• 대한원격탐사학회지
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• 제32권6호
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• pp.629-637
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• 2016

본 연구에서는 2005년부터 2007년 사이에 중국 공업지대에서 Ozone Monitoring Instrument (OMI) 센서에서 관측한 이산화황 값의 증가에 따른 Total Ozone Mapping Spectrometer (OMI-TOMS)와 Differential Optical Absorption Spectrometer (OMI-DOAS) 오존전량 값의 차이를 위성자료를 이용하여 비교를 수행하였다. 중국 공업지대에서는 Planetary boundary layer (PBL)내의 이산화황을 나타내는 PBL $SO_2$ 자료가 사용되었다. 중국 공업지대에서 PBL내의 이산화황 농도 증가에 대하여 두 오존 값의 차이가 증가하는 경향성(R (Correlation coefficient) = 0.36)이 나타났다. 이산화황 이외에 두 오존 산출 알고리즘에 모두 영향을 미칠 수 있는 에어로솔 광학 두께(AOD; Aerosol Optical Depth)가 증가하는 경우 이산화황과 두 오존 값의 차이 사이의 회귀식의 기울기($1.83{\leq}slope{\leq}2.36$)가 비슷하게 유지되는 경향이 나타났다. 이는 다양한 AOD 조건에서도 이산화황이 두 오존 값의 차이를 증가시키는 관계가 나타나는 경향은 거의 비슷하게 유지되는 것으로 생각된다. 중국 공업지대에서 PBL내에 존재하는 이산화황과 화산 폭발에 의하여 고층(Middle troposphere (TRM), Upper troposphere and Stratosphere (STL))에서 존재하는 이산화황의 농도가 1 DU 증가하는 경우 두 오존 값의 차이는 각각 1.6 DU, 3.9 DU, 4.9 DU로 계산되었다. 고층(TRM, STL)의 이산화황과 저층(PBL)의 이산화황이 증가하는 경우 두 오존 값의 차이가 다르게 나타나는 것은 이산화황이 존재하는 고도에 따라서 두 오존 값의 차이에 미치는 영향이 다름을 의미한다. 이는 OMI-TOMS 오존을 산출하는데 사용되는 파장영역(317.5 nm)에서 행성경계층에서 이산화황에 의해 흡수되는 복사휘도의 감소된 민감도에 의한 것으로 생각된다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.59-60
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• 2003

In this study, we present the analysis of vertical ozone sounding data observed over Pohang, Korea, and investigate to understand the governing mechanisms for seasonal ozone maximum in June. The vertical ozone profiles in June show that the ozone enhancement is clearly shown in the middle and upper troposphere. We have found that the June maximum is associated with the transport of ozone rich air from the stratosphere and polluted continental air mass. This is different from the previous studies shown that the regionally polluted continental air mass, influenced by the intense anthropogenic activities m northeast Asia during transport, is responsible for the ozone maximum in spring.

• 대기
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• 제23권4호
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• pp.377-387
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• 2013

Projections of changes in the low latitude atmospheric circulation under global warming are investigated using the results of the CMIP5 ensemble mean. For this purpose, 30-yr periods for the present day (1971~2000) and the end of the $21^{st}$ century (2071~2100) according to the RCP emission scenarios are compared. The wintertime subtropical jet is projected to strengthen on the upper side of the jet due to increase in meridional temperature gradient induced by warming in the tropical upper-troposphere and cooling in the stratosphere except for the RCP2.6. It is also found that a strengthening of the upper side of the wintertime subtropical jet in the RCP2.6 due to tropical upper-tropospheric warmings. Model-based projection shows a weakening of the mean intensity of the Hadley cell, an upward shift of cell, and poleward shift of the Hadley circulation for the winter cell in both hemispheres. A weakening of the Walker circulation, which is one of the most robust atmospheric responses to global warming, is also projected. These results are consistent with findings in the previous studies based on CMIP3 data sets. A weakening of the Walker circulation is accompanied with decrease (increase) in precipitation over the Indo-Pacific warm pool region (the equatorial central and east Pacific). In addition, model simulation shows a decrease in precipitation over subtropical regions where the descending branch of the winter Hadley cell in both hemispheres is strengthened.

• 한국대기환경학회지
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• 제28권5호
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• pp.581-594
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• 2012

The goal of this study is to investigate the effects of the chemical lateral boundary conditions (CLBCs) on Community Multi-scale Air Quality (CMAQ) simulations of tropospheric ozone for East Asia. We developed linking tool to produce CLBCs of CMAQ from Goddard Earth Observing System-Chemistry (GEOS-Chem) as a global chemistry model. We examined two CLBCs: the fixed CLBC in CMAQ (CLBC-CMAQ) and the CLBC from GEOS-Chem (CLBC-GEOS). The ozone fields by CMAQ simulation with these two CLBCs were compared to Tropospheric Emission Spectrometer (TES) satellite data, ozonesonde and surface measurements for May and August in 2008. The results with CLBC-GOES showed a better tropospheric ozone prediction than that with CLBC-CMAQ. The CLBC-GEOS simulation led to the increase in tropospheric ozone concentrations throughout the model domain, due to be influenced high ozone concentrations of upper troposphere and near inflow western and northern boundaries. Statistical evaluations also showed that the CLBC-GEOS case had better results of both the index of Agreement (IOA) and mean normalized bias. In the case of IOA, the CLBC-GEOS simulation was improved about 0.3 compared to CLBC-CMAQ due to the better predictions for high ozone concentrations in upper troposphere.

• 한국지구과학회지
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• 제26권6호
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• pp.560-572
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• 2005

이 연구에서는 1979년부터 1999년까지 21년 동안에 한반도 겨울철 한파와 관련된 대기 순환 및 열원$(Q_1)$의 분포 특성을 조사하였다. 한파 발생 빈도는 1년간 약 1개로 나타났으며, 1989년을 중심으로 전반기에 전체의 $60\%$가 발생하였다. 한파 발생 동안 하층의 대기 순환 패턴은 평년에 비해 서고동저형의 기압 패턴이 더 뚜렷하며, 상층에서도 한반도에 기압골의 영향이 더 강하게 나타난다. 한파가 발생하는 동안에 한반도 부근의 기온 하강 패턴은 바이칼호 부근의 기온 패턴과 반대로 나타나며, 기온의 연직 구조에서도 400 hPa을 기준으로 하층과 상층의 기온 편차는 반대로 나타난다. 열원에 대한 분석은 한파 발생 시 한랭 이류에 의한 냉각은 하강 운동에 의한 단열 승온에 의해 균형을 이룬다는 것을 보여주는데, 이것은 한랭 핵의 이동이 열흡수원의 이동 경로와 연관되어 있음을 나타낸다. 따라서 한파의 유지 기작을 이해하고 한파를 예측하기 위해서는 열원 그리고 열흡수원의 이동 기작이 밝혀져야 할 것이다.

• 대기
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• 제28권3호
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• pp.233-245
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• 2018

This study explores the Subseasonal-to-Seasonal (S2S) prediction skills of the Northern Hemisphere mid-latitude geopotential height in the Global Seasonal forecasting model version 5 (GloSea5) hindcast experiment. The prediction skills are quantitatively verified for the period of 1991~2010 by computing the Anomaly Correlation Coefficient (ACC) and Mean Square Skill Score (MSSS). GloSea5 model shows a higher prediction skill in winter than in summer at most levels regardless of verification methods. Quantitatively, the prediction limit diagnosed with ACC skill of 500 hPa geopotential height, averaged over $30^{\circ}N{\sim}90^{\circ}N$, is 11.0 days in winter, but only 9.1 days in summer. These prediction limits are primarily set by the planetary-scale eddy phase errors. The stratospheric prediction skills are typically higher than the tropospheric skills except in the summer upper-stratosphere where prediction skills are substantially lower than upper-troposphere. The lack of the summer upper-stratospheric prediction skill is caused by zonal mean error, perhaps strongly related to model mean bias in the stratosphere.

• 대기
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• 제16권2호
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• pp.67-83
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• 2006

The statistical analysis for the springtime windstorm in Korea shows that Yeongdong region has the highest occurrence frequency during recent 10 years. The objective of this study is to find possible mechanisms for the downslope windstorm formation in the Yeongdong region by using a mesoscale numerical model, WRF. Dynamical process, wave breaking (hereafter WB), is qualitatively investigated as the candidate mechanism for a windstorm event occurred in 5 April, 2005. WB is developed in upper troposphere downstream, since stable air is lifted by the Taebaek mountain. This process can cause and maintain the severe downslope windstorm by drawing the upper flow down to the surface. And the intensified downslope wind leads the hydraulic jump (hereafter HJ) in downstream region. Froude numbers at Chuncheon (upslope side), Seorak Mountain (crest), Yangyang (lee side), and the East Sea (distant downstream position) are estimated by about 0.4, 1.0, 1.6, and 0.6, respectively. This result implies that the accelerated and supercritical (Fr>1) flow adjusts to the ambient subcritical (Fr<1) conditions in the turbulent HJ. In addition, we find the formation of upstream inversion near top level of the mountain cause the intensification of HJ. Experiments to examine the orographic effect on the mechanisms suggest that the magnitudes of WB and HJ are larger in the experiment of higher topography, but there is no significant difference of windstorm magnitude among the experiments. Another important result from these sensitivity experiments is that the intensity of downslope windstorm strongly depends on the magnitude of upper (2~4 km) wind in upstream side.

• 한국환경과학회지
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• 제12권4호
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• pp.419-426
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• 2003

This study was performed to research ozone concentration related to airmass thunderstorm using 12 years meteorological data(1990~2001) at Busan. The occurrence frequency of thunderstorm during 12 years was 156 days(annual mean 13days). The airmass thunderstorm frequency was 14 days, most of those occurrence at summertime(59%). In case August 4, 1996, increase of ozone concentration was simultaneous with the decrease of temperature and increase of relative humidity, In case July 23, 1997, ozone concentration of western site at Busan increased, while its of eastern site decreased as airmass thunderstorm occurred(about 1500LST). It is supposed that these ozone increases are the effect of ozone rich air that is brought down by cumulus downdrafts from height levels where the ozone mixing ratio is larger. Thunderstorms can cause downward transport of ozone from the reservoir layer in the upper troposphere into planeta교 boundary layer(PBL). This complex interaction of source and sink processes can result in large variability fer vertical and horizontal ozone distributions. Thus a variety of meteorological precesses can act to enhance vertical mixing between the earth's surface and the atmospheric in the manner described fer thunderstorm.

• 한국대기환경학회지
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• 제22권3호
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• pp.271-285
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• 2006

A two-dimensional photochemical transport model (2D PTM) is simulated to describe the transport and chemical reaction of ozone related to aerosols in the troposphere and stratosphere. The vertical profiles and total amounts of ozone, which are advected by both residual Eulerian circulation and the adiabatic circulation under certain circumstance, have been compared with the observation data such as ozonesondes, Brewer spectrometer, the Upper Atmosphere Research Satellite (UARS), and the Total Ozone Mapping Spectrophotometer (TOMS). As a result, we find that the observed distribution of ozone Is adequately reproduced in the model at middle and high latitude in the Northern Hemisphere as well as at Phang ($36^{\circ}\;02'N,\;129^{\circ}\;23'E$) in South Korea. In particular, the 2D PTM is well simulated in the ozone decrease due to the Pinatubo volcanic eruption in 1991. However, ozone mixing ratio are more underestimated than those of UARS and ozonesondes, because are very sensitive to the latitude of transport across the tropopause associated with both Rummukainen errors and off-line model. Relative mean bias errors and relative root mean square errors of ozone calculations using the 2D PTM are shown within${\pm}10%$, respectively.

• 대기
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• 제16권3호
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• pp.235-246
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• 2006

Remote sensing techniques using satellites or the scanning weather radars depend mostly on the presence of clouds or precipitation, and leave the extensive regions of clear air unobserved. But wind profilers provide the most direct measurements of mesoscale vertical air motion in the troposphere, even in the context of heavy precipitation. In this paper, the precipitation events during the Changma period was classified into 4 precipitation types - stratiform, mixed stratiform/ convective, deep convective, and shallow convective. The parameters for the classification of analysis are the vertical structure of reflectivity, Doppler velocity, and spectral width measured with the wind profiler at Haenam for a three-year period (2003-2005). In addition, the synoptic fields and total amount of precipitation were analyzed using the Global Final Analyses (FNL) data and the Global Precipitation Climatology Project (GPCP) data. During the Changma period, the results show that the stratiform type was dominant under the moist-neutral atmosphere in 2003, whereas the deep convective type was under the moist unstable condition in 2004. The stratiform type was no less popular than the deep convective type among four seasons because the moist neutral layer was formed by the convergence between the upper-level jet and the low-level jet, and by the moisture transport along the western rim of the North Pacific subtropical anticyclone.