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Improvement of OMI ozone profile retrievals by simultaneously fitting polar mesospheric clouds
Bak, Juseon,Liu, Xiong,Kim, Jae H.,Deland, Matthew T.,Chance, Kelly Copernicus GmbH 2016 Atmospheric measurement techniques Vol.9 No.9
<P><p><strong>Abstract.</strong> The presence of polar mesospheric clouds (PMCs) at summer high latitudes could affect the retrieval of ozone profiles using backscattered ultraviolet (UV) measurements. PMC-induced errors in ozone profile retrievals from Ozone Monitoring Instrument (OMI) backscattered UV measurements are investigated through comparisons with Microwave Limb Sounder (MLS) ozone measurements. This comparison demonstrates that the presence of PMCs leads to systematic biases for pressures smaller than 6<span class='thinspace'></span>hPa; the biases increase from ∼ −2<span class='thinspace'></span>% at 2<span class='thinspace'></span>hPa to ∼ −20<span class='thinspace'></span>% at 0.5<span class='thinspace'></span>hPa on average and are significantly correlated with brightness of PMCs. Sensitivity studies show that the radiance sensitivity to PMCs strongly depends on wavelength, increasing by a factor of ∼ <span class='thinspace'></span>4 from 300 to 265<span class='thinspace'></span>nm. It also strongly depends on the PMC scattering, thus depending on viewing geometry. The optimal estimation-based retrieval sensitivity analysis shows that PMCs located at 80-85<span class='thinspace'></span>km have the greatest effect on ozone retrievals at ∼ <span class='thinspace'></span>0.2<span class='thinspace'></span>hPa ( ∼ <span class='thinspace'></span>60<span class='thinspace'></span>km), where the retrieval errors range from −2.5<span class='thinspace'></span>% with PMC vertical optical depth (POD) of 10<sup>−4</sup> to −20<span class='thinspace'></span>% with 10<sup>−3</sup> POD at backscattering angles. The impacts increase by a factor of ∼ <span class='thinspace'></span>5 at forward-scattering angles due to stronger PMC sensitivities. To reduce the interference of PMCs on ozone retrievals, we perform simultaneous retrievals of POD and ozone with a loose constraint of 10<sup>−3</sup> for POD, which results in retrieval errors of 1-4 × 10<sup>−4</sup>. It is demonstrated that the negative bias of OMI ozone retrievals relative to MLS can be improved by including the PMC in the forward-model calculation and retrieval.</p> </P>
기상 입력장 오차에 대한 자외선 오존 프로파일 산출 알고리즘 민감도 분석
신대근 ( Daegeun Shin ),박주선 ( Juseon Bak ),김재환 ( Jae Hwan Kim ) 대한원격탐사학회 2018 大韓遠隔探査學會誌 Vol.34 No.3
The accurate radiative transfer model simulation is essential for an accurate ozone profile retrieval using optimal estimation from backscattered ultraviolet (BUV) measurement. The input parameters of the radiative transfer model are the main factors that determine the model accuracy. In particular, meteorological parameters such as temperature and surface pressure have a direct effect on simulating radiation spectrum as a component for calculating ozone absorption cross section and Rayleigh scattering. Hence, a sensitivity of UV ozone profile retrievals to these parameters has been investigated using radiative transfer model. The surface pressure shows an average error within 100 hPa in the daily / monthly climatological data based on the numerical weather prediction model, and the calculated ozone retrieval error is less than 0.2 DU for each layer. On the other hand, the temperature shows an error of 1- 7K depending on the observation station and altitude for the same daily / monthly climatological data, and the calculated ozone retrieval error is about 4 DU for each layer. These results can help to understand the obtained vertical ozone information from satellite. In addition, they are expected to be used effectively in selecting the meteorological input data and establishing the system design direction in the process of applying the algorithm to satellite operation.
정지궤도 위성 대류권 오존 관측 자료를 이용한 대류권 이동벡터 산출 가능성 연구
신대근,김소명,박주선,백강현,홍성재,김재환,Shin, Daegeun,Kim, Somyoung,Bak, Juseon,Baek, Kanghyun,Hong, Sungjae,Kim, Jaehwan 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6
The tropospheric ozone is a pollutant that causes a great deal of damage to humans and ecosystems worldwide. In the event that ozone moves downwind from its source, a localized problem becomes a regional and global problem. To enhance ozone monitoring efficiency, geostationary satellites with continuous diurnal observations have been developed. The objective of this study is to derive the Tropospheric Ozone Movement Vector (TOMV) by employing continuous observations of tropospheric ozone from geostationary satellites for the first time in the world. In the absence of Geostationary Environmental Monitoring Satellite (GEMS) tropospheric ozone observation data, the GEOS-Chem model calculated values were used as synthetic data. Comparing TOMV with GEOS-Chem, the TOMV algorithm overestimated wind speed, but it correctly calculated wind direction represented by pollution movement. The ozone influx can also be calculated using the calculated ozone movement speed and direction multiplied by the observed ozone concentration. As an alternative to a backward trajectory method, this approach will provide better forecasting and analysis by monitoring tropospheric ozone inflow characteristics on a continuous basis. However, if the boundary of the ozone distribution is unclear, motion detection may not be accurate. In spite of this, the TOMV method may prove useful for monitoring and forecasting pollution based on geostationary environmental satellites in the future.