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In this present study, we quantified the effect on retrieval from the Ozone Monitoring Instrument (OMI) measurement. The difference between OMI-Total Ozone Mapping Spectrometer (TOMS) and OMI-Differential Optical Absorption Spectrometer (DOAS) total is calculated in high volcanic plume on several volcanic eruptions (Anatahan, La Cumbre, Sierra Negra, and Piton) from 2005 through 2008. There is a certain correlation () between the difference and in volcanic plumes and the significant difference close to 100 DU. The high condition found to affect TOMS retrieval significantly due to a strong absorption at the TOMS retrieval wavelengths. Besides, we calculated the difference against various levels. There is the considerable difference (average = 32.9 DU; standard deviation = 13.5 DU) in the high condition (). We also found that the rate of change in the difference per 1.0 DU change in middle troposphere (TRM) and upper troposphere and stratosphere (STL) columns are 3.9 DU and 4.9 DU, respectively.

A Multiple Regression Method (MRM) is used for the first time with Ozone MonitoringInstrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) data to estimateformaldehyde (HCHO) Vertical Column Density (VCD). For a 3.5-year period from January 2005 throughJuly 2008, HCHO VCD estimation is investigated in cities over Asia in two categorized areas: (1) Majorcities in Northeast Asia (Beijing, Seoul, and Tokyo), (2) Major cities in Southeast Asia (New Delhi, Dhaka,and Bangkok). In the Major cities in Northeast Asia, there are good agreements between HCHO estimatedby the multiple linear regression method (HCHO MRM ) and HCHO measured by OMI (HCHO OMI ) (0.78

In this present paper, we, for the first time, calculated SO2 inflow from China to Korea peninsula based on OMI SO2 products and HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) backward trajectory calculations. The major factors used to estimate SO2 flux are long range transported SO2 concentration, transport speed of air mass, and thickness of transported air mass layer. The mean and maximum SO2 fluxes are estimated to be 0.81 and 2.11 g·m-2·h-1, respectively based on OMI products while, those of SO2 fluxes are 0.50 and 1.18 g·m-2·h-1 respectively using insitu data obtained at the surface. For most cases, larger SO2 inflow values were found at the surface than those estimated for the air mass layer which extends from surface up to 1.5 km. However, increased transport speed of air mass leads to the enhanced SO2 flux at the altitude up to 1.5 km at the receptor sites. Additionally, we calculate uncertainties of SO2 flux using error propagation method.

Total Vertical Column Density (VCD) of NO 2, a key component in air quality and tropospheric chemistry was measured using a ground-based instrument, Pandora, in Seoul from March 2012 to October 2013. The NO 2 measurements using Pandora were compared with those obtained by satellite remote sensing from Ozone Monitoring Instrument (OMI) where the intercomparison characteristics were analyzed as a function of measurement geometry, cloud amount and aerosol loading. The negative biases of the OMI NO 2 VCD were larger when cloud amount and Aerosol Optical Depth (AOD) were higher. The correlation coefficient between NO 2 VCDs from Pandora and OMI was 0.53 for the entire measurement period, whereas the correlation coefficient between the two was 0.74 when the cloud amount and AOD were low (cloud amount

The comparison between CO 2 volume mixing ratios observed by GOSAT and TCCON from September 2009 through November 2012 was performed at Tsukuba and Saga, two downwind sites in East Asia. The temporal trends of CO 2 values obtained from GOSAT show good agreement with those observed by TCCON at these two by the TCCON, showing a coefficient of determination (R 2 ) of 0.65. The regression slop we obtained was 0.92, showing a small bias of GOSAT CO 2 values compared to those observed by TCCON. However, we found the higher correlation in fall and winter than that in spring and summer. The CO 2 volume mixing ratios observ sites. The CO 2 volume mixing ratios observed by GOSAT are also in good agreement with those measured ed by GOSAT are in good agreement with those measured by the TCCON at those two sites in fall and winter, showing a coefficient of determination (R 2 ) of 0.66 where as the correlation of determination obtained between GOSAT and TCCON was only 0.27 in spring and summer.

This present study describes an application of UV scanning spectrometer O 4 data for retrieval of aerosol vertical profiles in Seoul during the measurement period that includes two Asian dust event days. The results show large variations of aerosol load in vertical and temporal scales. Large variations in aerosol were observed at 1 km in height during the daytime in the measurement period when the Asian dust events took place. The aerosol load, however, was found to be largest at the surface compared to those retrieved at the higher atmospheric layers. The results also clearly identified the diurnal patterns of aerosol vertical distributions. The aerosol load was high in the morning and noon whereas it was low in the afternoon. This study demonstrates that UV scanning spectrometer observations of the oxygen dimer can serve as a potential method for determination of atmospheric aerosol vertical distributions and optical properties.

NO2 vertical column densities were retrieved via ground based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements for the first time for 6 months over the spring season in 2007 and 2008 in Seoul, one the megacities in the Northeast Asia. The retrieved NO2 vertical column densities were compared with those obtained from space borneOzone Monitoring Instrument (OMI). Over the entire measurement period, the NO2 vertical column densities measured by MAX-DOAS ranged from 1.0×1015 molec·cm_2 to 6.0×1016 molec·cm_2 while those obtained by OMI ranged 1.0×1015 molec·cm_2 to 7.0×1016 molec·cm_2. The correlation coefficient between NO2 vertical column densities obtained from MAX-DOAS and OMI is 0.73 for the entire measurement period whereas the correlation coefficient of 0.85 is found for the dates under the clear sky condition. The cloudy condition is thought to play a major role in increase in uncertainty of the retrieved OMI NO2 vertical column densities since air mass factor may induce high uncertainty due to the lack of cloud and aerosol vertical distribution information.

The diurnal variation in pollen vertical distributions in the atmosphere was observed by a surface-based lidar remote sensing technique. Aerosol extinction coefficient and depolarization ratio at 532 nm were obtained from lidar measurements in spring (4th May - 2nd June) 2009 at Gwangju Institute of Science & Technology (GIST) located in Gwangju, Korea (35.15°E, 126.53°N). Unusual variations of depolarization ratio were observed for six days from 4th to 9th May. Depolarization ratios varied from 0.08 to 0.14 were detected at the low altitude in the morning. The altitude with those high depolarization ratios was increased up to 1.5 - 2.0 km at the time interval between 12:00 and 14:00 LT and then decreased. The temporal variations in high values of depolarization ratios from lidar measurements show good agreement in patterns with the sampled pollen concentrations measured using the Burkard trap sampler. This study demonstrates that the pollen distribution data obtained by lidar measurements can be a useful tool for investigating spatial and temporal characteristic of pollen particles.

Air-borne pollen, biogenically created aerosol particle, influences Earth's radiative balance, visibility impairment, and human health. The importance of pollens has resulted in numerous experimental studies aimed at characterizing their dispersion and transport, as well as health effects. There is, however, limited scientific information concerning the optical properties of airborne pollen particles contributing to total ambient aerosols. In this study, for the first time, optical characteristics of pollen such as aerosol backscattering coefficient, aerosol extinction coefficient, and depolarization ratio at 532 nm and their effect to the atmospheric aerosol were studied by lidar remotes sensing technique. Dual-Lidar observations were carried out at the Gwangju Institute of Science & Technology (GIST) located in Gwagnju, Korea (35.15Š E, 126.53Š N) for a spring pollen event from 5 to 7 May 2009. The pollen concentration was measured at the rooftop of Gwangju Bohoon hospital where the building is located 1.0 km apart from lidar site by using Burkard trap sampler. During intensive observation period, high pollen concentration was detected as 1360, 2696, and 1952 m _ 3 in 5, 6, and 7 May, and increased lidar return signal below 1.5km altitude. Pollen optical depth retrieved from depolarization ratio was 0.036, 0.021, and 0.019 in 5, 6, and 7 May, respectively. Pollen particles mainly detected in daytime resulting increased aerosol optical depth and decrease of Angstrom exponent.