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Hannadige NK, Zhai PW, Werdell PJ, Gao M, Franz BA, Knobelspiesse K, Ibrahim A. Optimizing retrieval spaces of bio-optical models for remote sensing of ocean color. APPLIED OPTICS 2023; 62:3299-3309. [PMID: 37132830 DOI: 10.1364/ao.484082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We investigated the optimal number of independent parameters required to accurately represent spectral remote sensing reflectances (R rs) by performing principal component analysis on quality controlled in situ and synthetic R rs data. We found that retrieval algorithms should be able to retrieve no more than four free parameters from R rs spectra for most ocean waters. In addition, we evaluated the performance of five different bio-optical models with different numbers of free parameters for the direct inversion of in-water inherent optical properties (IOPs) from in situ and synthetic R rs data. The multi-parameter models showed similar performances regardless of the number of parameters. Considering the computational cost associated with larger parameter spaces, we recommend bio-optical models with three free parameters for the use of IOP or joint retrieval algorithms.
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Li LW, Rubin NA, Juhl M, Park JS, Capasso F. Evaluation and characterization of imaging polarimetry through metasurface polarization gratings. APPLIED OPTICS 2023; 62:1704-1722. [PMID: 37132917 DOI: 10.1364/ao.480487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Metasurfaces are a new class of diffractive optical elements with subwavelength elements whose behavior can be lithographically tailored. By leveraging form birefringence, metasurfaces can serve as multifunctional freespace polarization optics. Metasurface gratings are novel, to the best of our knowledge, polarimetric components that integrate multiple polarization analyzers into a single optical element enabling the realization of compact imaging polarimeters. The promise of metasurfaces as a new polarization building block is contingent on the calibration of metagrating-based optical systems. A prototype metasurface full Stokes imaging polarimeter is compared to a benchtop reference instrument using an established linear Stokes test for 670, 532, and 460 nm gratings. We propose a complementary full Stokes accuracy test and demonstrate it using the 532 nm grating. This work presents methods and practical considerations involved in producing accurate polarization data from a metasurface-based Stokes imaging polarimeter and informs their use in polarimetric systems more generally.
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Hannadige NK, Zhai PW, Gao M, Franz BA, Hu Y, Knobelspiesse K, Jeremy Werdell P, Ibrahim A, Cairns B, Hasekamp OP. Atmospheric correction over the ocean for hyperspectral radiometers using multi-angle polarimetric retrievals. OPTICS EXPRESS 2021; 29:4504-4522. [PMID: 33771027 DOI: 10.1364/oe.408467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
We developed a fast and accurate polynomial based atmospheric correction (POLYAC) algorithm for hyperspectral radiometric measurements, which parameterizes the atmospheric path radiances using aerosol properties retrieved from co-located multi-wavelength multi-angle polarimeter (MAP) measurements. This algorithm has been applied to co-located spectrometer for planetary exploration (SPEX) airborne and research scanning polarimeter (RSP) measurements, where SPEX airborne was used as a proxy of hyperspectral radiometers, and RSP as the MAP. The hyperspectral remote sensing reflectance obtained from POLYAC is accurate when compared to Aerosol Robotic Network (AERONET), and Visible Infrared Imaging Radiometer Suite (VIIRS) ocean color products. POLYAC provides a robust alternative atmospheric correction algorithm for hyperspectral or multi-spectral radiometric measurements for scenes involving coastal oceans and/or absorbing aerosols, where traditional atmospheric correction algorithms are less reliable.
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Li D, Chen F, Zeng N, Qiu Z, He H, He Y, Ma H. Study on polarization scattering applied in aerosol recognition in the air. OPTICS EXPRESS 2019; 27:A581-A595. [PMID: 31252839 DOI: 10.1364/oe.27.00a581] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
In this work, we present an in situ online aerosol recognition scheme by synchronized parallel polarization scattering analysis. By theoretical simulations, we select the feasible scattering angles and evaluate the potential of Stokes parameters to identify aerosols. Correspondingly, we develop a measurement system based on multi-angle optical scattering and multidimensional polarization analyzing technique. We construct two index groups based on non-normalized and normalized polarization parameters respectively, and employ their frequency distribution histograms instead of the simple average values to identify and classify different types of aerosols. The experimental verification confirms a future way of a multi-dimensional polarization parameter group applied in a fast and effective air pollutants monitoring.
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Optimal Estimation Retrieval of Aerosol Fine-Mode Fraction from Ground-Based Sky Light Measurements. ATMOSPHERE 2019. [DOI: 10.3390/atmos10040196] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this paper, the feasibility of retrieving the aerosol fine-mode fraction (FMF) from ground-based sky light measurements is investigated. An inversion algorithm, based on the optimal estimation (OE) theory, is presented to retrieve FMF from single-viewing multi-spectral radiance measurements and to evaluate the impact of utilization of near-infrared (NIR) measurements at a wavelength of 1610 nm in aerosol remote sensing. Self-consistency tests based on synthetic data produced a mean relative retrieval error of 4.5%, which represented the good performance of the OE inversion algorithm. The proposed algorithm was also performed on real data taken from field experiments in Beijing during a haze pollution event. The correlation coefficients (R) for the retrieved aerosol volume fine-mode fraction (FMFv) and optical fine-mode fraction (FMFo) against AErosol RObotic NETwork (AERONET) products were 0.94 and 0.95 respectively, and the mean residual error was 4.95%. Consequently, the inversion of FMFv and FMFo could be well constrained by single-viewing multi-spectral radiance measurement. In addition, by introducing measurements of 1610 nm wavelength into the retrieval, the validation results showed a significant improvement in the R value for FMFo (from 0.89–0.94). These results confirm the high value of NIR measurements for the retrieval of coarse mode aerosols.
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Knobelspiesse K, Tan Q, Bruegge C, Cairns B, Chowdhary J, van Diedenhoven B, Diner D, Ferrare R, van Harten G, Jovanovic V, Ottaviani M, Redemann J, Seidel F, Sinclair K. Intercomparison of airborne multi-angle polarimeter observations from the Polarimeter Definition Experiment. APPLIED OPTICS 2019; 58:650-669. [PMID: 30694252 PMCID: PMC6996873 DOI: 10.1364/ao.58.000650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
In early 2013, three airborne polarimeters were flown on the high altitude NASA ER-2 aircraft in California for the Polarimeter Definition Experiment (PODEX). PODEX supported the pre-formulation NASA Aerosol-Cloud-Ecosystem (ACE) mission, which calls for an imaging polarimeter in polar orbit (among other instruments) for the remote sensing of aerosols, oceans, and clouds. Several polarimeter concepts exist as airborne prototypes, some of which were deployed during PODEX as a capabilities test. Two of those instruments to date have successfully produced Level 1 (georegistered, calibrated radiance and polarization) data from that campaign: the Airborne Multiangle Spectropolarimetric Imager (AirMSPI) and the Research Scanning Polarimeter (RSP). We compared georegistered observations of a variety of scene types by these instruments to test whether Level 1 products agreed within stated uncertainties. Initial comparisons found radiometric agreement, but polarimetric biases beyond measurement uncertainties. After subsequent updates to calibration, georegistration, and the measurement uncertainty models, observations from the instruments now largely agree within stated uncertainties. However, the 470 nm reflectance channels have a roughly +6% bias of AirMSPI relative to RSP, beyond expected measurement uncertainties. We also find that observations of dark (ocean) scenes, where polarimetric uncertainty is expected to be largest, do not agree within stated polarimetric uncertainties. Otherwise, AirMSPI and RSP observations are consistent within measurement uncertainty expectations, providing credibility for the subsequent creation of Level 2 (geophysical product) data from these instruments, and comparison thereof. The techniques used in this work can also form a methodological basis for other intercomparisons, for example, of the data gathered during the recent Aerosol Characterization from Polarimeter and Lidar (ACEPOL) field campaign, carried out in October and November of 2017 with four polarimeters (including AirMSPI and RSP).
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Affiliation(s)
| | - Qian Tan
- NASA Ames Research Center, Moffett Field, CA, USA
- Bay Area Environmental Research Institute, Petaluma, CA, USA
| | - Carol Bruegge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Brian Cairns
- NASA Goddard Institute for Space Studies, New York, NY, USA
| | - Jacek Chowdhary
- NASA Goddard Institute for Space Studies, New York, NY, USA
- Columbia University, New York, NY, USA
| | - Bastiaan van Diedenhoven
- NASA Goddard Institute for Space Studies, New York, NY, USA
- Columbia University, New York, NY, USA
| | - David Diner
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Gerard van Harten
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Veljko Jovanovic
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Matteo Ottaviani
- NASA Goddard Institute for Space Studies, New York, NY, USA
- SciSpaceLLC, Bethesda, MD, USA
| | | | - Felix Seidel
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Kenneth Sinclair
- NASA Goddard Institute for Space Studies, New York, NY, USA
- Columbia University, New York, NY, USA
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7
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Frouin RJ, Franz BA, Ibrahim A, Knobelspiesse K, Ahmad Z, Cairns B, Chowdhary J, Dierssen HM, Tan J, Dubovik O, Huang X, Davis AB, Kalashnikova O, Thompson DR, Remer LA, Boss E, Coddington O, Deschamps PY, Gao BC, Gross L, Hasekamp O, Omar A, Pelletier B, Ramon D, Steinmetz F, Zhai PW. Atmospheric Correction of Satellite Ocean-Color Imagery During the PACE Era. FRONTIERS IN EARTH SCIENCE 2019; 7:10.3389/feart.2019.00145. [PMID: 32440515 PMCID: PMC7241613 DOI: 10.3389/feart.2019.00145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission will carry into space the Ocean Color Instrument (OCI), a spectrometer measuring at 5nm spectral resolution in the ultraviolet (UV) to near infrared (NIR) with additional spectral bands in the shortwave infrared (SWIR), and two multi-angle polarimeters that will overlap the OCI spectral range and spatial coverage, i. e., the Spectrometer for Planetary Exploration (SPEXone) and the Hyper-Angular Rainbow Polarimeter (HARP2). These instruments, especially when used in synergy, have great potential for improving estimates of water reflectance in the post Earth Observing System (EOS) era. Extending the top-of-atmosphere (TOA) observations to the UV, where aerosol absorption is effective, adding spectral bands in the SWIR, where even the most turbid waters are black and sensitivity to the aerosol coarse mode is higher than at shorter wavelengths, and measuring in the oxygen A-band to estimate aerosol altitude will enable greater accuracy in atmospheric correction for ocean color science. The multi-angular and polarized measurements, sensitive to aerosol properties (e.g., size distribution, index of refraction), can further help to identify or constrain the aerosol model, or to retrieve directly water reflectance. Algorithms that exploit the new capabilities are presented, and their ability to improve accuracy is discussed. They embrace a modern, adapted heritage two-step algorithm and alternative schemes (deterministic, statistical) that aim at inverting the TOA signal in a single step. These schemes, by the nature of their construction, their robustness, their generalization properties, and their ability to associate uncertainties, are expected to become the new standard in the future. A strategy for atmospheric correction is presented that ensures continuity and consistency with past and present ocean-color missions while enabling full exploitation of the new dimensions and possibilities. Despite the major improvements anticipated with the PACE instruments, gaps/issues remain to be filled/tackled. They include dealing properly with whitecaps, taking into account Earth-curvature effects, correcting for adjacency effects, accounting for the coupling between scattering and absorption, modeling accurately water reflectance, and acquiring a sufficiently representative dataset of water reflectance in the UV to SWIR. Dedicated efforts, experimental and theoretical, are in order to gather the necessary information and rectify inadequacies. Ideas and solutions are put forward to address the unresolved issues. Thanks to its design and characteristics, the PACE mission will mark the beginning of a new era of unprecedented accuracy in ocean-color radiometry from space.
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Affiliation(s)
- Robert J. Frouin
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
- Correspondence: Robert J. Frouin,
| | - Bryan A. Franz
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
| | - Amir Ibrahim
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
- Science Systems and Applications Inc., Lanham, MD, United States
| | - Kirk Knobelspiesse
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
| | - Ziauddin Ahmad
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
- Science Application International Corporation, McLean, VA, United States
| | - Brian Cairns
- NASA Goddard Institute for Space Studies, New York, NY, United States
| | - Jacek Chowdhary
- NASA Goddard Institute for Space Studies, New York, NY, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, United States
| | - Heidi M. Dierssen
- Department of Marine Sciences, University of Connecticut, Groton, CT, United States
| | - Jing Tan
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Oleg Dubovik
- Laboratoire d’Optique Atmosphérique, Université de Lille, Villeneuve d’Ascq, France
| | - Xin Huang
- Laboratoire d’Optique Atmosphérique, Université de Lille, Villeneuve d’Ascq, France
| | - Anthony B. Davis
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - Olga Kalashnikova
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - David R. Thompson
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - Lorraine A. Remer
- Joint Center for Earth System Technology, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Emmanuel Boss
- School of Marine Sciences, University of Maine, Orono, ME, United States
| | - Odele Coddington
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, United States
| | | | - Bo-Cai Gao
- Naval Research Laboratory, Washington, DC, United States
| | | | - Otto Hasekamp
- Earth Science Group, Netherlands Institute for Space Research, Utrecht, Netherlands
| | - Ali Omar
- Atmospheric Composition Branch, NASA Langley Research Center, Hampton, VA, United States
| | - Bruno Pelletier
- Institut de Recherche Mathématique, Université de Rennes, Rennes, Franc
| | | | | | - Peng-Wang Zhai
- Department of Physics, University of Maryland Baltimore County, Baltimore, MD, United States
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Knobelspiesse K, Nag S. Remote sensing of aerosols with small satellites in formation flight. ATMOSPHERIC MEASUREMENT TECHNIQUES 2018; 11:3935-3954. [PMID: 32704331 PMCID: PMC7376713 DOI: 10.5194/amt-11-3935-2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Determination of aerosol optical properties with orbital passive remote sensing is a difficult task, as observations often have limited information. Multi-angle instruments, such as the Multi-angle Imaging SpectroRadiometer (MISR) and the POlarization and Directionality of the Earth's Reflectances (POLDER), seek to address this by making information rich multi-angle observations, which can be used to better retrieve aerosol optical properties. The paradigm for such instruments is that each angle view is made from one platform, with, for example, a gimbaled sensor or multiple fixed view angle sensors. This restricts the observing geometry to a plane within the scene Bidirectional Reflectance Distribution Function (BRDF ) observed at the top of the atmosphere (TOA). New technological developments, however, support sensors on small satellites flying in formation, which could be a beneficial alternative. Such sensors may have only one viewing direction each, but the agility of small satellites allows one to control this direction and change it over time. When such agile satellites are flown in formation and their sensors pointed to the same location at approximately the same time, they could sample a distributed set of geometries within the scene BRDF . In other words, observations from multiple satellites can take a variety of view zenith and azimuth angles, and are not restricted to one azimuth plane as is the case with a single multi-angle instrument. It is not known, however, if this is as potentially capable as a multi-angle platform for the purposes of aerosol remote sensing. Using a systems engineering tool coupled with an information content analysis technique, we investigate the feasibility of such an approach for the remote sensing of aerosols. These tools test the mean results of all geometries encountered in an orbit. We find that small satellites in formation are equally capable as multi-angle platforms for aerosol remote sensing, as long as their calibration accuracies and measurement uncertainties are equivalent. As long as the viewing geometries are dispersed throughout the BRDF , it appears the quantity of view angles determines the information content of the observations, not the specific observation geometry. Given the smoothly varying nature of BRDF 's observed at the TOA, this is reasonable, and supports the viability of aerosol remote sensing with small satellites flying in formation. The incremental improvement in information content that we found with number of view angles also supports the concept of a resilient mission comprised of multiple satellites that are continuously replaced as they age or fail.
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Affiliation(s)
| | - Sreeja Nag
- Bay Area Environmental Research Institute, Petaluma, CA, USA
- NASA Ames Research Center, Moffett Field, CA, USA
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GAO MENG, ZHAI PENGWANG, FRANZ BRYAN, HU YONGXIANG, KNOBELSPIESSE KIRK, WERDELL PJEREMY, IBRAHIM AMIR, XU FENG, CAIRNS BRIAN. Retrieval of aerosol properties and water-leaving reflectance from multi-angular polarimetric measurements over coastal waters. OPTICS EXPRESS 2018; 26:8968-8989. [PMID: 29715856 PMCID: PMC7517593 DOI: 10.1364/oe.26.008968] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/21/2018] [Indexed: 05/20/2023]
Abstract
Ocean color remote sensing is an important tool to monitor water quality and biogeochemical conditions of ocean. Atmospheric correction, which obtains water-leaving radiance from the total radiance measured by satellite-borne or airborne sensors, remains a challenging task for coastal waters due to the complex optical properties of aerosols and ocean waters. In this paper, we report a research algorithm on aerosol and ocean color retrieval with emphasis on coastal waters, which uses coupled atmosphere and ocean radiative transfer model to fit polarized radiance measurements at multiple viewing angles and multiple wavelengths. Ocean optical properties are characterized by a generalized bio-optical model with direct accounting for the absorption and scattering of phytoplankton, colored dissolved organic matter (CDOM) and non-algal particles (NAP). Our retrieval algorithm can accurately determine the water-leaving radiance and aerosol properties for coastal waters, and may be used to improve the atmospheric correction when apply to a hyperspectral ocean color instrument.
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Affiliation(s)
- MENG GAO
- JCET, Physics Department, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - PENG-WANG ZHAI
- JCET, Physics Department, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - BRYAN FRANZ
- NASA Goddard Space Flight Center, Code 616, Greenbelt, Maryland 20771, USA
| | - YONGXIANG HU
- MS 475 NASA Langley Research Center, Hampton, VA 23681-2199, USA
| | - KIRK KNOBELSPIESSE
- NASA Goddard Space Flight Center, Code 616, Greenbelt, Maryland 20771, USA
| | - P. JEREMY WERDELL
- NASA Goddard Space Flight Center, Code 616, Greenbelt, Maryland 20771, USA
| | - AMIR IBRAHIM
- NASA Goddard Space Flight Center, Code 616, Greenbelt, Maryland 20771, USA
| | - FENG XU
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - BRIAN CAIRNS
- NASA Goddard Institute for Space Studies, New York, NY 10025, USA
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10
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Ottaviani M, Foster R, Gilerson A, Ibrahim A, Carrizo C, El-habashi A, Cairns B, Chowdhary J, Hostetler C, Hair J, Burton S, Hu Y, Twardowski M, Stockley N, Gray D, Slade W, Cetinic I. Airborne and shipborne polarimetric measurements over open ocean and coastal waters: intercomparisons and implications for spaceborne observations. REMOTE SENSING OF ENVIRONMENT 2018; 206:375-390. [PMID: 33414567 PMCID: PMC7787256 DOI: 10.1016/j.rse.2017.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Comprehensive polarimetric closure is demonstrated using observations from two in-situ polarimeters and Vector Radiative Transfer (VRT) modeling. During the Ship-Aircraft Bio-Optical Research (SABOR) campaign, the novel CCNY HyperSAS-POL polarimeter was mounted on the bow of the R/V Endeavor and acquired hyperspectral measurements from just above the surface of the ocean, while the NASA GISS Research Scanning Polarimeter was deployed onboard the NASA LaRC's King Air UC-12B aircraft. State-of-the-art, ancillary measurements were used to characterize the atmospheric and marine contributions in the VRT model, including those of the High Spectral Resolution Lidar (HSRL), the AErosol RObotic NETwork for Ocean Color (AERONET-OC), a profiling WETLabs ac-9 spectrometer and the Multi-spectral Volume Scattering Meter (MVSM). An open-ocean and a coastal scene are analyzed, both affected by complex aerosol conditions. In each of the two cases, it is found that the model is able to accurately reproduce the Stokes components measured simultaneously by each polarimeter at different geometries and viewing altitudes. These results are mostly encouraging, considering the different deployment strategies of RSP and HyperSAS-POL, which imply very different sensitivities to the atmospheric and ocean contributions, and open new opportunities in above-water polarimetric measurements. Furthermore, the signal originating from each scene was propagated to the top of the atmosphere to explore the sensitivity of polarimetric spaceborne observations to changes in the water type. As expected, adding polarization as a measurement capability benefits the detection of such changes, reinforcing the merits of the full-Stokes treatment in modeling the impact of atmospheric and oceanic constituents on remote sensing observations.
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Affiliation(s)
- Matteo Ottaviani
- The City College of New York, CUNY, New York, NY 10031
- NASA Goddard Institute for Space Studies, New York, NY 10025
| | - Robert Foster
- The City College of New York, CUNY, New York, NY 10031
- Naval Research Laboratory, Washington, DC 20375
| | | | - Amir Ibrahim
- Universities Space Research Association, Columbia, MD 21044
- NASA Goddard Space Flight Center, Greenbelt, MD 10025
| | | | | | - Brian Cairns
- NASA Goddard Institute for Space Studies, New York, NY 10025
| | - Jacek Chowdhary
- NASA Goddard Institute for Space Studies, New York, NY 10025
- Columbia University, New York, NY 10025
| | | | | | | | | | | | - Nicole Stockley
- Harbor Branch Oceanographic Institute, Fort Pierce, FL 34946
| | - Deric Gray
- Naval Research Laboratory, Washington, DC 20375
| | | | - Ivona Cetinic
- Universities Space Research Association, Columbia, MD 21044
- NASA Goddard Space Flight Center, Greenbelt, MD 10025
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11
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Shi C, Nakajima T. Estimation of chlorophyll concentration in waters near Hokkaido using the linear combination method. OPTICS EXPRESS 2017; 25:A963-A979. [PMID: 29041340 DOI: 10.1364/oe.25.00a963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 09/03/2017] [Indexed: 06/07/2023]
Abstract
An inversion algorithm is implemented to retrieve the surface chlorophyll a (Chl) concentration using satellite observation data from the MODIS instrument. The algorithm employs a simple and flexible index (LCI) to combine with the Chl without explicit correction for aerosol scattering. To investigate the sensitivity of LCI to Chl and other influence factors, an oceanic radiative transfer model coupled with a comprehensive bio-optical module is developed. It is studied that the LCI is significantly linear to Chl and not sensitive to other influence factors, except in very low oceanic salinity or scattering angle conditions, where over a 12% relative difference of derived Chl exists. Inversion results show the retrieved Chl are highly consistent with the MODIS operational data products in waters near Hokkaido, with the correlation coefficient, root mean square deviation, and average percentage difference of 0.9702, 0.3756 mg m-3, and 13.89%, respectively. Investigation of the validity of this algorithm with a variety of atmospheric conditions indicates that the residual influence of atmosphere on the LCI index, after Rayleigh scattering correction, is generally within ± 0.001, allowing the retrieval error of Chl at less than 25% in most cases. A good comparison between retrieval and in situ measurements is also identified and implies that the retrieval accuracy via the LCI method depends on the linear combination coefficients used and the bio-optical module selected, while effects of polarization can be ignored.
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12
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Li D, Zeng N, Zhan D, Chen Y, Zeng M, Ma H. Differentiation of soot particulates in air using polarized light scattering method. APPLIED OPTICS 2017; 56:4123-4129. [PMID: 29047545 DOI: 10.1364/ao.56.004123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Soot is the main light-absorbing particle in the visible range. Light scattering and absorption by air particulates can change their optical polarization state, and the information upon polarization can reflect the nature of particles. In this paper, a polarization scattering method has been developed for the feasibility study concerning differentiating soot from other typical air particulates. Simulation results indicate that S2/S0 at the scattering angle of 115° can identify the soot particles specifically. Single component experiments and double composition experiments are carried out, which confirm the validity of differentiating soot by a polarization indicator. These preliminary simulations, experiments, and field tests also imply the potential of polarization characterization applied in air pollutants analysis.
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Wu L, Hasekamp O, van Diedenhoven B, Cairns B, Yorks JE, Chowdhary J. Passive remote sensing of aerosol layer height using near-UV multi-angle polarization measurements. GEOPHYSICAL RESEARCH LETTERS 2016; 43:8783-8790. [PMID: 30002565 PMCID: PMC6038705 DOI: 10.1002/2016gl069848] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We demonstrate that multi-angle polarization measurements in the near-UV and blue part of the spectrum are very well suited for passive remote sensing of aerosol layer height. For this purpose we use simulated measurements with different set-ups (different wavelength ranges, with and without polarization, different polarimetric accuracies) as well as airborne measurements from the Research Scanning Polarimeter (RSP) obtained over the continental USA. We find good agreement of the retrieved aerosol layer height from RSP with measurements from the Cloud Physics Lidar (CPL) showing a mean absolute difference of less than 1 km. Furthermore, we found that the information on aerosol layer height is provided for large part by the multi-angle polarization measurements with high accuracy rather than the multi-angle intensity measurements. The information on aerosol layer height is significantly decreased when the shortest RSP wavelength (410 nm) is excluded from the retrieval and is virtually absent when 550 nm is used as shortest wavelength.
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Affiliation(s)
- Lianghai Wu
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, the Netherlands
| | - Otto Hasekamp
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, the Netherlands
| | - Bastiaan van Diedenhoven
- Columbia University, Center for Climate System Research, 2880 Broadway, New York, NY 10025, USA
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - Brian Cairns
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - John E. Yorks
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Jacek Chowdhary
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, 2880 Broadway, New York, NY 10025, USA
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Sentis M, Onofri FRA, Dhez O, Laurent JY, Chauchard F. Organic photo sensors for multi-angle light scattering characterization of particle systems. OPTICS EXPRESS 2015; 23:27536-27541. [PMID: 26480413 DOI: 10.1364/oe.23.027536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Organic Photo Sensor (OPS) technology allows printing on conformable plastic-like substrates complex-shaped, arbitrarily-sized and pre-aligned photosensitive elements. This article reports, to the best of our knowledge, the first investigation to implement this emerging technology for Multi-Angle Light Scattering (MALS) characterization of nano- and microparticle suspensions. Monte Carlo and Lorenz-Mie theory calculations as well as preliminary experimental results on latex suspensions clearly demonstrate the potential of the proposed approach.
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Dolgos G, Martins JV. Polarized Imaging Nephelometer for in situ airborne measurements of aerosol light scattering. OPTICS EXPRESS 2014; 22:21972-21990. [PMID: 25321572 DOI: 10.1364/oe.22.021972] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Global satellite remote sensing of aerosols requires in situ measurements to enable the calibration and validation of algorithms. In order to improve our understanding of light scattering by aerosol particles, and to enable routine in situ airborne measurements of aerosol light scattering, we have developed an instrument, called the Polarized Imaging Nephelometer (PI-Neph). We designed and built the PI-Neph at the Laboratory for Aerosols, Clouds and Optics (LACO) of the University of Maryland, Baltimore County (UMBC). This portable instrument directly measures the ambient scattering coefficient and phase matrix elements of aerosols, in the field or onboard an aircraft. The measured phase matrix elements are the P(11), phase function, and P(12). Lasers illuminate the sampled ambient air and aerosol, and a wide field of view camera detects scattered light in a scattering angle range of 3° to 176°. The PI-Neph measures an ensemble of particles, supplying the relevant quantity for satellite remote sensing, as opposed to particle-by-particle measurements that have other applications. Comparisons with remote sensing measurements will have to consider aircraft inlet effects. The PI-Neph first measured at a laser wavelength of 532nm, and was first deployed successfully in 2011 aboard the B200 aircraft of NASA Langley during the Development and Evaluation of satellite ValidatiOn Tools by Experimenters (DEVOTE) project. In 2013, we upgraded the PI-Neph to measure at 473nm, 532nm, and 671nm nearly simultaneously. LACO has deployed the PI-Neph on a number of airborne field campaigns aboard three different NASA aircraft. This paper describes the PI-Neph measurement approach and validation by comparing measurements of artificial spherical aerosols with Mie theory. We provide estimates of calibration uncertainties, which show agreement with the small residuals between measurements of P(11) and -P(12)/P(11) and Mie theory. We demonstrate the capability of the PI-Neph to measure ambient aerosol with two data sets from the Deep Convective Clouds and Chemistry (DC3) field campaign, from flights over Colorado in June 2012.
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