• Atmosphere
• /
• v.33 no.5
• /
• pp.457-475
• /
• 2023

Accurately predicting localized heavy rainfall is challenging without high-resolution mesoscale cloud information in the numerical model's initial field, as precipitation intensity and amount vary significantly across regions. In the Korean Peninsula, the radar observation network covers the entire country, providing high-resolution data on hydrometeors which is suitable for data assimilation (DA). During the pre-processing stage, radar reflectivity is classified into hydrometeors (e.g., rain, snow, graupel) using the background temperature field. The mixing ratio of each hydrometeor is converted and inputted into a numerical model. Moreover, assimilating saturated water vapor mixing ratio and decomposing radar radial velocity into a three-dimensional wind vector improves the atmospheric dynamic field. This study presents radar DA experiments using a numerical prediction model to enhance the wind, water vapor, and hydrometeor mixing ratio information. The impact of radar DA on precipitation prediction is analyzed separately for each radar component. Assimilating radial velocity improves the dynamic field, while assimilating hydrometeor mixing ratio reduces the spin-up period in cloud microphysical processes, simulating initial precipitation growth. Assimilating water vapor mixing ratio further captures a moist atmospheric environment, maintaining continuous growth of hydrometeors, resulting in concentrated heavy rainfall. Overall, the radar DA experiment showed a 32.78% improvement in precipitation forecast accuracy compared to experiments without DA across four cases. Further research in related fields is necessary to improve predictions of mesoscale heavy rainfall in South Korea, mitigating its impact on human life and property.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.2
• /
• pp.161-174
• /
• 2014

The methodology report '2006 IPCC Guidelines for National Greenhouse Gas Inventories' shows higher tier method can be a good practice, which uses country-specific or plant-specific data when calculating greenhouse gas emissions by country. We review the methodology report to present principles of using plant-level data and also examine examples of using plant-level data in chemical and metal industry in 20 countries for the purpose of quality improvement of national greenhouse gas inventories. We propose that Korea consider utilizing plant-level data, as reported according to 'Greenhouse gas and Energy Target Management Scheme', in the following order as a preference. First, the data can be utilized for quality control of Korea's own parameters, when Tier 2 method is adopted and bottom-up approach is not applicable. Second, both plant-level data and IPCC default data can be used together, combining Tier 1 method with Tier 3 method. Third, we can also use acquired plant-level data and country specific parameters, combining Tier 2 method with Tier 3 method. Fourth, if the plant-level data involves all categories of emissions and the data is proven to be representative, we can apply Tier 3 method. In this case, we still need to examine the data to check its reliability by a consistent framework, including appropriate quality control.

• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.E2
• /
• pp.57-65
• /
• 2007

In Korea, there is a general lack of information available on air emissions from industry. The reasons for this include the lack of regulatory requirements for emission monitoring, limited information on specific industries, and difficulties in monitoring certain sources. This paper presents the first detailed air pollutant emission factors from composite wood product manufacturing in Korea. This study introduced emission factors for wood-based panels such as plywood, particle board (PB), and medium density fiberboard (MDF). The emission factors of particulate matters (PM) and hazardous air pollutants (HAPs) from MDF were higher than that from other wood products. The concentration of total volatile organic compounds (TVOCs) for hot press from wood-based panels was higher than drying or gluing processes. Emissions data from NPIP were compared to the data from the suggested emission factors in this study and the US EPA's. The data from our emission factors were closer to the observed results than the data using the US EPA's emission factor.

• Journal of Environmental Science International
• /
• v.17 no.10
• /
• pp.1093-1109
• /
• 2008

This paper aims to provide a fundamental basis for the improvement and verification of existing wind chill temperature index through the observation of skin temperature change of human body with air temperature and wind speed. For this, we control air temperature $5^{\circ}C$ interval from $0^{\circ}C$ to $-20^{\circ}C$ and classify wind speed by 0, 2, 6 and 8 m $s^{-1}$ respectively. The results are as follows; At each combination of air temperature and wind speed, the reduction rate of the mean skin temperature are different. When our body is exposed to the atmosphere, the mean skin temperature decreases at an exponential rate. The duration of the steady state is more than one hour, while it decreases with strong wind speed. Among 4 sites on a face, the skin temperature of forehead is the highest, followed by one of chin, left cheek, right cheek in orders. Especially, since the skin temperature of right cheek is the lowest, we think that it is suitable to use the data set of the right cheek skin temperature for the development of a Korea wind chill temperature index as a worst case.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.4
• /
• pp.264-274
• /
• 2009

Concentration of Air Quality Models (CMAQ) has a deep connection with emissions and wind fields. In particular the wind field is highly affected by local topography and plays an important role in transport and dispersion of contaminants from the pollution sources. The purpose of this study is to examine the impact of interpolation on Air quality model. This study was designed to evaluate enhancement of MM5 and CMAQ predictions by using Four Dimensional Data Assimilation (FDDA), the SONDE data and the national meteorological station and the MODerate resolution Imaging Spectroradiometer (MODIS). The alternative meteorological fields predicted with and without MODIS data were used to simulate spatial and temporal variations of ozone in combined with CMAQ on June 2006. The result of this study indicated that data assimilation using MODIS data provided an attractive method for generating realistic meteorological fields and dispersion fields of ozone in the Korea peninsular, because MODIS data in 10 km domain are grid horizontally and vertically. In order to ensure the success of Air quality model, it is necessary to FDDA using MODIS data.

• Journal of Korean Society for Atmospheric Environment
• /
• v.21 no.5
• /
• pp.537-545
• /
• 2005

A new dispersion model for dense gas is constructed in the Lagrangian framework. Prediction of concentration by the proposed model is compared with measure data obtained in the experiment conducted in Thorney Island in 1984. Two major effects of dense gas dispersion, gravity slumping and stratification effect, are successfully incorporated into LDM (Lagrangian dense gas model). Entrainment effect is naturally modelled by introducing stochastic dispersion model with the effect of turbulence suppression by stratification. Not only various releasing conditions but also complex terrain can be extended to, although proposed model is appropriate for flat terrain.

• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.4
• /
• pp.317-326
• /
• 2000

Carbonyl compounds have been measured in downtown Seoul for September 1998 using 2-series impinger method. Average concentration (ppbv) of carbonyl compounds were 12.66$\pm$5.77 HCHO, 12.05$\pm$4.86 CH3CHO and 7.92$\pm$2.63 CH3CHCH3 These compounds were the most abundant carbonyl,. They showed maximum concentration during the daytime when photochemical activity was very strong minimum concentration were usually showed during the night and early morning. Comparison of diurnal variation of carbonyl compounds with the concentration of O3, NMHC, CO and meteorological data indicated that primary and secondary sources contributed the observed carbonyl compounds. Photochemical Formation Rate(PFR) of carbonyl compounds dur-ing the sampling periods were 61% HCHO, 85% CH3CHO, 85% CH3CHO, 71% CH3COCH3.

• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.1
• /
• pp.59-65
• /
• 2002

The application of local air circulation models in the field of air pollution research has become more and more popular with increasing demands of detailed wind data for obtaining precise information on spatial and temporal variations. However the prediction of air circulation near the surface is generally not a simple task because of intricate interactions between surface and air. Particularly in Korea, many areas are mountainous with a complicated shoreline. Because considerable errors could be introduced into the model predictions, it is necessary to confirm their feasibility by comparing model predictions with observations. In this paper, the results from the evaluation of model predictions in selected publications in Korea as well as their procedures were reviewed. Various aspects of errors in the model predictions. such as possible sources, vulnerable conditions, and reduction methods, were discussed.

• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.5
• /
• pp.411-420
• /
• 1998

To estimate the dispersion coefficients in a coastal area with complex topography, several schemes using empirical equations expressed with and in lateral and vertical directions, respectively have been examined. Estimation results using these equations and meteorological data obtained from SODAR system were compared' with previously measured dispersion coefficients in other coastal areas. Validations of estimation results have been performed by comparing the measured concentrations with predicted ones empolying in Boryung coastal area. Important conclusions were drawn as follows; (1) Variations of lateral and vertical wind direction revealed different height dependency in upper and lower mixed boundary layer. (2) Because of turbulent constraint effect by large water body in a coastal region, the lateral and the vertical dispersion coefficients were smaller than those of P-G system. (3) As a result of examining the performance measure of these schemes through checking of coincidence between measured and predicted concentrations, vertical dispersion coefficients were smaller than those of P-G system, and the Cramer scheme was found to be more appropriate rather than others in the coastal area surrounding Boryung power plant.

• Journal of Korean Society for Atmospheric Environment
• /
• v.15 no.1
• /
• pp.13-22
• /
• 1999

This study is carried out to investigate the chemical composition of atmospheric deposition in Cheju Island, Korea. For this purpose, dustfall matter samples are collected by dust jar from August, 1995 to July, 1996 at five sampling sites and total suspended particulate matters (TSP) and rain are also collected at one site from October, 1995 to July, 1996. All the samples collected are analyzed, and then the information of the 19 chemical species and deposition amount of each species is obtained. These data are used to determine the regional trends in dustfall chemistry and deposition, and compare the characteristics of chemical compositions between dustfall, TSP and rainwater.