Download or read book Differential Absorption Lidar Measurements of Atmospheric Water Vapor Using a Pseudonoise Code Modulated AlGaAs Laser written by and published by . This book was released on 1994 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Differential Absorption Lidar Measurements of Atmospheric Water Vapor Using a Pseudonoise Code Modulated AIGaAs Laser written by Jonathan A.R. Rall and published by . This book was released on 1994 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Differential Absorption Lidar Measurements of Atmospheric Water Vapor Using a Pseudonise Code Modulated AIGaAs Laser written by Jonathan Andrew Reily Rall and published by . This book was released on 1993 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design of Advanced Atmospheric Water Vapor Differential Absorption Lidar Dial Detection System written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-19 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The lidar atmospheric sensing experiment (LASE) is an instrument designed and operated by the Langley Research Center for high precision water vapor measurements. The design details of a new water vapor lidar detection system that improves the measurement sensitivity of the LASE instrument by a factor of 10 are discussed. The new system consists of an advanced, very low noise, avalanche photodiode (APD) and a state-of-the-art signal processing circuit. The new low-power system is also compact and lightweight so that it would be suitable for space flight and unpiloted atmospheric vehicles (UAV) applications. The whole system is contained on one small printed circuit board (9 x 15 sq cm). The detection system is mounted at the focal plane of a lidar receiver telescope, and the digital output is read by a personal computer with a digital data acquisition card.Refaat, Tamer F. and Luck, William S., Jr. and DeYoung, Russell J.Langley Research CenterATMOSPHERIC MOISTURE; WATER VAPOR; DESIGN ANALYSIS; DIFFERENTIAL ABSORPTION LIDAR; DETECTION; AVALANCHES; SENSITIVITY; LOW NOISE; PHOTODIODES; SIGNAL PROCESSING; PRINTED CIRCUITS; LOW WEIGHT; SIGNAL TO NOISE RATIOS; ATMOSPHERIC SOUNDING

Download or read book Differential Absorption Lidars for Remote Sensing of Atmospheric Pressure and Temperature Profiles written by and published by . This book was released on 1995 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultra Narrowband Optical Filters for Water Vapor Differential Absorption Lidar Dial Atmospheric Measurements written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-17 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Differential absorption lidar (DIAL) systems are being deployed to make vertical profile measurements of atmospheric water vapor from ground and airborne platforms. One goal of this work is to improve the technology of such DIAL systems that they could be deployed on space-based platforms. Since background radiation reduces system performance, it is important to reduce it. One way to reduce it is to narrow the bandwidth of the optical receiver system. However, since the DIAL technique uses two or more wavelengths, in this case separated by 0.1 nm, a fixed-wavelength narrowband filter that would encompass both wavelengths would be broader than required for each line, approximately 0.02 nm. The approach employed in this project is to use a pair of tunable narrowband reflective fiber Bragg gratings. The Bragg gratings are germanium-doped silica core fiber that is exposed to ultraviolet radiation to produce index-of-refraction changes along the length of the fiber. The gratings can be tuned by stretching. The backscattered laser radiation is transmitted through an optical circulator to the gratings, reflected back to the optical circulator by one of the gratings, and then sent to a photodiode. The filter reflectivities were >90 percent, and the overall system efficiency was 30 percent.Stenholm, Ingrid and DeYoung, Russell J.Langley Research CenterBRAGG GRATINGS; DIFFERENTIAL ABSORPTION LIDAR; NARROWBAND; OPTICAL FILTERS; REFLECTANCE; ATMOSPHERIC MOISTURE; BACKSCATTERING; DOPED CRYSTALS

Download or read book Design of Advanced Atmospheric Water Vapor Differential Absorption Lidar DIAL Detection System written by Tamer F. Refaat and published by . This book was released on 1999 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The lidar atmospheric sensing equipment (LASE) is an instrument designed and operated by Langley Research Center for high precision water vapor measurements. The design details of a new water vapor lidar detection system that improves the measurement sensitivity of the LASE instrument by a factor of 10 are discussed. The new system consists of an advanced, very low noise, avalanche photodiode (APD) and a state-of-the-art signal processing unit. The new low-power system is also compact and lightweight so that it would be suitable for space flight and unpiloted atmospheric vehicles (UAV) applications. The whole system is contained on one small printed circuit board (9 by 15 cm[squared]). The detection system is mounted at the focal plane of a lidar receiver telescope, and the digital output is read by a personal computer with a digital data acquisition card.

Download or read book Advances in Atmospheric Remote Sensing with Lidar written by Albert Ansmann and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 603 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lidar or laser radar, the depth-resolved remote measurement of atmospheric parameters with optical means, has become an important tool in the field of atmospheric and environmental remote sensing. In this volume the latest progress in the development of Lidar methods, experiments, and applications is described. The content is based on selected and thoroughly refereed papers presented at the 18th International Laser Radar Conference, Berlin, 22 - 26 July 1996. The book is divided into six parts which cover the topics of tropospheric aerosols and clouds, Lidar in space, wind, water vapor, troposheric trace gases and plumes, and stratospheric and mesospheric profiling. As a supplement to fundamental LIDAR textbooks this volume may serve as a guide through the blossoming field of modern Lidar techniques.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1995 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lidar Remote Sensing for Environmental Monitoring written by and published by . This book was released on 2005 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of an Eye safe Diode laser based Micro pulse Differential Absorption Lidar mp DIAL for Atmospheric Water vapor and Aerosol Studies written by Amin Reza Nehrir and published by . This book was released on 2011 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the design, construction, and testing of an all diode-laser-based water-vapor differential absorption lidar (DIAL) instrument through two distinct stages of development. A second generation low pulse energy, high pulse repetition frequency DIAL instrument was developed to overcome the power limitations of the first generation instrument which required unrealistic integration times approaching 1 hour. The second generation DIAL transmitter used a custom built external cavity diode laser (ECDL) as the seed source for an actively current pulsed tapered semiconductor optical amplifier (TSOA), yielding a maximum output transmitter pulse energy of 2 microjoules over a 1 microsecond duration pulse width at a 20 kHz pulse repetition frequency, decreasing the required integration Period to approximately 20-30 minutes. Nighttime and daytime water-vapor profiles were collected with the second generation DIAL instrument which showed good agreement with collocated radiosonde measurements from near the surface up to the top of the planetary boundary layer. Aerosol optical properties were also measured using the calibrated offline channel returns using the iterative Fernald solution to the lidar equation. Most recently, a third generation DIAL transmitter has been developed to further increase the output pulse energy and to also decrease the DIAL atmospheric spectral sampling time. Two custom built high power ECDL's and an electro-mechanical based fiber optic switch are used to sequentially seed a single stage actively current pulsed TSOA in order to minimize the systematic errors introduced in the DIAL retrievals resulting from air-mass miss-sampling between the two DIAL wavelengths. Peak output pulse energies of 7 microjoules have been measured over 1 microsecond pulse durations at a 10 kHz pulse repetition frequency with a 1-6 second DIAL spectral switching time, further decreasing the total required integration period to 20 minutes for both nighttime and daytime operation. The increased performance of the third generation transmitter has allowed for nighttime and daytime water vapor profiling under varying atmospheric conditions that shows good agreement with collocated radiosonde measurements up to ~ 6 km and ~ 3 km, respectively. A detailed description of the second and third generation DIAL instrument performance as well as data retrievals are presented in this dissertation. Future work to improve the current third generation DIAL instrument for full-time autonomous measurements of atmospheric water-vapor and aerosols is also discussed.

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1995 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water Vapor Profiling Using a Compact Widely Tunable Diode Laser Differential Absorption Lidar DIAL written by Amin Reza Nehrir and published by . This book was released on 2008 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric water vapor is an important driver of cloud formation, precipitation, and cloud microphysical structure. Changes in the cloud microphysical structure due to the interaction of aerosols and water vapor can produce more reflective clouds, resulting in more incoming solar radiation being reflected back into space, leading to an overall negative radiative forcing. Water vapor also plays an important role in the atmospheric feedback process that acts to amplify the positive radiative forcing resulting from increasing levels of atmospheric CO2. In the troposphere, where the water vapor greenhouse effect is most important, the situation is harder to quantify. A need exists for tools that allow for high spatial resolution range resolved measurements of water vapor number density up to about 4 km. One approach to obtaining this data within the boundary layer is with the Differential Absorption Lidar (DIAL) that is being developed at Montana State University. A differential absorption lidar (DIAL) instrument for automated profiling of water vapor in the lower troposphere has been designed, tested, and is in routine operation. The laser transmitter for the DIAL instrument uses a widely tunable external cavity diode laser (ECDL) to injection seed two cascaded semiconductor optical amplifiers (SOA) to produce a laser transmitter that accesses the 824-841 nm spectral range. The DIAL receiver utilizes a 28-cm-diameter Schmidt-Cassegrain telescope, an avalanche photodiode (APD) detector, and a narrow band optical filter to collect, discriminate, and measure the scattered light. A technique of correcting for the wavelength-dependent incident angle upon the narrow band optical filter as a function of range has been developed to allow accurate water vapor profiles to be measured down to 225 m above the surface. Data comparisons using the DIAL instrument and co-located radiosonde measurements are presented demonstrating the capabilities of the DIAL instrument.

Download or read book IGARSS written by and published by . This book was released on 1996 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water Vapor Profiling Using a Widely Tunable Amplified Diode Laser Differential Absorption Lidar DIAL written by Michael Drew Obland and published by . This book was released on 2007 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis work involved the design, construction, and testing of a highly-tunable Differential Absorption Lidar (DIAL) instrument utilizing an all-semiconductor transmitter. It was an attempt to take advantage of semiconductor laser technology to obtain range-resolved water vapor profiles with an instrument that is cheaper, smaller, and more robust than existing field instruments. The eventual goal of this project was to demonstrate the feasibility of this DIAL instrument as a candidate for deployment in multi-point networks or satellite arrays to study water vapor flux profiles.