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Littérature scientifique sur le sujet « Aerosol profile retrieval »

Auteur : Grafiati

Publié le 10 mars 2023

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Articles de revues sur le sujet "Aerosol profile retrieval"

Li, Chong, Jing Li, Oleg Dubovik, Zhao-Cheng Zeng et Yuk L. Yung. « Impact of Aerosol Vertical Distribution on Aerosol Optical Depth Retrieval from Passive Satellite Sensors ». Remote Sensing 12, n^o 9 (11 mai 2020) : 1524. http://dx.doi.org/10.3390/rs12091524.

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When retrieving Aerosol Optical Depth (AOD) from passive satellite sensors, the vertical distribution of aerosols usually needs to be assumed, potentially causing uncertainties in the retrievals. In this study, we use the Moderate Resolution Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors as examples to investigate the impact of aerosol vertical distribution on AOD retrievals. A series of sensitivity experiments was conducted using radiative transfer models with different aerosol profiles and surface conditions. Assuming a 0.2 AOD, we found that the AOD retrieval error is the most sensitive to the vertical distribution of absorbing aerosols; a −1 km error in aerosol scale height can lead to a ~30% AOD retrieval error. Moreover, for this aerosol type, ignoring the existence of the boundary layer can further result in a ~10% AOD retrieval error. The differences in the vertical distribution of scattering and absorbing aerosols within the same column may also cause −15% (scattering aerosols above absorbing aerosols) to 15% (scattering aerosols below absorbing aerosols) errors. Surface reflectance also plays an important role in affecting the AOD retrieval error, with higher errors over brighter surfaces in general. The physical mechanism associated with the AOD retrieval errors is also discussed. Finally, by replacing the default exponential profile with the observed aerosol vertical profile by a micro-pulse lidar at the Beijing-PKU site in the VIIRS retrieval algorithm, the retrieved AOD shows a much better agreement with surface observations, with the correlation coefficient increased from 0.63 to 0.83 and bias decreased from 0.15 to 0.03. Our study highlights the importance of aerosol vertical profile assumption in satellite AOD retrievals, and indicates that considering more realistic profiles can help reduce the uncertainties.

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Loughman, Robert, Pawan K. Bhartia, Zhong Chen, Philippe Xu, Ernest Nyaku et Ghassan Taha. « The Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) Version 1 aerosol extinction retrieval algorithm : theoretical basis ». Atmospheric Measurement Techniques 11, n^o 5 (4 mai 2018) : 2633–51. http://dx.doi.org/10.5194/amt-11-2633-2018.

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Abstract. The theoretical basis of the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) Version 1 aerosol extinction retrieval algorithm is presented. The algorithm uses an assumed bimodal lognormal aerosol size distribution to retrieve aerosol extinction profiles at 675 nm from OMPS LP radiance measurements. A first-guess aerosol extinction profile is updated by iteration using the Chahine nonlinear relaxation method, based on comparisons between the measured radiance profile at 675 nm and the radiance profile calculated by the Gauss–Seidel limb-scattering (GSLS) radiative transfer model for a spherical-shell atmosphere. This algorithm is discussed in the context of previous limb-scattering aerosol extinction retrieval algorithms, and the most significant error sources are enumerated. The retrieval algorithm is limited primarily by uncertainty about the aerosol phase function. Horizontal variations in aerosol extinction, which violate the spherical-shell atmosphere assumed in the version 1 algorithm, may also limit the quality of the retrieved aerosol extinction profiles significantly.

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Taha, G., D. F. Rault, R. P. Loughman, A. E. Bourassa et C. von Savigny. « SCIAMACHY stratospheric aerosol extinction profile retrieval ». Atmospheric Measurement Techniques Discussions 3, n^o 6 (24 novembre 2010) : 5343–74. http://dx.doi.org/10.5194/amtd-3-5343-2010.

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Abstract. The Ozone Mapper and Profiler Suite Limp Profiler (OMPS/LP) algorithm is used to retrieve ozone and aerosol profiles using a series of 120 SCIAMACHY limb measurements collocated with SAGE II solar occultation events. The primary goal of the study is to ascertain the capability of the OMPS/LP retrieval algorithm to accurately retrieve the vertical distribution of stratospheric aerosol extinction coefficient so as to better account for aerosol effects in the ozone profiling retrieval process. Using simulated radiances, we show that the aerosol extinction coefficient can be retrieved from limb scatter measurements within 5% and a standard deviation better than 15%, which is more than sufficient to improve the OMPS/LP ozone products to be used as Environmental Data Records. We also illustrate the ability of SCIAMACHY limb measurements to retrieve stratospheric aerosol profiles with accuracy comparable to other instruments. The retrieved aerosol profiles agree with collocated SAGE II measurements on average to within 25%, with a standard deviation of 35%.

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Geddes, A., et H. Bösch. « Aerosol profile information from high resolution oxygen A-Band measurements from space ». Atmospheric Measurement Techniques Discussions 7, n^o 6 (17 juin 2014) : 6021–63. http://dx.doi.org/10.5194/amtd-7-6021-2014.

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Abstract. Aerosols are an important factor of the Earth climatic system and they play a key role for air quality and public health. Observations of the oxygen A-Band at 760 nm can provide information on the vertical distribution of aerosols from passive satellite sensors, that can be of great interest for operational monitoring applications with high coverage if the aerosol information is obtained with sufficient precision, accuracy and vertical resolution. To address this issue, retrieval simulations of the aerosol vertical profile retrieval from O2 A Band observations by GOSAT, the upcoming OCO-2 and Sentinel 5-P mission and the proposed CarbonSat mission have been carried out. Precise retrievals of AOD within the boundary layer were found to favour low resolution, high SNR instruments such as Sentinel-5 P, whereas higher resolution instruments such as OCO-2 showed greater performance at higher altitudes and in information content above the boundary layer. Accurate retrievals of the AOD in the 0–2 km range appears difficult from all studied instruments and the retrieval errors typically exceed a value of 0.05. Constraining the surface albedo is a promising and effective way of improving the retrieval of aerosol, but the required level of a priori knowledge is very high. Due to the limited information content of the aerosol profile retrieval, the use of a parameterised aerosol distribution has been assessed and we show that the AOD and height of an aerosol layer can be retrieved well if the aerosol layer is uplifted to the free troposphere but errors are often large for aerosol layers in the boundary layer. Additional errors will be introduced by incorrect assumptions on surface pressure and aerosol type which can both bias retrieved AOD and height by up to 40%. We conclude the aerosol profile retrievals from O2 A Band using existing or upcoming satellite sensors will only provide limited information on aerosols in the boundary layer but such observations can be of great value for observing and mapping aerosol plumes in the free troposphere.

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Geddes, A., et H. Bösch. « Tropospheric aerosol profile information from high-resolution oxygen A-band measurements from space ». Atmospheric Measurement Techniques 8, n^o 2 (20 février 2015) : 859–74. http://dx.doi.org/10.5194/amt-8-859-2015.

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Abstract. Aerosols are an important factor in the Earth climatic system and they play a key role in air quality and public health. Observations of the oxygen A-band at 760 nm can provide information on the vertical distribution of aerosols from passive satellite sensors that can be of great interest for operational monitoring applications with high spatial coverage if the aerosol information is obtained with sufficient precision, accuracy and vertical resolution. To address this issue, retrieval simulations of the aerosol vertical profile retrieval from O2 A-band observations by GOSAT, the upcoming Orbiting Carbon Observatory-2 (OCO-2) and Sentinel 5-P missions, and the proposed CarbonSat mission have been carried out. Precise retrievals of aerosol optical depth (AOD) within the boundary layer were found to favour low-resolution, high signal-to-noise instruments such as Sentinel-5 P, whereas higher-resolution instruments such as OCO-2 showed greater performance at higher altitudes and in information content above the boundary layer. Retrieval of the AOD in the 0–2 km range with precision appears difficult from all studied instruments and the retrieval errors typically exceed a value of 0.05 for AODs up to 0.3. Constraining the surface albedo is a promising and effective way of improving the retrieval of aerosol, but the accuracy of the required prior knowledge is very high. Due to the limited information content of the aerosol profile retrieval, the use of a parameterised aerosol distribution is assessed, and we show that the AOD and height of an aerosol layer can be retrieved well if the aerosol layer is uplifted to the free troposphere; however, errors are often large for aerosol layers in the boundary layer. Additional errors are introduced by incorrect assumptions on surface pressure and aerosol mixture, which can both bias retrieved AOD and height by up to 45%. In addition, assumptions of the boundary layer temperature are found to yield an additional error of up to 8%. We conclude that the aerosol profile retrievals from O2 A-band using existing or upcoming satellite sensors will only provide limited information on aerosols in the boundary layer but such observations can be of great value for observing and mapping aerosol plumes in the free troposphere.

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Lin, J. T., R. V. Martin, K. F. Boersma, M. Sneep, P. Stammes, R. Spurr, P. Wang, M. Van Roozendael, K. Clémer et H. Irie. « Retrieving tropospheric nitrogen dioxide over China from the Ozone Monitoring Instrument : effects of aerosols, surface reflectance anisotropy and vertical profile of nitrogen dioxide ». Atmospheric Chemistry and Physics Discussions 13, n^o 8 (14 août 2013) : 21203–57. http://dx.doi.org/10.5194/acpd-13-21203-2013.

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Abstract. Retrievals of tropospheric nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) are subject to errors in the treatments of aerosols, surface reflectance anisotropy, and vertical profile of NO2. Here we quantify the influences over China via an improved retrieval process. We explicitly account for aerosol optical effects (simulated by nested GEOS-Chem at 0.667° lon × 0.5° lat and constrained by aerosol measurements), surface reflectance anisotropy, and high-resolution vertical profiles of NO2 (simulated by GEOS-Chem). Prior to the NO2 retrieval, we derive the cloud information using consistent ancillary assumptions. We compare our retrieval to the widely used DOMINO v2 product, using as reference MAX-DOAS measurements at three urban/suburban sites in East China and focusing the analysis on the 127 OMI pixels (in 30 days) closest to the MAX-DOAS sites. We find that our retrieval reduces the interference of aerosols on the retrieved cloud properties, thus enhancing the number of valid OMI pixels by about 25%. Compared to DOMINO v2, our retrieval improves the correlation with the MAX-DOAS data in the day-to-day variability of NO2 (R2 = 0.96 vs. 0.72). Our retrieved NO2 columns are about 50% of the MAX-DOAS data on average. This reflects the inevitable spatial inconsistency between the two types of measurement, uncertainties in MAX-DOAS data, and residual uncertainties in our OMI retrievals related to aerosols and vertical profile of NO2. Through a series of tests, we find that excluding aerosol scattering/absorption can either increase or decrease the retrieved NO2, with a mean absolute difference by about 20%. Concentrating aerosols at the boundary layer top enhances the retrieved NO2 by 8% on average with a mean absolute difference by 23%. The aerosol perturbations also affect nonlinearly the retrieved cloud fraction and particularly cloud pressure. Employing various surface albedo datasets alters the retrieved NO2 by 0–7% on average. The retrieved NO2 columns increase when the NO2 profiles are taken from MAX-DOAS retrievals (by 20% on average) or TM4 simulations (by 10%) instead of GEOS-Chem simulations. Our findings are also relevant to retrievals of other pollutants (e.g., sulfur dioxide, formaldehyde, glyoxal) from UV-vis backscatter satellite instruments.

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Lin, J. T., R. V. Martin, K. F. Boersma, M. Sneep, P. Stammes, R. Spurr, P. Wang, M. Van Roozendael, K. Clémer et H. Irie. « Retrieving tropospheric nitrogen dioxide from the Ozone Monitoring Instrument : effects of aerosols, surface reflectance anisotropy, and vertical profile of nitrogen dioxide ». Atmospheric Chemistry and Physics 14, n^o 3 (7 février 2014) : 1441–61. http://dx.doi.org/10.5194/acp-14-1441-2014.

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Abstract. Retrievals of tropospheric nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) are subject to errors in the treatments of aerosols, surface reflectance anisotropy, and vertical profile of NO2. Here we quantify the influences over China via an improved retrieval process. We explicitly account for aerosol optical effects (simulated by nested GEOS-Chem at 0.667° long. × 0.5° lat. and constrained by aerosol measurements), surface reflectance anisotropy, and high-resolution vertical profiles of NO2 (simulated by GEOS-Chem). Prior to the NO2 retrieval, we derive the cloud information using consistent ancillary assumptions. We compare our retrieval to the widely used DOMINO v2 product, using MAX-DOAS measurements at three urban/suburban sites in East China as reference and focusing the analysis on the 127 OMI pixels (in 30 days) closest to the MAX-DOAS sites. We find that our retrieval reduces the interference of aerosols on the retrieved cloud properties, thus enhancing the number of valid OMI pixels by about 25%. Compared to DOMINO v2, our retrieval better captures the day-to-day variability in MAX-DOAS NO2 data (R2 = 0.96 versus 0.72), due to pixel-specific radiative transfer calculations rather than the use of a look-up table, explicit inclusion of aerosols, and consideration of surface reflectance anisotropy. Our retrieved NO2 columns are 54% of the MAX-DOAS data on average, reflecting the inevitable spatial inconsistency between the two types of measurement, errors in MAX-DOAS data, and uncertainties in our OMI retrieval related to aerosols and vertical profile of NO2. Sensitivity tests show that excluding aerosol optical effects can either increase or decrease the retrieved NO2 for individual OMI pixels with an average increase by 14%. Excluding aerosols also complexly affects the retrievals of cloud fraction and particularly cloud pressure. Employing various surface albedo data sets slightly affects the retrieved NO2 on average (within 10%). The retrieved NO2 columns increase when the NO2 profiles are taken from MAX-DOAS retrievals (by 19% on average) or TM4 simulations (by 13%) instead of GEOS-Chem simulations. Our findings are also relevant to retrievals of other pollutants (e.g., sulfur dioxide, ormaldehyde, glyoxal) from UV–visible backscatter satellite instruments.

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Ernst, F., C. von Savigny, A. Rozanov, V. Rozanov, K. U. Eichmann, L. A. Brinkhoff, H. Bovensmann et J. P. Burrows. « Global stratospheric aerosol extinction profile retrievals from SCIAMACHY limb-scatter observations ». Atmospheric Measurement Techniques Discussions 5, n^o 4 (21 août 2012) : 5993–6035. http://dx.doi.org/10.5194/amtd-5-5993-2012.

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Abstract. Stratospheric aerosol extinction profiles are retrieved from SCIAMACHY/Envisat limb-scatter observations in the visible spectral range. The retrieval algorithm is based on a colour-index approach using the normalized limb-radiance profiles at 470 nm and 750 nm wavelength. The optimal estimation approach in combination with the radiative transfer model SCIATRAN is employed for the retrievals. This study presents a detailed description of the retrieval algorithm, and a sensitivity analysis investigating the impact of the most important parameters that affect the aerosol extinction profile retrieval accuracy. It is found that the parameter with the largest impact is surface albedo, particularly for SCIAMACHY observations in the Southern Hemisphere where the error in stratospheric aerosol extinction can be up to 50% if the surface albedo is not well known. The effect of errors in the assumed ozone and neutral density profiles on the aerosol profile retrievals is with generally less than 6% relatively small. The aerosol extinction profiles retrieved from SCIAMACHY are compared with co-located SAGE II solar occultation measurements of stratospheric aerosol extinction during the period 2003–2005. The mean aerosol extinction profiles averaged over all co-locations agree to within 20% between 15 and 35 km altitude. However, larger differences are observed at specific latitudes.

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Taha, G., D. F. Rault, R. P. Loughman, A. E. Bourassa et C. von Savigny. « SCIAMACHY stratospheric aerosol extinction profile retrieval using the OMPS/LP algorithm ». Atmospheric Measurement Techniques 4, n^o 3 (16 mars 2011) : 547–56. http://dx.doi.org/10.5194/amt-4-547-2011.

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Abstract. The Ozone Mapper and Profiler Suite, Limp Profiler (OMPS/LP) algorithm is used to retrieve ozone concentration and aerosol extinction profiles using a series of 120 SCIAMACHY limb measurements collocated with SAGE II solar occultation events. The primary goal of the study is to ascertain the capability of the OMPS/LP retrieval algorithm to accurately retrieve the vertical distribution of stratospheric aerosol extinction coefficient so as to better account for aerosol effects in the ozone profiling retrieval process. Using simulated radiances, we show that the aerosol extinction coefficient can be retrieved from limb scatter measurements within 5% and a standard deviation better than 15%, which is more than sufficient to improve the OMPS/LP ozone products to be used as Environmental Data Records. We also illustrate the ability of SCIAMACHY limb measurements to retrieve stratospheric aerosol extinction profiles with accuracy comparable to other instruments. The retrieved aerosol extinction profiles agree with collocated SAGE II measurements on average to within 25%, with a standard deviation of 35%.

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Sanders, A. F. J., J. F. de Haan, M. Sneep, A. Apituley, P. Stammes, M. O. Vieitez, L. G. Tilstra, O. N. E. Tuinder, C. E. Koning et J. P. Veefkind. « Evaluation of the operational Aerosol Layer Height retrieval algorithm for Sentinel-5 Precursor : application to O<sub>2</sub> ; A band observations from GOME-2A ». Atmospheric Measurement Techniques 8, n^o 11 (25 novembre 2015) : 4947–77. http://dx.doi.org/10.5194/amt-8-4947-2015.

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Abstract. An algorithm setup for the operational Aerosol Layer Height product for TROPOMI on the Sentinel-5 Precursor mission is described and discussed, applied to GOME-2A data, and evaluated with lidar measurements. The algorithm makes a spectral fit of reflectance at the O2 A band in the near-infrared and the fit window runs from 758 to 770 nm. The aerosol profile is parameterised by a scattering layer with constant aerosol volume extinction coefficient and aerosol single scattering albedo and with a fixed pressure thickness. The algorithm's target parameter is the height of this layer. In this paper, we apply the algorithm to observations from GOME-2A in a number of systematic and extensive case studies, and we compare retrieved aerosol layer heights with lidar measurements. Aerosol scenes cover various aerosol types, both elevated and boundary layer aerosols, and land and sea surfaces. The aerosol optical thicknesses for these scenes are relatively moderate. Retrieval experiments with GOME-2A spectra are used to investigate various sensitivities, in which particular attention is given to the role of the surface albedo. From retrieval simulations with the single-layer model, we learn that the surface albedo should be a fit parameter when retrieving aerosol layer height from the O2 A band. Current uncertainties in surface albedo climatologies cause biases and non-convergences when the surface albedo is fixed in the retrieval. Biases disappear and convergence improves when the surface albedo is fitted, while precision of retrieved aerosol layer pressure is still largely within requirement levels. Moreover, we show that fitting the surface albedo helps to ameliorate biases in retrieved aerosol layer height when the assumed aerosol model is inaccurate. Subsequent retrievals with GOME-2A spectra confirm that convergence is better when the surface albedo is retrieved simultaneously with aerosol parameters. However, retrieved aerosol layer pressures are systematically low (i.e., layer high in the atmosphere) to the extent that retrieved values no longer realistically represent actual extinction profiles. When the surface albedo is fixed in retrievals with GOME-2A spectra, convergence deteriorates as expected, but retrieved aerosol layer pressures become much higher (i.e., layer lower in atmosphere). The comparison with lidar measurements indicates that retrieved aerosol layer heights are indeed representative of the underlying profile in that case. Finally, subsequent retrieval simulations with two-layer aerosol profiles show that a model error in the assumed profile (two layers in the simulation but only one in the retrieval) is partly absorbed by the surface albedo when this parameter is fitted. This is expected in view of the correlations between errors in fit parameters and the effect is relatively small for elevated layers (less than 100 hPa). If one of the scattering layers is near the surface (boundary layer aerosols), the effect becomes surprisingly large, in such a way that the retrieved height of the single layer is above the two-layer profile. Furthermore, we find that the retrieval solution, once retrieval converges, hardly depends on the starting values for the fit. Sensitivity experiments with GOME-2A spectra also show that aerosol layer height is indeed relatively robust against inaccuracies in the assumed aerosol model, even when the surface albedo is not fitted. We show spectral fit residuals, which can be used for further investigations. Fit residuals may be partly explained by spectroscopic uncertainties, which is suggested by an experiment showing the improvement of convergence when the absorption cross section is scaled in agreement with Butz et al. (2013) and Crisp et al. (2012), and a temperature offset to the a priori ECMWF temperature profile is fitted. Retrieved temperature offsets are always negative and quite large (ranging between −4 and −8 K), which is not expected if temperature offsets absorb remaining inaccuracies in meteorological data. Other sensitivity experiments investigate fitting of stray light and fluorescence emissions. We find negative radiance offsets and negative fluorescence emissions, also for non-vegetated areas, but from the results it is not clear whether fitting these parameters improves the retrieval. Based on the present results, the operational baseline for the Aerosol Layer Height product currently will not fit the surface albedo. The product will be particularly suited for elevated, optically thick aerosol layers. In addition to its scientific value in climate research, anticipated applications of the product for TROPOMI are providing aerosol height information for aviation safety and improving interpretation of the Absorbing Aerosol Index.

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Thèses sur le sujet "Aerosol profile retrieval"

Liu, Lixian. « The effect of order of inversion on SAGE II profile retrieval ». Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/25866.

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Pitts, Michael Charles. « Retrieval of temperature and pressure profiles for the Stratospheric Aerosol and Gas Experiment III ». W&M ScholarWorks, 1999. https://scholarworks.wm.edu/etd/1539623950.

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The goals of this research are to develop an algorithm to operationally retrieve profiles of atmospheric temperature and pressure for the upcoming Stratospheric Aerosol and Gas Experiment (SAGE) III satellite missions, validate the approach through simulated retrievals, and derive an error budget for the retrieved products. The retrieval algorithm is based on SAGE III multi-spectral measurements of the oxygen A-band absorption feature centered near 762 nm. The retrieved products will consist of vertical profiles of temperature and pressure at 1-km intervals from 1 to 85 km.;The A-band absorptivity measurements are dependent on temperature and pressure in a complicated, non-linear fashion and, as a result, an iterative retrieval approach has been proposed. The retrieval algorithm uses a global fitting technique that solves for successive adjustments to trial solution temperature and pressure profiles by minimizing the residuals between the SAGE III measured absorptivities and a set of modeled absorptivities produced from a numerical model of the measurements. A modified Levenberg-Marquardt non-linear least squares routine is used to perform the minimization.;The feasibility of the proposed retrieval algorithm was demonstrated through a series of simulation studies using synthetic measurements with realistic noise. The sensitivity of the retrievals to measurement noise increases significantly above 40 km and induces undesirable oscillations in the retrieved profiles. The implementation of an implicit hydrostatic constraint was shown to effectively reduce the magnitude of these noise-induced oscillations. A statistical analysis based on sixty simulations indicates that the retrieval algorithm introduces negligible bias in the solution profiles and produces consistent results for all atmospheric conditions.;A formal characterization and error analysis was performed on the retrievals. Potential sources of random and systematic uncertainty were identified and a comprehensive error budget for the temperature and pressure retrievals was derived. The estimated accuracy of the temperature retrievals is better than 2 K below 55 km, but increases to 4.5 K at 85 km. The estimated accuracy of the pressure retrievals is better than 2% at all altitudes. Based on this assessment, the retrieved products will meet the SAGE III algorithm and science requirements for temperature and pressure measurements.

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Ernst, Florian [Verfasser], John [Akademischer Betreuer] Burrows et Otto [Akademischer Betreuer] Schrems. « Stratospheric aerosol extinction profile retrievals from SCIAMACHY limb-scatter observations / Florian Ernst. Gutachter : John Burrows ; Otto Schrems. Betreuer : John Burrows ». Bremen : Staats- und Universitätsbibliothek Bremen, 2013. http://d-nb.info/1072078414/34.

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Yilmaz, Selami [Verfasser], et Ulrich [Akademischer Betreuer] Platt. « Retrieval of Atmospheric Aerosol and Trace Gas Vertical Profiles using Multi-Axis Differential Optical Absorption Spectroscopy / Selami Yilmaz ; Betreuer : Ulrich Platt ». Heidelberg : Universitätsbibliothek Heidelberg, 2012. http://d-nb.info/1179783867/34.

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Corradini, S. « Aerosol extinction coefficient profile retrieval procedure for satellite measurements in multiple scattering atmosphere ». Thesis, 2004. http://hdl.handle.net/2122/4762.

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The aim of this work is to develop a multiple scattering inversion procedure for the aerosol extinction coefficient profile retrieval and error assessment for nadir and multi-angle passive remote sensing instruments. The procedure will be applied for the tropospheric aerosol extinction coefficient profile retrieval from SCIAMACHY nadir simulated measurements using atmospheric windows and oxygen A-band wavelengths. Also the contemporary use of atmospheric windows and oxygen A-band wavelengths will be discussed. SCIAMACHY simulated measurement has been used because, due to calibration real data procedure problems, until now SCIAMACHY data are not available.
Università degli Studi di Genova. DIpartimento Per lo studio del TErritorio e delle sue RISorse (DIPTERIS)
Unpublished
1.10. TTC - Telerilevamento
open

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Chapitres de livres sur le sujet "Aerosol profile retrieval"

Rosenfeld, Daniel. « Cloud-Aerosol-Precipitation Interactions Based of Satellite Retrieved Vertical Profiles of Cloud Microstructure ». Dans Remote Sensing of Aerosols, Clouds, and Precipitation, 129–52. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-810437-8.00006-2.

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Ansmann, Albert. « Molecular-Backscatter Lidar Profiling of the Volume-Scattering Coefficient in Cirrus ». Dans Cirrus. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195130720.003.0013.

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Backscatter and polarization lidars have already been used extensively to investigate ice clouds (see chapters 2 and 10). A severe limitation is that trustworthy values of the volume-scattering coefficient, one of the most important parameters in the description of the impact of cirrus on climate, cannot be derived from data taken with these lidars. Even the retrieved cirrus backscatter-coefficient profile is often questionable. A discussion of achievements and limitations of the lidar method can be found in the literature (e.g., Fernald et al. 1972; Klett 1981; Fernald 1984; Klett 1985; Sasano et al. 1985; Bissonnette 1986; Ansmann et al. 1992b; Kovalev 1995). The procedure, with all its subsequent modifications and improvements, suffers from the fact that two physical quantities, the particle backscatter coefficient and the particle extinction coefficient, must be determined from only one lidar signal. The uncertainties in the estimated optical parameters are especially large in cirrus, in which the relationship between particle extinction and backscattering can vary strongly in space and time. The situation improved significantly when the first molecular (Raman)-backscatter lidar experiments demonstrated that accurate extinction profiling throughout the entire troposphere is possible (Ansmann et al. 1990, 1992b). After the Pinatubo eruption, it was shown that even at stratospheric heights profiles of the volume-scattering coefficient can easily be obtained with a Raman lidar (Ansmann et al. 1991, 1993a, 1997; Ferrare et al. 1992; Gross et al. 1995; Donavan und Carswell 1997). Two types of molecular-backscatter lidars for extinction measurements are available. The Raman lidar measures lidar return signals elastically backscattered by air molecules and particles and inelastically (Raman) backscattered by nitrogen and/or oxygen molecules (Cooney et al. 1969; Melfi 1972; Ansmann et al. 1992a; Whiteman et al. 1992; Reichardt et al. 1996). Interference-filter polychromators and double-grating monochromators (Arshinov et al. 1983; Wandinger et al. 1998) are used to separate the aerosol signal from the vibrational-rotational or pure rotational Raman signals, to reduce the sky background radiation, and, for the Raman channels, to block the strong elastic-backscatter radiation at the laser wavelength. The suppression has to be better than 10-8. The second type of a molecular-backscatter lidar is the High Spectral Resolution Lidar (HSRL).

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Actes de conférences sur le sujet "Aerosol profile retrieval"

Shan, Huihui, Hui Zhang, Junjian Liu, Shenhao Wang, Xiaomin Ma, Lianqing Zhang, Dong Liu, Chenbo Xie et Zongming Tao. « Retrieval method of aerosol extinction coefficient profile by an integral lidar system and case study ». Dans Fourth Seminar on Novel Optoelectronic Detection Technology and Application, sous la direction de Weiqi Jin et Ye Li. SPIE, 2018. http://dx.doi.org/10.1117/12.2314300.

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Wang, Zhuoru, Ka Lok Chan, Klaus-Peter Heue et Matthias Wiegner. « Aerosol Profile Retrieval from a High-altitude MAX-DOAS Measurement using a Parameterized Look-up Table Method ». Dans Hyperspectral Imaging and Sounding of the Environment. Washington, D.C. : OSA, 2018. http://dx.doi.org/10.1364/hise.2018.hw3c.5.

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Kovalev, Vladimir A., et Ramesh Viswanathan. « Application of a New Iterative Technique for Determining Particulate Extinction Profiles from Airborne Lidar Data Obtained in Clear Tropospheric Conditions ». Dans Optical Remote Sensing of the Atmosphere. Washington, D.C. : Optica Publishing Group, 1993. http://dx.doi.org/10.1364/orsa.1993.the.21.

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In this paper we present preliminary results of the application and potential of a new iterative extinction profile retrieval technique for lidar measurements. Lidar data were collected during May 11-14, 1992, in the Detroit, Michigan area, using a compact airborne nadir looking UV-DIAL.1,2 The system was developed for making simultaneous measurements of ozone, sulfur dioxide, and aerosol distributions in the lowest 3-4 km. of the troposphere. The aerosol data are used to obtain semi-quantitative information relating to the atmospheric boundary-layer structure and to develop correction procedure for the DIAL-derived concentrations that are influenced by differential scattering and extinction effects.

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Grabowski, Jozef, et Alexandros Papayannis. « Lidar inversion algorithm for the simultaneous retrieval of the vertical profile of the aerosol extinction and backscattering coefficients in the troposphere ». Dans Industrial Lasers and Inspection (EUROPTO Series), sous la direction de Michel R. Carleer, Moira Hilton, Torsten Lamp, Rainer Reuter, George M. Russwurm, Klaus Schaefer, Konradin Weber, Klaus C. H. Weitkamp, Jean-Pierre Wolf et Ljuba Woppowa. SPIE, 1999. http://dx.doi.org/10.1117/12.364212.

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Chu, W. P. « Estimation of aerosol optical properties from the Inversion of extinction measurements ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.ww1.

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This paper deals with the problem of estimating the optical properties of aerosols based on a finite number of extinction measurements. This kind of problem arises in many situations involving the remote sensing of aerosols with optical instrumentation such as radiometers for extinction measurements and lidar systems for backscattering measurements. A technique has been developed so that extinction measurements at a finite number of spectral regions can be inverted directly to yield either extinction or backscattering values at other wavelength regions without solving for the aerosol size distribution function. This technique is based on the inversion method developed by Backus and Gilbert. The approach has been successfully used in the retrieval algorithm for the SAGE II satellite measurements of aerosol and ozone vertical profiles. Extension of this method to the conversion of extinction measurements into backscattering values has been applied to the comparison of SAGE II aerosol extinction data with coincident lidar backscattering measurements.

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Longtin, D. R., E. P. Shettle et J. R. Hummel. « Using Satellite Aerosol Optical Depths to Estimate Surface Meteorological Ranges and Aerosol Vertical Profiles ». Dans Optical Remote Sensing of the Atmosphere. Washington, D.C. : Optica Publishing Group, 1990. http://dx.doi.org/10.1364/orsa.1990.tud14.

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NOAA/NESDIS is producing on an experimental basis global data sets of total aerosol optical depth over oceans. These data are derived from the Advanced Very High Resolution Radiometer (AVHRR) measurements aboard NOAA polar orbiting satellites. Effectively, the retrieval algorithm correlates aerosol optical thickness with the radiance from the upwelling Channel 1 (0.58-0.68 μm) as described by Rao et al.1 and Griggs and Stowe2. Regions containing clouds have been filtered out in the aerosol retrieval algorithm.

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Larsen, J. C., W. P. Chu, M. P. McCormick et D. Rind. « Aspects of the SAGE III/Eos Water Vapor Retrieval ». Dans Optical Remote Sensing of the Atmosphere. Washington, D.C. : Optica Publishing Group, 1990. http://dx.doi.org/10.1364/orsa.1990.wc3.

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The utility of the solar occultation remote sensing technique for providing accurate, high vertical resolution, global distributions of aerosols and atmospheric gases is now well established following a number of space flight experiments; SAM II (McCormick et al., 1979), SAGE (McCormick et al., 1979), and SAGE II (McMaster, 1986). The Stratospheric Aerosol and Gas Experiment (SAGE III) will continue these measurements through the Eos era. SAGE III has been chosen for definition phase study(phase B) for both the NASA Polar Orbiting Platform (NPOP) and the Space Station Freedom Attached Payload (SSF/AP) of Eos. Like SAGE II, SAGE III will measure aerosols, ozone, nitrogen dioxide, and water vapor. Enhanced measurement capabilities include coverage of the oxygen-A band from which pressure and temperature profiles will be inferred (Chu et al., 1990), additional aerosol channels, and an additional channel for mesospheric ozone. Spectral coverage of the water vapor band will be expanded to most of the band at higher resolution. Twenty radiometric channels, each with 2 nm spectral resolution, provide contiguous coverage from 920 nm to 960 nm. This paper examines how the multiple channel measurements may be best used to minimize uncertainties in the retrieved water vapor and to optimize vertical coverage.

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McGee, T. J., D. Whiteman, Jim Butler, A. Torres, J. Miller, R. Ferrare, J. Burris, M. Owens, R. Barnes et R. Nagatani. « Lidar Observations of Upper Atmosphere Temperatures During the Stoic Campaign at Table Mountain ». Dans Optical Remote Sensing of the Atmosphere. Washington, D.C. : Optica Publishing Group, 1990. http://dx.doi.org/10.1364/orsa.1990.wd20.

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In July, 1989, the Goddard Space Flight Center mobile stratospheric lidar was deployed at JPL's Table Mountain Facility in the San Gabriel Mountains east of Los Angeles (34.4N, 117.7W). The purpose was a major intercomparison of ozone sensors in order to validate the lidar technique as a reliable, accurate and precise instrument for the measurement of stratospheric ozone. The GSFC lidar data have also been used to extract a temperature profile between 30 and 65 km. The temperature retrieval utilizes the ozone profile reference wavelength (355 nm) which is essentially no absorption due to ozone. Because the retrieval is sensitive to aerosols, no attempt is made to extract temperature below 30 km.

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Post, Madison J., Christian J. Grund et Terry Deshler. « Measuring the Microphysical Evolution of Mt. Pinatubo Aerosols by Multiwavelength Lidar Backscattering ». Dans Optical Remote Sensing of the Atmosphere. Washington, D.C. : Optica Publishing Group, 1997. http://dx.doi.org/10.1364/orsa.1997.omb.3.

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From July 28, 1991 until September 26, 1993 NOAA researchers collected 45 nearly simultaneous, collocated, vertical backscatter profiles with ruby (0.693 μm) and CO2 (10.591 μm) lidars near Boulder, Colorado. We used a graphical technique (Post, 1996) to retrieve information on the microphysical nature of stratospheric aerosol particles arising from the June 15, 1991, eruption of Mt. Pinatubo in the Philippines (15.14°, 120.35°E). Normally three independent backscatter measurements are needed to recover three model size distribution parameters, such as the three lognormal parameters of number density, median radius, and standard deviation. Instead we constrained our solutions using contemporaneous, in-situ, optical particle counter (OPC)-derived, unimodal, lognormal standard deviations from the University of Wyoming’s balloonborne sounding taken 100 km to the north (Deshler et al., 1993), and then retrieved median radius and number density.

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Jingmei, Yang, et Zong Xuemei. « The retrieval of stratospheric aerosol extinction profiles from limb scatter measurements ». Dans IGARSS 2015 - 2015 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2015. http://dx.doi.org/10.1109/igarss.2015.7326600.

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