Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472373
V. M. Zemlianskii, F.J. Yanovsky
Presents a strategy for sizing aerosols and water droplets in air using multiwavelength and multisensor technology. The proposed optical-microwave measurement method is based upon the assumptions that the particles to be sized are spherical and traverse a uniform field of plane waves. The optical-microwave system with fixed differential frequency shift f/sub m/ between two beams of different wavelength has two microwave detectors and two detector receiving optics. Mie and Rayleigh theory are used in this analysis.<>
{"title":"Phase optical-microwave method for sizing droplets in air. Theory and numerical treatment","authors":"V. M. Zemlianskii, F.J. Yanovsky","doi":"10.1109/COMEAS.1995.472373","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472373","url":null,"abstract":"Presents a strategy for sizing aerosols and water droplets in air using multiwavelength and multisensor technology. The proposed optical-microwave measurement method is based upon the assumptions that the particles to be sized are spherical and traverse a uniform field of plane waves. The optical-microwave system with fixed differential frequency shift f/sub m/ between two beams of different wavelength has two microwave detectors and two detector receiving optics. Mie and Rayleigh theory are used in this analysis.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116827273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472394
A. Fung, D. Gibbs, Z. Li, C. Betty
In modeling of electromagnetic (EM) interaction with terrain one must first examine the geometry of the scatterers relative to the incident wavelength and the electromagnetic properties of the terrain in the frequency region of interest. The purpose of this study is to examine the similarities and differences in developing scattering models for soil and leaves in the optical and microwave regions. For interpretation of remotely sensed data, the scattering model should be a function of geometric and EM parameters which in turn may depend on other physical, biological and physiological parameters of interest. The authors discuss the anticipated sources of scattering, the absorption properties that are known and the geometry of the scattering problem appropriate for each frequency region.<>
{"title":"Modeling considerations of EM scattering from soil and leaves in the optical and microwave regions","authors":"A. Fung, D. Gibbs, Z. Li, C. Betty","doi":"10.1109/COMEAS.1995.472394","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472394","url":null,"abstract":"In modeling of electromagnetic (EM) interaction with terrain one must first examine the geometry of the scatterers relative to the incident wavelength and the electromagnetic properties of the terrain in the frequency region of interest. The purpose of this study is to examine the similarities and differences in developing scattering models for soil and leaves in the optical and microwave regions. For interpretation of remotely sensed data, the scattering model should be a function of geometric and EM parameters which in turn may depend on other physical, biological and physiological parameters of interest. The authors discuss the anticipated sources of scattering, the absorption properties that are known and the geometry of the scattering problem appropriate for each frequency region.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122767166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472343
F. Solheim
A temperature profiling radiometer based on a highly stable synthesizer, rather than traditionally used Gunn oscillators, has been designed and fabricated under contract to White Sands Missile Range. This profiler is capable of tuning a user-selected ensemble of frequencies in the range of 52.85 to 58.8 GHz as well as fixed water vapor and water channels at 25.8 and 31.4 GHz. This instrument weighs about 30 kg and consumes about 200 watts. Because of the frequency stability of the receiver, and because of the large number of observing frequencies possible, improved profile accuracy and resolution is expected over Gunn-based temperature profilers. An inexpensive, simple, and accurate calibration target system that includes the antenna system has been developed for this profiler. The calibration target can be loaded with liquid nitrogen or other cryogenic liquids. Tests with a Radiometrics water vapor radiometer have demonstrated stability of 0.1 K over 6 hours. The cryogenic liquid temperature can be known by its boiling point to within several hundredths of a Kelvin by a simple barometric pressure measurement. Preliminary design work has also been accomplished on a portable (35 kg) water vapor profiling radiometer. This radiometer is to utilize a stable synthesizer to map pressure broadening by tuning across the 22 GHz water vapor line.<>
{"title":"Microwave methods of atmospheric temperature and water vapor profiling","authors":"F. Solheim","doi":"10.1109/COMEAS.1995.472343","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472343","url":null,"abstract":"A temperature profiling radiometer based on a highly stable synthesizer, rather than traditionally used Gunn oscillators, has been designed and fabricated under contract to White Sands Missile Range. This profiler is capable of tuning a user-selected ensemble of frequencies in the range of 52.85 to 58.8 GHz as well as fixed water vapor and water channels at 25.8 and 31.4 GHz. This instrument weighs about 30 kg and consumes about 200 watts. Because of the frequency stability of the receiver, and because of the large number of observing frequencies possible, improved profile accuracy and resolution is expected over Gunn-based temperature profilers. An inexpensive, simple, and accurate calibration target system that includes the antenna system has been developed for this profiler. The calibration target can be loaded with liquid nitrogen or other cryogenic liquids. Tests with a Radiometrics water vapor radiometer have demonstrated stability of 0.1 K over 6 hours. The cryogenic liquid temperature can be known by its boiling point to within several hundredths of a Kelvin by a simple barometric pressure measurement. Preliminary design work has also been accomplished on a portable (35 kg) water vapor profiling radiometer. This radiometer is to utilize a stable synthesizer to map pressure broadening by tuning across the 22 GHz water vapor line.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123751929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472342
A. K. Arakelian, V. Hambaryan
Discusses the spatially and temporally combined use of microwave radar and microwave radiometry for remote sensing. Wind speeds, SST and sea surface roughness applications are considered.<>
讨论了微波雷达与微波辐射测量技术在遥感中的时空结合应用。考虑了风速、海温和海面粗糙度的应用
{"title":"X-band Doppler-radar and radiometer system","authors":"A. K. Arakelian, V. Hambaryan","doi":"10.1109/COMEAS.1995.472342","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472342","url":null,"abstract":"Discusses the spatially and temporally combined use of microwave radar and microwave radiometry for remote sensing. Wind speeds, SST and sea surface roughness applications are considered.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114257253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472389
K. Sassen
Joint cloud remote sensing research using radar, lidar, and passive optical and microwave techniques began over 25 years ago, not long after the development of field-worthy laser systems. Concurrent field measurements of thunderstorm clouds and anvils were made in 1970 by a polarization ruby (0.69 /spl mu/m) lidar transported from New York University and a scanning 10-cm radar system from the South Dakota School of Mines and Technology near Rapid City. At about the same time, a program was initiated at the NOAA Wave Propagation Laboratory in Boulder, CO, primarily from laser eye-safety concerns, to coalign a K-band radar with a scanning mirror assembly used to point the laser beam. Although polarization lidar findings from this early research phase were published (1), serious intercomparisons with the radar data were not attempted. However, since that time the multiple remote sensor approach has steadily gained acceptance in the cloud physics research community with the recognition of the synergistic qualities of diverse, multiwavelength datasets. Examples of the integration of active and passive optical and microwave remote sensing methods, which currently constitute a major meteorological research emphasis, as applied to cloud research programs are reviewed.<>
{"title":"Combined microwave and optical remote sensing of clouds: a review","authors":"K. Sassen","doi":"10.1109/COMEAS.1995.472389","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472389","url":null,"abstract":"Joint cloud remote sensing research using radar, lidar, and passive optical and microwave techniques began over 25 years ago, not long after the development of field-worthy laser systems. Concurrent field measurements of thunderstorm clouds and anvils were made in 1970 by a polarization ruby (0.69 /spl mu/m) lidar transported from New York University and a scanning 10-cm radar system from the South Dakota School of Mines and Technology near Rapid City. At about the same time, a program was initiated at the NOAA Wave Propagation Laboratory in Boulder, CO, primarily from laser eye-safety concerns, to coalign a K-band radar with a scanning mirror assembly used to point the laser beam. Although polarization lidar findings from this early research phase were published (1), serious intercomparisons with the radar data were not attempted. However, since that time the multiple remote sensor approach has steadily gained acceptance in the cloud physics research community with the recognition of the synergistic qualities of diverse, multiwavelength datasets. Examples of the integration of active and passive optical and microwave remote sensing methods, which currently constitute a major meteorological research emphasis, as applied to cloud research programs are reviewed.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121545850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472325
S. Ismail, E. Browell
The Lidar Atmospheric Sensing Experiment (LASE) is a highly engineered and autonomous Differential Absorption Lidar (DIAL) system developed at NASA Langley Research Center (LaRC) to measure high-resolution water vapor and aerosol profiles in the troposphere. LASE is being developed as a precursor to the deployment of a spaceborne DIAL system for global measurement of high-resolution water vapor profiles. The LASE system uses a tunable Ti:sapphire laser that is frequency locked to pre-selected water vapor lines in the 815-nm region. LASE is undergoing a series of engineering test flights onboard a high-altitude ER-2 aircraft to evaluate its initial performance before deployment on field programs. During the first engineering test flight conducted near NASA Ames Research Center in May 1994, LASE was operated in the backscattered lidar mode and obtained high-quality aerosol profiles in the 0-20 km altitude region. During a subsequent engineering flight series conducted near NASA Wallops Flight facility in September 1994, water vapor and aerosol profiles were obtained simultaneously under a variety of cloud and background conditions. This paper discusses the results of the water vapor and aerosol measurements made during these flights. These measurements will be used to evaluate the performance of the instrument and for comparison with predicted values of atmospheric signals and water vapor profiles derived from in situ measurements from radiosondes launched in the vicinity of LASE measurements. These results will be used to refine the LASE system for a final engineering test series planned for early 1995. Plans for the validation of the LASE instrument with other in situ and remote sensors and the anticipated field program participation are also discussed.<>
{"title":"NASA LASE water vapor differential absorption lidar measurements and performance evaluation","authors":"S. Ismail, E. Browell","doi":"10.1109/COMEAS.1995.472325","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472325","url":null,"abstract":"The Lidar Atmospheric Sensing Experiment (LASE) is a highly engineered and autonomous Differential Absorption Lidar (DIAL) system developed at NASA Langley Research Center (LaRC) to measure high-resolution water vapor and aerosol profiles in the troposphere. LASE is being developed as a precursor to the deployment of a spaceborne DIAL system for global measurement of high-resolution water vapor profiles. The LASE system uses a tunable Ti:sapphire laser that is frequency locked to pre-selected water vapor lines in the 815-nm region. LASE is undergoing a series of engineering test flights onboard a high-altitude ER-2 aircraft to evaluate its initial performance before deployment on field programs. During the first engineering test flight conducted near NASA Ames Research Center in May 1994, LASE was operated in the backscattered lidar mode and obtained high-quality aerosol profiles in the 0-20 km altitude region. During a subsequent engineering flight series conducted near NASA Wallops Flight facility in September 1994, water vapor and aerosol profiles were obtained simultaneously under a variety of cloud and background conditions. This paper discusses the results of the water vapor and aerosol measurements made during these flights. These measurements will be used to evaluate the performance of the instrument and for comparison with predicted values of atmospheric signals and water vapor profiles derived from in situ measurements from radiosondes launched in the vicinity of LASE measurements. These results will be used to refine the LASE system for a final engineering test series planned for early 1995. Plans for the validation of the LASE instrument with other in situ and remote sensors and the anticipated field program participation are also discussed.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125867541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472374
T. D. Stevens, C. R. Philbrick
The scattering of optical radiation in the visible, ultraviolet and infrared regions of the spectrum has a major impact on commercial air traffic and on many military systems. It has become critically important, with modern systems, that the electro-optical environment be properly characterized. Lidar techniques show great promise for describing the electro-optical scattering environment. Most of the past applications of lidar have failed to provide satisfactory results because the techniques have generally focused on measurements of the backscattered radiation at the laser fundamental wavelength. The authors have been able to demonstrate that the rotational and vibrational Raman backscatter can be used to determine the extinction profile through optical scattering regions containing aerosols and cloud layers. They have developed a secondary bi-static remote receiver designed to collect scattering angle and polarization information from a laser remote sensing system. This instrument collects an image of the radiation scattered from the first few kilometers of the atmospheric path to help determine atmospheric particle size distributions. By collecting data at different angles from the laser transmitter, additional information contained in the scattering angle phase function can be obtained. The Raman lidar extinction together with the backscatter phase function and polarization provide information on the particle size distribution that should allow extension of the extinction and transmission calculations to a wider range of wavelengths.<>
{"title":"Atmospheric extinction from Raman lidar and a bi-static remote receiver","authors":"T. D. Stevens, C. R. Philbrick","doi":"10.1109/COMEAS.1995.472374","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472374","url":null,"abstract":"The scattering of optical radiation in the visible, ultraviolet and infrared regions of the spectrum has a major impact on commercial air traffic and on many military systems. It has become critically important, with modern systems, that the electro-optical environment be properly characterized. Lidar techniques show great promise for describing the electro-optical scattering environment. Most of the past applications of lidar have failed to provide satisfactory results because the techniques have generally focused on measurements of the backscattered radiation at the laser fundamental wavelength. The authors have been able to demonstrate that the rotational and vibrational Raman backscatter can be used to determine the extinction profile through optical scattering regions containing aerosols and cloud layers. They have developed a secondary bi-static remote receiver designed to collect scattering angle and polarization information from a laser remote sensing system. This instrument collects an image of the radiation scattered from the first few kilometers of the atmospheric path to help determine atmospheric particle size distributions. By collecting data at different angles from the laser transmitter, additional information contained in the scattering angle phase function can be obtained. The Raman lidar extinction together with the backscatter phase function and polarization provide information on the particle size distribution that should allow extension of the extinction and transmission calculations to a wider range of wavelengths.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133084155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472393
Yong Han, S. Melfi, J. Snider, R. Ferrare, E. Westwater
In radiometric remote sensing of the atmosphere, the ability to calculate radiances from underlying state variables is fundamental. Traditionally, such "forward model" calculations have coupled radiosonde observations of the state variables with detailed absorption and radiative transfer models to compare with radiance observations. However, for a variety of reasons, radiosondes are not always satisfactory, especially during low humidity conditions, or when there are large horizontal or temporal gradients in the humidity structure. The use of Raman lidar is an alternative method of measuring humidity profiles, and has the added advantage of providing knowledge that the atmosphere above the instruments is clear. In November-December 1991, a substantial number of remote sensor and in situ instruments were operated together in Coffeyville, Kansas, USA, during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE II). Included in the suite of instruments were (a) the NOAA Environmental Technology Laboratory's (ETL) three channel microwave radiometer; (b) the NASA/Goddard Space Flight Center's (GSFC) Raman lidar; (c) ETL's Radio Acoustic Sounding System (RASS) (7); and (d) frequent research-quality radiosondes. The authors present results of simultaneous microwave radiometer measurements with collocated Raman lidar measurements of water vapor. Information on temperature profiles was obtained from composite data from radiosondes and RASS. The Raman lidar soundings of humidity routinely reach 8.5 km during clear nighttime conditions, but reach only to 3-4 km during the day. During the presence of liquid-bearing clouds, the Raman lidar may not penetrate much beyond cloud base. However, a suite of ground-based sensors, such as Raman lidar, RASS, and microwave radiometers, could perhaps provide soundings during both day and night and during cloudy conditions that are also useful for meteorological remote sensing. Such an array of sensors has been operated on an experimental basis by the Department of Energy's Atmospheric Radiation Program, and further deployment by the ARM program is also planned.<>
{"title":"Comparison of measurements of water vapor by a microwave radiometer and Raman lidar","authors":"Yong Han, S. Melfi, J. Snider, R. Ferrare, E. Westwater","doi":"10.1109/COMEAS.1995.472393","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472393","url":null,"abstract":"In radiometric remote sensing of the atmosphere, the ability to calculate radiances from underlying state variables is fundamental. Traditionally, such \"forward model\" calculations have coupled radiosonde observations of the state variables with detailed absorption and radiative transfer models to compare with radiance observations. However, for a variety of reasons, radiosondes are not always satisfactory, especially during low humidity conditions, or when there are large horizontal or temporal gradients in the humidity structure. The use of Raman lidar is an alternative method of measuring humidity profiles, and has the added advantage of providing knowledge that the atmosphere above the instruments is clear. In November-December 1991, a substantial number of remote sensor and in situ instruments were operated together in Coffeyville, Kansas, USA, during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE II). Included in the suite of instruments were (a) the NOAA Environmental Technology Laboratory's (ETL) three channel microwave radiometer; (b) the NASA/Goddard Space Flight Center's (GSFC) Raman lidar; (c) ETL's Radio Acoustic Sounding System (RASS) (7); and (d) frequent research-quality radiosondes. The authors present results of simultaneous microwave radiometer measurements with collocated Raman lidar measurements of water vapor. Information on temperature profiles was obtained from composite data from radiosondes and RASS. The Raman lidar soundings of humidity routinely reach 8.5 km during clear nighttime conditions, but reach only to 3-4 km during the day. During the presence of liquid-bearing clouds, the Raman lidar may not penetrate much beyond cloud base. However, a suite of ground-based sensors, such as Raman lidar, RASS, and microwave radiometers, could perhaps provide soundings during both day and night and during cloudy conditions that are also useful for meteorological remote sensing. Such an array of sensors has been operated on an experimental basis by the Department of Energy's Atmospheric Radiation Program, and further deployment by the ARM program is also planned.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116023640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472337
M. Keller, B. Gotwols, W. Plant, W. Keller
Microwave backscatter from the ocean surface has long been assumed to be proportional to the spectral density of windwaves at the Bragg-resonant wavelength. Although the spectral density of gravity-capilary waves is primarily a function of wind forcing, interactions with longer waves are also an important factor in wave-wave energy transfer. Thus, the microwave backscatter should be affected by the presence of longer waves as well. Any effort to measure the effects of longer waves on the backscatter, usually referred to as the modulation transfer function, or mtf: should include both direct measurement of the backscatter and direct measurement of the short-wave spectral density. The authors have used microwave and millimeter-wave scatterometers at 10 GHz (X-band), 35 GHz (K/sub /spl alpha// band), and 70 GHz (V band) to measure the backscatter. All three microwave instruments are CW Doppler systems. The X-band scatterometer offsets the Doppler by 400 Hz so both the upwind and downwind peaks can recorded. The remaining systems are I&Q instruments, where the RF signal modulates a 60 MHz carrier wave, and the I&Q are retrieved from the 60 MHz carrier in a separate section. The microwave signals are sampled at 3 kHz using a Data Translation A/D card in a PC, and the data are stored on 8 mm EXABYTE type. The microwave and optical systems were all aligned to view the same spot on the water, at a fetch of 16.5 meters.<>
{"title":"Wave-wave interactions in a wind-wavetank as measured with microwave and optical systems","authors":"M. Keller, B. Gotwols, W. Plant, W. Keller","doi":"10.1109/COMEAS.1995.472337","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472337","url":null,"abstract":"Microwave backscatter from the ocean surface has long been assumed to be proportional to the spectral density of windwaves at the Bragg-resonant wavelength. Although the spectral density of gravity-capilary waves is primarily a function of wind forcing, interactions with longer waves are also an important factor in wave-wave energy transfer. Thus, the microwave backscatter should be affected by the presence of longer waves as well. Any effort to measure the effects of longer waves on the backscatter, usually referred to as the modulation transfer function, or mtf: should include both direct measurement of the backscatter and direct measurement of the short-wave spectral density. The authors have used microwave and millimeter-wave scatterometers at 10 GHz (X-band), 35 GHz (K/sub /spl alpha// band), and 70 GHz (V band) to measure the backscatter. All three microwave instruments are CW Doppler systems. The X-band scatterometer offsets the Doppler by 400 Hz so both the upwind and downwind peaks can recorded. The remaining systems are I&Q instruments, where the RF signal modulates a 60 MHz carrier wave, and the I&Q are retrieved from the 60 MHz carrier in a separate section. The microwave signals are sampled at 3 kHz using a Data Translation A/D card in a PC, and the data are stored on 8 mm EXABYTE type. The microwave and optical systems were all aligned to view the same spot on the water, at a fetch of 16.5 meters.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134511852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472381
R. Hardesty, J. Intrieri
Characterization of wind structure in the marine boundary layer is important for understanding the processes affecting ocean-atmosphere exchange of heat, moisture and momentum, marine stratus formation and dissipation, and emission and scattering of electromagnetic radiation from the ocean surface. Although wind information in the lower boundary layer can be obtained from balloons, anemometers mounted on ship masts, and/or radar wind profilers, Doppler lidars offer the capability of interrogating a large area segment of the marine layer from a single location with high vertical and moderate horizontal spatial resolution. Application of Doppler lidar to marine studies was first demonstrated by Banta et al. (1993), who used lidar wind measurements to illustrate the temporal and spatial evolution of the sea breeze near Monterey, CA. The present authors extend the applications to include measurements of vertical motion for better understanding of stratocumulus cloud breakup, as well as wind field characterization and the effect of winds on the radar scattering signal from the ocean surface. They also describe a new, container-mounted lidar system specifically designed for shipboard wind measurements.<>
{"title":"Doppler lidar measurements of wind and turbulence in the marine boundary layer","authors":"R. Hardesty, J. Intrieri","doi":"10.1109/COMEAS.1995.472381","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472381","url":null,"abstract":"Characterization of wind structure in the marine boundary layer is important for understanding the processes affecting ocean-atmosphere exchange of heat, moisture and momentum, marine stratus formation and dissipation, and emission and scattering of electromagnetic radiation from the ocean surface. Although wind information in the lower boundary layer can be obtained from balloons, anemometers mounted on ship masts, and/or radar wind profilers, Doppler lidars offer the capability of interrogating a large area segment of the marine layer from a single location with high vertical and moderate horizontal spatial resolution. Application of Doppler lidar to marine studies was first demonstrated by Banta et al. (1993), who used lidar wind measurements to illustrate the temporal and spatial evolution of the sea breeze near Monterey, CA. The present authors extend the applications to include measurements of vertical motion for better understanding of stratocumulus cloud breakup, as well as wind field characterization and the effect of winds on the radar scattering signal from the ocean surface. They also describe a new, container-mounted lidar system specifically designed for shipboard wind measurements.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124890955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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