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Pieternel F. Levelt - One of the best experts on this subject based on the ideXlab platform.
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SO2 data from the ozone Monitoring Instrument
2020Co-Authors: Nickolay A. Krotkov, S A Carn, Pawan K. Bhartia, Kai Yang, Aj Krüger, Pieternel F. LeveltAbstract:We discuss collection 2 SO2 data from the Dutch-Finnish Ozone Monitoring Instrument (OMI) on board NASA EOS/Aura spacecraft and show examples of detected volcanic and anthropogenic SO2 emissions. Quantification of anthropogenic SO2 emissions requires collection 3 reprocessing available in the fall 2007.
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Science Objectives of EOS-Aura's Ozone Monitoring Instrument (OMI)
2020Co-Authors: Pieternel F. Levelt, J. P. Veefkind, Pawan K. Bhartia, E. Hilsenrath, G.w. Leppelmeier, Piet Stammes, Kelly Chance, A. MaelkkiAbstract:The Ozone Monitoring Instrument (OMI) will fly on NASA's satellite EOS-Aura, which is scheduled for launch in June 2003. The EOS-Aura satellite is focussed on atmospheric chemistry and climate issues. The main science objectives of the EOS-Aura mission are:
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From ozone Monitoring Instrument (OMI) to tropospheric Monitoring Instrument (TROPOMI)
International Conference on Space Optics — ICSO 2008, 2017Co-Authors: M R Dobber, Pepijn Veefkind, Pieternel F. Levelt, Q. Kleipool, Johan De Vries, Nico Rozemeijer, Ruud W. M. Hoogeveen, Ilse Aben, Gerard OtterAbstract:The OMI Instrument is an ultraviolet-visible imaging spectrograph that uses two-dimensional CCD detectors to register both the spectrum and the swath perpendicular to the flight direction with a 115° wide swath, which enables global daily ground coverage with high spatial resolution. This paper presents a selection of in-flight radiometric and CCD detector calibration and performance Monitoring results since the launch in July 2004. From these examples it will be shown that OMI is performing very well after more than four years in orbit. It is shown how the OMI irradiance measurement data have been used to derive a high resolution solar reference spectrum with good radiometric calibration, good wavelength calibration and high spectral sampling. The surface reflectance climatology derived from three years of in-orbit OMI measurement data is presented and discussed. The OMI mission may possibly be extended in 2009 for another two or four years, depending on the performance of the Instrument. By 2013-2014 OMI on EOS-Aura and SCIAMACHY on ENVISAT will have reached more that twice their anticipated lifetimes. In order to guarantee continuity of Earth atmosphere tropospheric and climate measurement data new Instrumentation shall be available around that time. A successor of OMI and SCIAMACHY, named TROPOspheric Monitoring Instrument (TROPOMI), scheduled for launch by the end of 2013, is discussed in this paper.
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the ozone Monitoring Instrument overview of 14 years in space
Atmospheric Chemistry and Physics, 2017Co-Authors: Pieternel F. Levelt, Joanna Joiner, Pepijn Veefkind, Pawan K. Bhartia, David G Streets, J Tamminen, Deborah Stein Zweers, B N Duncan, Henk Eskes, Ronald Van Der AAbstract:This overview paper highlights the successes of the Ozone Monitoring Instrument (OMI) on board the Aura satellite spanning a period of nearly 14 years. Data from OMI has been used in a wide range of applications and research resulting in many new findings. Due to its unprecedented spatial resolution, in combination with daily global coverage, OMI plays a unique role in measuring trace gases important for the ozone layer, air quality, and climate change. With the operational very fast delivery (VFD; direct readout) and near real-time (NRT) availability of the data, OMI also plays an important role in the development of operational services in the atmospheric chemistry domain.
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in flight performance of the ozone Monitoring Instrument
Atmospheric Measurement Techniques, 2017Co-Authors: V Erik M Schenkeveld, Pepijn Veefkind, Pieternel F. Levelt, Q. Kleipool, G. Jaross, Nico Rozemeijer, Sergey Marchenko, D P HaffnerAbstract:The Dutch-Finnish Ozone Monitoring Instrument (OMI) is an imaging spectrograph flying on NASA's EOS Aura satellite since 15 July 2004. OMI is primarily used to map trace-gas concentrations in the Earth's atmosphere, obtaining mid-resolution (0.4-0.6 nm) ultraviolet-visible (UV-VIS; 264-504 nm) spectra at multiple (30-60) simultaneous fields of view. Assessed via various approaches that include Monitoring of radiances from selected ocean, land ice and cloud areas, as well as measurements of line profiles in the solar spectra, the Instrument shows low optical degradation and high wavelength stability over the mission lifetime. In the regions relatively free from the slowly unraveling "row anomaly" (RA) the OMI irradiances have degraded by 3-8 %, while radiances have changed by 1-2 %. The long-term wavelength calibration of the Instrument remains stable to 0.005-0.020 nm.
P F Levelt - One of the best experts on this subject based on the ideXlab platform.
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evaluation of stratospheric no2 retrieved from the ozone Monitoring Instrument intercomparison diurnal cycle and trending
Journal of Geophysical Research, 2011Co-Authors: R. Dirksen, Henk Eskes, P F Levelt, E.j. Bucsela, K Folkert F Boersma, Dmitry V Ionov, H KelderAbstract:[1] A 5+ year record of satellite measurements of nitrogen dioxide columns from the Ozone Monitoring Instrument (OMI) is evaluated to establish the quality of the OMI retrievals and to test our understanding of stratospheric NO2. The use of assimilation techniques to retrieve stratospheric vertical columns of NO2 from OMI slant column observations is described in detail. Over remote areas the forecast model state is generally within 0.15 × 1015 molecules/cm2 of the analysis. Dutch OMI NO2 (DOMINO) and Standard Product (SP) stratospheric NO2 columns agree within 0.3 × 1015 molecules/cm2 (13%) with independent, ground-based measurements. This is comparable to the level of consistency (15–20%) among ground-based techniques. On average, DOMINO stratospheric NO2 is higher than SP by 0.2 × 1015 molecules/cm2, but larger differences occur on the synoptic scale. Overlapping OMI orbits poleward of 30° enabled us to extract information on the diurnal variation in stratospheric NO2. We find that in the Arctic, the daytime increase of NO2 has a distinct seasonal dependence that peaks in spring and fall. Daytime increase rates inside the denoxified Arctic polar vortex are low, but we find high rates (>0.4 × 1015 molecules/cm2/h) outside the vortex. A multilinear regression to the DOMINO record shows a distinct quasi-biennial oscillation (QBO) signal in stratospheric NO2 columns over the tropics. The QBO's amplitude is comparable to the annual cycle and stronger over the Southern Hemisphere than over the Northern Hemisphere. We infer near-identical trends from DOMINO observations (+0.4%/decade) as from ground-based Instrumentation over Lauder (+0.6%/decade) in the 2004–2010 period.
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effective cloud fractions from the ozone Monitoring Instrument theoretical framework and validation
Journal of Geophysical Research, 2008Co-Authors: P Stammes, J. P. Veefkind, J.f. De Haan, M Sneep, P Wang, P F LeveltAbstract:[1] The Dutch-Finnish Ozone Monitoring Instrument (OMI) on board NASA's EOS-Aura satellite is measuring ozone, NO2, and other trace gases with daily global coverage. To correct these trace gas retrievals for the presence of clouds, there are two OMI cloud products, based on different physical processes, namely, absorption by O2–O2 at 477 nm (OMCLDO2) and rotational Raman scattering (RRS) in the UV (OMCLDRR). Both cloud products use a Lambertian cloud model with albedo 0.8 and contain the effective (i.e., radiometric) cloud fraction and the cloud pressure. First, the theoretical framework for the Lambertian cloud model is given and the concept of effective cloud fraction is discussed. Next, an intercomparison of the effective cloud fractions from both products is presented, as well as a comparison with MODIS cloud data. It is shown that the O2–O2 and RRS effective cloud fractions correlate very well (95%) but that there is an offset of about 0.10. From MODIS geometric cloud fraction and cloud optical thickness data a MODIS effective cloud fraction was calculated. The effective cloud fractions from OMCLDO2 and MODIS show a high correlation of 92% with a very small offset (0.01). In order to guide users, a summary of the validation status of effective cloud fraction and cloud pressure from the OMCLDO2 and OMCLDRR cloud products is presented.
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validation of so2 retrievals from the ozone Monitoring Instrument over ne china
Journal of Geophysical Research, 2008Co-Authors: Nickolay A. Krotkov, S A Carn, Kai Yang, P K Bhartia, Arlin J Krueger, Can Li, Brittany Mcclure, Russell R Dickerson, Zhanqing Li, P F LeveltAbstract:[1] The Dutch-Finnish Ozone Monitoring Instrument (OMI) launched on the NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space-based UV measurements of sulfur dioxide (SO2). We present a first validation of the OMI SO2 data with in situ aircraft measurements in NE China in April 2005. The study demonstrates that OMI can distinguish between background SO2 conditions and heavy pollution on a daily basis. The noise (expressed as the standard deviation, σ) is ∼1.5 DU (Dobson units; 1 DU = 2.69 · 1016 molecules/cm2) for instantaneous field of view boundary layer (PBL) SO2 data. Temporal and spatial averaging can reduce the noise to σ ∼ 0.3 DU over a remote region of the South Pacific; the long-term average over this remote location was within 0.1 DU of zero. Under polluted conditions collection 2 OMI data are higher than aircraft measurements by a factor of two. Improved calibrations of the radiance and irradiance data (collection 3) result in better agreement with aircraft measurements on polluted days. The air mass–corrected collection 3 data still show positive bias and sensitivity to UV absorbing aerosols. The difference between the in situ data and the OMI SO2 measurements within 30 km of the aircraft profiles was about 1 DU, equivalent to ∼5 ppb from 0 to 3000 m altitude. Quantifying the SO2 and aerosol profiles and spectral dependence of aerosol absorption between 310 and 330 nm are critical for an accurate estimate of SO2 from satellite UV measurements.
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validation of ozone Monitoring Instrument level 1b data products
Journal of Geophysical Research, 2008Co-Authors: M R Dobber, R. Dirksen, Q. Kleipool, G. Jaross, G.w. Leppelmeier, P F Levelt, S Taylor, T Kelly, L E Flynn, Nico RozemeijerAbstract:[1] The validation of the collection 2 level 1b radiance and irradiance data measured with the Ozone Monitoring Instrument (OMI) on NASA’s Earth Observing System (EOS) Aura satellite is investigated and described. A number of improvements from collection 2 data to collection 3 data are identified and presented. It is shown that with these improvements in the calibration and in the data processing the accuracy of the geophysically calibrated level 1b radiance and irradiance is improved in the collection 3 data. It is shown that the OMI level 1b irradiance product can be reproduced from a high-resolution solar reference spectrum convolved with the OMI spectral slit functions within 3% for the Fraunhofer structure and within 0.5% for the offset. The agreement of the OMI level 1b irradiance data product with other available literature irradiance spectra is within 4%. The viewing angle dependence of the irradiance and the irradiance goniometry are discussed, and improvements in the collection 3 data are described. The in-orbit radiometric degradation since launch is shown to be smaller than 0.5% above 310 nm and increases to about 1.2% at 270 nm. It is shown how the viewing angle dependence of the radiance is improved in the collection 3 data. The calculation of the surface albedo from OMI measurement data is discussed, and first results are presented. The OMI surface albedo values are compared to literature values from the Total Ozone Mapping Spectrometer (TOMS) and the Global Ozone Monitoring Experiment (GOME). Finally, improvements in the spectral and spatial stray light corrections from collection 2 data to collection 3 data are presented and discussed.
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validation of the aura ozone Monitoring Instrument total column ozone product
Journal of Geophysical Research, 2008Co-Authors: R D Mcpeters, J. P. Veefkind, M Kroon, E.j. Brinksma, P K Bhartia, G Labow, Dimitris Balis, Irina Petropavlovskikh, P F LeveltAbstract:[1] This paper is an overview of the validation of the total column ozone data products from the Ozone Monitoring Instrument (OMI) on board the NASA EOS-Aura satellite. OMI is an imaging UV/visible spectrometer that maps global ozone on a daily basis. There are two ozone products from OMI, one derived using the traditional TOMS retrieval algorithm and another derived using a Differential Optical Absorption Spectroscopy algorithm that is being developed to take advantage of the hyperspectral capabilities of OMI. Validation is primarily performed through comparison with a network of Dobson and Brewer ground stations and secondarily through campaigns conducted specifically to validate Aura. Comparison with an ensemble of 76 Northern Hemisphere ground stations shows that OMI-TOMS total column ozone averages 0.4% higher than the station average, with station-to-station standard deviation of ±0.6%. The comparison shows that the OMI-TOMS ozone was stable over the 2-year period with no evidence of drift relative to the ground network. The OMI-DOAS product is also stable but with a 1.1% offset and a seasonal variation of ±2%. During four aircraft validation campaigns using the NASA DC-8 and WB-57 aircraft, ozone above the aircraft was measured using an actinic flux Instrument and compared with OMI ozone. These comparisons showed agreement within 2% over a broad range of latitude and viewing conditions. Only during the high-latitude flights did the OMI-DOAS ozone show the effects of a solar zenith angle dependent error.
P K Bhartia - One of the best experts on this subject based on the ideXlab platform.
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a fast and sensitive new satellite so2 retrieval algorithm based on principal component analysis application to the ozone Monitoring Instrument
Geophysical Research Letters, 2013Co-Authors: Joanna Joiner, Nickolay A. Krotkov, Can Li, P K BhartiaAbstract:[1] We describe a new algorithm to retrieve SO2 from satellite-measured hyperspectral radiances. We employ the principal component analysis technique in regions with no significant SO2 to capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering and ozone absorption) and measurement artifacts. We use the resulting principal components and SO2 Jacobians calculated with a radiative transfer model to directly estimate SO2 vertical column density in one step. Application to the Ozone Monitoring Instrument (OMI) radiance spectra in 310.5–340 nm demonstrates that this approach can greatly reduce biases in the operational OMI product and decrease the noise by a factor of 2, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for Instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing long-term, consistent SO2 records for air quality and climate research.
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ozone profile retrievals from the ozone Monitoring Instrument
Atmospheric Chemistry and Physics, 2009Co-Authors: P K Bhartia, Kelly Chance, Robert Spurr, T P KurosuAbstract:Abstract. Ozone profiles from the surface to about 60 km are retrieved from Ozone Monitoring Instrument (OMI) ultraviolet radiances using the optimal estimation technique. OMI provides daily ozone profiles for the entire sunlit portion of the earth at a horizontal resolution of 13 km×48 km for the nadir position. The retrieved profiles have sufficient accuracy in the troposphere to see ozone perturbations caused by convection, biomass burning and anthropogenic pollution, and to track their spatiotemporal transport. However, to achieve such accuracy it has been necessary to calibrate OMI radiances carefully (using two days of Aura/Microwave Limb Sounder data taken in the tropics). The retrieved profiles contain ~6–7 degrees of freedom for signal, with 5–7 in the stratosphere and 0–1.5 in the troposphere. Vertical resolution varies from 7–11 km in the stratosphere to 10–14 km in the troposphere. Retrieval precisions range from 1% in the middle stratosphere to 10% in the lower stratosphere and troposphere. Solution errors (i.e., root sum square of precisions and smoothing errors) vary from 1–6% in the middle stratosphere to 6–35% in the troposphere, and are dominated by smoothing errors. Total, stratospheric, and tropospheric ozone columns can be retrieved with solution errors typically in the few Dobson unit range at solar zenith angles less than 80°.
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validation of so2 retrievals from the ozone Monitoring Instrument over ne china
Journal of Geophysical Research, 2008Co-Authors: Nickolay A. Krotkov, S A Carn, Kai Yang, P K Bhartia, Arlin J Krueger, Can Li, Brittany Mcclure, Russell R Dickerson, Zhanqing Li, P F LeveltAbstract:[1] The Dutch-Finnish Ozone Monitoring Instrument (OMI) launched on the NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space-based UV measurements of sulfur dioxide (SO2). We present a first validation of the OMI SO2 data with in situ aircraft measurements in NE China in April 2005. The study demonstrates that OMI can distinguish between background SO2 conditions and heavy pollution on a daily basis. The noise (expressed as the standard deviation, σ) is ∼1.5 DU (Dobson units; 1 DU = 2.69 · 1016 molecules/cm2) for instantaneous field of view boundary layer (PBL) SO2 data. Temporal and spatial averaging can reduce the noise to σ ∼ 0.3 DU over a remote region of the South Pacific; the long-term average over this remote location was within 0.1 DU of zero. Under polluted conditions collection 2 OMI data are higher than aircraft measurements by a factor of two. Improved calibrations of the radiance and irradiance data (collection 3) result in better agreement with aircraft measurements on polluted days. The air mass–corrected collection 3 data still show positive bias and sensitivity to UV absorbing aerosols. The difference between the in situ data and the OMI SO2 measurements within 30 km of the aircraft profiles was about 1 DU, equivalent to ∼5 ppb from 0 to 3000 m altitude. Quantifying the SO2 and aerosol profiles and spectral dependence of aerosol absorption between 310 and 330 nm are critical for an accurate estimate of SO2 from satellite UV measurements.
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validation of the aura ozone Monitoring Instrument total column ozone product
Journal of Geophysical Research, 2008Co-Authors: R D Mcpeters, J. P. Veefkind, M Kroon, E.j. Brinksma, P K Bhartia, G Labow, Dimitris Balis, Irina Petropavlovskikh, P F LeveltAbstract:[1] This paper is an overview of the validation of the total column ozone data products from the Ozone Monitoring Instrument (OMI) on board the NASA EOS-Aura satellite. OMI is an imaging UV/visible spectrometer that maps global ozone on a daily basis. There are two ozone products from OMI, one derived using the traditional TOMS retrieval algorithm and another derived using a Differential Optical Absorption Spectroscopy algorithm that is being developed to take advantage of the hyperspectral capabilities of OMI. Validation is primarily performed through comparison with a network of Dobson and Brewer ground stations and secondarily through campaigns conducted specifically to validate Aura. Comparison with an ensemble of 76 Northern Hemisphere ground stations shows that OMI-TOMS total column ozone averages 0.4% higher than the station average, with station-to-station standard deviation of ±0.6%. The comparison shows that the OMI-TOMS ozone was stable over the 2-year period with no evidence of drift relative to the ground network. The OMI-DOAS product is also stable but with a 1.1% offset and a seasonal variation of ±2%. During four aircraft validation campaigns using the NASA DC-8 and WB-57 aircraft, ozone above the aircraft was measured using an actinic flux Instrument and compared with OMI ozone. These comparisons showed agreement within 2% over a broad range of latitude and viewing conditions. Only during the high-latitude flights did the OMI-DOAS ozone show the effects of a solar zenith angle dependent error.
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aerosols and surface uv products from ozone Monitoring Instrument observations an overview
Journal of Geophysical Research, 2007Co-Authors: Omar Torres, Aapo Tanskanen, Remco Braak, Pepijn Veefkind, Ben Veihelmann, P K Bhartia, Pieternel F. LeveltAbstract:We present an overview of the theoretical and algorithmic aspects of the Ozone Monitoring Instrument (OMI) aerosol and surface UV algorithms. Aerosol properties are derived from two independent algorithms. The nearUV algorithm makes use of OMI observations in the 350-390 nm spectral region to retrieve information on the absorption capacity of tropospheric aerosols. OMI-derived information on aerosol absorption includes the UV Aerosol Index and absorption optical depth at 388 nm. The other algorithm makes use of the full UV-to-visible OMI spectral coverage to derive spectral aerosol extinction optical depth. OMI surface UV products include erythemally weighted daily dose as well as erythemal dose rate and spectral UV irradiances calculated for local solar noon conditions. The advantages and limitations of the current algorithms are discussed, and a brief summary of several validation and evaluation analysis carried out to assess the current level of uncertainty of these products is presented. Copyright 2007 by the American Geophysical Union. U7 - Export Date: 2 August 2010 U7 - Source: Scopus U7 - Art. No.: D24S47
Nickolay A. Krotkov - One of the best experts on this subject based on the ideXlab platform.
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SO2 data from the ozone Monitoring Instrument
2020Co-Authors: Nickolay A. Krotkov, S A Carn, Pawan K. Bhartia, Kai Yang, Aj Krüger, Pieternel F. LeveltAbstract:We discuss collection 2 SO2 data from the Dutch-Finnish Ozone Monitoring Instrument (OMI) on board NASA EOS/Aura spacecraft and show examples of detected volcanic and anthropogenic SO2 emissions. Quantification of anthropogenic SO2 emissions requires collection 3 reprocessing available in the fall 2007.
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a fast and sensitive new satellite so2 retrieval algorithm based on principal component analysis application to the ozone Monitoring Instrument
Geophysical Research Letters, 2013Co-Authors: Joanna Joiner, Nickolay A. Krotkov, Can Li, P K BhartiaAbstract:[1] We describe a new algorithm to retrieve SO2 from satellite-measured hyperspectral radiances. We employ the principal component analysis technique in regions with no significant SO2 to capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering and ozone absorption) and measurement artifacts. We use the resulting principal components and SO2 Jacobians calculated with a radiative transfer model to directly estimate SO2 vertical column density in one step. Application to the Ozone Monitoring Instrument (OMI) radiance spectra in 310.5–340 nm demonstrates that this approach can greatly reduce biases in the operational OMI product and decrease the noise by a factor of 2, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for Instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing long-term, consistent SO2 records for air quality and climate research.
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A fast and sensitive new satellite SO2 retrieval algorithm based on principal component analysis: Application to the ozone Monitoring Instrument
Geophysical Research Letters, 2013Co-Authors: Changjun Li, Joanna Joiner, Nickolay A. Krotkov, Pawan K. BhartiaAbstract:We describe a new algorithm to retrieve SO 2 from satellite-measured hyperspectral radiances. We employ the principal component analysis technique in regions with no significant SO 2 to capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering and ozone absorption) and measurement artifacts. We use the resulting principal components and SO 2 Jacobians calculated with a radiative transfer model to directly estimate SO 2 vertical column density in one step. Application to the Ozone Monitoring Instrument (OMI) radiance spectra in 310.5-340 nm demonstrates that this approach can greatly reduce biases in the operational OMI product and decrease the noise by a factor of 2, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for Instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing long-term, consistent SO 2 records for air quality and climate research. Key Points Fundamentally different and fast approach for spectral fitting of SO2 signals Biases in operational product largely eliminated, noise reduced by half Easily adapted to other sensors to produce consistent long-term data sets ©2013. American Geophysical Union. All Rights Reserved.
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Ozone Monitoring Instrument observations of interannual increases in SO2 emissions from Indian coal-fired power plants during 2005-2012
Environmental Science and Technology, 2013Co-Authors: Zifeng Lu, B. De Foy, David G Streets, Nickolay A. KrotkovAbstract:Due to the rapid growth of electricity demand and the absence of regulations, sulfur dioxide (SO2) emissions from coal-fired power plants in India have increased notably in the past decade. In this study, we present the first interannual comparison of SO2 emissions and the satellite SO2 observations from the Ozone Monitoring Instrument (OMI) for Indian coal-fired power plants during the OMI era of 2005-2012. A detailed unit-based inventory is developed for the Indian coal-fired power sector, and results show that its SO2 emissions increased dramatically by 71% during 2005-2012. Using the oversampling technique, yearly high-resolution OMI maps for the whole domain of India are created, and they reveal a continuous increase in SO2 columns over India. Power plant regions with annual SO2 emissions greater than 50 Gg year(-1) produce statistically significant OMI signals, and a high correlation (R = 0.93) is found between SO2 emissions and OMI-observed SO2 burdens. Contrary to the decreasing trend of national mean SO2 concentrations reported by the Indian Government, both the total OMI-observed SO2 and annual average SO2 concentrations in coal-fired power plant regions increased by >60% during 2005-2012, implying the air quality Monitoring network needs to be optimized to reflect the true SO2 situation in India.
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recent large reduction in sulfur dioxide emissions from chinese power plants observed by the ozone Monitoring Instrument
Geophysical Research Letters, 2010Co-Authors: Nickolay A. Krotkov, David G Streets, Can Li, Qiang Zhang, Kebin He, Sichee Tsay, J F GleasonAbstract:[1] The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite observed substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where large coal-fired power plants were built during this period. The OMI-observed SO2/NO2 ratio is consistent with the SO2/NOx emissions estimated from a bottom-up approach. In 2008 over the same areas, OMI detected little change in NO2, suggesting steady electricity output from the power plants. However, dramatic reductions of SO2 emissions were observed by OMI at the same time. These reductions confirm the effectiveness of the flue-gas desulfurization (FGD) devices in reducing SO2 emissions, which likely became operational between 2007 and 2008. This study further demonstrates that the satellite sensors can monitor and characterize anthropogenic emissions from large point sources.
Can Li - One of the best experts on this subject based on the ideXlab platform.
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a global catalogue of large so 2 sources and emissions derived from theozone Monitoring Instrument
Atmospheric Chemistry and Physics, 2016Co-Authors: V Fioletov, Joanna Joiner, S A Carn, Nicolas Theys, Can Li, N A Krotkov, C A Mclinden, M D MoranAbstract:Abstract. Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr−1 to more than 4000 kt yr−1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smelters (53); and sources related to the oil and gas industry (65). The sources were identified using different methods, including through OMI measurements themselves applied to a new emission detection algorithm, and their evolution during the 2005–2014 period was traced by estimating annual emissions from each source. For volcanic sources, the study focused on continuous degassing, and emissions from explosive eruptions were excluded. Emissions from degassing volcanic sources were measured, many for the first time, and collectively they account for about 30 % of total SO2 emissions estimated from OMI measurements, but that fraction has increased in recent years given that cumulative global emissions from power plants and smelters are declining while emissions from oil and gas industry remained nearly constant. Anthropogenic emissions from the USA declined by 80 % over the 2005–2014 period as did emissions from western and central Europe, whereas emissions from India nearly doubled, and emissions from other large SO2-emitting regions (South Africa, Russia, Mexico, and the Middle East) remained fairly constant. In total, OMI-based estimates account for about a half of total reported anthropogenic SO2 emissions; the remaining half is likely related to sources emitting less than 30 kt yr−1 and not detected by OMI.
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a fast and sensitive new satellite so2 retrieval algorithm based on principal component analysis application to the ozone Monitoring Instrument
Geophysical Research Letters, 2013Co-Authors: Joanna Joiner, Nickolay A. Krotkov, Can Li, P K BhartiaAbstract:[1] We describe a new algorithm to retrieve SO2 from satellite-measured hyperspectral radiances. We employ the principal component analysis technique in regions with no significant SO2 to capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering and ozone absorption) and measurement artifacts. We use the resulting principal components and SO2 Jacobians calculated with a radiative transfer model to directly estimate SO2 vertical column density in one step. Application to the Ozone Monitoring Instrument (OMI) radiance spectra in 310.5–340 nm demonstrates that this approach can greatly reduce biases in the operational OMI product and decrease the noise by a factor of 2, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for Instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing long-term, consistent SO2 records for air quality and climate research.
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recent large reduction in sulfur dioxide emissions from chinese power plants observed by the ozone Monitoring Instrument
Geophysical Research Letters, 2010Co-Authors: Nickolay A. Krotkov, David G Streets, Can Li, Qiang Zhang, Kebin He, Sichee Tsay, J F GleasonAbstract:[1] The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite observed substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where large coal-fired power plants were built during this period. The OMI-observed SO2/NO2 ratio is consistent with the SO2/NOx emissions estimated from a bottom-up approach. In 2008 over the same areas, OMI detected little change in NO2, suggesting steady electricity output from the power plants. However, dramatic reductions of SO2 emissions were observed by OMI at the same time. These reductions confirm the effectiveness of the flue-gas desulfurization (FGD) devices in reducing SO2 emissions, which likely became operational between 2007 and 2008. This study further demonstrates that the satellite sensors can monitor and characterize anthropogenic emissions from large point sources.
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validation of so2 retrievals from the ozone Monitoring Instrument over ne china
Journal of Geophysical Research, 2008Co-Authors: Nickolay A. Krotkov, S A Carn, Kai Yang, P K Bhartia, Arlin J Krueger, Can Li, Brittany Mcclure, Russell R Dickerson, Zhanqing Li, P F LeveltAbstract:[1] The Dutch-Finnish Ozone Monitoring Instrument (OMI) launched on the NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space-based UV measurements of sulfur dioxide (SO2). We present a first validation of the OMI SO2 data with in situ aircraft measurements in NE China in April 2005. The study demonstrates that OMI can distinguish between background SO2 conditions and heavy pollution on a daily basis. The noise (expressed as the standard deviation, σ) is ∼1.5 DU (Dobson units; 1 DU = 2.69 · 1016 molecules/cm2) for instantaneous field of view boundary layer (PBL) SO2 data. Temporal and spatial averaging can reduce the noise to σ ∼ 0.3 DU over a remote region of the South Pacific; the long-term average over this remote location was within 0.1 DU of zero. Under polluted conditions collection 2 OMI data are higher than aircraft measurements by a factor of two. Improved calibrations of the radiance and irradiance data (collection 3) result in better agreement with aircraft measurements on polluted days. The air mass–corrected collection 3 data still show positive bias and sensitivity to UV absorbing aerosols. The difference between the in situ data and the OMI SO2 measurements within 30 km of the aircraft profiles was about 1 DU, equivalent to ∼5 ppb from 0 to 3000 m altitude. Quantifying the SO2 and aerosol profiles and spectral dependence of aerosol absorption between 310 and 330 nm are critical for an accurate estimate of SO2 from satellite UV measurements.