scholarly journals Validation of OMI, GOME-2A and GOME-2B tropospheric NO<sub>2</sub>, SO<sub>2</sub> and HCHO products using MAX-DOAS observations from 2011 to 2014 in Wuxi, China

2016 ◽  
Author(s):  
Yang Wang ◽  
Steffen Beirle ◽  
Johannes lampel ◽  
Mariliza Koukouli ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Satellite Data ◽  
Trace Gases ◽  
Satellite Observations ◽  
Urban Region ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Shape Factors ◽  
Weekly Cycle ◽  
Comparison Results ◽  
Ozone Monitoring

Abstract. Tropospheric vertical column densities (VCDs) of NO2, SO2 and HCHO derived from Ozone Monitoring Instrument (OMI) on AURA and Global Ozone Monitoring Experiment 2 aboard METOP-A (GOME-2A) and METOP-B (GOME-2B) are widely used to characterize the global distributions, trends, dominating sources of the trace gases and for comparisons with chemical transport models (CTM). We use tropospheric VCDs and vertical profiles of NO2, SO2 and HCHO derived from MAX-DOAS measurements from 2011 to 2014 in Wuxi, China, to validate the corresponding products derived from OMI, GOME-2A/B by different scientific teams (daily and bimonthly averaged data). Prior to the comparison we investigate the effects of the spatial and temporal coincidence criteria for MAX-DOAS and satellite data on the comparison results. We find that the distance of satellite data from the location of the MAX-DOAS station is the dominating effect, and we make suggestions for the spatial (20 km for OMI NO2 and SO2 products and 50 km for OMI HCHO and all GOME-2A/B products) and temporal averaging (2 hours around satellite overpass time). We also investigate the effect of clouds on both MAX-DOAS and satellite observations. Our results indicate that the discrepancies between satellite and MAX-DOAS results increase with increasing effective cloud fractions and are dominated by the cloud effect on the satellite products. Our comparison results indicate a systematic underestimation of all SO2 (40 % to 57 %) and HCHO products (about 20 %) and an overestimation of the GOME-2A/B NO2 products (about 30 %) (DOMINO NO2 product is only slightly underestimated by 1 %). To better understand the reasons for the differences, we recalculated the AMFs for satellite observations based on the shape factors (SFs) derived from MAX-DOAS. The recalculated satellite VCDs agree better with the MAX-DOAS VCDs than those from the original products by up to 10 %, 47 % and 35 % for NO2, SO2 and HCHO, respectively. The improvement is strongest for periods with large trace gas VCDs. Finally we investigate the effect of aerosols on the satellite retrievals. We find an increasing underestimation of the OMI NO2, SO2 and HCHO products with increasing AOD by up to 8 %, 12 % and 2 %, respectively. One reason for this finding is that aerosols systematically affect the satellite cloud retrievals and can lead to apparent effective cloud fractions of up to 10 % and apparent cloud top pressures of down to 830 hPa for the typical urban region in Wuxi. We show that in such cases the implicit aerosol correction could cause a strong underestimation of tropospheric VCDs by up to about 45 %, 77 % and 100 % for NO2, SO2 and HCHO, respectively. For such conditions it might be better to apply AMFs for clear sky conditions than AMFs based on the satellite cloud retrievals. We find that the satellites systematically overestimate the magnitude of the diurnal variations of NO2 and HCHO. No significant weekly cycle for all trace gases is found by either the satellites or the MAX-DOAS measurements.

scholarly journals Long-term MAX-DOAS network observations of NO<sub>2</sub> in Russia and Asia (MADRAS) during the period 2007–2012: instrumentation, elucidation of climatology, and comparisons with OMI satellite observations and global model simulations

2014 ◽  
Vol 14 (15) ◽  
pp. 7909-7927 ◽  
Author(s):  
Y. Kanaya ◽  
H. Irie ◽  
H. Takashima ◽  
H. Iwabuchi ◽  
H. Akimoto ◽  
...  
Keyword(s):  
Satellite Data ◽  
Transport Model ◽  
Satellite Observations ◽  
Global Model ◽  
Optical Absorption Spectroscopy ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Data Set ◽  
Model Simulations

Abstract. We conducted long-term network observations using standardized Multi-Axis Differential optical absorption spectroscopy (MAX-DOAS) instruments in Russia and ASia (MADRAS) from 2007 onwards and made the first synthetic data analysis. At seven locations (Cape Hedo, Fukue and Yokosuka in Japan, Hefei in China, Gwangju in Korea, and Tomsk and Zvenigorod in Russia) with different levels of pollution, we obtained 80 927 retrievals of tropospheric NO2 vertical column density (TropoNO2VCD) and aerosol optical depth (AOD). In the technique, the optimal estimation of the TropoNO2VCD and its profile was performed using aerosol information derived from O4 absorbances simultaneously observed at 460–490 nm. This large data set was used to analyze NO2 climatology systematically, including temporal variations from the seasonal to the diurnal scale. The results were compared with Ozone Monitoring Instrument (OMI) satellite observations and global model simulations. Two NO2 retrievals of OMI satellite data (NASA ver. 2.1 and Dutch OMI NO2 (DOMINO) ver. 2.0) generally showed close correlations with those derived from MAX-DOAS observations, but had low biases of up to ~50%. The bias was distinct when NO2 was abundantly present near the surface and when the AOD was high, suggesting a possibility of incomplete accounting of NO2 near the surface under relatively high aerosol conditions for the satellite observations. Except for constant biases, the satellite observations showed nearly perfect seasonal agreement with MAX-DOAS observations, suggesting that the analysis of seasonal features of the satellite data were robust. Weekend reduction in the TropoNO2VCD found at Yokosuka and Gwangju was absent at Hefei, implying that the major sources had different weekly variation patterns. While the TropoNO2VCD generally decreased during the midday hours, it increased exceptionally at urban/suburban locations (Yokosuka, Gwangju, and Hefei) during winter. A global chemical transport model, MIROC-ESM-CHEM (Model for Interdisciplinary Research on Climate–Earth System Model–Chemistry), was validated for the first time with respect to background NO2 column densities during summer at Cape Hedo and Fukue in the clean marine atmosphere.

scholarly journals Validation of OMI, GOME-2A and GOME-2B tropospheric NO<sub>2</sub>, SO<sub>2</sub> and HCHO products using MAX-DOAS observations from 2011 to 2014 in Wuxi, China: investigation of the effects of priori profiles and aerosols on the satellite products

2017 ◽  
Vol 17 (8) ◽  
pp. 5007-5033 ◽  
Author(s):  
Yang Wang ◽  
Steffen Beirle ◽  
Johannes Lampel ◽  
Mariliza Koukouli ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Cloud Fraction ◽  
Satellite Observations ◽  
Data Sets ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Air Mass ◽  
Clear Sky ◽  
Satellite Retrievals ◽  
Mass Factor ◽  
Ozone Monitoring

Abstract. Tropospheric vertical column densities (VCDs) of NO2, SO2 and HCHO derived from the Ozone Monitoring Instrument (OMI) on AURA and the Global Ozone Monitoring Experiment 2 aboard METOP-A (GOME-2A) and METOP-B (GOME-2B) are widely used to characterize the global distributions, trends and dominating sources of these trace gases. They are also useful for the comparison with chemical transport models (CTMs). We use tropospheric VCDs and vertical profiles of NO2, SO2 and HCHO derived from MAX-DOAS measurements from 2011 to 2014 in Wuxi, China, to validate the corresponding products (daily and bi-monthly-averaged data) derived from OMI and GOME-2A/B by different scientific teams. Prior to the comparison, the spatial and temporal coincidence criteria for MAX-DOAS and satellite data are determined by a sensitivity study using different spatial and temporal averaging conditions. Cloud effects on both MAX-DOAS and satellite observations are also investigated. Our results indicate that the discrepancies between satellite and MAX-DOAS results increase with increasing effective cloud fraction and are dominated by the effects of clouds on the satellite products. In comparison with MAX-DOAS, we found a systematic underestimation of all SO2 (40 to 57 %) and HCHO products (about 20 %), and an overestimation of the GOME-2A/B NO2 products (about 30 %), but good consistency with the DOMINO version 2 NO2 product. To better understand the reasons for these differences, we evaluated the a priori profile shapes used in the OMI retrievals (derived from CTM) by comparison with those derived from the MAX-DOAS observations. Significant differences are found for the SO2 and HCHO profile shapes derived from the IMAGES model, whereas on average good agreement is found for the NO2 profile shapes derived from the TM4 model. We also applied the MAX-DOAS profile shapes to the satellite retrievals and found that these modified satellite VCDs agree better with the MAX-DOAS VCDs than the VCDs from the original data sets by up to 10, 47 and 35 % for NO2, SO2 and HCHO, respectively. Furthermore, we investigated the effect of aerosols on the satellite retrievals. For OMI observations of NO2, a systematic underestimation is found for large AOD, which is mainly attributed to effect of the aerosols on the cloud retrieval and the subsequent application of a cloud correction scheme (implicit aerosol correction). In contrast, the effect of aerosols on the clear-sky air mass factor (explicit aerosol correction) has a smaller effect. For SO2 and HCHO observations selected in the same way, no clear aerosol effect is found, probably because for the considered data sets no cloud correction is applied (and also because of the larger scatter). From our findings we conclude that for satellite observations with cloud top pressure (CTP) > 900 hPa and effective cloud fraction (eCF) < 10 % the application of a clear-sky air mass factor might be a good option if accurate aerosol information is not available. Another finding of our study is that the ratio of morning-to-afternoon NO2 VCDs can be considerably overestimated if results from different sensors and/or retrievals (e.g. OMI and GOME-2) are used, whereas fewer deviations for HCHO and SO2 VCDs are found.

scholarly journals Extended observations of volcanic SO<sub>2</sub> and sulfate aerosol in the stratosphere

2007 ◽  
Vol 7 (1) ◽  
pp. 2857-2871 ◽  
Author(s):  
S. A. Carn ◽  
N. A. Krotkov ◽  
K. Yang ◽  
R. M. Hoff ◽  
A. J. Prata ◽  
...  
Keyword(s):  
Climate Change ◽  
Sulfur Dioxide ◽  
Satellite Data ◽  
Volcanic Eruptions ◽  
Sulfate Aerosol ◽  
Satellite Observations ◽  
Ozone Monitoring Instrument ◽  
Ozone Monitoring ◽  
Composition Structure ◽  
Stratospheric Composition

Abstract. Sulfate aerosol produced after injection of sulfur dioxide (SO2) into the stratosphere by volcanic eruptions can trigger climate change. We present new satellite data from the Ozone Monitoring Instrument (OMI) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) missions that reveal the composition, structure and longevity of a stratospheric SO2 cloud and derived sulfate layer following a modest eruption (0.2 Tg total SO2) of Soufriere Hills volcano, Montserrat on 20 May 2006. The SO2 cloud alone was tracked for over 3 weeks and a distance of over 20 000 km; unprecedented for an eruption of this size. Derived sulfate aerosol at an altitude of ~20 km had circled the globe by 22 June and remained visible in CALIPSO data until at least 6 July. These synergistic NASA A-Train observations permit a new appreciation of the potential effects of frequent, small-to-moderate volcanic eruptions on stratospheric composition and climate.

scholarly journals OMI total bromine monoxide (OMBRO) data product: Algorithm, retrieval and measurement comparisons

2018 ◽  
Author(s):  
Raid M. Suleiman ◽  
Kelly Chance ◽  
Xiong Liu ◽  
Gonzalo González Abad ◽  
Thomas P. Kurosu ◽  
...  
Keyword(s):  
Cross Sections ◽  
Salt Lake ◽  
Nonlinear Least Squares ◽  
Satellite Observations ◽  
Retrieval Algorithm ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Residual Spectrum ◽  
Data Product ◽  
Ozone Monitoring

Abstract. This paper presents the retrieval algorithm for the operational Ozone Monitoring Instrument (OMI) total bromine monoxide (BrO) data product (OMBRO) developed at the Smithsonian Astrophysical Observatory (SAO), and shows some validation with correlative measurements and retrieval results. The algorithm is based on direct nonlinear least squares fitting of radiances from the spectral range 319.0–347.5 nm. Radiances are modeled from the solar irradiance, attenuated by contributions from BrO and interfering gases, and including rotational Raman scattering, additive and multiplicative closure polynomials, correction for Nyquist undersampling, and the average fitting residual spectrum. The retrieval uses albedo- and wavelength-dependent air mass factors (AMFs), which have been pre-computed using a single mostly stratospheric BrO profile. The BrO cross sections are multiplied by the wavelength- dependent AMFs before fitting so that the vertical column densities (VCDs) are retrieved directly. The fitting uncertainties of BrO VCDs typically vary between 4 and 7 × 1012 molecules cm−2 (~ 10–20 % of the measured BrO VCDs). The retrievals agree well with GOME-2 observations at simultaneous nadir overpasses and ground-based zenith-sky measurements at 25 Harestua, Norway, with mean biases less than 0.12 ± 0.76 × 1013 molecules cm−2 (3.2 ± 16.3 %). Global distribution and seasonal variation of OMI BrO are generally consistent with previous satellite observations. The retrievals show enhancement of BrO at US Great Salt Lake. It also shows significant BrO enhancement from the eruption of the Eyjafjallajökull volcano, although the BrO retrievals can be affected under high SO2 loading conditions by the sub-optimum choice of SO2 cross sections.

Examining the accuracy of satellite retrievals of trace-gas emissions and lifetimes using high-resolution plume modelling.

2021 ◽  
Author(s):  
Zoe Davis ◽  
Debora Griffin ◽  
Yue Jia ◽  
Susann Tegtmeier ◽  
Mallory Loria ◽  
...  
Keyword(s):  
Wind Direction ◽  
Vertical Profile ◽  
Trace Gases ◽  
Meteorological Conditions ◽  
Point Sources ◽  
Satellite Observations ◽  
Trace Gas ◽  
Vertical Column ◽  
Retrieval Method ◽  
The Impact

&lt;p&gt;A recent method uses satellite measurements to estimate lifetimes and emissions of trace-gases from point sources (Fioletov et al., 2015). Emissions are retrieved by fitting measured vertical column densities (VCDs) of trace-gases to a three-dimensional function of the wind speed and spatial coordinates. In this study, a plume model generated &amp;#8220;synthetic&amp;#8221; satellite observations of prescribed emissions to examine the accuracy of the retrieved emissions. The Lagrangian transport and dispersion model FLEXPART (v10.0) modelled the plume from a point source over a multi-day simulation period at a resolution much higher than current satellite observations. The study aims to determine how various assumptions in the retrieval method and local meteorological conditions affect the accuracy and precision of emissions. These assumptions include that the use of a vertical mean of the wind profile is representative of the transport of the plume&amp;#8217;s vertical column. In the retrieval method, the VCDs&amp;#8217; pixel locations are rotated around the source based on wind direction so that all plumes have a common wind direction. Retrievals using a vertical mean wind for rotation will be compared to retrievals using VCDs determined by rotating each altitude of the vertical profile of trace-gas using the respective wind-direction. The impact of local meteorological factors on the two approaches will be presented, including atmospheric mixing, vertical wind shear, and boundary layer height. The study aims to suggest which altitude(s) of the vertical profile of winds results in the most accurate retrievals given the local meteorological conditions. The study will also examine the impact on retrieval accuracy due to satellite resolution, trace-gas lifetime, plume source altitude, number of overpasses, and random and systematic errors. Sensitivity studies repeated using a second, &amp;#8220;line-density&amp;#8221;, retrieval method will also be presented (Adams et al., 2019; Goldberg et al., 2019).&lt;/p&gt;

scholarly journals Estimating European volatile organic compound emissions using satellite observations of formaldehyde from the Ozone Monitoring Instrument

2010 ◽  
Vol 10 (23) ◽  
pp. 11501-11517 ◽  
Author(s):  
G. Curci ◽  
P. I. Palmer ◽  
T. P. Kurosu ◽  
K. Chance ◽  
G. Visconti
Keyword(s):  
Satellite Observations ◽  
Atmospheric Composition ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Bottom Up ◽  
Voc Emissions ◽  
The Balkans ◽  
Monitoring Instrument ◽  
Volatile Organic ◽  
Ozone Monitoring

Abstract. Emission of non-methane Volatile Organic Compounds (VOCs) to the atmosphere stems from biogenic and human activities, and their estimation is difficult because of the many and not fully understood processes involved. In order to narrow down the uncertainty related to VOC emissions, which negatively reflects on our ability to simulate the atmospheric composition, we exploit satellite observations of formaldehyde (HCHO), an ubiquitous oxidation product of most VOCs, focusing on Europe. HCHO column observations from the Ozone Monitoring Instrument (OMI) reveal a marked seasonal cycle with a summer maximum and winter minimum. In summer, the oxidation of methane and other long-lived VOCs supply a slowly varying background HCHO column, while HCHO variability is dominated by most reactive VOC, primarily biogenic isoprene followed in importance by biogenic terpenes and anthropogenic VOCs. The chemistry-transport model CHIMERE qualitatively reproduces the temporal and spatial features of the observed HCHO column, but display regional biases which are attributed mainly to incorrect biogenic VOC emissions, calculated with the Model of Emissions of Gases and Aerosol from Nature (MEGAN) algorithm. These "bottom-up" or a-priori emissions are corrected through a Bayesian inversion of the OMI HCHO observations. Resulting "top-down" or a-posteriori isoprene emissions are lower than "bottom-up" by 40% over the Balkans and by 20% over Southern Germany, and higher by 20% over Iberian Peninsula, Greece and Italy. We conclude that OMI satellite observations of HCHO can provide a quantitative "top-down" constraint on the European "bottom-up" VOC inventories.

Algorithm for NO/sub 2/ vertical column retrieval from the ozone monitoring instrument

2006 ◽  
Vol 44 (5) ◽  
pp. 1245-1258 ◽  
Author(s):  
E.J. Bucsela ◽  
E.A. Celarier ◽  
M.O. Wenig ◽  
J.F. Gleason ◽  
J.P. Veefkind ◽  
...  
Keyword(s):  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Monitoring Instrument ◽  
Ozone Monitoring

scholarly journals First estimates of global free-tropospheric NO<sub>2</sub> abundances derived using a cloud-slicing technique applied to satellite observations from the Aura Ozone Monitoring Instrument (OMI)

2014 ◽  
Vol 14 (19) ◽  
pp. 10565-10588 ◽  
Author(s):  
S. Choi ◽  
J. Joiner ◽  
Y. Choi ◽  
B. N. Duncan ◽  
A. Vasilkov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Profile Analysis ◽  
Middle Latitude ◽  
Optical Absorption Spectroscopy ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Monitoring Instrument ◽  
Single Orbit ◽  
Tropospheric No2 ◽  
Ozone Monitoring

Abstract. We derive free-tropospheric NO2 volume mixing ratios (VMRs) by applying a cloud-slicing technique to data from the Ozone Monitoring Instrument (OMI) on the Aura satellite. In the cloud-slicing approach, the slope of the above-cloud NO2 column versus the cloud scene pressure is proportional to the NO2 VMR. In this work, we use a sample of nearby OMI pixel data from a single orbit for the linear fit. The OMI data include cloud scene pressures from the rotational-Raman algorithm and above-cloud NO2 vertical column density (VCD) (defined as the NO2 column from the cloud scene pressure to the top of the atmosphere) from a differential optical absorption spectroscopy (DOAS) algorithm. We compare OMI-derived NO2 VMRs with in situ aircraft profiles measured during the NASA Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in 2006. The agreement is generally within the estimated uncertainties when appropriate data screening is applied. We then derive a global seasonal climatology of free-tropospheric NO2 VMR in cloudy conditions. Enhanced NO2 in the free troposphere commonly appears near polluted urban locations where NO2 produced in the boundary layer may be transported vertically out of the boundary layer and then horizontally away from the source. Signatures of lightning NO2 are also shown throughout low and middle latitude regions in summer months. A profile analysis of our cloud-slicing data indicates signatures of lightning-generated NO2 in the upper troposphere. Comparison of the climatology with simulations from the global modeling initiative (GMI) for cloudy conditions (cloud optical depth > 10) shows similarities in the spatial patterns of continental pollution outflow. However, there are also some differences in the seasonal variation of free-tropospheric NO2 VMRs near highly populated regions and in areas affected by lightning-generated NOx.

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