Dr. Stephan Randolph Kawa Profile

Dr. Stephan Randolph Kawa

at NASA Goddard Space Flight Ctr

SPIE Involvement:

Author

Publications (12)

Proceedings Article | 24 October 2018 Paper

Lidar measurements of CO2 column concentrations in the Arctic region of North America from the ASCENDS 2017 airborne campaign

Graham Allan, James Abshire, Haris Riris, Jianping Mao, William Hasselbrack, Kenji Numata, Jeffrey Chen, Randy Kawa, Michael Rodriguez, Mark Stephen

Proceedings Volume 10779, 1077906 (2018) https://doi.org/10.1117/12.2325908

KEYWORDS: Carbon dioxide, LIDAR, Clouds, Aerosols, Absorption, Atmospheric particles, Atmospheric modeling, Backscatter

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SPIE Journal Paper | 1 September 2017 Open Access

Methane optical density measurements with an integrated path differential absorption lidar from an airborne platform

Haris Riris, Kenji Numata, Stewart Wu, Brayler Gonzalez, Michael Rodriguez, Stan Scott, Stephan Kawa, Jianping Mao

JARS, Vol. 11, Issue 03, 034001, (September 2017) https://doi.org/10.1117/12.10.1117/1.JRS.11.034001

KEYWORDS: LIDAR, Optical parametric oscillators, Absorption, Transmitters, Methane, Sensors, Absorbance, Optical testing, Clouds, Receivers

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Proceedings Article | 5 May 2017 Presentation + Paper

Methane measurements from space: technical challenges and solutions

Haris Riris, Kenji Numata, Stewart Wu, Brayler Gonzalez, Michael Rodriguez, Stephan Kawa, Jianping Mao

Proceedings Volume 10191, 1019104 (2017) https://doi.org/10.1117/12.2262516

KEYWORDS: Methane, Absorption, LIDAR, Carbon, Climate change, Laser applications, Spectroscopy, Optical parametric oscillators, Transmitters, Receivers, Sensors, Fiber lasers, Beam splitters, Airborne laser technology

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Proceedings Article | 24 October 2012 Paper

Airborne measurement of atmospheric methane concentration using pulsed lidar

Anand Ramanathan, Kenji Numata, Stewart Wu, Steven Li, Martha Dawsey, Jianping Mao, Stephan Kawa, Haris Riris

Proceedings Volume 8511, 85110E (2012) https://doi.org/10.1117/12.929990

KEYWORDS: Methane, LIDAR, Absorption, Carbon dioxide, Earth's atmosphere, Electronic support measures, Infrared radiation, Atmospheric optics, Climate change, Carbon

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SPIE Journal Paper | 12 September 2012

Ground demonstration of trace gas lidar based on optical parametric amplifier

Kenji Numata, Haris Riris, Steven Li, Stewart Wu, Stephan Kawa, Michael Krainak, James Abshire

JARS, Vol. 6, Issue 01, 063561, (September 2012) https://doi.org/10.1117/12.10.1117/1.JRS.6.063561

KEYWORDS: LIDAR, Carbon monoxide, Optical amplifiers, Crystals, Near infrared, Gases, Fiber amplifiers, Gas lasers, Absorption, Signal detection

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Proceedings Article | 14 May 2012 Paper

Ground and airborne methane measurements with an optical parametric amplifier

Kenji Numata, Haris Riris, Steve Li, Stewart Wu, Stephan Kawa, Martha Dawsey, Anand Ramanathan, Jianping Mao, Michael Krainak, James Abshire

Proceedings Volume 8379, 83790H (2012) https://doi.org/10.1117/12.918100

KEYWORDS: Methane, LIDAR, Optical amplifiers, Nonlinear crystals, Signal detection, Earth's atmosphere, Sensors, Optical testing, Atmospheric optics, Absorption

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Proceedings Article | 14 September 2011 Paper

Development of optical parametric amplifier for lidar measurements of trace gases on Earth and Mars

Kenji Numata, Haris Riris, Steve Li, Stewart Wu, Stephan Kawa, Michael Krainak, James Abshire

Proceedings Volume 8159, 81590E (2011) https://doi.org/10.1117/12.896307

KEYWORDS: LIDAR, Gases, Carbon dioxide, Optical amplifiers, Near infrared, Mars, Crystals, Earth's atmosphere, Absorption, Sensors

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Proceedings Article | 20 August 2011 Paper

Lidar technology for measuring trace gases on Mars and Earth

Haris Riris, Kenji Numata, Steve Li, Stewart Wu, James Abshire, Graham Allan, William Hasselbrack, Mike Rodriguez, Jeffrey Chen, Stephen Kawa, Jianping Mao, Clark Weaver, Anthony Yu, Xiaoli Sun

Proceedings Volume 8192, 819203 (2011) https://doi.org/10.1117/12.900870

KEYWORDS: Methane, Gases, Mars, LIDAR, Absorption, Carbon dioxide, Earth's atmosphere, Spectrometers, Climate change, Signal detection

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Proceedings Article | 17 October 2007 Paper

A laser sounder for measuring atmospheric trace gases from space

Haris Riris, James Abshire, Graham Allan, John Burris, Jeffrey Chen, Stephen Kawa, Jian-Ping Mao, Michael Krainak, Mark Stephen, Xiaoli Sun, Emily Wilson

Proceedings Volume 6750, 67500U (2007) https://doi.org/10.1117/12.737607

KEYWORDS: Carbon monoxide, Absorption, Signal to noise ratio, Gas lasers, Sensors, Spectroscopy, Fabry–Perot interferometers, Gases, Climate change, Atmospheric modeling

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Proceedings Article | 30 December 2004 Paper

Ultra-precise measurement of CO2 from space

William Heaps, Stephan Kawa, Elena Georgieva, Emily Wilson

Proceedings Volume 5652, (2004) https://doi.org/10.1117/12.578521

KEYWORDS: Fabry–Perot interferometers, Carbon monoxide, Absorption, Oxygen, Atmospheric sensing, Remote sensing, Sun, Refractive index, Temperature metrology, Earth's atmosphere

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The experimental data on CO₂ and O₂ detection in atmosphere using Fabry-Perot technique are presented. The atmosphere's irradiance measurements are an important tool for the remote sensing study. We show results from lab, ground and flight testing of a new instrument called FPICC (Fabry-Perot Interferometer for Column CO₂) which is intended for a very precise measurements of atmospheric carbon dioxide and oxygen. The optical setup consists of three channels. The first channel is built to measure the carbon dioxide. This channel operates using the reflected sunlight off the ground and solid Fabry-Perot etalon to restrict the measurement to light in CO₂ absorption bands. The free spectral range of the etalon is calculated to be equal to the almost regular spacing between the CO₂ spectral bands located near 1,571 μm, R band, where CO₂ absorption is significant. The precise alignment of the transmission peaks of the Fabry-Perot etalon to the CO₂ absorption lines is achieved through altering the refractive index of the material (fused silica) using its temperature dependence. The second and third channels foucs on the O₂ A band (759 - 771 nm) composed of about 300 absorption lines, which vary in strength and width according to pressure and temperature. We performed measurements using solid Fabry-Perot etalons with different FSR and two different pre-filters. The first pre-filter selects a spectral range around 762 nm which is between the P and R branches, where the absorption coefficient is insensitive to temperature, but is sensitive to pressure changes and therefore to the variations in the O₂ column. The second pre-filter is selecting several absorption bands between 765 and 770 nm, which are more sensitive to temperature changes. The experimental data presented show excellent agreement with our theoretical expectations. They are recorded at different gas pressures, temperatures and different weather conditions. Some of the major advantages of the optical setup are its compactness, high sensitivity, high signal-to-noise ratio, and stability.

Proceedings Article | 16 February 2004 Paper

Measurement of atmospheric carbon dioxide column from space using reflected sunlight

Jianping Mao, Stephan Kawa

Proceedings Volume 5235, (2004) https://doi.org/10.1117/12.511323

KEYWORDS: Aerosols, Scattering, Absorption, Clouds, Atmospheric modeling, Atmospheric particles, Atmospheric sensing, Sensors, Spectral resolution, Carbon monoxide

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Proceedings Article | 16 June 2003 Paper

Progress on passive sensor for ultraprecise measurement of carbon dioxide from space

William Heaps, S. Randolph Kawa

Proceedings Volume 4897, (2003) https://doi.org/10.1117/12.466163

KEYWORDS: Carbon monoxide, Absorption, Atmospheric sciences, Carbon, Carbon dioxide, Fabry–Perot interferometers, Temperature metrology, Atmospheric sensing, Climatology, Atmospheric modeling

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Showing 5 of 12 publications

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