Dr. Andrea M. Brown Profile

Dr. Andrea M. Brown

Engineer at Johns Hopkins Univ Applied Physics Lab LLC

SPIE Involvement:

Author | Instructor

Publications (19)

SPIE Journal Paper | 17 August 2023

Statistical approach to electro-optic and infrared transmission within the atmosphere through empirical cumulative distributions via modeling, simulation, and data on a global scale

Adam Willitsford, Parker Coye, Claire Trop, Andrea Brown

JARS, Vol. 17, Issue 03, 038504, (August 2023) https://doi.org/10.1117/12.10.1117/1.JRS.17.038504

KEYWORDS: Transmittance, Visibility, Aerosols, Atmospheric modeling, Infrared radiation, Electro optical modeling, Data modeling, Data transmission, Electro optics, Mid-IR

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Electro-optical and infrared propagation within the troposphere is strongly determined by the atmospheric path along the line-of-sight. The industry standard program moderate resolution transmittance (MODTRAN) model can be used to approximate path transmittance and radiance from the ultraviolet to the infrared. To understand the variability in the path effects (transmittance/radiance), one must accurately represent the environment in which they are operating. One significant knowledge gap is a universal and consistent means to inform the aerosol component of the atmospheric modeling within MODTRAN. The aerosol component can be highly variable, which can result in significant changes to the overall path transmittance and radiance depending on aerosol size and type. A fusion of European Centre for Medium Range Weather Forecasts Re-Analysis 5 atmospheric profile data and statistical draws from the global NOAA-ISD visibility archives are presented to construct regionally specific atmospheric inputs to MODTRAN. Using a 6 km horizontal path geometry, a year’s worth of hourly (8760 times) data is modeled to determine the path transmittance. The results are aggregated via empirical cumulative distribution functions of the path transmittance. We determine the type of day one is operating within by defining a bad day as the 10th percentile low transmission, an average day as the 50th percentile, and a good day as the 90th percentile high transmission. Using the percentile atmospheres determined by transmittance, one can analyze expected performance levels from current sensor systems, e.g., if a detection threshold is met on the 50th percentile day, one can expect this threshold to be met 50% of the time. In addition, the specific atmospheres (visibility, pressure, temperature, humidity, rain, etc.), which were determined to result in the 10th, 50th, or 90th percentile day, can be analyzed to build synthetic scenes, construct modeling environments, and ultimately drive design and system trades to optimize performance from the visible to the longwave infrared.

Proceedings Article | 8 May 2020 Presentation + Paper

Modeling and measurements using polarimetric lidar

Andrea Brown, Michael Thomas, David Brown, Richard Joseph, Rebecca Eager, Jessica Makowski, Randall Hanna, Nicole Steiner, Diane Tang, Christopher Carter

Proceedings Volume 11416, 114160D (2020) https://doi.org/10.1117/12.2559128

KEYWORDS: Aerosols, LIDAR, Atmospheric particles, Clouds, Particles, Atmospheric modeling, Polarimetry, Polarization

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Proceedings Article | 14 May 2019 Paper

Measuring optical turbulence using a laser DIMM in support of characterization of imaging system performance

Randall Hanna, David Brown, Andrea Brown, Kevin Baldwin, Jonathan Hixson

Proceedings Volume 11001, 1100110 (2019) https://doi.org/10.1117/12.2520597

KEYWORDS: Data modeling, Turbulence, Receivers, Atmospheric modeling, Transmitters, Retroreflectors, Imaging systems, Near field optics, Scintillation, Optical turbulence

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Proceedings Article | 4 May 2018 Paper

Initial test of MITA/DIMM with an operational CBP system

Kevin Baldwin, Randall Hanna, Andrea Brown, David Brown, Steven Moyer, Jonathan Hixson

Proceedings Volume 10625, 106250J (2018) https://doi.org/10.1117/12.2314659

KEYWORDS: Modulation transfer functions, Receivers, Turbulence, Sensors, Imaging systems, Cameras, Atmospheric modeling, Image processing, Atmospheric turbulence, Fiber optic illuminators

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Proceedings Article | 13 May 2016 Paper

Lasercomm system development for high-bandwidth terrestrial communications

Juan Juarez, Katherine Souza, Natalie Bos, Andrea Brown, Brice Cannon, Keith Petrillo, James Riggins, Joseph Sluz, Hala Tomey, Radha Venkat

Proceedings Volume 9833, 98330A (2016) https://doi.org/10.1117/12.2229996

KEYWORDS: Telecommunications, Laser development, Free space optics, Receivers, Control systems, Turbulence, Polarization, Forward error correction, Data communications, Scintillation

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Proceedings Article | 22 May 2015 Paper

Scatter properties of polycrystalline YAG in the visible and near-infrared

R. M. Springer, M. Thomas, A. M. Brown

Proceedings Volume 9453, 945307 (2015) https://doi.org/10.1117/12.2181913

KEYWORDS: YAG lasers, Sensors, Refractive index, Optical spheres, Particles, Crystals, Backscatter, Signal detection, Data modeling, Near infrared

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Proceedings Article | 5 September 2014 Paper

Temperature dependent BRDF facility

Marc Airola, Andrea Brown, Daniel Hahn, Michael Thomas, Elizabeth Congdon, Douglas Mehoke

Proceedings Volume 9205, 920503 (2014) https://doi.org/10.1117/12.2062838

KEYWORDS: Bidirectional reflectance transmission function, Temperature metrology, Long wavelength infrared, Reflectivity, Ceramics, Scattering, Statistical modeling, Carbon dioxide lasers, Ultraviolet radiation, Solids

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SPIE Journal Paper | 3 September 2014 Open Access

Measurement of atmospheric oxygen using long-path supercontinuum absorption spectroscopy

David Brown, Andrea Brown, Perry Edwards, Zhiwen Liu, C. Russell Philbrick

JARS, Vol. 8, Issue 01, 083557, (September 2014) https://doi.org/10.1117/12.10.1117/1.JRS.8.083557

KEYWORDS: Oxygen, Absorption, Absorption spectroscopy, Spectroscopic atmospheric monitoring techniques, Atmospheric laser remote sensing, Atmospheric sensing, Supercontinuum sources, Algorithm development, Atmospheric optics, Optical filters

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Proceedings Article | 9 June 2014 Paper

Developing a broad spectrum atmospheric aerosol characterization for remote sensing platforms over desert regions

Shadrian Strong, Andrea Brown

Proceedings Volume 9071, 907115 (2014) https://doi.org/10.1117/12.2050575

KEYWORDS: Aerosols, Sun, Atmospheric modeling, Photometry, Atmospheric particles, MODIS, Clouds, Absorption, Radiative transfer, Refraction

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Proceedings Article | 29 May 2013 Paper

Models to support active sensing of biological aerosol clouds

Andrea Brown, Jeffrey Kalter, Elizabeth Corson, Zahra Chaudhry, Nathan Boggs, David Brown, Michael Thomas, Christopher Carter

Proceedings Volume 8710, 871013 (2013) https://doi.org/10.1117/12.2016324

KEYWORDS: Atmospheric modeling, Aerosols, LIDAR, Backscatter, Refractive index, Clouds, Particles, Atmospheric particles, Scattering, Thin films

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Proceedings Article | 9 June 2011 Paper

Sensitivity of the polarization ratio method to aerosol concentration

Michelle Snyder, Andrea Brown, C. Russell Philbrick

Proceedings Volume 8037, 80370K (2011) https://doi.org/10.1117/12.884206

KEYWORDS: Polarization, Aerosols, Scattering, Light scattering, Laser scattering, Refraction, Genetic algorithms, Imaging systems, Mie scattering, Atmospheric particles

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Proceedings Article | 3 June 2011 Paper

Ground truth methods for optical cross-section modeling of biological aerosols

J. Kalter, E. Thrush, J. Santarpia, Z. Chaudhry, J. Gilberry, D. Brown, A. Brown, C. Carter

Proceedings Volume 8018, 801805 (2011) https://doi.org/10.1117/12.883314

KEYWORDS: Luminescence, Atmospheric particles, Particles, Clouds, Aerosols, Atmospheric modeling, LIDAR, Atrial fibrillation, Aerodynamics, Backscatter

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Proceedings Article | 10 September 2010 Paper

A general BRDF/BSDF model including out-of-plane dependence

M. Thomas, R. Joseph, W. Tropf, A. Brown

Proceedings Volume 7792, 77920I (2010) https://doi.org/10.1117/12.861046

KEYWORDS: Reflectivity, Silicon, Bidirectional reflectance transmission function, Transmittance, Reflection, Light scattering, Data modeling, Absorption, Diffuse reflectance spectroscopy, Monte Carlo methods

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Proceedings Article | 2 September 2010 Paper

Optical material characterization through BSDF measurement and analysis

Andrea Brown, Daniel Hahn, Michael Thomas, David Brown, Jessica Makowski

Proceedings Volume 7792, 779211 (2010) https://doi.org/10.1117/12.861499

KEYWORDS: Bidirectional reflectance transmission function, Reflectivity, Scattering, Sensors, Reflection, Visible radiation, Applied physics, Scatter measurement, Metals, Transmittance

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Proceedings Article | 5 May 2010 Paper

Optical properties and cross-sections of biological aerosols

E. Thrush, D. Brown, N. Salciccioli, J. Gomes, A. Brown, K. Siegrist, M. Thomas, N. Boggs, C. Carter

Proceedings Volume 7665, 766507 (2010) https://doi.org/10.1117/12.850464

KEYWORDS: Particles, Backscatter, Atmospheric particles, Absorption, Atmospheric modeling, Aerosols, Ultraviolet radiation, Long wavelength infrared, Refractive index, LIDAR

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Proceedings Article | 29 April 2010 Paper

Optical remote sensing techniques characterize the properties of atmospheric aerosols

Russell Philbrick, Hans Hallen, Andrea Wyant, Tim Wright, Michelle Snyder

Proceedings Volume 7684, 76840J (2010) https://doi.org/10.1117/12.850453

KEYWORDS: Aerosols, Scattering, LIDAR, Laser scattering, Raman spectroscopy, Raman scattering, Atmospheric particles, Polarization, Atmospheric optics, Refractive index

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Proceedings Article | 29 April 2010 Paper

Atmospheric aerosol characterization using multiwavelength multistatic light scattering

Andrea Brown, Michelle Snyder, Lydia Brouwer, C. Russell Philbrick

Proceedings Volume 7684, 76840I (2010) https://doi.org/10.1117/12.850080

KEYWORDS: Polarization, Aerosols, Scattering, Atmospheric particles, Particles, Genetic algorithms, Laser scattering, Light scattering, Mie scattering, Fiber optic gyroscopes

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Proceedings Article | 2 May 2009 Paper

Supercontinuum laser sensing of atmospheric constituents

Perry Edwards, Andrea Wyant, David Brown, Zhiwen Liu, C. Russell Philbrick

Proceedings Volume 7323, 73230S (2009) https://doi.org/10.1117/12.818697

KEYWORDS: Absorption, Atmospheric sensing, Oxygen, LIDAR, Absorption spectroscopy, Atmospheric optics, Error analysis, Supercontinuum sources, Spectroscopy, Transmittance

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Proceedings Article | 2 May 2009 Paper

Multi-wavelength multi-angular lidar for aerosol characterization

Andrea Wyant, David Brown, Perry Edwards, C. Russell Philbrick

Proceedings Volume 7323, 73230R (2009) https://doi.org/10.1117/12.818686

KEYWORDS: Aerosols, Scattering, Laser scattering, Polarization, LIDAR, Atmospheric particles, Light scattering, Imaging systems, Charge-coupled devices, Diffraction gratings

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Showing 5 of 19 publications

Conference Committee Involvement (2)

Reflection, Scattering, and Diffraction from Surfaces IV

17 August 2014 | San Diego, California, United States

Reflection, Scattering, and Diffraction from Surfaces III

14 August 2012 | San Diego, California, United States

Course Instructor

SC1107: IR Atmospheric Propagation for Sensor Systems

This course reviews the fundamental principles and applications concerning absorption, refraction and scattering phenomena in the atmosphere that impact infrared sensor performance. Topics include an introduction to atmospheric structure, a background reviewing the basic formulas concerning the complex index of refraction, a survey of molecular absorption bands and continuum absorption, the HITRAN database, atmospheric refractivity, molecular Rayleigh scattering, particle distribution functions, Mie scattering and anomalous diffraction approximation. This background is applied to atmospheric transmittance, path radiance, imaging systems and path fluctuations with examples from field measurements. These topics are further reinforced by practical examples on atmospheric optics whenever possible. A set of contemporary references is provided.

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