation of the DALYs, the following parameters were estimated: prevalence rate, disability weight and duration of each disease. To estimate the prevalence rate of infectious diseases, this study used National Health Insurance utilization data and the nationwide Automatic Weather System during 2005∼2007 in South Korea. Results: When considering future population change, the burden of disease varied to age groups and the type of diseases. Absolute amount of disease burden was higher in the adults, but those of children and young adults (under 35) relatively increased due to decrease of population size of those groups. The order of future burden of disease was estimated tsutsugamushi fever, malaria, shigellosis, vibrio vulnificus sepsis, and leptospirosis. The DALYs of tsutsugamushi fever, malaria, shigellosis, vibrio vulnificus sepsis and leptospirosis was 1.7314, 0.4493, 0.2480, 0.1514, 0.1478, respectively when the yearly average temperature increased 1 degree Celcius. Conclusion: Despite the significance of the burden of disease due to climate change, strategies and researches required in this regard are only in their beginning stages in South Korea. As one of the most prominent and prompt preparations, burden of disease attracted the popular. The findings were expected to contribute to priority setting and effective resource allocation in public health policy.

AWS 데이터를 이용한 부산 해안의 바람분포 특성 해석

이 연구에서는 10년간(1997-2006년)의 기상청 AWS(Automatic Weather System) 자료를 이용하여 선박의 안전과 항만구조물 등의 안정성에 매우 중요한 부산 해안의 바람분포 특성을 분석하였다. 그리고 부산 해안의 바람분포 특성을 명확히 파악하기 위하여 해륙풍의 영향을 받지 않는 밀양의 바람분포 특성도 해석하여 비교하였다. 부산 해안의 평균풍속은 밀양보다 강하고, 부산 해안 중에서도 섬인 영도와 가덕도의 평균풍속은 일광, 해운대 및 대연의 그것보다 약 2.0배 강한 특성을 보인다. 상관분석에 의하여, 부산 해안의 월별 평균풍속은 서로 변화 경향이 매우 유사함을 확인하였다. 부산 해안의 월별 평균풍속의 최대값은 9월에 나타나는데, 이는 태풍의 영향과 밀접히 관련되어 있다. 최대 순간풍속도 섬인 영도와 가덕도에서 특히 강하고, 부산 해안의 최대순간풍속은 주로 8-9월에 그 최대값이 관측된다. 부산 해안의 풍향별 관측 횟수의 백분율을 살펴보면, 겨울은 남서풍-북북동풍이 우세하고 봄은 남서풍과 북동풍이 우세하다. 여름의 풍향 분포는 봄과 비슷하고, 가을의 풍향 분포는 겨울과 유사한 경향을 보인다. Wind velocity and wind direction are very important in the viewpoint of ship's safety and stability of port structure. The characteristics of wind distribution in the coast of Busan are analyzed for 10 years from 1997 to 2006 using AWS(Automatic Weather System) data. The characteristics of wind distribution of Miryang, is not affected by the land and sea breeze are also examined to understand clearly the characteristics of wind distribution in the coast of Busan. The mean wind velocity in the coast of Busan is stronger than that of Miryang. The mean wind velocitie at Youngdo and Gadukdo stations of Busan are stronger about 2.0 times than those at IlGwang, Haeundae and Daeyeon stations. The correlation a states show that the variation tendencies of monthly mean wind velocitie in the coast of Busan are very similar. The maximum monthly mean velocitie in the coast of Busan are recorded in September. This re ult is closely related to the influence of typhoon. The maximum instantaneous wind velocitie are also strong at Youngdo and Gadukdo stations and the peaks of maximum instantaneous wind <TEX>$velocit^9$</TEX> are observed mainly from August to September. In the coast of Busan, the SW'ly-NNE'ly wind are prevailing in the winter and the SW'ly and NE'ly wind are predomi snt in the spring. w that the vs of wind direction in the summer and athumn are similar with those in the spring and winter, respectively.

연직관측자료를 통한 복잡 연안지역의 오존 이류특성

In order to clarify the vertical ozone distribution in planetary boundary layer of coastal area with complex terrain, an observation campaign was carried out around Gwangyang Bay with dense pollutant emission sources during two days from June, 4 2007. For this observation are Radiosonde, SODAR(SOnic Detection And Ranging) and Tethered ozone sonde were employed. The surface meteorological and photochemical observation data provided by AWS (Automatic Weather System) and AQMS (Air Quality Monitoring System) were also applied for analysis. Synoptic condition is strongly associated with lower level ozone distribution in complex terrain coastal area. Since mesoscale circulation induced by difference of characteristics of land and sea and orographic forcing is predominant under calm synoptic condition, vertical distribution of ozone is complicate and vertical ozone concentration greatly fluctuated. However in second day when synoptic influence become strong, ozone concentration in lower levels is vertically uniform regardless of observation level. This results in vertical observation indicates that vertical ozone distribution is often determined by synoptic condition and also affects surface ozone concentration.

대기환경영향평가를 위한 대구광역시 상인동 달비골의 봄철 기상관측 사례분석

This study aims to produce fundamental database for Environment Impact Assessment by monitoring vertical structure of the atmosphere due to the mountain valley wind in spring season. For this, we observed surface and upper meteorological elements in Sangin-dong, Daegu using the rawinsonde and automatic weather system(AWS). In Sangin-dong, the weather condition was largely affected by mountains when compared to city center. The air temperature was low during the night time and day break, and similar to that of city center during the day time. Relative humidity also showed similar trend; high during the night time and day break and similar to that of city center during the day time. Solar radiation was higher than the city, and the daily maximum temperature was observed later than the city. The synoptic wind during the measurement period was west wind. But during the day time, the west wind was joined by the prevailing wind to become stronger than the night time. During the night time and daybreak, the impact of mountain wind lowered the overall temperature, showing strong geographical influence. The vertical structure of the atmosphere in Dalbi valley, Sangin-dong had a sharp change in air temperature, relative humidity, potential temperature and equivalent potential temperature when measured at the upper part of the mixing layer height. The mixing depth was formed at maximum 1896m above the ground, and in the night time, the inversion layer was formed by radiational cooling and cold mountain wind.

Automatic identification of weather systems from numerical weather prediction data using genetic algorithm

Weather systems such as tropical cyclones, fronts, troughs and ridges affect our daily lives. Yet, they are often manually located and drawn on weather charts based on forecasters’ experience. To identify them, multiple atmospheric elements need to be considered, and the results may vary among forecasters. In this paper, we propose an automatic weather system identification method. A generic model of weather systems is designed, along with a genetic algorithm-based framework for finding them automatically from multidimensional numerical weather prediction data. The framework allows multiple weather elements to be analyzed. It is found that our method not only can locate weather systems with 80–100% precision, but can also discover features that could indicate the genesis or dissipation of such systems that forecasters may overlook. The method provides an independent and objective source of information to assist forecasters in identifying and positioning weather systems.

대규모 주택단지내의 인공구조물에 의한 승온화효과에 관한 연구

In mid-August 2002, under clear summer pressure patterns, we carried out an intensive meteorological observation to examine the warming effects due to artificial constructions in a large housing complex. We set an automatic weather system(AWS) at two places in a bare soil surface within a limited development district and an asphalt surface within a large apartment residence area, respectively. As a result of observation, it became clear that the difference of the surface air(ground) temperature between the bare soil surface and its peripheral asphalt area reached about 4<TEX>$^{\circ}C$</TEX>(13<TEX>$^{\circ}C$</TEX>) at the maximum from diurnal variation of surface temperatures on AWS data. Through the heat balance analysis using measurement data, it became clear that the thermal conditions at two places are dependent on the properties of surface material. The latent heat flux over the bare soil surface reached to about 300 W/㎡, which is more than a half of net radiation during the daytime. On the other hand, it was nearly zero over the asphalt surface. Hence, the sensible heat flux over the asphalt surface was far more than that of the bare soil surface. The sensible heat flux over the asphalt surface showed about 20∼30 W/㎡ during the night. It was released from asphalt surface which have far more heat capacity than that of bare soil surface.