• 한국환경과학회지
• /
• 제25권3호
• /
• pp.345-359
• /
• 2016

This study analyze the synoptic meteorological cause of rainfall, rainfall intensity, drop size distribution(DSD), fall velocity and oblateness measured by the 2D-Video distrometer(2DVD) by comparing two cases which are heavy rainfall event case and a case that is not classified as heavy rainfall but having more than $30mm\;h^{-1}$ rainrate in July, 2014 at Gimhae region. As a results; Over the high pressure edge area where strong upward motion exists, the convective rain type occurred and near the changma front, convective and frontal rainfall combined rain type occurred. Therefore, rainrate varies based on the synoptic meteorological condition. The most rain drop distribution appeared in the raindrops with diameters between 0.4 mm and 0.6 mm and large particles appeared for the convective rain type since strong upward motion provide favorable conditions for the drops to grow by colliding and merging so the drop size distribution varies based on the location or rainfall types. The rainfall phases is mainly rain and as the diameter of the raindrop increase the fall velocity increase and oblateness decrease. The equation proposed based on the 2DVD tends to underestimated both fall velocity and oblateness compared with observation. Since these varies based on the rainfall characteristics of the observation location, standard equation for fall velocity and oblateness fit for Gimhae area can be developed by continuous observation and data collection hereafter.

• 한국대기환경학회지
• /
• 제29권3호
• /
• pp.297-306
• /
• 2013

This study used long-term air and weather data from 2000 to 2009 as raw data sets to develop regression models in order to estimate precipitation scavenging contributions of ambient $PM_{10}$ and $NO_2$ in Korea. The data were initially analyzed to calculate scavenging ratio (SR), defined as the removal efficiency for $PM_{10}$ and $NO_2$ by actual precipitation. Next, the effective scavenging contributions (ESC) with considering precipitation probability density were calculated for each sector of precipitation range. Finally, the empirical regression equations for the two air pollutants were separately developed, and then the equations were applied to test the model validity with the raw data sets of 2010 and 2011, which were not involved in the modeling process. The results showed that the predicted $PM_{10}$ ESC by the model was 23.8% and the observed $PM_{10}$ ESCs were 23.6% in 2010 and 24.0% in 2011, respectively. As for $NO_2$, the predicted ESC by the model was 16.3% and the observed ESCs were 16.4% in 2010 and 16.6% in 2011, respectively. Thus the developed regression models fitted quite well the actual scavenging contribution for both ambient $PM_{10}$ and $NO_2$. The models can then be used as a good tool to quantitatively apportion the natural and anthropogenic sink contribution in Korea. However, to apply the models for far future, the precipitation probability density function (PPDF) as a weather variable in the model equations must be renewed periodically to increase prediction accuracy and reliability. Further, in order to apply the models in a specific local area, it is recommended that the long-term oriented local PPDF should be inserted in the models.

• 한국대기환경학회지
• /
• 제22권4호
• /
• pp.487-498
• /
• 2006

Total 438 precipitation samples were collected in Jeju City between 1997 and 2005, and their major ionic components were analyzed. The comparison tests using ion balance, electric conductivity and acid fraction were performed. It was found their correlation coefficients were in the range of 0.977$\sim$0.994, indicating the good quality of collected dam. The volume-weighted mean pH and electric conductivity were 4.8 and 23.0 $\mu$S/cm, respectively. with the ionic strength of 0.23$\pm$0.20 mM. The marine ($Na^+$, $Mg^{2+}$, and $CI^-$), anthropogenic (nss$SO_4{2-}$, $NO_3^-$, and $NH_4^+$) and soil (nss-$Ca^{2+}$) species have contributed to the ionic components of precipitation samples with 43$\sim$74%, 16$\sim$37% and $\sim$5%, respectively. The seasonal variations of $NO_3^-$ and nss-$SO_4^{2-}$ showed a distinct seasonality with higher concentrations in winter than summer, indicating an increase of fossil fuel consumption and a possibility of long-range transport of those pollutants from continental area along the dominant winter westerly. The levels of nss-$Ca^{2+}$ also were appeared the highest in winter and increased comparatively in spring season. possibly due to the soil influences including the Asian Dust. The acidification contribution of nss-$SO_4^{2-}$ and $NO_3^-$ showed 88$\sim$96%, and the free acidity was in the range of 6.0$\sim$40.1%. Interestingly, the backward trajectories for the case of upper 10% nss-$SO_4^{2-}$ and $NO_3^-$ levels have passed through the China continent before their arrival to Jeju. The precipitation of pH below 4.5 has been occurred frequently when the trajectory's path lied over the China continents. On the other hand, the air masses from the North Pacific area were characterized by lower 10% of nss-$SO_4^{2-}$- and $NO_3^-$ concentration, which demonstrated that air mass from the North Pacific was the cleanest among air masses moved to Jeju.

• 한국대기환경학회지
• /
• 제22권4호
• /
• pp.459-467
• /
• 2006

This study was carried out to characteristics and distributions of acid deposition in Korea. Precipitation was collected by acid deposition monitoring networks and analyzed for pH, conductivity, and following major ionic components $SO_4^{2-}$, $CI^-$, $NO_3^-$, $NH_4^+$, $Na^+$, $K^+$, $Ca^{2+}$, $Mg{2+}$. During the investigation period, Volume weighted annual mean pH of precipitation in Korea is 4.8, showing slightly acidic level. The amount of rainfall in the range of pH 5.1$\sim$5.5 charged approximately 28% of annual precipitation,23.4% in pH 4.6$\sim$5.0, and contributed 16.2% under pH 4.5. Among seasons, alkaline precipitation has occurred more often in spring, meanwhile acidic precipitation in which pH is under 4.5 has frequently occurred in autumn. Volume weighted annual mean concentrations of $SO_4^{2-}$, $NO_3^-$, $CI^-$ are 2.558 mg/L, 1.590 mg/L, 1.286 mg/L respectively, and provided that $SO_4^{2-}$, is the major contributor, followed by $NO_3^-$, $CI^-$. In case of cation, annual mean concentration for $NH_4^+$, $Na^+$, $K^+$, $Ca^{2+}$, $Mg{2+}$, $H^+$ are 0.693 mg/L, 0.528 mg/L, 0.439 mg/L, 0.455 mg/L, 0.089 mg/L,0.015 mg/L, and $NH_4$ were decided as the main contributor, followed by $Na^+$, $K^+$, $Ca^{2+}$, $Mg{2+}$, $H^+$. Annual wet deposition rate for sulfate, nitrate and ammonia are $3.316gm^{-2}yr^{-1}$, $2.057gm^{-2}yr{-1}$, $0.894gm^{-2}yr{-1}$, respectively, and it was founded that the deposition flux in summer contributes about 38.42% to 67.62% to total deposition.

• 한국대기환경학회지
• /
• 제13권5호
• /
• pp.371-381
• /
• 1997

Precipitation sampls were collected in Chonju-city during October 1994 to September 1995 and were analysed for major ions (N $a^{+}$, $K^{+}$, $Ca^{2+}$, $Mg^{2+}$, C $l^{[-10]}$ , NO/$_3$, S $O_4$$^{2-}$) and trace metals (Al, Cd, Ni, Pb, Sr, Zn) in addition to pH, in order to understand the chemical characteristics of acid rain and to estimate the origin of the determined ions. Most rain showed a neutral or alkaline character, and only 35% had a pH lower than 5.6. S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ are identified as the primary contributors to precipitation acidity in this region. Neutralization of precipitation acidity occurs as a result of the dissolution of alkaline compounds containing $Ca^{2+}$, $Mg^{2+}$ and $K^{+}$. S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ precipitation concentrations exhibit a seasonal pattern in which higher concentrations are observed during spring months and lower concentrations during summer months. However, the seasonal behavior of $H^{+}$ concentrations differs from this pattern, in that the highest concentrations occur during autumn months, owing to the different influence of neutralization processes. In all rain, S $O_4$$^{2-}$ concentration exceeded NO/$_3$$^{[-10]}$ concentration. The contribution of maritime sources to the total S $O_4$$^{2-}$ concentration was very low or negligible. For rain strongly affacted by yellow sand, $Ca^{2+}$, $Mg^{2+}$ and $K^{+}$ ions show a sharp increase in concentration, reflecting the increased amount of dust and soil suspended in atmosphere. At the same time, S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ concentrations are at their highest levels while $H^{+}$ values are not comparably elevated, presumably beacause much of the acidity has been neutralized by alkaline substances. The seasonal variance of trace metal concentrations in rainwater is similar to that of major cations. The annual wet flux of acidic pollutants and trace metals wat calculated to be as follows: N $O_3$$^{[-10]}$ ; 2.32 g/$m^2$, S $O_4$$^{2-}$, 5.34 g/$m^2$, Al; 6.30 mg/$m^2$, Cd; 0.62 mg/$m^2$, Ni; 4.08 mg/$m^2$, Pb: 9.76 mg/$m^2$, Sr; 5.94 mg/$m^2$, Zn; 111 mg/$m^2$./$m^2$.

• 한국대기환경학회지
• /
• 제7권3호
• /
• pp.145-149
• /
• 1991

A one dimensiional cumulus cloud model has been developed for the investigation of temporal and altitudinal variation of trace gases and the wet deposition rates of sulfate for different simulation conditions. The results show that the dynamic field, liquid mixing ratios and the solubility of trace gases affect the distribution of trace gases and the droplet pH. Temporal variation of the predicted surface precipitation and sulfate deposition rates agree well with the field data.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
• /
• pp.275-278
• /
• 2002

In this study, to increase removal efficiency of traditional electrokinetic treatment and to reduce contaminant load of wastewater that discharged through cathode compartment, enhanced electrode compartments were investigated. Hydroxide precipitation near the cathode electrode that encounter during traditional electrokinetic treatment were prevented by enhanced electrokinetic remediation test with newly invented electrode compartment. And heavy metal concentration in wastewater showed 0 ppm thus, additive post-treatment cost were not needed.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
• /
• pp.279-282
• /
• 2002

In this study, mine tailing buffer zone in cathode was used to overcome precipitation of heavy metals that reducing remediation efficiency during electrokinetic remediation. Test results showed that heavy metal transportation affected by initial soil pH which was verified through traditional test and enhanced test with two type of soils. With mine tailing enhanced method 39% of extraction rate was achieved in surface soil and significant transportation trend was observed in deep soil.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
• /
• pp.47-48
• /
• 2005

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2002년도 추계학술발표회
• /
• pp.152-155
• /
• 2002

강수의 중수소과잉값(d-값)은 바다와 대기와의 접촉 과정에 의하여 일차적으로 지배되지만 빗방울의 부분증발, 응축온도의 변화 또는 d-값이 다른 수증기와의 혼합에 의하여 이차적으로 변화될 수 있다. 이 연구에서는 동북아시아 강수의 d-값 변화에 영향을 미치는 요인들에 대하여 논의하였다. 아울러 제주도 한라산에 내리는 강수의 d-값이 고도가 높아짐에 따라 커지는 원인에 대하여 검토하였다.