R. Basistyy, Adrien P. Genoud, Adrian Diaz, F. Moshary, B. Thomas
Active stand-off detection and hard-target lidars are common methodologies for gas identification, chemical emission tracing, hazardous material sensing, or explosive detection to name a few. By their nature, this type of instrument heavily relies on the reflectivity or backscattering properties of distant targets. While some applications allow the use of retroreflectors, most mobile systems require the use of actual topographic targets, such as the ground, roads, buildings, roofs, or vegetation. In this work, N2O path-averaged mixing ratios are measured with the 10 Hz frequency using a quantum cascade laser open path system operating at 7.7 μm wavelength. Measurements are performed by detecting the light backscattered from common topographic targets located 5.5 m away from the instrument. For each topographic target, the detection limit and accuracy of the retrieved mixing ratios are presented and discussed showing detection limits between 0.008 and 1.36 ppm depending on the target and mixing ratio relative errors between 4 and 80 %.
{"title":"Active standoff mixing-ratio measurements of N2O from topographic targets using an open-path quantum cascade laser system","authors":"R. Basistyy, Adrien P. Genoud, Adrian Diaz, F. Moshary, B. Thomas","doi":"10.1117/12.2323548","DOIUrl":"https://doi.org/10.1117/12.2323548","url":null,"abstract":"Active stand-off detection and hard-target lidars are common methodologies for gas identification, chemical emission tracing, hazardous material sensing, or explosive detection to name a few. By their nature, this type of instrument heavily relies on the reflectivity or backscattering properties of distant targets. While some applications allow the use of retroreflectors, most mobile systems require the use of actual topographic targets, such as the ground, roads, buildings, roofs, or vegetation. In this work, N2O path-averaged mixing ratios are measured with the 10 Hz frequency using a quantum cascade laser open path system operating at 7.7 μm wavelength. Measurements are performed by detecting the light backscattered from common topographic targets located 5.5 m away from the instrument. For each topographic target, the detection limit and accuracy of the retrieved mixing ratios are presented and discussed showing detection limits between 0.008 and 1.36 ppm depending on the target and mixing ratio relative errors between 4 and 80 %.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128324263","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}
Physical deterministic sea surface temperature (PDSST) retrieval scheme is built on radiative transfer forward model and a mathematically deterministic approach to the solution for inverse problem. This requires atmospheric profiles information from Numerical Weather Prediction (NWP), which offers the prospect to account for local retrieval conditions and yields a more uniform product with superior accuracy. One of the unprecedented capabilities of the PDSST scheme is that it can use aerosol profiles in addition to atmospheric profiles information for the forward modeling, and also allows for adjustment of the aerosol burden by including it as a retrieved element. Cloud detection is a vital part of SST retrieval processing. An innovative cloud and error masking (CEM) algorithm has been developed, combining the functional spectral differences and radiative transfer based cloud detection tests, especially the functional double difference tests are unique. These advancements have led to substantial improvements in information retrieval from expensive satellite measurement. This improvement refers to a dual benefit of increased data coverage (reduced false alarms) and detection of actual cloud contamination (improved detection rate). The PDSST retrieval suite, is combining the PDSST retrieval scheme and CEM, demonstrates the superiority of this approach with an overall ~3-4 times information gain when implemented on data from MODIS-Aqua and GOES Imager. For example, RMSE reduction from 0.52 K to 0.35 K and data coverage enhanced from ~9% to ~19% as compared to NASA operational MODIS-AQUA SST products.
{"title":"Theoretical aspects and operational results of physical deterministic sea surface temperature retrieval","authors":"P. Koner","doi":"10.1117/12.2323429","DOIUrl":"https://doi.org/10.1117/12.2323429","url":null,"abstract":"Physical deterministic sea surface temperature (PDSST) retrieval scheme is built on radiative transfer forward model and a mathematically deterministic approach to the solution for inverse problem. This requires atmospheric profiles information from Numerical Weather Prediction (NWP), which offers the prospect to account for local retrieval conditions and yields a more uniform product with superior accuracy. One of the unprecedented capabilities of the PDSST scheme is that it can use aerosol profiles in addition to atmospheric profiles information for the forward modeling, and also allows for adjustment of the aerosol burden by including it as a retrieved element. Cloud detection is a vital part of SST retrieval processing. An innovative cloud and error masking (CEM) algorithm has been developed, combining the functional spectral differences and radiative transfer based cloud detection tests, especially the functional double difference tests are unique. These advancements have led to substantial improvements in information retrieval from expensive satellite measurement. This improvement refers to a dual benefit of increased data coverage (reduced false alarms) and detection of actual cloud contamination (improved detection rate). The PDSST retrieval suite, is combining the PDSST retrieval scheme and CEM, demonstrates the superiority of this approach with an overall ~3-4 times information gain when implemented on data from MODIS-Aqua and GOES Imager. For example, RMSE reduction from 0.52 K to 0.35 K and data coverage enhanced from ~9% to ~19% as compared to NASA operational MODIS-AQUA SST products.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130907161","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}
J. Aminuddin, N. Manago, N. Lagrosas, S. Okude, H. Kuze
The influence of aerosols to the atmosphere has been discussed in the context of the Earth radiation budget and global climate change. Therefore, precise monitoring of aerosol parameters is important for better understanding of their real characteristics and impacts on the environment. In this study, we report on a novel method of concurrent measurements of aerosol near the surface level by means of slant-path (SP) and plan position indicator (PPI) lidars. The SP lidar utilizes a diode-laser-pumped Nd:YAG laser operating at 532 nm, while the PPI is based on a Nd:YLF laser at 349 nm. The PPI system including the laser transmitter and telescope section is rotated over 360° for covering all the horizontal directions with the maximum observation range up to around 3 km. At the same time, the SP lidar is employed for monitoring the near surface region that cannot be covered by vertical observation lidars. Furthermore, the backscattered signals recorded by both PPI and SP lidars are analyzed using the Fernald method to retrieve aerosol extinction coefficient by employing lidar ratios for 349 and 532 nm. These values of lidar ratio are estimated by adjusting and fitting parameters in the Mie scattering calculation (mode radius, variance, and both real and imaginary parts of refractive index) to real data from ground-based sampling instruments, namely, the scattering coefficient, absorption coefficient, and size distribution observed with an integrating nephelometer, an aethalometer, and an optical particle counter, respectively. Real-time values of the extinction coefficient inside the atmospheric boundary-layer are derived as the summation of scattering and absorption coefficients. The results are then compared with those from a vertical lidar, operated by the National Institute of Environmental Studies (NIES) on the campus of Chiba University. We discuss the observed features of aerosol characteristics that vary both temporally and spatially.
{"title":"Simultaneous observation of temporal and spatial distribution of atmospheric aerosol by means of slant-path and plan position indicator lidars","authors":"J. Aminuddin, N. Manago, N. Lagrosas, S. Okude, H. Kuze","doi":"10.1117/12.2324688","DOIUrl":"https://doi.org/10.1117/12.2324688","url":null,"abstract":"The influence of aerosols to the atmosphere has been discussed in the context of the Earth radiation budget and global climate change. Therefore, precise monitoring of aerosol parameters is important for better understanding of their real characteristics and impacts on the environment. In this study, we report on a novel method of concurrent measurements of aerosol near the surface level by means of slant-path (SP) and plan position indicator (PPI) lidars. The SP lidar utilizes a diode-laser-pumped Nd:YAG laser operating at 532 nm, while the PPI is based on a Nd:YLF laser at 349 nm. The PPI system including the laser transmitter and telescope section is rotated over 360° for covering all the horizontal directions with the maximum observation range up to around 3 km. At the same time, the SP lidar is employed for monitoring the near surface region that cannot be covered by vertical observation lidars. Furthermore, the backscattered signals recorded by both PPI and SP lidars are analyzed using the Fernald method to retrieve aerosol extinction coefficient by employing lidar ratios for 349 and 532 nm. These values of lidar ratio are estimated by adjusting and fitting parameters in the Mie scattering calculation (mode radius, variance, and both real and imaginary parts of refractive index) to real data from ground-based sampling instruments, namely, the scattering coefficient, absorption coefficient, and size distribution observed with an integrating nephelometer, an aethalometer, and an optical particle counter, respectively. Real-time values of the extinction coefficient inside the atmospheric boundary-layer are derived as the summation of scattering and absorption coefficients. The results are then compared with those from a vertical lidar, operated by the National Institute of Environmental Studies (NIES) on the campus of Chiba University. We discuss the observed features of aerosol characteristics that vary both temporally and spatially.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134389907","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}
Genki Terauchi, E. R. Maúre, Zhiming Yu, Zaixing Wu, Chan-Man Lee, V. Kachur, J. Ishizaka
The Northwest Pacific region, which includes parts of northeast China, Japan, Korea and southeast Russia, is one of the most densely populated areas of the world. Eutrophication is an emerging environmental problem in this region, where a significant number of red tides and hypoxic conditions have been reported in coastal waters - possibly due to anthropogenic influences such as extensive chemical fertilizer use and sewage effluent. To assess this problem, NOWPAP CEARAC, the Special Monitoring and Coastal Environment Assessment Regional Activity Centre of the Action Plan for the Protection, Management and Development of the Marine and Coastal Environment of the Northwest Pacific Region of the United Nations Environmental Programme, has developed "Procedures for assessment of eutrophication status including the evaluation of land-based sources of nutrients for the NOWPAP region" (NOWPAP Common Procedures). The NOWPAP Common Procedures include the screening procedure to detect symptoms of eutrophication with selected parameters. One of the selected parameters is remotely sensed chlorophyll-a concentration (satellite Chl-a). To prepare a long-term consistent satellite Chl-a from 1998 to 2016, regression analysis was conducted by pixel to pixel using the daily composites of SeaWiFS and MODIS Remote Sensing Reflectance for overlapping period (July 2002 to December 2004). Two different empirical in-water algorithms, a NASA standard and a regionally developed one for turbid water, were applied to estimate Chl-a in the eastern and western parts of the Northwest Pacific region, respectively. The assessment of eutrophication was then conducted by the level and trend of satellite Chl-a.
{"title":"Assessment of eutrophication using remotely sensed chlorophyll-a in the Northwest Pacific region","authors":"Genki Terauchi, E. R. Maúre, Zhiming Yu, Zaixing Wu, Chan-Man Lee, V. Kachur, J. Ishizaka","doi":"10.1117/12.2324641","DOIUrl":"https://doi.org/10.1117/12.2324641","url":null,"abstract":"The Northwest Pacific region, which includes parts of northeast China, Japan, Korea and southeast Russia, is one of the most densely populated areas of the world. Eutrophication is an emerging environmental problem in this region, where a significant number of red tides and hypoxic conditions have been reported in coastal waters - possibly due to anthropogenic influences such as extensive chemical fertilizer use and sewage effluent. To assess this problem, NOWPAP CEARAC, the Special Monitoring and Coastal Environment Assessment Regional Activity Centre of the Action Plan for the Protection, Management and Development of the Marine and Coastal Environment of the Northwest Pacific Region of the United Nations Environmental Programme, has developed \"Procedures for assessment of eutrophication status including the evaluation of land-based sources of nutrients for the NOWPAP region\" (NOWPAP Common Procedures). The NOWPAP Common Procedures include the screening procedure to detect symptoms of eutrophication with selected parameters. One of the selected parameters is remotely sensed chlorophyll-a concentration (satellite Chl-a). To prepare a long-term consistent satellite Chl-a from 1998 to 2016, regression analysis was conducted by pixel to pixel using the daily composites of SeaWiFS and MODIS Remote Sensing Reflectance for overlapping period (July 2002 to December 2004). Two different empirical in-water algorithms, a NASA standard and a regionally developed one for turbid water, were applied to estimate Chl-a in the eastern and western parts of the Northwest Pacific region, respectively. The assessment of eutrophication was then conducted by the level and trend of satellite Chl-a.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124060627","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}
T. Refaat, M. Petros, Jane Lee, Teh-Hwa Wong, R. Remus, U. Singh
Integrated path differential absorption (IPDA) lidar is an active remote sensing technique for monitoring different atmospheric species. The technique relies on wavelength differentiation between strong and weak absorbing features normalized to the transmitted energy. An advanced 2-μm triple-pulse IPDA lidar was developed at NASA Langley Research Center for active sensing of carbon dioxide and water vapor simultaneously. The IPDA transmitter produces three successive laser pulses separated by a short interval (200 μs) with a repetition rate of 50Hz. Measurement of laser pulse energy accurately is a prerequisite for the retrieval of gas mixing ratios from IPDA. Due to the short interval between the three transmitted pulses, conventional thermal energy monitors underestimate the total transmitted energy. The design and calibration of a 2-μm triple-pulse laser energy monitor are presented. The design is based on a high speed, extended range InGaAs pin quantum detector suitable for separating the three pulse events. Pulse integration is applied for converting the detected pulse power into energy. The results obtained from the laser energy monitor were compared to an ultra-fast energy-meter reference for energy scaling and verification. High correlations between the pin energy monitor and the total transmitted energy were obtained. The objective of this development is to reduce measurement biases and errors using the triple-pulse IPDA technique.
{"title":"Laser energy monitor for triple-pulse 2-μm IPDA lidar application","authors":"T. Refaat, M. Petros, Jane Lee, Teh-Hwa Wong, R. Remus, U. Singh","doi":"10.1117/12.2324782","DOIUrl":"https://doi.org/10.1117/12.2324782","url":null,"abstract":"Integrated path differential absorption (IPDA) lidar is an active remote sensing technique for monitoring different atmospheric species. The technique relies on wavelength differentiation between strong and weak absorbing features normalized to the transmitted energy. An advanced 2-μm triple-pulse IPDA lidar was developed at NASA Langley Research Center for active sensing of carbon dioxide and water vapor simultaneously. The IPDA transmitter produces three successive laser pulses separated by a short interval (200 μs) with a repetition rate of 50Hz. Measurement of laser pulse energy accurately is a prerequisite for the retrieval of gas mixing ratios from IPDA. Due to the short interval between the three transmitted pulses, conventional thermal energy monitors underestimate the total transmitted energy. The design and calibration of a 2-μm triple-pulse laser energy monitor are presented. The design is based on a high speed, extended range InGaAs pin quantum detector suitable for separating the three pulse events. Pulse integration is applied for converting the detected pulse power into energy. The results obtained from the laser energy monitor were compared to an ultra-fast energy-meter reference for energy scaling and verification. High correlations between the pin energy monitor and the total transmitted energy were obtained. The objective of this development is to reduce measurement biases and errors using the triple-pulse IPDA technique.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126938182","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}
T. Mcgee, L. Twigg, J. Sullivan, T. Leblanc, J. Barnes, Grant K. Sumnicht, Stuart McDermid
NASA’s Goddard Space Flight Center (GSFC) transported two lidar instruments to the NOAA facility at the Mauna Loa Observatory (MLO) on the Big Island of Hawaii, to participate in an official, extended validation campaign. This site is situated 11,141 ft. above sea level on the side of the mountain. The observatory has been making atmospheric measurements regularly since the 1950’s, and has hosted the GSFC Stratospheric Ozone (STROZ) Lidar and the GSFC Aerosol and Temperature (AT) Lidar on several occasions, most recently between November, 2012 and November, 2015. The purpose of this extended deployment was to participate in Network for the Detection of Atmospheric Composition Change (NDACC) Validation campaigns with the JPL Stratospheric Ozone Lidar and the NOAA Temperature, Aerosol and Water Vapor instruments as part of the routine NDACC Validation Protocol.
{"title":"Lidar validation measurements at the NOAA Mauna Loa Observatory NDACC Station","authors":"T. Mcgee, L. Twigg, J. Sullivan, T. Leblanc, J. Barnes, Grant K. Sumnicht, Stuart McDermid","doi":"10.1117/12.2324714","DOIUrl":"https://doi.org/10.1117/12.2324714","url":null,"abstract":"NASA’s Goddard Space Flight Center (GSFC) transported two lidar instruments to the NOAA facility at the Mauna Loa Observatory (MLO) on the Big Island of Hawaii, to participate in an official, extended validation campaign. This site is situated 11,141 ft. above sea level on the side of the mountain. The observatory has been making atmospheric measurements regularly since the 1950’s, and has hosted the GSFC Stratospheric Ozone (STROZ) Lidar and the GSFC Aerosol and Temperature (AT) Lidar on several occasions, most recently between November, 2012 and November, 2015. The purpose of this extended deployment was to participate in Network for the Detection of Atmospheric Composition Change (NDACC) Validation campaigns with the JPL Stratospheric Ozone Lidar and the NOAA Temperature, Aerosol and Water Vapor instruments as part of the routine NDACC Validation Protocol.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125890885","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}
Coral reef live percent cover (LPC) mapping has always been a challenging application for remote-sensing. The adoption of machine-learning algorithm in remote-sensing has opened-up the possibility of mapping coral reef at higher accuracy. This paper presents the application of machine-learning regression in the empirical modeling of coral reef LPC mapping. Stepwise regression, Support Vector Machine (SVM) regression, and Random Forest (RF) regression were used model the percentage of live coral cover in optically shallow water of Parang Island, Central Java, Indonesia using field photo-transect data to train the PlanetScope image. PlanetScope multispectral bands were transformed into water column corrected bands, Principle Component bands, and Cooccurrence texture analysis bands to be used as predictors in the regression process. The results indicate that the accuracy of machine learning algorithm to map coral reef LPC is relatively low due to the radiometric quality issue in the PlanetScope image (RMSE = 15.43%). We could not yet fairly justify the performance of machine learning algorithm until we applied the algorithms in other images.
{"title":"Machine-learning regression for coral reef percentage cover mapping","authors":"P. Wicaksono, W. Lazuardi, Afif Al Hadi, M. Kamal","doi":"10.1117/12.2324028","DOIUrl":"https://doi.org/10.1117/12.2324028","url":null,"abstract":"Coral reef live percent cover (LPC) mapping has always been a challenging application for remote-sensing. The adoption of machine-learning algorithm in remote-sensing has opened-up the possibility of mapping coral reef at higher accuracy. This paper presents the application of machine-learning regression in the empirical modeling of coral reef LPC mapping. Stepwise regression, Support Vector Machine (SVM) regression, and Random Forest (RF) regression were used model the percentage of live coral cover in optically shallow water of Parang Island, Central Java, Indonesia using field photo-transect data to train the PlanetScope image. PlanetScope multispectral bands were transformed into water column corrected bands, Principle Component bands, and Cooccurrence texture analysis bands to be used as predictors in the regression process. The results indicate that the accuracy of machine learning algorithm to map coral reef LPC is relatively low due to the radiometric quality issue in the PlanetScope image (RMSE = 15.43%). We could not yet fairly justify the performance of machine learning algorithm until we applied the algorithms in other images.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115560891","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}
Multiband LiDAR systems, which are typically single wavelength in transmission and reception, are becoming more applicable for scientific use. However, traditional LiDAR receivers do not scale well to tens or hundreds of received bands. We introduce the design for a spectrographic receiver using an array detector for laser spectrometers and present two of the many possible applications: fluorescence spectroscopy in the visible range and IR reflectance spectroscopy. Each laser pulse has the capability of exciting a target in various wavelengths, and a spectrographic receiver would be able to interpret this excitation, while a typical LiDAR consisting of single wavelength receiver would not. Using a spectrograph in a system with a pulsed laser in the visible or UV range is capable of the detection of fluorescent signal. These spectra reveal the presence of organics and is an applicable technology for planetary science. A spectrograph coupled with a pulsed laser in the IR range shows capability of detecting the presence of water in various forms also applicable technology for both Earth and planetary science. Both systems utilize a Czerny-Turner spectrograph design with a ZnSe prism for the dispersion of light onto an Avalanche Photo Diode (APD). This paper introduces the concept and design of a spectrographic receiver for laser spectrometers, as well as two possible applications.
{"title":"A spectrographic receiver for laser spectrometers","authors":"M. Sandford, P. Lucey, Xiaoli Sun, D. Cremons","doi":"10.1117/12.2324818","DOIUrl":"https://doi.org/10.1117/12.2324818","url":null,"abstract":"Multiband LiDAR systems, which are typically single wavelength in transmission and reception, are becoming more applicable for scientific use. However, traditional LiDAR receivers do not scale well to tens or hundreds of received bands. We introduce the design for a spectrographic receiver using an array detector for laser spectrometers and present two of the many possible applications: fluorescence spectroscopy in the visible range and IR reflectance spectroscopy. Each laser pulse has the capability of exciting a target in various wavelengths, and a spectrographic receiver would be able to interpret this excitation, while a typical LiDAR consisting of single wavelength receiver would not. Using a spectrograph in a system with a pulsed laser in the visible or UV range is capable of the detection of fluorescent signal. These spectra reveal the presence of organics and is an applicable technology for planetary science. A spectrograph coupled with a pulsed laser in the IR range shows capability of detecting the presence of water in various forms also applicable technology for both Earth and planetary science. Both systems utilize a Czerny-Turner spectrograph design with a ZnSe prism for the dispersion of light onto an Avalanche Photo Diode (APD). This paper introduces the concept and design of a spectrographic receiver for laser spectrometers, as well as two possible applications.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121820086","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}
Spaceborne infrared atmospheric sounders measure the spectrum of the upwelling radiance in the infrared with ultra-high spectral resolution. The resolution is sufficient to measure absorption features of atmospheric constituents enabling retrieval of atmospheric temperature and water vapor profiles, surface emission and atmospheric constituents. The Atmospheric Infrared Sounder (AIRS) on Aqua launched in May of 2002 was the first hyperspectral grating-based infrared sounder designed for this purpose and is still operational today. AIRS has been followed by the Infrared Atmospheric Sounding Interferometer (IASI) on MetOp A and B, and the Cross-track Infrared Sounder (CrIS) on Suomi NPP and JPSS. All instruments are operating well improving weather forecast and providing a wealth of information about the atmosphere. Additional CrIS and IASI instruments are expected to be launched providing data of this type into the late 2030’s. AIRS, CrIS and IASI are all Low Earth Orbit (LEO) instruments with nominal spatial resolutions of 14km. Future IR sounders must achieve higher spatial and temporal resolution to match improvements in forecast models and be less costly to match anticipated future budget pressures. Higher temporal resolution can be achieved in several ways including operation in Geostationary Earth Orbit (GEO) or in constellations of LEO satellites. Higher spatial resolution can be achieved using larger format focal plane assemblies in the instruments and larger aperture telescopes. Grating spectrometers are well suited to large format FPAs by allowing a wide field of view in a compact package. They also provide long life and are easy to operate. Concepts for next generation grating spectrometer IR sounders that have been developed over the years at JPL are presented along with technology advancements made to enable these concepts to achieve their stated goals.
{"title":"Concepts for next generation grating spectrometer imaging atmospheric sounders from LEO and GEO","authors":"T. Pagano","doi":"10.1117/12.2324606","DOIUrl":"https://doi.org/10.1117/12.2324606","url":null,"abstract":"Spaceborne infrared atmospheric sounders measure the spectrum of the upwelling radiance in the infrared with ultra-high spectral resolution. The resolution is sufficient to measure absorption features of atmospheric constituents enabling retrieval of atmospheric temperature and water vapor profiles, surface emission and atmospheric constituents. The Atmospheric Infrared Sounder (AIRS) on Aqua launched in May of 2002 was the first hyperspectral grating-based infrared sounder designed for this purpose and is still operational today. AIRS has been followed by the Infrared Atmospheric Sounding Interferometer (IASI) on MetOp A and B, and the Cross-track Infrared Sounder (CrIS) on Suomi NPP and JPSS. All instruments are operating well improving weather forecast and providing a wealth of information about the atmosphere. Additional CrIS and IASI instruments are expected to be launched providing data of this type into the late 2030’s. AIRS, CrIS and IASI are all Low Earth Orbit (LEO) instruments with nominal spatial resolutions of 14km. Future IR sounders must achieve higher spatial and temporal resolution to match improvements in forecast models and be less costly to match anticipated future budget pressures. Higher temporal resolution can be achieved in several ways including operation in Geostationary Earth Orbit (GEO) or in constellations of LEO satellites. Higher spatial resolution can be achieved using larger format focal plane assemblies in the instruments and larger aperture telescopes. Grating spectrometers are well suited to large format FPAs by allowing a wide field of view in a compact package. They also provide long life and are easy to operate. Concepts for next generation grating spectrometer IR sounders that have been developed over the years at JPL are presented along with technology advancements made to enable these concepts to achieve their stated goals.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125336919","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}
A microscene is a hyperspectral image collected using a hyperspectral sensor mounted above a tray, typically in a laboratory setting. Materials can be placed in the tray and illumination controlled to either analyze the materials used or to simulate overhead (aerial or satellite) imagery. Choosing the materials allows simulation of overhead imagery in controlled experiments, for example mixtures and abundances of chemicals, materials as they undergo physical and chemical processes such as oxidation and weathering, and vegetation at different stages in environmental processes. Microscene imagery enables experiments in controlled circumstances not easily producible in overhead imagery. Moreover, the cost of collecting microscene imagery is a small fraction of overhead collection. Microscene imagery is an emerging technology, and in this paper we address an evaluation microscene imagery to determine how well it simulates overhead imagery, comparing microscene imagery of vegetation to overhead AVIRIS and HYDICE imagery over vegetation. We use statistical measures to compare microscene imagery to overhead imagery, including comparing material spectra, means, eigenvalues, the Mahalanobis distance between image means, and for the first time the Bhattacharyya distance between image covariances. The Bhattacharyya is a statistical measure of the distance between two statistical distributions, related to the Mahalanobis distance.
{"title":"Microscene evaluation using the Bhattacharyya distance","authors":"William F Basener, Marty Flynn","doi":"10.1117/12.2327004","DOIUrl":"https://doi.org/10.1117/12.2327004","url":null,"abstract":"A microscene is a hyperspectral image collected using a hyperspectral sensor mounted above a tray, typically in a laboratory setting. Materials can be placed in the tray and illumination controlled to either analyze the materials used or to simulate overhead (aerial or satellite) imagery. Choosing the materials allows simulation of overhead imagery in controlled experiments, for example mixtures and abundances of chemicals, materials as they undergo physical and chemical processes such as oxidation and weathering, and vegetation at different stages in environmental processes. Microscene imagery enables experiments in controlled circumstances not easily producible in overhead imagery. Moreover, the cost of collecting microscene imagery is a small fraction of overhead collection. Microscene imagery is an emerging technology, and in this paper we address an evaluation microscene imagery to determine how well it simulates overhead imagery, comparing microscene imagery of vegetation to overhead AVIRIS and HYDICE imagery over vegetation. We use statistical measures to compare microscene imagery to overhead imagery, including comparing material spectra, means, eigenvalues, the Mahalanobis distance between image means, and for the first time the Bhattacharyya distance between image covariances. The Bhattacharyya is a statistical measure of the distance between two statistical distributions, related to the Mahalanobis distance.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125510852","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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