• Korean Journal of Remote Sensing
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• v.15 no.3
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• pp.253-266
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• 1999

ADEOS(Advanced Earth Observing Satellite)/IMG(Interferometric Monitor for Greenhouse Gases) measurements - temperature, water vapor($H_2O$), ozone($O_3$) have been compared with the radio sonde and ozone sonde observations at Osan and Pohang stations for the 4 cases on 10 Jan.(a), 28 Jan.(b), 2 Apr.(c), and 19 Jun.(d) 1997 to detect the error ranges of the IMG data. It showed that the IMG data of the cases (b), (d) when the ADEOS passed over the central part of Korea were quite stable with the good agreement with the sonde observations, however, that of (a),(c) when the ADEOS passed over south- east coastal area were unstable with the larger differences from the sonde-observations. The RMSE and bias analyses of temperature for the stable cases (b),(d) showed that the differences between the IMG data and the sonde observations were about 1~4 K at the 700~300 hPa level and about 4~5 K or more at the higher level, and the IMG measurements tended to be larger than the sonde observations at the higher level above 200 hPa, while no typical bias was seen at the lower level. The RMSE and bias analysis for the version of level 2 5_6_4_4 of ozone showed that the RMSE of ozone were quite small, in general, except at the higher level above 50~60 hPa in the all 4 cases, however the bias was generally big with the positive value in the troposphere and the negative in the stratosphere. An example of vertical profile of trace gases such as $CO_2, N_2O, CH_4, HNO_3$, CO measured by IMG was also presented and it showed that the IMG data had large differences between the 5 different observation points.

• Atmosphere
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• v.26 no.3
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• pp.387-400
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• 2016

In this study, the atmospheric $CO_2$ concentrations estimated by CT2013B, a recent version of CarbonTracker, are compared with $CO_2$ measurements from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project during 2010-2011. CarbonTracker is an inversion system that estimates surface $CO_2$ fluxes using atmospheric $CO_2$ concentrations. Overall, the model results represented the atmospheric $CO_2$ concentrations well with a slight overestimation compared to observations. In the case of horizontal distribution, variations in the model and observation difference were large in northern Eurasia because most of the model and data mismatch were located in the stratosphere where the model could not represent $CO_2$ variations well enough due to low model resolution at high altitude and existing phase shift from the troposphere. In addition, the model and observation difference became larger in boreal summer. Despite relatively large differences at high latitudes and in boreal summer, overall, the modeled $CO_2$ concentrations fitted well to observations. Vertical profiles of modeled and observed $CO_2$ concentrations showed that the model overestimates the observations at all altitudes, showing nearly constant differences, which implies that the surface $CO_2$ concentration is transported well vertically in the transport model. At Narita, overall differences were small, although the correlation between modeled and observed $CO_2$ concentrations decreased at higher altitude, showing relatively large differences above 225 hPa. The vertical profiles at Moscow and Delhi located on land and at Hawaii on the ocean showed that the model is less accurate on land than on the ocean due to various effects (e.g., biospheric effect) on land compared to the homogeneous ocean surface.

• Asian Journal of Atmospheric Environment
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• v.8 no.3
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• pp.162-174
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• 2014

An abnormal decrease in ozonesonde sensor signal occurred during air-pollution study campaigns in November 2011 and March 2012 in Mexico City Metropolitan Area (MCMA). Sharp drops in sensor signal around 5 km above sea level and above were observed in November 2011, and a reduction of signal over a broad range of altitude was observed in the convective boundary layer in March 2012. Circumstantial evidence indicated that $SO_2$ gas interfered with the electrochemical concentration cell (ECC) ozone sensors in the ozonesonde and that this interference was the cause of the reduced sensor signal output. The sharp drops in November 2011 were attributed to the $SO_2$ plume from Popocat$\acute{e}$petl volcano southeast of MCMA. Experiments on the response of the ECC sensor to representative atmospheric trace gases showed that only $SO_2$ could cause the observed abrupt drops in sensor signal. The vertical profile of the plume reproduced by a Lagrangian particle diffusion simulation supported this finding. A near-ground reduction in the sensor signal in March 2012 was attributed to an $SO_2$ plume from the Tula industrial complex north-west of MCMA. Before and at the time of ozonesonde launch, intermittent high $SO_2$ concentrations were recorded at ground-level monitoring stations north of MCMA. The difference between the $O_3$ concentration measured by the ozonesonde and that recorded by a UV-based $O_3$ monitor was consistent with the $SO_2$ concentration recorded by a UV-based monitor on the ground. The vertical profiles of the plumes estimated by Lagrangian particle diffusion simulation agreed fairly well with the observed profile. Statistical analysis of the wind field in MCMA revealed that the effect Popocat$\acute{e}$petl was most likely to have occurred from June to October, whereas the effect of the industries north of MCMA, including the Tula complex, was predicted to occur throughout the year.