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  1. Article ; Online: Biomass burning combustion efficiency observed from space using measurements of CO and NO 2 by the TROPOspheric Monitoring Instrument (TROPOMI)

    I. R. van der Velde / G. R. van der Werf / S. Houweling / H. J. Eskes / J. P. Veefkind / T. Borsdorff / I. Aben

    Atmospheric Chemistry and Physics, Vol 21, Pp 597-

    2021  Volume 616

    Abstract: The global fire emission inventories depend on ground and airborne measurements of species-specific emission factors (EFs), which translate dry matter losses due to fires to actual trace gas and aerosol emissions. The EFs of nitrogen oxides (NO x ) and ... ...

    Abstract The global fire emission inventories depend on ground and airborne measurements of species-specific emission factors (EFs), which translate dry matter losses due to fires to actual trace gas and aerosol emissions. The EFs of nitrogen oxides (NO x ) and carbon monoxide (CO) can function as a proxy for combustion efficiency to distinguish flaming from smoldering combustion. The uncertainties in these EFs remain large as they are limited by the spatial and temporal representativeness of the measurements. The global coverage of satellite observations has the advantage of filling this gap, making these measurements highly complementary to ground-based or airborne data. We present a new analysis of biomass burning pollutants using space-borne data to investigate the spatiotemporal efficiency of fire combustion. Column measurements of nitrogen dioxide and carbon monoxide ( X NO 2 and X CO ) from the TROPOspheric Monitoring Instrument (TROPOMI) are used to quantify the relative atmospheric enhancements of these species over different fire-prone regions around the world. We find spatial and temporal patterns in the Δ X NO 2 ∕ Δ X CO ratio that point to distinct differences in biomass burning behavior. Such differences are induced by the burning phase of the fire (e.g., high-temperature flaming vs. low-temperature smoldering combustion) and burning practice (e.g., the combustion of logs, coarse woody debris and soil organic matter vs. the combustion of fine fuels such as savanna grasses). The sampling techniques and the signal-to-noise ratio of the retrieved Δ X NO 2 ∕ Δ X CO signals were quantified with WRF-Chem experiments and showed similar distinct differences in combustion types. The TROPOMI measurements show that the fraction of surface smoldering combustion is much larger for the boreal forest fires in the upper Northern Hemisphere and peatland fires in Indonesia. These types of fires cause a much larger increase (3 to 6 times) in Δ X CO relative to Δ X NO 2 than elsewhere in the world. The high spatial and ...
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 550
    Language English
    Publishing date 2021-01-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Air quality impacts of COVID-19 lockdown measures detected from space using high spatial resolution observations of multiple trace gases from Sentinel-5P/TROPOMI

    P. F. Levelt / D. C. Stein Zweers / I. Aben / M. Bauwens / T. Borsdorff / I. De Smedt / H. J. Eskes / C. Lerot / D. G. Loyola / F. Romahn / T. Stavrakou / N. Theys / M. Van Roozendael / J. P. Veefkind / T. Verhoelst

    Atmospheric Chemistry and Physics, Vol 22, Pp 10319-

    2022  Volume 10351

    Abstract: The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace gas data can best be used and interpreted to understand event-based impacts on air quality from regional to city scales around the globe. For this study, we ... ...

    Abstract The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace gas data can best be used and interpreted to understand event-based impacts on air quality from regional to city scales around the globe. For this study, we present the observed changes in the atmospheric column amounts of five trace gases (NO 2 , SO 2 , CO, HCHO, and CHOCHO) detected by the Sentinel-5P TROPOMI instrument and driven by reductions in anthropogenic emissions due to COVID-19 lockdown measures in 2020. We report clear COVID-19-related decreases in TROPOMI NO 2 column amounts on all continents. For megacities, reductions in column amounts of tropospheric NO 2 range between 14 % and 63 %. For China and India, supported by NO 2 observations, where the primary source of anthropogenic SO 2 is coal-fired power generation, we were able to detect sector-specific emission changes using the SO 2 data. For HCHO and CHOCHO, we consistently observe anthropogenic changes in 2-week-averaged column amounts over China and India during the early phases of the lockdown periods. That these variations over such a short timescale are detectable from space is due to the high resolution and improved sensitivity of the TROPOMI instrument. For CO, we observe a small reduction over China, which is in concert with the other trace gas reductions observed during lockdown; however, large interannual differences prevent firm conclusions from being drawn. The joint analysis of COVID-19-lockdown-driven reductions in satellite-observed trace gas column amounts using the latest operational and scientific retrieval techniques for five species concomitantly is unprecedented. However, the meteorologically and seasonally driven variability of the five trace gases does not allow for drawing fully quantitative conclusions on the reduction in anthropogenic emissions based on TROPOMI observations alone. We anticipate that in future the combined use of inverse modeling techniques with the high spatial resolution data from S5P/TROPOMI for all observed ...
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 550 ; 520
    Language English
    Publishing date 2022-08-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Validation of the TROPOMI/S5P aerosol layer height using EARLINET lidars

    K. Michailidis / M.-E. Koukouli / D. Balis / J. P. Veefkind / M. de Graaf / L. Mona / N. Papagianopoulos / G. Pappalardo / I. Tsikoudi / V. Amiridis / E. Marinou / A. Gialitaki / R.-E. Mamouri / A. Nisantzi / D. Bortoli / M. João Costa / V. Salgueiro / A. Papayannis / M. Mylonaki /
    L. Alados-Arboledas / S. Romano / M. R. Perrone / H. Baars

    Atmospheric Chemistry and Physics, Vol 23, Pp 1919-

    2023  Volume 1940

    Abstract: The purpose of this study is to investigate the ability of the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) to derive accurate geometrical features of lofted aerosol layers, selecting the Mediterranean Basin as the study area. Comparisons ... ...

    Abstract The purpose of this study is to investigate the ability of the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) to derive accurate geometrical features of lofted aerosol layers, selecting the Mediterranean Basin as the study area. Comparisons with ground-based correlative measurements constitute a key component in the validation of passive and active satellite aerosol products. For this purpose, we use ground-based observations from quality-controlled lidar stations reporting to the European Aerosol Research Lidar Network (EARLINET). An optimal methodology for validation purposes has been developed and applied using the EARLINET optical profiles and TROPOMI aerosol products, aiming at the in-depth evaluation of the TROPOMI aerosol layer height (ALH) product for the period 2018 to 2022 over the Mediterranean Basin. Seven EARLINET stations were chosen, taking into consideration their proximity to the sea, which provided 63 coincident aerosol cases for the satellite retrievals. In the following, we present the first validation results for the TROPOMI/S5P ALH using the optimized EARLINET lidar products employing the automated validation chain designed for this purpose. The quantitative validation at pixels over the selected EARLINET stations illustrates that the TROPOMI ALH product is consistent with the EARLINET lidar products, with a high correlation coefficient R =0.82 ( R =0.51 ) and a mean bias of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">0.51</mn><mo>±</mo><mn mathvariant="normal">0.77</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="64pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="eb86c47683a107d355a686e9238afc79"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-1919-2023-ie00001.svg" width="64pt" height="10pt" ...<br />
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 551
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Quantification of uncertainty in aerosol optical thickness retrieval arising from aerosol microphysical model and other sources, applied to Ozone Monitoring Instrument (OMI) measurements

    A. Määttä / M. Laine / J. Tamminen / J. P. Veefkind

    Atmospheric Measurement Techniques, Vol 7, Iss 5, Pp 1185-

    2014  Volume 1199

    Abstract: Satellite instruments are nowadays successfully utilised for measuring atmospheric aerosol in many applications as well as in research. Therefore, there is a growing need for rigorous error characterisation of the measurements. Here, we introduce a ... ...

    Abstract Satellite instruments are nowadays successfully utilised for measuring atmospheric aerosol in many applications as well as in research. Therefore, there is a growing need for rigorous error characterisation of the measurements. Here, we introduce a methodology for quantifying the uncertainty in the retrieval of aerosol optical thickness (AOT). In particular, we concentrate on two aspects: uncertainty due to aerosol microphysical model selection and uncertainty due to imperfect forward modelling. We apply the introduced methodology for aerosol optical thickness retrieval of the Ozone Monitoring Instrument (OMI) on board NASA's Earth Observing System (EOS) Aura satellite, launched in 2004. We apply statistical methodologies that improve the uncertainty estimates of the aerosol optical thickness retrieval by propagating aerosol microphysical model selection and forward model error more realistically. For the microphysical model selection problem, we utilise Bayesian model selection and model averaging methods. Gaussian processes are utilised to characterise the smooth systematic discrepancies between the measured and modelled reflectances (i.e. residuals). The spectral correlation is composed empirically by exploring a set of residuals. The operational OMI multi-wavelength aerosol retrieval algorithm OMAERO is used for cloud-free, over-land pixels of the OMI instrument with the additional Bayesian model selection and model discrepancy techniques introduced here. The method and improved uncertainty characterisation is demonstrated by several examples with different aerosol properties: weakly absorbing aerosols, forest fires over Greece and Russia, and Sahara desert dust. The statistical methodology presented is general; it is not restricted to this particular satellite retrieval application.
    Keywords Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; Environmental engineering ; TA170-171 ; Earthwork. Foundations ; TA715-787
    Subject code 310
    Language English
    Publishing date 2014-05-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Sensitivity of the OMI ozone profile retrieval (OMO3PR) to a priori assumptions

    T. Mielonen / J. F. de Haan / J. P. Veefkind

    Atmospheric Measurement Techniques Discussions, Vol 7, Iss 2, Pp 1835-

    2014  Volume 1869

    Abstract: We have assessed the sensitivity of the operational OMI ozone profile retrieval (OMO3PR) algorithm to a number of a priori assumptions. We studied the effect of stray light correction, surface albedo assumptions and a priori ozone profiles on the ... ...

    Abstract We have assessed the sensitivity of the operational OMI ozone profile retrieval (OMO3PR) algorithm to a number of a priori assumptions. We studied the effect of stray light correction, surface albedo assumptions and a priori ozone profiles on the retrieved ozone profile. Then, we studied how to modify the algorithm to improve the retrieval of tropospheric ozone. We found that stray light corrections have a significant effect on the retrieved ozone profile but mainly at high altitudes. Surface albedo assumptions, on the other hand, have the largest impact at the lowest layers. Selection of an ozone profile climatology which is used as a priori information has small effects on the retrievals at all altitudes. However, the usage of climatological a priori covariance matrix has a significant effect. Based on these sensitivity tests, we made several modifications to the OMO3PR algorithm: the a priori ozone climatology was replaced with a new climatology (TpO3), the a priori covariance matrix was calculated from the climatological ozone variance values, and the surface albedo was assumed to be linearly dependent on wavelength in the UV2 channel. We found that the a priori covariance matrix basically defines the vertical distribution of degrees of freedom for a retrieval. Moreover, all the studied versions of the OMO3PR algorithm were equally effective in reducing uncertainty in the retrieved ozone profile. This implies that the posterior error values depend mostly on the assumed a priori errors. Our case study over Europe showed that the new version produced over 10% smaller ozone abundances which reduced the systematic overestimation of ozone in the OMO3PR algorithm and improved correspondence with IASI retrievals.
    Keywords Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Earthwork. Foundations ; TA715-787
    Subject code 290
    Language English
    Publishing date 2014-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Quantification of model uncertainty in aerosol optical thickness retrieval from Ozone Monitoring Instrument (OMI) measurements

    A. Määttä / M. Laine / J. Tamminen / J. P. Veefkind

    Atmospheric Measurement Techniques Discussions, Vol 6, Iss 5, Pp 8509-

    2013  Volume 8541

    Abstract: We study uncertainty quantification in remote sensing of aerosols in the atmosphere with top of the atmosphere reflectance measurements from the nadir-viewing Ozone Monitoring Instrument (OMI). Focus is on the uncertainty in aerosol model selection of ... ...

    Abstract We study uncertainty quantification in remote sensing of aerosols in the atmosphere with top of the atmosphere reflectance measurements from the nadir-viewing Ozone Monitoring Instrument (OMI). Focus is on the uncertainty in aerosol model selection of pre-calculated aerosol models and on the statistical modelling of the model inadequacies. The aim is to apply statistical methodologies that improve the uncertainty estimates of the aerosol optical thickness (AOT) retrieval by propagating model selection and model error related uncertainties more realistically. We utilise Bayesian model selection and model averaging methods for the model selection problem and use Gaussian processes to model the smooth systematic discrepancies from the modelled to observed reflectance. The systematic model error is learned from an ensemble of operational retrievals. The operational OMI multi-wavelength aerosol retrieval algorithm OMAERO is used for cloud free, over land pixels of the OMI instrument with the additional Bayesian model selection and model discrepancy techniques. The method is demonstrated with four examples with different aerosol properties: weakly absorbing aerosols, forest fires over Greece and Russia, and Sahara dessert dust. The presented statistical methodology is general; it is not restricted to this particular satellite retrieval application.
    Keywords Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Earthwork. Foundations ; TA715-787
    Subject code 310
    Language English
    Publishing date 2013-09-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article: Evaluation of broadband surface solar irradiance derived from the Ozone Monitoring Instrument

    Wang, P / J.P. Veefkind / M. Sneep / P. Stammes / P.F. Levelt

    Remote sensing of environment. 2014 June, v. 149

    2014  

    Abstract: Surface solar irradiance (SSI) data are important for planning and estimating the production of solar power plants. Long-term high quality surface solar radiation data are needed for monitoring climate change. This paper presents a new surface solar ... ...

    Abstract Surface solar irradiance (SSI) data are important for planning and estimating the production of solar power plants. Long-term high quality surface solar radiation data are needed for monitoring climate change. This paper presents a new surface solar irradiance dataset, the broadband (0.2–4μm) surface solar irradiance product derived from the Ozone Monitoring Instrument (OMI). The OMI SSI algorithm is based on the Heliosat method and uses the OMI O2–O2 cloud product as main input. The OMI SSI data are validated against the globally distributed Baseline Surface Radiation Network (BSRN) measurements at 19 stations for the year 2008. Furthermore, the monthly mean OMI SSI data are compared to independent surface solar irradiance products from International Satellite Cloud Climatology Project Flux Data (ISCCP-FD) and Clouds and the Earth's Radiant Energy System (CERES) data for the year 2005. The mean difference between OMI SSI and BSRN global (direct+diffuse) irradiances is −1.2Wm−2 (−0.2%), the root mean square error is 100.1Wm−2 (18.1%), and the mean absolute error is 67.8Wm−2 (12.2%). The differences between OMI SSI and BSRN global irradiances are smaller over continental and coastal sites and larger over deserts and islands. OMI SSI has a good agreement with the CERES shortwave (SW) model B surface downward flux (SDF) product. The correlation coefficient and index of agreement between monthly mean 1-degree gridded OMI SSI and CERES SW SDF are >0.99. OMI SSI is lower than CERES SW SDF which is partly due to the solar zenith angle. On average, OMI SSI is 13.5Wm−2 (2.5%) lower than the ISCCP-FD SW surface downward flux and the correlation coefficient and index of agreement are >0.98 for every month.
    Keywords algorithms ; climate change ; climatology ; correlation ; data collection ; deserts ; energy ; islands ; monitoring ; ozone ; planning ; power plants ; remote sensing ; satellites ; solar energy ; solar radiation
    Language English
    Dates of publication 2014-06
    Size p. 88-99.
    Publishing place Elsevier Inc.
    Document type Article
    ZDB-ID 431483-9
    ISSN 0034-4257
    ISSN 0034-4257
    DOI 10.1016/j.rse.2014.03.036
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: Towards the retrieval of tropospheric ozone with the Ozone Monitoring Instrument (OMI)

    T. Mielonen / J. F. de Haan / J. C. A. van Peet / M. Eremenko / J. P. Veefkind

    Atmospheric Measurement Techniques, Vol 8, Iss 2, Pp 671-

    2015  Volume 687

    Abstract: We have assessed the sensitivity of the operational Ozone Monitoring Instrument (OMI) ozone profile retrieval algorithm to a number of a priori and radiative transfer assumptions. We studied the effect of stray light correction, surface albedo ... ...

    Abstract We have assessed the sensitivity of the operational Ozone Monitoring Instrument (OMI) ozone profile retrieval algorithm to a number of a priori and radiative transfer assumptions. We studied the effect of stray light correction, surface albedo assumptions and a priori ozone profiles on the retrieved ozone profile. Then, we studied how to modify the algorithm to improve the retrieval of tropospheric ozone. We found that stray light corrections have a significant effect on the retrieved ozone profile but mainly at high altitudes. Surface albedo assumptions, on the other hand, have the largest impact at the lowest layers. Choice of an ozone profile climatology which is used as a priori information has small effects on the retrievals at all altitudes. However, the usage of climatological a priori covariance matrix has a significant effect. Based on these sensitivity tests, we made several modifications to the retrieval algorithm: the a priori ozone climatology was replaced with a new tropopause-dependent climatology, the a priori covariance matrix was calculated from the climatological ozone variability values, and the surface albedo was assumed to be linearly dependent on wavelength in the 311.5–330 nm channel. As expected, we found that the a priori covariance matrix basically defines the vertical distribution of degrees of freedom for a retrieval. Moreover, our case study over Europe showed that the modified version produced over 10% smaller ozone abundances in the troposphere which reduced the systematic overestimation of ozone in the retrieval algorithm and improved correspondence with Infrared Atmospheric Sounding Instrument (IASI) retrievals. The comparison with ozonesonde measurements over North America showed that the operational retrieval performed better in the upper troposphere/lower stratosphere (UTLS), whereas the modified version improved the retrievals in the lower troposphere and upper stratosphere. These comparisons showed that the systematic biases in the OMI ozone profile retrievals are not caused by the a priori information but by some still unidentified problem in the radiative transfer modelling. Instead, the a priori information pushes the systematically wrong ozone profiles towards the true values. The smaller weight of the a priori information in the modified retrieval leads to better visibility of tropospheric ozone structures, because it has a smaller tendency to damp the variability of the retrievals in the troposphere. In summary, the modified retrieval unmasks systematic problems in the radiative transfer/instrument model and is more sensitive to tropospheric ozone variation; that is, it is able to capture the tropospheric ozone morphology better.
    Keywords Science ; Q ; Physics ; QC1-999 ; Meteorology. Climatology ; QC851-999 ; Environmental engineering ; TA170-171 ; Earthwork. Foundations ; TA715-787
    Subject code 290
    Language English
    Publishing date 2015-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Quantification of nitrogen oxides emissions from build-up of pollution over Paris with TROPOMI

    A. Lorente / K. F. Boersma / H. J. Eskes / J. P. Veefkind / J. H. G. M. van Geffen / M. B. de Zeeuw / H. A. C. Denier van der Gon / S. Beirle / M. C. Krol

    Scientific Reports, Vol 9, Iss 1, Pp 1-

    2019  Volume 10

    Abstract: Abstract Nitrogen dioxide (NO2) is a regulated air pollutant that is of particular concern in many cities, where concentrations are high. Emissions of nitrogen oxides to the atmosphere lead to the formation of ozone and particulate matter, with adverse ... ...

    Abstract Abstract Nitrogen dioxide (NO2) is a regulated air pollutant that is of particular concern in many cities, where concentrations are high. Emissions of nitrogen oxides to the atmosphere lead to the formation of ozone and particulate matter, with adverse impacts on human health and ecosystems. The effects of emissions are often assessed through modeling based on inventories relying on indirect information that is often outdated or incomplete. Here we show that NO2 measurements from the new, high-resolution TROPOMI satellite sensor can directly determine the strength and distribution of emissions from Paris. From the observed build-up of NO2 pollution, we find highest emissions on cold weekdays in February 2018, and lowest emissions on warm weekend days in spring 2018. The new measurements provide information on the spatio-temporal distribution of emissions within a large city, and suggest that Paris emissions in 2018 are only 5–15% below inventory estimates for 2011–2012, reflecting the difficulty of meeting NOx emission reduction targets.
    Keywords Medicine ; R ; Science ; Q
    Subject code 336
    Language English
    Publishing date 2019-12-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Simulation study of the aerosol information content in OMI spectral reflectance measurements

    B. Veihelmann / P. F. Levelt / P. Stammes / J. P. Veefkind

    Atmospheric Chemistry and Physics Discussions, Vol 7, Iss 1, Pp 1785-

    2007  Volume 1821

    Abstract: The Ozone Monitoring Instrument (OMI) is designed and used primarily to retrieve trace gases like O 3 and NO 2 from the measured Earth reflectance spectrum in the UV-visible (270–500 nm). However, also aerosols are an important science target of OMI. ... ...

    Abstract The Ozone Monitoring Instrument (OMI) is designed and used primarily to retrieve trace gases like O 3 and NO 2 from the measured Earth reflectance spectrum in the UV-visible (270–500 nm). However, also aerosols are an important science target of OMI. Therefore, a Principal Component Analysis (PCA) is performed to quantify the information content of OMI reflectance measurements on aerosols. This analysis is applied to synthetic reflectance measurements for desert dust, biomass burning aerosols, and weakly absorbing anthropogenic aerosol with a variety of aerosol optical thicknesses, aerosol layer altitudes, refractive indices and size distributions. The range of aerosol parameters considered covers the natural variability of tropospheric aerosols. This theoretical analysis is performed for a large number of scenarios with various geometries and surface albedo spectra for ocean, soil and vegetation. When the surface albedo spectrum is accurately known and clouds are absent, OMI reflectance measurements have 2 to 4 degrees of freedom that can be attributed to aerosol parameters. This information content depends on the observation geometry, the surface albedo spectrum, and on the aerosol parameters themselves. An additional wavelength band is evaluated, that comprises the O 2 -O 2 absorption band at a wavelength of 477 nm. It is found that this wavelength band adds significantly more information than any other individual band. The PCA is applied to assess the capability of the aerosol retrieval to discern various aerosol types as well as clouds.
    Keywords Environmental sciences ; GE1-350 ; Geography. Anthropology. Recreation ; G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; Geophysics. Cosmic physics ; QC801-809
    Language English
    Publishing date 2007-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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