Dr. Roland W. Lawrence Profile

Dr. Roland W. Lawrence

at Old Dominion Univ

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Author

Publications (7)

Proceedings Article | 18 October 2019 Presentation

Potential satellite mission on atmospheric dynamics for severe weather forecasts (Conference Presentation)

Bing Lin, Qilong Min, Steven Harrah, Yongxiang Hu, Roland Lawrence

Proceedings Volume 11151, 111510J (2019) https://doi.org/10.1117/12.2531710

KEYWORDS: Satellites, Meteorological satellites, Remote sensing, Radar, Oxygen, Absorption, Sensing systems, Environmental sensing, Sensors, Atmospheric sensing

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Surface air pressure is the most important atmospheric variable for atmospheric dynamics. It is regularly measured by in-situ meteorological sensors, and there are no operational capabilities that could remotely sense the pressure over the globe. The poor spatiotemporal coverage of this dynamically crucial variable is a significant observational gap in weather predictions. To improve forecasts of severe weather conditions, especially the intensity and track of tropical storms, large spatial coverage and frequent sampling of surface barometry are critically needed for numerical weather forecast models. Recent development in remote sensing techniques provides a great hope of atmospheric barometry in large spatiotemporal scales. Currently, NASA Langley Research Center tries to use the concept of Differential-absorption Barometric Radar (DiBAR) working at the 50-56 GHz O2 absorption bands to fill the observational gap. The numerical simulation shows that with this DiBAR remote sensing system, the uncertainty in instantaneous radar surface air pressure estimates can be as low as ~1 mb. Prototype instrumentation and its related laboratory, ground and airborne experiments indicate that satellite DiBAR remote sensing systems will obtain needed air pressure observations and meet or exceed the science requirements for surface air pressure fields. Observational system simulation experiments (OSSEs) for space DiBAR performance based on the existing DiBAR technology and capability show substantial improvements in tropical storm predictions, not only for the typhoon track and position but also for the typhoon intensity. Satellite DiBAR measurements will provide an unprecedented level of the prediction and knowledge on global extreme weather conditions. A space multi-frequency differential oxygen absorption radar system will fill the gap in the global observations of atmospheric air pressure, increase our knowledge in the dynamics, and significantly improve weather, especially severe weather such as typhoon and hurricane, predictions. Advanced tropical storm forecasts are expected with the studied capability. The development of the DiBAR system and associated OSSE results will be presented.

Proceedings Article | 25 August 2008 Paper

Airborne bistatic radar for external hazard detection and avoidance

Roland Lawrence, Omar Torres, George Ganoe, Brett Saywer

Proceedings Volume 7088, 70880G (2008) https://doi.org/10.1117/12.795229

KEYWORDS: Scattering, Sensors, Absorption, Microwave radiation, Atmospheric modeling, Radar, Oxygen, Atmospheric propagation, Environmental sensing, Dielectrics

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Proceedings Article | 22 December 2004 Paper

Multidimensional analysis of autonomous aerial observation systems (AAOS) for scientific, civil, and defense applications

Mark Hutchinson, Doris Hamill, F. Harrison, Jeffrey Yetter, Roland Lawrence, Edward Healy, Henry Wright

Proceedings Volume 5661, (2004) https://doi.org/10.1117/12.582036

KEYWORDS: Sensors, Unmanned aerial vehicles, Defense and security, Associative arrays, Control systems, Antennas, Navigation systems, Infrared sensors, Telecommunications, Atmospheric sciences

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Proceedings Article | 22 December 2004 Paper

Mission concept for the remote sensing of the cryosphere using autonomous aerial observation systems

Roland Lawrence, Larry Hilliard

Proceedings Volume 5661, (2004) https://doi.org/10.1117/12.582121

KEYWORDS: Microwave radiation, Unmanned aerial vehicles, Sensors, Spatial resolution, Stars, Antennas, Remote sensing, Satellites, Radiometry, Receivers

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Improving the understanding of the Cryosphere and its impact on global hydrology is an important element of NASA’s Earth Science Enterprise (ESE). A Cold Land Processes Working Group (CLPWG) was formed by the NASA Terrestrial Hydrology Program to identify important science objectives necessary to address ESE priorities. These measurement objectives included Snow Water Equivalent (SWE), snow wetness, and freeze/thaw status of underlying soil. The spatial resolution requirement identified by the CLPWG was 100 m to 5000 m. Microwave sensors are well suited to measure these and other properties of interests to the study of the terrestrial cryosphere. It is well known that the EM properties of snow and soil at microwave frequencies are a strong function of the phase of water, i.e. ice/water. Further, both active and passive microwave sensors have demonstrated sensitivity to important properties of snowpack including, depth, density, wetness, crystal size, ice crust layer structure, and surface roughness. These sensors are also sensitive to the underlying soil state (frozen or thawed). Multiple microwave measurements including both active and passive sensors will likely be required to invert the effects of various snowpack characteristics, vegetation, and underlying soil properties to provide the desired characterization of the surface and meet the science needs required by the ESE. A major technology driver with respect to fully meeting these measurement needs is the 100 to 5000 m spatial resolution requirement. Meeting the threshold requirement of 5000 m at microwave frequencies from Low Earth Orbit is a technology challenge. The emerging capabilities of unmanned aircraft and particularly the system perspective of the Autonomous Aerial Observation Systems (AAOS) may provide high-fidelity/high-resolution measurements on regional scales or larger that could greatly improve our measurement capability. This paper explores a vehicle/sensor concept that could augment satellite measurements to enhance our understanding of the Cryosphere. The measurement performance and technology issues related to the sensor and aircraft will be assessed. Finally, specific technology needs and research necessary to enable this AAOS concept will be discussed.

Proceedings Article | 15 December 1995 Paper

Design and calibration features of the clouds and the earth's radiant energy system (CERES) instrument

G. Louis Smith, Robert Lee, Bruce Barkstrom, John Cooper, Leonard Kopia, Roland Lawrence

Proceedings Volume 2583, (1995) https://doi.org/10.1117/12.228599

KEYWORDS: Calibration, Shortwaves, Sensors, Radiometry, Space operations, Clouds, Data modeling, Solar energy, Telescopes, Black bodies

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Proceedings Article | 19 August 1993 Paper

Microwave radiometer sensor technology research for Earth science measurements

Richard Harrington, Marion Bailey, Bruce Kendall, Lyle Schroeder, Roland Lawrence, Thomas Campbell

Proceedings Volume 1935, (1993) https://doi.org/10.1117/12.152596

KEYWORDS: Radiometry, Reflectors, Antennas, Microwave radiation, Calibration, Imaging systems, Spatial resolution, Space operations, Soil science, Receivers

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Proceedings Article | 19 August 1993 Paper

Measurement of calibration stability of radiometer sensor systems

Roland Lawrence, Mike Scherner, Ben Grady

Proceedings Volume 1935, (1993) https://doi.org/10.1117/12.152597

KEYWORDS: Radiometry, Switches, Calibration, Systems modeling, Microwave radiation, Receivers, Dicke radiometers, Phased arrays, Correlation function, Sensors

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