• 대기
• /
• 제29권1호
• /
• pp.53-59
• /
• 2019

The quality of troposphere ozone in three reanalysis datasets is evaluated with longterm ozonesonde measurement at Pohang, South Korea. The Monitoring Atmospheric Composition and Climate (MACC), European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERAI) and Modern Era Retrospective-Analysis for Research and Applications version 2 (MERRA2) are particularly examined in terms of the vertical ozone structure, seasonality and long-term trend in the lower troposphere. It turns out that MACC shows the smallest biases in the ozone profile, and has realistic seasonality of lower-tropospheric ozone concentration with a maximum ozone mixing ratio in spring and early summer and minimum in winter. MERRA2 also shows reasonably small biases. However, ERAI exhibits significant biases with substantially lower ozone mixing ratio in most seasons, except in mid summer, than the observation. It even fails to reproduce the seasonal cycle of lower-tropospheric ozone concentration. This result suggests that great caution is needed when analyzing tropospheric ozone using ERAI data. It is further found that, although not statistically significant, all datasets consistently show a decreasing trend of 850-hPa ozone concentration since 2003 as in the observation.

• 천문학회보
• /
• 제46권2호
• /
• pp.78.1-78.1
• /
• 2021

A Lunar observatory not only provides ideas and experiences for space settlements from the Moon to Mars, but also puts the telescope in an optimal position to compete with space telescopes. Earth observation on the Moon's surface has the advantage of no atmospheric scattering or light pollution and is a stable fuel-free observation platform, allowing all longitude and latitude of the Earth to be observed for a month. Observing the entire globe with a single observation instrument, which has never been attempted before, and calculating the global albedo will significantly help predict the weather and climate change. Spectropolarimetric observations can reveal the physical and chemical properties of the Earth's atmosphere, track the global distribution and migration path of aerosols and air pollutants, and can also help detect very small space debris of which the risk has increased recently. In addition, the zodiacal light, which is difficult to observe from Earth, is very easy to observe from the lunar observatory, so it will be an opportunity to reveal the origin of the solar system and take a step closer to understanding the exoplanet system. In conclusion, building and developing a lunar observatory will be a groundbreaking study to become the world's leader that we have never tried before as a first step in expanding human experience and intelligence.

• 대기
• /
• 제27권4호
• /
• pp.467-481
• /
• 2017

A correction method of reflectivity in partial beam blockage (PBB) area is suggested, which is based on the combination of digital terrain information and self-consistency principle between polarimetric observation. First, the reflectivity was corrected by adding the radar energy loss estimated from beam blockage simulation using digital elevation model (DEM) and beam propagation geometry in standard atmosphere. The additional energy loss by unexpected obstacles and non-standard beam propagation was estimated by using the coefficient between accumulated reflectivity ($Z_H$) and differences of differential phase shift (${\Phi}_{DP}$) along radial direction. The proposed method was applied to operational S-band dual-polarization radar at Jindo and its performance was compared with those of simulation method and self-consistency method for six rainfall cases. When the accumulated reflectivity and increment of ${\Phi}_{DP}$ along radial direction are too small, the self-consistency method has failed to correct the reflectivity while the combined method has corrected the reflectivity bias reasonably. The correction based on beam simulation showed the underestimation. For evaluation of rainfall estimation, the FBs (FRMSEs) of simulation method and self-consistency principle were -0.32 (0.59) and -0.30 (0.57), respectively. The proposed method showed the lowest FB (-0.24) and FRMSE (0.50). The FB and FMSE were improved by about 18% and by 19% in comparison to those before correction (-0.42 and 0.70). We can conclude that the proposed method can improve the accuracy of rainfall estimation in PBB area.

• 대한토목학회논문집
• /
• 제35권2호
• /
• pp.319-326
• /
• 2015

수자원 설계 및 홍수 예 경보 등을 위한 수문분석 시, 강우자료는 필수요소이다. 현재 수문분석 시 비교적 장기간의 자료를 보유하고 있는 기상청, 국토교통부 등의 지상기상관측지점(SSS, Surface Synoptic Stations)에 시 강우자료를 이용하고 있으나, 집중호우가 빈번히 발생하는 현실정과 집중호우의 발생빈도가 증가할 것으로 예상되는 향후에는 더욱 조밀한 관측망을 구성하고 있는 방재기상관측지점(AWS, Automatic Weather Stations)의 분 단위 강우자료를 이용한 분석이 필요하다. 그러나 방재기상관측지점의 분 단위 강우자료는 자동으로 관측되고 있어, 자료품질에 대한 문제점이 매번 지적되고 있다. 본 연구에서는 서울지역을 중심으로 기상청 방재기상관측지점의 분 단위 강우자료의 품질개선 방안에 관한 연구를 실시하였다. 분 단위 강우자료의 품질관리방안은 크게 3단계로 결측치 품질관리, 이상치 품질관리 그리고 강우 보완 품질관리로 구분하여 품질관리 방안을 제시하고 분석을 수행하였다. 마지막으로 서울지점의 분 단위 강우자료와 시 단위 강우자료의 비교분석을 통해 강우 품질관리에 대한 평가를 실시하였다. 이는 향후 분 단위 강우자료를 이용한 수문분석 시, 강우자료 품질관리 방안으로 활용될 것으로 판단된다.

• 한국대기환경학회지
• /
• 제32권1호
• /
• pp.46-56
• /
• 2016

In order to analyze the surface temperature in accordance with the surface material, surface temperatures between Thermal InfraRed Image (TIRI) and Landsat 8 satellite observed at the commercial area (Gwanghwamun) and residential area (Jungnang) are compared. The surface temperature from TIRI had applied atmospheric correction and compared with that from Landsat 8. The surface temperatures from Landsat 8 at Gwanghwamun and Jungnang are underestimated in comparison with that from TIRI. The difference of surface temperature between the two methods is greater in summer than in winter. When the analysis area was divided into detailed regions, depending on the material and the position of the surface, correlation of surface temperature between TIRI with Landsat 8 is as low as 0.29 (Gwanghwamun) and 0.18 (Jungnang), respectively. The results were caused from the resolution difference between the two methods. While the surface temperatures of each zone from Landsat 8 were observed almost constant, high-resolution TIRI observed relatively precise surface temperatures. When the each area was averaged as one space, correlation of surface temperature between TIRIs and Landsat 8 is more than 0.95. The spatially averaged surface temperature is higher at Jungnang, representing residential areas, than at Gwanghwamun, representing commercial areas. As a result, the observation of high resolution is required in order to observe the precise surface temperature. This is because it appears that the spatial distribution of the various surface temperature in the range of micro-scale according to the conditions of the ground surface.

• 대기
• /
• 제30권3호
• /
• pp.277-291
• /
• 2020

Low-level wind shear (LLWS) events on glide path at Jeju International Airport (CJU) are evaluated using the Aircraft Meteorological Data Relay (AMDAR) and Korea Meteorological Administration Post-Processing (KMAPP) with 100 m spatial resolution. LLWS that occurs in the complex terrains such as Mt. Halla on the Jeju Island affects directly aircraft approaching to and/or departing from the CJU. For this reason, accurate prediction of LLWS events is important in the CJU. Therefore, the use of high-resolution Numerical Weather Prediction (NWP)-based forecasts is necessary to cover and resolve these small-scale LLWS events. The LLWS forecasts based on the KMAPP along the glide paths heading to the CJU is developed and evaluated using the AMDAR observation data. The KMAPP-LLWS developed in this paper successfully detected the moderate-or-greater wind shear (strong than 5 knots per 100 feet) occurred on the glide paths at CJU. In particular, this wind shear prediction system showed better performance than conventional 1-D column-based wind shear forecast.

• 한국환경과학회지
• /
• 제26권10호
• /
• pp.1167-1180
• /
• 2017

Numerical Weather Prediction (NWP) models such as the Weather Research and Forecasting (WRF) model are essential for forecasting one-day-ahead solar irradiance. In order to evaluate the performance of the WRF in forecasting solar irradiance over the Korean Peninsula, we compared WRF prediction data from 2008 to 2010 corresponding to weather observation data (OBS) from the Korean Meteorological Administration (KMA). The WRF model showed poor performance at polluted regions such as Seoul and Suwon where the relative Root Mean Square Error (rRMSE) is over 30%. Predictions by the WRF model alone had a large amount of potential error because of the lack of actual aerosol radiative feedbacks. For the purpose of reducing this error induced by atmospheric particles, i.e., aerosols, the WRF model was coupled with the Community Multiscale Air Quality (CMAQ) model. The coupled system makes it possible to estimate the radiative feedbacks of aerosols on the solar irradiance. As a result, the solar irradiance estimated by the coupled system showed a strong dependence on both the aerosol spatial distributions and the associated optical properties. In the NF (No Feedback) case, which refers to the WRF-only stimulated system without aerosol feedbacks, the GHI was overestimated by $50-200W\;m^{-2}$ compared with OBS derived values at each site. In the YF (Yes Feedback) case, in contrast, which refers to the WRF-CMAQ two-way coupled system, the rRMSE was significantly improved by 3.1-3.7% at Suwon and Seoul where the Particulate Matter (PM) concentrations, specifically, those related to the $PM_{10}$ size fraction, were over $100{\mu}g\;m^{-3}$. Thus, the coupled system showed promise for acquiring more accurate solar irradiance forecasts.

• 한국태양에너지학회 논문집
• /
• 제40권5호
• /
• pp.13-22
• /
• 2020

Day ahead forecast is necessary for the electricity market to stabilize the electricity penetration. Numerical weather prediction is usually employed to produce the solar irradiance as well as electric power forecast for longer than 12 hours forecast horizon. Korea Meteorological Administration operates the UM-LDAPS model to produce the 36 hours forecast of hourly total irradiance 4 times a day. This study interpolates the hourly total irradiance into 15 minute instantaneous irradiance and then compare them with observed solar irradiance at four ground stations at 1 minute resolution. Numerical weather prediction model employed here was produced at 00 UTC or 18 UTC from January to December, 2018. To compare the statistical model for the forecast horizon less than 3 hours, smart persistent model is used as a reference model. Relative root mean square error of 15 minute instantaneous irradiance are averaged over all ground stations as being 18.4% and 19.6% initialized at 18 and 00 UTC, respectively. Numerical weather prediction is better than smart persistent model at 1 hour after simulation began.

• 한국농림기상학회지
• /
• 제25권2호
• /
• pp.99-107
• /
• 2023

농업은 기상에 매우 민감한 산업으로, 따라서 농업분야의 기상을 이용한 연구는 더욱 중요해지고 있다. 연구자들은 기상청과 농촌진흥청에서 제공하는 기상정보서비스 웹사이트에 접속해 기상관측자료를 다운로드할 수 있다. 그러나 대량의 기상자료를 받아야 할 때는 여러 번의 조회작업이 필요한 단점이 있다. 본 데이터 논문은 기상청과 농촌진흥청에서 수집한 자료를 원격 저장소 서비스인 깃허브에 업로드하고 소프트웨어 프로그램인 파이썬을 이용해 기상자료에 쉽게 접근할 수 있는 패키지를 제작했다. 이를 통해 추가적인 인증 절차 없이 누구나 자료를 가져갈 수 있는 방식을 채택하여 농업 관계자들의 기상자료에 대한 접근성 및 활용성을 높이는 방법을 제안한다. 자료와 패키지는 분산 버전 관리 시스템인 깃에 업로드하여 수정 및 관리가 용이하게 하였다.

• 한국전자파학회논문지
• /
• 제27권6호
• /
• pp.521-530
• /
• 2016

기상레이다는 전자기파를 대기 중에 방사하여 목표물에 부딪혀서 되돌아오는 후방산란 신호를 수신하는 기상장비이다. 기상청의 기상레이다는 도플러 관측 기능을 가지고 있기 때문에 목표물의 시선속도를 산출할 수 있다. 그러나 기상레이다의 넓은 관측 반경을 확보하려면 관측 속도 범위가 작아져 이를 넘어서는 시선속도는 접힘 현상이 발생한다. 따라서 최대 관측 반경을 유지한 채 관측 속도 범위를 넓히기 위해서는 high PRF와 low PRF 두 개의 서로 다른 PRF로 신호를 송 수신하는 dual PRF(Pulse Repetition Frequency) 모드 기능을 이용해야 한다. Dual PRF 모드를 이용하면 high와 low PRF로 관측된 두 최대 속도의 최소공배수만큼 관측 속도 범위를 넓힐 수 있다. 이를 위해 본 연구에서는 high PRF와 low PRF로 관측된 시선속도의 차이값과 이에 대한 오차를 고려한 분류 기준을 만들고, 분류된 영역별로 보정 인자를 산출하여 시선속도 펼침을 수행하는 시선속도 접힘 풀기 알고리즘을 개발하였다. 이를 용인테스트베드레이다에 적용한 결과, 기존에 산출되는 시선속도보다 개선된 성능을 보였다.