Pub Date : 1995-04-03DOI: 10.1109/COMEAS.1995.472380
G. Gimmestad, M. Belen'kii
There is currently no active, single-ended optical technique for remotely sensing the parameters of atmospheric refractive turbulence, such as the structure characteristic C/sub n//sup 2/ and the inner scale l/sub 0/. Researchers in basic atmospheric physics currently use radar and acoustic sounders to measure turbulence, but both of these techniques are sensitive to water vapor fluctuations as well as temperature fluctuations. An optical technique would be sensitive to refractive index fluctuations, which are almost completely due to temperature fluctuations in the optical spectral region. An optical remote sensor for C/sub n//sup 2/ could also be used for horizontal, path-averaged measurements, to infer fluxes of heat and momentum. Scintilometers are currently used for such measurements, but they have the disadvantage of a fixed optical path, and they require long averaging times. A single-ended sensor could be pointed in any direction, so it could be used over the sea surface, and fast spatial averaging could be accomplished by scanning in azimuth angle. Any optical sensor for turbulence must make use of some atmospheric optical phenomenon caused by turbulence. Three different lidar-type techniques have been recently proposed by the present authors. These techniques are based on the following phenomena: enhanced backscattering, residual turbulent scintillation, and image distortion. Each of these approaches is reviewed in terms of its advantages and disadvantages for various applications, and some considerations for practical systems are also discussed.<>
{"title":"Prospects for laser remote sensing of refractive turbulence","authors":"G. Gimmestad, M. Belen'kii","doi":"10.1109/COMEAS.1995.472380","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472380","url":null,"abstract":"There is currently no active, single-ended optical technique for remotely sensing the parameters of atmospheric refractive turbulence, such as the structure characteristic C/sub n//sup 2/ and the inner scale l/sub 0/. Researchers in basic atmospheric physics currently use radar and acoustic sounders to measure turbulence, but both of these techniques are sensitive to water vapor fluctuations as well as temperature fluctuations. An optical technique would be sensitive to refractive index fluctuations, which are almost completely due to temperature fluctuations in the optical spectral region. An optical remote sensor for C/sub n//sup 2/ could also be used for horizontal, path-averaged measurements, to infer fluxes of heat and momentum. Scintilometers are currently used for such measurements, but they have the disadvantage of a fixed optical path, and they require long averaging times. A single-ended sensor could be pointed in any direction, so it could be used over the sea surface, and fast spatial averaging could be accomplished by scanning in azimuth angle. Any optical sensor for turbulence must make use of some atmospheric optical phenomenon caused by turbulence. Three different lidar-type techniques have been recently proposed by the present authors. These techniques are based on the following phenomena: enhanced backscattering, residual turbulent scintillation, and image distortion. Each of these approaches is reviewed in terms of its advantages and disadvantages for various applications, and some considerations for practical systems are also discussed.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"33 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":"133747821","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.1995.472375
R. S. Harris, S. Mathur, C. R. Philbrick
Stratospheric aerosols significantly influence both the Earth's climate and the chemical composition of the stratosphere. Volcanic aerosols injected into the stratosphere, due to large volcanic eruptions, further enhance the effect on the climate and possibly lead to ozone depletion in the middle latitude stratosphere. The authors studies focus primarily on the change in the distribution of stratospheric aerosols before and after volcanic activity. The particle backscatter and other properties of stratospheric aerosols are studied to describe their variations. The Penn State Rayleigh/Raman lidar utilizes a Nd:YAG laser transmitting at both the doubled (532 nm) and tripled (355 nm) frequencies. The detector is equipped with separate channels to measure the low and high altitude signals from both the 532 nm and 355 nm as well as the Raman shifted returns due to N/sub 2/ and H/sub 2/O (660 nm and 607 nm). The LAMP lidar was first deployed on board the RV Polarstem during the LADIMAS campaign and has since been in operation in the United States. Scattering due to stratospheric aerosols from volcanic activity has been studied across different latitudes and over time. The effects due to Mt. Pinatubo (Philippines) and Mt. Hudson (Chile) eruptions have been compared.<>
{"title":"Optical properties and distribution of stratospheric aerosols","authors":"R. S. Harris, S. Mathur, C. R. Philbrick","doi":"10.1109/COMEAS.1995.472375","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472375","url":null,"abstract":"Stratospheric aerosols significantly influence both the Earth's climate and the chemical composition of the stratosphere. Volcanic aerosols injected into the stratosphere, due to large volcanic eruptions, further enhance the effect on the climate and possibly lead to ozone depletion in the middle latitude stratosphere. The authors studies focus primarily on the change in the distribution of stratospheric aerosols before and after volcanic activity. The particle backscatter and other properties of stratospheric aerosols are studied to describe their variations. The Penn State Rayleigh/Raman lidar utilizes a Nd:YAG laser transmitting at both the doubled (532 nm) and tripled (355 nm) frequencies. The detector is equipped with separate channels to measure the low and high altitude signals from both the 532 nm and 355 nm as well as the Raman shifted returns due to N/sub 2/ and H/sub 2/O (660 nm and 607 nm). The LAMP lidar was first deployed on board the RV Polarstem during the LADIMAS campaign and has since been in operation in the United States. Scattering due to stratospheric aerosols from volcanic activity has been studied across different latitudes and over time. The effects due to Mt. Pinatubo (Philippines) and Mt. Hudson (Chile) eruptions have been compared.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"191 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":"129007590","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.1995.472384
A. V. Kazansky
Accurate determination of cloud parameters and, particularly, of the cloud-top temperature and cloud emissivity are considered. The recognized ISCCP algorithm relies on relationships between bispectral data taken at visible (VIS, /spl sim/0.65 /spl mu/m) and infrared (IR, /spl sim/11.5 /spl mu/m) wavelengths. Granted that such relating of the VIS extinction coefficient to the IR absorption coefficient is admissible, headway in developing a technique based upon thermal IR-channels is of vital significance, because it promises the retrieval of cloud parameters both day and night while avoiding some problems inherent in the VIS-IR approach. It is accepted that the emissivity of opaque clouds approaches unity thus permitting for infrared methods to retrieve accurate cloud-top temperature. Even that, current IR methods based solely on attenuation effect of clouds are incapable to measure radiative characteristics of opaque clouds. To cope with this problem, it was proposed recently to use submillimeter wave frequencies at which most clouds are transparent enough. Although no specific microwave cloud algorithms have been developed, it was pointed out that subceiling probing of radiometrically opaque nimbus clouds (rain cells) remains the challenge for microwave satellite sensing. On the other hand, many "multichannel" infrared cloud algorithms developed for semitransparent cirrus cases are based on a doubtful assumption that the cloud emissivity is independent of wavelength. In virtue of this, the authors intended to investigate this problem with a new dual-path (DP) approach, as the slant path (proportional to the secant of the satellite zenith angle) is different instead of wavelength thus obviating the obstacle of emissivity differences between wavelengths. Examination of AVHRR images from the triplet of nearly simultaneous NOAA. Polar orbiting satellites (namely: NOAA-9, -10, -12) revealed significant variances in the infrared radiation emitting by opaque clouds at different angles. To account for the effect of cloud temperatures changes with depth, causing the essential part of these angular differences, the current cloud radiative model is revised following the principles of radiative transfer. Based on the model analysis, the authors investigate in this paper the potential of DP method for retrieving parameters of opaque clouds.<>
{"title":"Subceiling probing of clouds using pairs of AVHRR images","authors":"A. V. Kazansky","doi":"10.1109/COMEAS.1995.472384","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472384","url":null,"abstract":"Accurate determination of cloud parameters and, particularly, of the cloud-top temperature and cloud emissivity are considered. The recognized ISCCP algorithm relies on relationships between bispectral data taken at visible (VIS, /spl sim/0.65 /spl mu/m) and infrared (IR, /spl sim/11.5 /spl mu/m) wavelengths. Granted that such relating of the VIS extinction coefficient to the IR absorption coefficient is admissible, headway in developing a technique based upon thermal IR-channels is of vital significance, because it promises the retrieval of cloud parameters both day and night while avoiding some problems inherent in the VIS-IR approach. It is accepted that the emissivity of opaque clouds approaches unity thus permitting for infrared methods to retrieve accurate cloud-top temperature. Even that, current IR methods based solely on attenuation effect of clouds are incapable to measure radiative characteristics of opaque clouds. To cope with this problem, it was proposed recently to use submillimeter wave frequencies at which most clouds are transparent enough. Although no specific microwave cloud algorithms have been developed, it was pointed out that subceiling probing of radiometrically opaque nimbus clouds (rain cells) remains the challenge for microwave satellite sensing. On the other hand, many \"multichannel\" infrared cloud algorithms developed for semitransparent cirrus cases are based on a doubtful assumption that the cloud emissivity is independent of wavelength. In virtue of this, the authors intended to investigate this problem with a new dual-path (DP) approach, as the slant path (proportional to the secant of the satellite zenith angle) is different instead of wavelength thus obviating the obstacle of emissivity differences between wavelengths. Examination of AVHRR images from the triplet of nearly simultaneous NOAA. Polar orbiting satellites (namely: NOAA-9, -10, -12) revealed significant variances in the infrared radiation emitting by opaque clouds at different angles. To account for the effect of cloud temperatures changes with depth, causing the essential part of these angular differences, the current cloud radiative model is revised following the principles of radiative transfer. Based on the model analysis, the authors investigate in this paper the potential of DP method for retrieving parameters of opaque clouds.<<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":"125795431","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.1995.472333
V. Etkin, V. Raizer, A. Stulov, K. Zhuravlev
During the 1992 joint US/Russia Internal Wave Remote Sensing Experiment the large-scale structure of the ocean surface was investigated using a high resolution optical air photocamera. Data were recorded on photographic film, and then two-dimensional Fourier spectra of optical images were computed digitally. It was found a strong changing of the spectrum of wind waves due to the influence of ocean internal waves. In particular, wavenumber spectrum of optical images is unstable in the field of internal waves. Multimode structure of the spectra of wind waves is usually very much more pronounced in the case of nonlinear internal waves. The observed picture could be interpreted as a result of the multiwave nonlinear interaction between surface gravity waves and internal waves.<>
{"title":"Airborne optical measurements of wind-wave spectral perturbations induced by ocean internal waves","authors":"V. Etkin, V. Raizer, A. Stulov, K. Zhuravlev","doi":"10.1109/COMEAS.1995.472333","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472333","url":null,"abstract":"During the 1992 joint US/Russia Internal Wave Remote Sensing Experiment the large-scale structure of the ocean surface was investigated using a high resolution optical air photocamera. Data were recorded on photographic film, and then two-dimensional Fourier spectra of optical images were computed digitally. It was found a strong changing of the spectrum of wind waves due to the influence of ocean internal waves. In particular, wavenumber spectrum of optical images is unstable in the field of internal waves. Multimode structure of the spectra of wind waves is usually very much more pronounced in the case of nonlinear internal waves. The observed picture could be interpreted as a result of the multiwave nonlinear interaction between surface gravity waves and internal waves.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"28 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":"121726340","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.1995.472320
S. Melfi, D. Whiteman, R. Ferrare, K. Evans
The WMO regularily distributes data from the upper-air balloon-sonde network made up of sites in participating countries around the world, but the quality varies significantly from country to country. Satellite observations of global water vapor hold the promise to meet the needs of the scientific community. At present passive sensors operating in the infrared and microwave are the only data source from which to derive atmospheric moisture information. A ground-based Raman lidar is an ideal sensor to obtain ground-truth data to compare with the satellite data. The Raman lidar provides vertical profiles of water vapor mixing ratio which can be used to directly compare with both the satellite derived data and aircraft versions of future satellite passive sensors. The lidar profiles can provide an important measure of atmospheric moisture variability. Knowledge of moisture variability is absolutely essential for a proper validation of passive sensors because ofthe errors associated with beam-filling. In general the measurement beam of a satellite-based IR or a microwave instrument is several 10s of kilometers at the Earth's surface. The upwelling radiation within this footprint is influenced not only by the total concentration of the species being measured but also by the distribution of that species in the instantaneous field-of-view. We must know both to perform a valid inversion. The Raman lidar developed at the Goddard Space Flight Center consists of an xenon fluoride excimer laser and a 0.75 meter telescope. The lidar in able, through the use of beamsplitters, to simultaneously measure laser scattering from aerosols, nitrogen, oxygen and water vapor. The ratio of the water vapor signal to the nitrogen signal after a small differential attenuation correction is proportional to water vapor mixing ratio. The ratio measured versus the time of flight of the laser pulse is easily converted into an altitude profile of moisture. A detailed description of the system along with data showing moisture and it's variability are given.<>
{"title":"Raman lidar measurements of water vapor as ground-truth for passive remote sensors","authors":"S. Melfi, D. Whiteman, R. Ferrare, K. Evans","doi":"10.1109/COMEAS.1995.472320","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472320","url":null,"abstract":"The WMO regularily distributes data from the upper-air balloon-sonde network made up of sites in participating countries around the world, but the quality varies significantly from country to country. Satellite observations of global water vapor hold the promise to meet the needs of the scientific community. At present passive sensors operating in the infrared and microwave are the only data source from which to derive atmospheric moisture information. A ground-based Raman lidar is an ideal sensor to obtain ground-truth data to compare with the satellite data. The Raman lidar provides vertical profiles of water vapor mixing ratio which can be used to directly compare with both the satellite derived data and aircraft versions of future satellite passive sensors. The lidar profiles can provide an important measure of atmospheric moisture variability. Knowledge of moisture variability is absolutely essential for a proper validation of passive sensors because ofthe errors associated with beam-filling. In general the measurement beam of a satellite-based IR or a microwave instrument is several 10s of kilometers at the Earth's surface. The upwelling radiation within this footprint is influenced not only by the total concentration of the species being measured but also by the distribution of that species in the instantaneous field-of-view. We must know both to perform a valid inversion. The Raman lidar developed at the Goddard Space Flight Center consists of an xenon fluoride excimer laser and a 0.75 meter telescope. The lidar in able, through the use of beamsplitters, to simultaneously measure laser scattering from aerosols, nitrogen, oxygen and water vapor. The ratio of the water vapor signal to the nitrogen signal after a small differential attenuation correction is proportional to water vapor mixing ratio. The ratio measured versus the time of flight of the laser pulse is easily converted into an altitude profile of moisture. A detailed description of the system along with data showing moisture and it's variability are given.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"8 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":"123734209","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.1995.472383
P.A.T. Haris, C. R. Philbrick
The use of rotational Raman scattering to measure temperature in the lower troposphere has been investigated. Initial results have shown the value of this technique for temperature measurements from the ground to 10 km using the Applied Research Laboratory/Penn State University LAMP lidar. Comparisons with standard rawinsonde balloons show the rotational Raman technique's accuracy and ability to measure temperature on small spatial and temporal scales. A statistical model of lidar performance. Assuming the use of the doubled wavelength (532 nm) Nd:YAG laser, has been developed to analyze the optimal instrumental configuration for rotational Raman temperature measurements in the mid-latitude troposphere.<>
{"title":"Rotational Raman lidar for temperature measurements in the troposphere","authors":"P.A.T. Haris, C. R. Philbrick","doi":"10.1109/COMEAS.1995.472383","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472383","url":null,"abstract":"The use of rotational Raman scattering to measure temperature in the lower troposphere has been investigated. Initial results have shown the value of this technique for temperature measurements from the ground to 10 km using the Applied Research Laboratory/Penn State University LAMP lidar. Comparisons with standard rawinsonde balloons show the rotational Raman technique's accuracy and ability to measure temperature on small spatial and temporal scales. A statistical model of lidar performance. Assuming the use of the doubled wavelength (532 nm) Nd:YAG laser, has been developed to analyze the optimal instrumental configuration for rotational Raman temperature measurements in the mid-latitude troposphere.<<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":"130780918","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.1995.472388
J. Spinhirne, J.R. Wang
An extensive set of combined visible, infrared, microwave and lidar observations for high tropical clouds were obtained during the TOGA/COARE field experiment from the ER-2 high altitude aircraft. Approximately ten flights from Australia to the West Pacific warm pool region north of New Guinea were flown. Some flights involved simultaneous in situ measurements of cloud microphysics and radiation by the DC-8 aircraft with excellent coordination between the aircraft. The two basic types of cloud systems that were studied were tropical convective systems and thin to moderately thick cirrus that covered large areas of the study legion both within the warm pool area and in the transit region to NE Australia. The two main objectives to the NASA field study were a study of the radiation influence and parameters of high tropical clouds and precipitation remote sensing of tropical convection. The authors consider the application of multi sensor remote sensing of tropical high clouds leading to radiation parameterization and influence. The experiment was the first in which airborne millimeter wavelength microwave radiometry was combined with vis/IR multispectral imaging: and active lidar measurements to define cloud structure.<>
{"title":"Combined high frequency microwave, visible and infrared and lidar sensing of tropical clouds from the ER-2 high altitude aircraft","authors":"J. Spinhirne, J.R. Wang","doi":"10.1109/COMEAS.1995.472388","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472388","url":null,"abstract":"An extensive set of combined visible, infrared, microwave and lidar observations for high tropical clouds were obtained during the TOGA/COARE field experiment from the ER-2 high altitude aircraft. Approximately ten flights from Australia to the West Pacific warm pool region north of New Guinea were flown. Some flights involved simultaneous in situ measurements of cloud microphysics and radiation by the DC-8 aircraft with excellent coordination between the aircraft. The two basic types of cloud systems that were studied were tropical convective systems and thin to moderately thick cirrus that covered large areas of the study legion both within the warm pool area and in the transit region to NE Australia. The two main objectives to the NASA field study were a study of the radiation influence and parameters of high tropical clouds and precipitation remote sensing of tropical convection. The authors consider the application of multi sensor remote sensing of tropical high clouds leading to radiation parameterization and influence. The experiment was the first in which airborne millimeter wavelength microwave radiometry was combined with vis/IR multispectral imaging: and active lidar measurements to define cloud structure.<<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":"133757807","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.1995.472400
G. Asrar, R. Myneni
Space-based observations provide a unique perspective of Earth which has led to the definition of Earth System Science (ESS), promoting inter-disciplinary study of Earth as an integrated and coupled system consisting of the atmosphere, oceans and continents interacting through exchange of energy, mass and momentum over a wide range of spatial and temporal scales. The concept of Earth System Science has gained considerable support among disparate disciplines of geology, atmospheric sciences, oceanography, hydrology, and ecological sciences during the past decade. During the past decade, a large number of multi-disciplinary coordinated field experiments have been conceived and implemented in support of ESS concept. These studies have relied to a large extent on use of in situ multispectral remotely sensed observations in conjunction with coupled surface-atmosphere models. To study the biosphere-atmosphere interactions Earth scientists adopted several strategies including retrospective studies, coordinated field experiments, and modeling simulation of major terrestrial ecosystems. In these efforts, applications of multispectral remote sensing observations gained considerable support. In addition to scientific utilization of current remote sensing observations, Earth scientists and remote sensing experts identified new measurement requirements which formed the bases of the next generation of remote sensing systems. The capabilities planned as part of future remote sensing systems will further enhance quantitative applications of multispectral remotely sensed observations in studies of Earth as a system, and in developing long-term climate prediction capabilities. These capabilities could be also used in assessing the impact of environmental changes on agricultural, industrial and social development activities.<>
{"title":"Multispectral remote sensing of biosphere-atmosphere processes","authors":"G. Asrar, R. Myneni","doi":"10.1109/COMEAS.1995.472400","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472400","url":null,"abstract":"Space-based observations provide a unique perspective of Earth which has led to the definition of Earth System Science (ESS), promoting inter-disciplinary study of Earth as an integrated and coupled system consisting of the atmosphere, oceans and continents interacting through exchange of energy, mass and momentum over a wide range of spatial and temporal scales. The concept of Earth System Science has gained considerable support among disparate disciplines of geology, atmospheric sciences, oceanography, hydrology, and ecological sciences during the past decade. During the past decade, a large number of multi-disciplinary coordinated field experiments have been conceived and implemented in support of ESS concept. These studies have relied to a large extent on use of in situ multispectral remotely sensed observations in conjunction with coupled surface-atmosphere models. To study the biosphere-atmosphere interactions Earth scientists adopted several strategies including retrospective studies, coordinated field experiments, and modeling simulation of major terrestrial ecosystems. In these efforts, applications of multispectral remote sensing observations gained considerable support. In addition to scientific utilization of current remote sensing observations, Earth scientists and remote sensing experts identified new measurement requirements which formed the bases of the next generation of remote sensing systems. The capabilities planned as part of future remote sensing systems will further enhance quantitative applications of multispectral remotely sensed observations in studies of Earth as a system, and in developing long-term climate prediction capabilities. These capabilities could be also used in assessing the impact of environmental changes on agricultural, industrial and social development activities.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"37 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":"132934000","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.1995.472346
I. Sergievskaya
On the sea surface it is often possible to observe spots and the bars with reduced intensity short surface waves, caused by the presence of a SAS film on the surface (an oil slick). The possibility of film slick observation does not only depend on the SAS properties. In this paper the influence of illumination and observation conditions, waves and SAS properties on possibility of observing slicks on the sea surface are investigated. It is assumed that the surface section of interest was illuminated by direct sunlight or diffuse light of a cloudless sky. Surface statistical characteristics variations resulting in apparent changing of surface brightness or inhomogeneity scales were estimated. These estimations were compared with the known data on the influence of SAS on the surface. It permitted the author to find out the optimal condition for film slicks observation from shipborne and airborne observations.<>
{"title":"On slick observation","authors":"I. Sergievskaya","doi":"10.1109/COMEAS.1995.472346","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472346","url":null,"abstract":"On the sea surface it is often possible to observe spots and the bars with reduced intensity short surface waves, caused by the presence of a SAS film on the surface (an oil slick). The possibility of film slick observation does not only depend on the SAS properties. In this paper the influence of illumination and observation conditions, waves and SAS properties on possibility of observing slicks on the sea surface are investigated. It is assumed that the surface section of interest was illuminated by direct sunlight or diffuse light of a cloudless sky. Surface statistical characteristics variations resulting in apparent changing of surface brightness or inhomogeneity scales were estimated. These estimations were compared with the known data on the influence of SAS on the surface. It permitted the author to find out the optimal condition for film slicks observation from shipborne and airborne observations.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"86 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":"133083404","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.1995.472352
E.J. Kim, A. England
Radiobrightness thermal inertia (RTI) can be used to estimate the moisture content of prairie grassland and agricultural soils. Moisture increases the apparent thermal inertia' of soil by increasing its thermal conductivity, density, and specific heat. Apparent thermal inertia is further increased by evapotranspiration during the day and by condensation at night. Increasing moisture content causes a decrease in microwave emissivity. Combined, these effects should enhance the dependence of RTI upon soil moisture. 37 GHz data from the Nimbus 7 SMMR have been used to demonstrate the plausibility of the RTI method. However, longer data sets over several contiguous days of moisture change were needed to more fully test the model. Also, the masking effect of a vegetation canopy is best handled through the use of a Soil Vegetation-Atmosphere Transfer (SVAT) model. From August 19 to September 8, 1992, the authors' Tower Mounted Radiometer System (TMRS) was operated at the Matthaei Botanical Gardens, Michigan. 19, 35, 37.0, and 85.5 GHz polarimetric observations were made. Simultaneous measurements of solar and net downwelling radiation, air temperature, precipitation, relative humidity, thermal IR surface temperature, wind speed, subsurface temperature, and soil heat flux were also made.<>
{"title":"Radiobrightness thermal inertia sensing of soil and canopy moistures for grassland areas","authors":"E.J. Kim, A. England","doi":"10.1109/COMEAS.1995.472352","DOIUrl":"https://doi.org/10.1109/COMEAS.1995.472352","url":null,"abstract":"Radiobrightness thermal inertia (RTI) can be used to estimate the moisture content of prairie grassland and agricultural soils. Moisture increases the apparent thermal inertia' of soil by increasing its thermal conductivity, density, and specific heat. Apparent thermal inertia is further increased by evapotranspiration during the day and by condensation at night. Increasing moisture content causes a decrease in microwave emissivity. Combined, these effects should enhance the dependence of RTI upon soil moisture. 37 GHz data from the Nimbus 7 SMMR have been used to demonstrate the plausibility of the RTI method. However, longer data sets over several contiguous days of moisture change were needed to more fully test the model. Also, the masking effect of a vegetation canopy is best handled through the use of a Soil Vegetation-Atmosphere Transfer (SVAT) model. From August 19 to September 8, 1992, the authors' Tower Mounted Radiometer System (TMRS) was operated at the Matthaei Botanical Gardens, Michigan. 19, 35, 37.0, and 85.5 GHz polarimetric observations were made. Simultaneous measurements of solar and net downwelling radiation, air temperature, precipitation, relative humidity, thermal IR surface temperature, wind speed, subsurface temperature, and soil heat flux were also made.<<ETX>>","PeriodicalId":274878,"journal":{"name":"Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing","volume":"27 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":"125008031","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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