Yun-Seob Moon

Characteristics of Asian dust transport based on synoptic meteorological analysis over Korea.

Classification of synoptic patterns and their correlation with dust events over East Asia were performed by means of cluster analysis. The average linkage and K-means clustering techniques were used to identify two major weather types during Asian dust events (ADEs; total 26 ADEs with 47 dusty days) of six spring seasons from 1996 to 2001. The first weather type mainly influenced neighboring Asian countries and frequently occurred with ADEs (∼23% of ADE cases). It mostly occurred under a surface high (low)-pressure system over the west (east) of the Korean peninsula coupled with an upper-level trough and cutoff low passage over the center of the Korean peninsula. It showed strong advection in the middle/upper troposphere with both a high aerosol index and enhanced coarse particulate matter (PM) loading over Korea. In contrast, the second weather type was mostly associated with long distance or continental-scale transport and occurred less frequently with ADEs (∼15%). It appeared with an upper-level trough and a cutoff low vertically connected with a surface low system that was formed by a strong cyclonic vortex over the north of the Korean peninsula. There were weak advection, low aerosol index, and low coarse PM concentration over the Korean peninsula during the second weather type. In addition, it was found to be mostly associated with the trans-Pacific transport of Asian dust to the western coast of North America.

An Estimation of Concentration of Asian Dust (PM 10 ) Using WRF-SMOKE-CMAQ (MADRID) During Springtime in the Korean Peninsula

In this study a modeling system consisting of Weather Research and Forecasting (WRF), Sparse Matrix Operator Kernel Emissions (SMOKE), the Community Multiscale Air Quality (CMAQ) model, and the CMAQ-Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) model has been applied to estimate enhancements of during Asian dust events in Korea. In particular, 5 experimental formulas were applied to the WRF-SMOKE-CMAQ (MADRID) model to estimate Asian dust emissions from source locations for major Asian dust events in China and Mongolia: the US Environmental Protection Agency (EPA) model, the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model, and the Dust Entrainment and Deposition (DEAD) model, as well as formulas by Park and In (2003), and Wang et al. (2000). According to the weather map, backward trajectory and satellite image analyses, Asian dust is generated by a strong downwind associated with the upper trough from a stagnation wave due to development of the upper jet stream, and transport of Asian dust to Korea shows up behind a surface front related to the cut-off low (known as comma type cloud) in satellite images. In the WRF-SMOKE-CMAQ modeling to estimate the PM10 concentration, Wang et al.`s experimental formula was depicted well in the temporal and spatial distribution of Asian dusts, and the GOCART model was low in mean bias errors and root mean square errors. Also, in the vertical profile analysis of Asian dusts using Wang et al`s experimental formula, strong Asian dust with a concentration of more than for the period of March 31 to April 1, 2007 was transported under the boundary layer (about 1 km high), and weak Asian dust with a concentration of less than for the period of 16-17 March 2009 was transported above the boundary layer (about 1-3 km high). Furthermore, the difference between the CMAQ model and the CMAQ-MADRID model for the period of March 31 to April 1, 2007, in terms of PM10 concentration, was seen to be large in the East Asia area: the CMAQ-MADRID model showed the concentration to be about higher than the CMAQ model. In addition, the concentration removed by the cloud liquid phase mechanism within the CMAQ-MADRID model was shown in the maximum in the Eastern Asia area.

Estimation of Hourly Emission Flux of Asian Dust Using Empirical Formulas in the Source Area

The purpose of this study is to estimate hourly Asian dust emission flux in springtime by using the optimized Weather Research Forecasting model (WRF) in order to accurately predict the horizontal flux of Asian dusts. Asian dust emission flux using 5 empirical formulas such as US EPA, Park and Inn, Wang, The Goddard Chemistry Aerosol Radiation and Transport (GOCART) and Dust Entrainment and Deposition (DEAD) were calculated and compared by using classified land-use types and size distribution at various locations in China and Mongolia together with the hourly meteorological elements of the WRF model. As a result, the empirical formula in US EPA among them, which was considered the various conditions such as vegetation, soil type and terrain, was better than the other 4 empirical formulas. However, these formulas were adjusted hourly and vertically in time and space because there was different order and time resolution of dust emissions from original empirical formulas.

Intercomparison of Wind and Air Temperature Fields of Meteorological Model for Forecasting Air Quality in Seoul Metropolitan Area

The MM5, RAMS and WRF, meteorological models have provided the dynamical parameters as inputs to air quality model. A major content of this study is that significant characteristics of three models for high-ozone occurrence analyze for surface wind and air temperature fields and compare with observation data in Seoul metropolitan area. An analysis of air temperature field revealed that location of core in high temperature of MM5 and WRF differed from that of RAMS. MM5 and WRF indicated high temperature in Seoul but RAMS represented it on the outskirts of Seoul. MM5 and WRF were underestimated maximum temperature during daytime but RAMS simulated similar value with observation data. Surface wind field with three models, it was shown many differences at horizontal distribution of wind direction. RAMS indicated weak wind speed in land and strong sea breeze at coastal areas than MM5 and WRF. However wind speed simulated by three model were overestimated during both daytime and nighttime.

Verification and Estimation of the Contributed Concentration of CH 4 Emissions Using the WRF-CMAQ Model in Korea

The purpose of this study was to estimate the contributed concentration of each emission source to by verifying the simulated concentration of in the Korean peninsula, and then to compare the emission used to the simulation with that of a box model. We simulated the Weather Research Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model to estimate the mean concentration of during the period of April 1 to 22 August 2010 in the Korean peninsula. The emissions within the model were adopted by the anthropogenic emission inventory of both the EDGAR of the global emissions and the GHG-CAPSS of the green house gases in Korea, and by the global biogenic emission inventory of the MEGAN. These emission data were validated by comparing the modeling data with the concentration data measured at two different location, Ulnungdo and Anmyeondo in Korea. The contributed concentration of estimated from the domestic emission sources in verification of the modeling at Ulnungdo was represented in about 20%, which originated from sources such as stock farm products (8%), energy contribution and industrial processes (6%), wastes (5%), and biogenesis and landuse (1%) in the Korean peninsula. In addition, one that transported from China was about 9%, and the background concentration of was shown in about 70%. Furthermore, the emission estimated from a box model was similar to that of the WRF-CMAQ model.

An Estimation of Probable Precipitation and an Analysis of Its Return Period and Distributions in Busan

In this study, a statistical estimation of probable precipitation and an analysis of its return period in Busan were performed using long-term precipitation data (1973-2007) collected from the Busan Regional Meteorological Administration. These analyses were based on the method of probability weighted moments for parameter estimation, the goodness-of-fit test of chi-square (χ 2 ) and the probability plot correlation coefficient (PPCC), and the generalized logistics (GLO) for optimum probability distribution. Moreover, the spatial distributions with the determination of probable precipitation were also investigated using precipitation data observed at 15 Automatic Weather Stations (AWS) in the target area. The return periods for the probable precipitation of 245.2 and 280.6 mm/6 hr with GLO distributions in Busan were estimated to be about 100 and 200 years, respectively. In addition, the high probable precipitation for 1-, 3-, 6-, and 12-hour durations was mostly distributed around Dongrae-gu site, all coastal sites in Busan, Busanjin and Yangsan sites, and the southeastern coastal and Ungsang sites, respectively.

Asian Dust Transport during Blocking Episode Days over Korea

Asian dust(or yellow sand) occurs mainly in spring and occasionally in winter in east Asia, when the weather conditions are under an upper trough/cut-off low and surface high/low pressure system during blocking episode days associated with the stationary patterns of the upper level jet stream. The transport mechanism for Asian dust during the blocking episode days in spring 2001 was analyzed using the TOMS aerosol index and meteorological mesoscale model 5(MM5). Based on the E vector, an extension of an Eliassen-Palm flux, the blocking episode days were found to be associated with the development of an upper cut-off low and surface cyclones. Concurrently, the occurrence of dust storms was also determined by strong cold advection at the rear of a jet streak, which exhibited a maximum wind speed within the upper jet stream. As such, the transport mechanism for Asian dust from China was due to advection of the isentropic potential vorticity(IPV) and isentropic surfaces associated with tropopause folding. The transport heights for Asian dust during the blocking episode days were found to be associated with the distribution of the isentropes below the IPV At the same time, lee waves propagated by topography affected the downward motion and blocking of Asian dust in China. The Asian dust transported from the dust source regions was deposited by fallout and rain-out with a reinforcing frontogenesis within a surface cyclone, as determined from satellite images using TOMS and GMS5. Accordingly, these results emphasize the importance of forecasting jet streaks, the IPV, and isentropes with geopotential heights in east Asia.

An Estimation of Mean Background Concentrations of Greenhouse Gases Observed on Ulleungdo

Mean background concentrations of greenhouse gases such as CO2 and CH4 were estimated on Ulleungdo using PICARRO Cavity Ring-Down Spectroscopy (CRDS) analyzer. To improve the accuracy of CO2 and CH4 concentrations, a standardized QA · QC (Quality Assurance · Quality Control) procedure was employed with three steps: 1) the inspection procedure of physical limitation (e.g. the exclusion of data corresponding to the number of data of ≤50%) for hourly mean values, 2) a stage inspection (e.g. the use of data corresponding to ≥15 observations per day) for daily mean values, and 3) a fast fourier transform (FFT) analysis using curve-fitting methods for the investigation of climatic characteristics. The monthly mean concentrations of CO2 and CH4 derived from three-step QA · QC procedure were then compared with those observed at Anmyundo (Korea) and Ryori (Japan). Overall, the error of mean CO2 and CH4 concentrations estimated in this study distinctly decreased. However, in comparison with their concentrations monitored at Ryori, the CO2 concentration at estimated at Ulleungdo is soemwhat lower than that of Anmyundo due to the missing data, which is statistically significant. On the other hand, the former has a statistically significant higher value of CH4 that of the latter.

Case Analysis on High Concentration of SO 2 and Review on Its Reduction Policy in the Ulsan Metropolitan Area since 2001

【Until comparatively lately, the annual time series of the

A numerical study on indicators of long-range transport potential for anthropogenic particulate matters over northeast Asia

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