Heekwan Lee

Estimation of the effective zone of sea/land breeze in a coastal area

Abstract Sea/Land breezes that are generated by mesoscale–thermally induced winds due to the different heat capacities of the land and the sea water along coastal lines, have been important issues for coastal air environments due to their significant role for the transport and diffusion of air pollution. The meso–scale modeling tool, A2C flow/A2C t&d (A2C represents Atmospheric to Computational Fluid Dynamics and t&d represents transport and diffusion) was applied to simulate the pure Sea/Land breeze mechanism. Geographic data of resolution USGS 30” were used for setting the modeling domain with a size of 248 km × 224 km and it covers both sea and land area of the west coast of Korean peninsula. Modeling period was selected in late July for typical summer conditions. Then the initial and boundary conditions were set and the modeling was carried out. Strong land breeze was observed around 6 a.m., just before sunrise and it was neutralized between 9 a.m.–10 a.m. then the sea breeze started. The sea breeze achieved its maximum strength around 3 p.m. when the temperature difference between surface and air above 10 m was about 15 K. Subsequently, the energy of sea breeze decreased with the decrease of solar radiation with time and again reached to transition period between 8 p.m.–10 p.m. Then the vortex of breeze was generated again along the coastal line, and enlarged its buffer zone with the increase in temperature and pressure differences between the land and sea surfaces. The vortex depth of 350 m was obtained in the early morning and about 1 000 m around 3 p.m. for the modeling period. The maximum speeds of the sea and land breezes were approximately 2.5 m/s and 1.5 m/s, respectively along the coastal line. The penetration lengths of sea and land breezes were approximately 25–30 km and 15–20km, respectively. The suction lengths of sea and land breezes were about 15–20 km and 10–15 km, respectively.

The Determination of Diffusion and Partition Coefficients of PUF

The diffusion and partition coefficients of polyurethane foam (PUF) are estimated using a microbalance experiment and small chamber test. The microbalance is used to measure sorption/desorption kinetics and equilibrium data. When the diffusion condition is controlled in the chamber of the sample, interactions between volatile organic compounds (VOCs) and PUF can lead to the estimation of a relatively homogenous rate of mass transfer in the interiors and surfaces of PUF. The estimates of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) are shown to be independent of the concentrations of VOCs. This approach, if applied to a diffusion-controlled or physically-based model, can facilitate more precise prediction of their source/sink behavior. Although further research and more rigorous validation is needed, an emission model applied with the diffusion and partition coefficients from this research holds promise for the improvement of reliability in predicting the behavior of VOCs emitted from porous building materials by D and K.

A Study on the Calculation of GHG Emissions from General Ships by Tier3 Method

Abstract : In this study, the emissions of GHG from general ships were calculated by Tier1 method based on the fuel consumption, and by Tier3 method based on the activities data such as power and SFOC of each engine, sailing characteristics (e.g. time and load factor, etc.) considering the ship type. In 2009, the emissions of GHG by Tier1 and Tier3 method were appeared 28.27 mega-ton CO 2eq and 30.81 mega-ton CO 2eq . The emissions by Tier3 were slightly more than those by Tier1. We found that the values of the sailing characteristics for surveyed data are overestimated slightly. In the near future, more detailed researches for sailing characteristics considering ship types would be needed for sailing, anchoring, and berthing condition, etc. Key Words : GHG (Greenhouse gas), Climate Change, General Ship, IMO, IPCC 요약: 본 연구에서는 일반선박으로부터 배출되는 온실가스 배출량을 연료소비를 근거로 한 배출 (Tier1)과 선종을 고려한 출력, SFOC, 운항특성(시간과 부하율 등) 등을 근거로 한 활동도에 의한 배출(Tier3)로 구분하여 산정하고 비교분석하였다. 2009년도 기준으로 배출량을 산정한 결과, Tier1 방법에 의한 배출량은 총 28,273천톤 CO