Proceedings Volume 4151

Hyperspectral Remote Sensing of the Land and Atmosphere

William L. Smith, Yoshifumi Yasuoka
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Proceedings Volume 4151

Hyperspectral Remote Sensing of the Land and Atmosphere

William L. Smith, Yoshifumi Yasuoka
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 8 February 2001
Contents: 10 Sessions, 33 Papers, 0 Presentations
Conference: Second International Asia-Pacific Symposium on Remote Sensing of the Atmosphere, Environment, and Space 2000
Volume Number: 4151

Table of Contents

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Table of Contents

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  • Instruments and Systems I
  • Instruments and Systems II
  • Instruments and Systems III
  • Atmospheric Science I
  • Atmospheric Science II
  • Ecosystems I
  • Ecosystems II
  • Applications I
  • Applications II
  • Poster Session
Instruments and Systems I
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Demonstration of imaging Fourier Transform Spectrometer (FTS) performance for planetary and geostationary Earth observing
Henry E. Revercomb, Lawrence A. Sromovsky, Patrick M. Fry, et al.
The combination of massively parallel spatial sampling and accurate spectral radiometry offered by imaging FTS makes it extremely attractive for earth and planetary remote sensing. We constructed a breadboard instrument to help assess the potential for planetary applications of small imaging FTS instruments in the 1-5 micrometers range. The results also support definition of the NASA Geostationary Imaging FTS instrument that will make key meteorological and climate observations from geostationary earth orbit. The PIFTS pivoting voice- coil delay scan mechanism, and laser diode metrology system. The interferometer optical output is measured by a commercial IR camera procured from Santa Barbara Focal plane. It uses an InSb 128 by 128 detector array that covers the entire FOV of the instrument when coupled with a 25-mm focal length commercial camera lens. With appropriate lenses and cold filters the instrument can be used from the visible to 5 micrometers . The delay scan is continuos, but slow, covering the maximum range of +/- 0.4 cm in 37.56 sec at a rate of 500 image frames per second. Image exposures are timed to be centered around predicted zero crossings. The design allows for prediction algorithms that account for the most recent fringe rate so that timing jitter produced by scan speed variations can be minimized. Response to a fixed source is linear with exposure time nearly to the point of saturation. Linearity with respect to input variations was demonstrated to within 0.16 percent using a 3-point blackbody calibration. Imaging of external complex scenes was carried out at low and high spectral resolution. These require full complex calibration to remove background contributions that vary dramatically over the instrument FOV. Testing is continuing to demonstrate the precise radiometric accuracy and noise characteristics.
Image stability requirements for a Geostationary Imaging Fourier Transform Spectrometer (GIFTS)
A geostationary Imaging Fourier Transform Spectrometer (GIFTS) has been selected for the NASA New Millennium Program (NMP) Earth Observing-3 (EO-3) mission. Our paper will discuss one of the key GIFTS NMP mission is designed to demonstrate new and emerging sensor and data processing technologies with the goal of making revolutionary improvements in meteorological observational capability and forecasting accuracy. The GIFTS payload is a versatile imaging FTS with programmable spectral resolution and spatial scene selection that allows radiometric accuracy and atmospheric sounding precision to be traded in near real time for area coverage. The GIFTS sensor combines high sensitivity with a massively parallel spatial data collection scheme to allow high spatial resolution measurement of the Earth's atmosphere and rapid broad area coverage. An objective of the GIFTS mission is to demonstrate the advantages of high spatial resolution on temperature and water vapor retrieval by allowing sampling in broken cloud regions. This small gsd, may require extremely good pointing control. This paper discusses the analysis of this requirement.
Calibration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS)
The NASA New Millennium Program's Geostationary Imaging Fourier Transform Spectrometer (GIFTS) requires highly accurate radiometric and spectral calibration in order to carry out its mission to provide water vapor, wind, temperature, and trace gas profiling from geostationary orbit. A calibration concept has bene developed for the GIFTS Phase A instrument design. The in-flight calibration is performed using views of two on-board blackbody sources along with cold space. A radiometric calibration uncertainty analysis has been developed and used to show that the expected performance for GIFTS exceeds its top level requirement to measure brightness temperature to better than 1 K. For the Phase A GIFTS design, the spectral calibration is established by the highly stable diode laser used as the reference for interferogram sampling, and verified with comparisons to atmospheric calculations.
Development of a visible and near-infrared spectrometer for Selenological and Engineering Explorer (SELENE)
Tsuneo Matsunaga, Makiko Ohtake, Yasuhiro Hirahara, et al.
Although the Moon has been investigated from the Earth, manned Apollo program, and numerous unmanned spacecraft including latest Clementine and Lunar Prospector, unresolved issues on the origin and evolution of the Moon still exist. To find clues or hopefully answers to these issues, Japan will send, to the Moon, an orbiting spacecraft called Selenological and Engineering Explore (SELENE) equipped with a suite of state-of-the-art mission instruments. Spectral Profiler (SP) is one of the instrument onboard SELENE, and will obtain 0.5-2.6 micrometers continuous reflectance spectra of the lunar surface just below SELENE with 500 m swath. As major minerals on the Moon, pyroxene, olivine, and feldspar, have diagnostic spectral features in this spectral region, SPs spectra will provide us information on mineral/rock distributions on the Moon surface globally. Such information from SP will, in combination with other instruments, clarify elemental/compositional characteristics of the lunar surface. This will contribute so much to depict a clear picture of the origin and the evolution of the Moon. To accomplish these scientific goals, engineering issues such as performance requirements and calibration procedures were discussed intensively and comprehensively among SP scientists and engineers. And based on such discussions, the basic instrument design of SP was determined and PM development was started in FY 1998. In FY 1999 and 2000, PM testings are being conducted. FM design will start in late- 2000. In the presentation, current status of SP development will be reported together with background information on SELENE, SP, and the science of the Moon.
Instruments and Systems II
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EO-1/Hyperion hyperspectral imager design, development, characterization, and calibration
Mark A. Folkman, Jay Pearlman, Lushalan B. Liao, et al.
The Hyperion Imaging Spectrometer is one of three principal instruments aboard the EO-1 spacecraft. Its mission as a technology demonstrator is to evaluate on-orbit issues for imaging spectroscopy and to assess the capabilities of a space-based imaging spectrometer for earth science and earth observation missions. The instrument provides earth imagery at 30 meter spatial resolution. 7.5 km swath width in 220 contiguous spectral bands at 10 nm spectral resolution. Spectral range is from 0.4 micrometers to 2.5 micrometers . The instrument includes internal and solar calibration sub- systems. This paper will review the design, construction and calibration of the Hyperion instrument. The on-orbit plans and operations will be presented along with updated calibration and characterization measurements.
Advanced technology imaging sounder testbed for future environmental satellite missions
Jeffery J. Puschell, Patricia Lynn Martin, W. Todd Hurt, et al.
This paper describes a ground-based testbed being developed by Raytheon Santa Barbara Remote Sensing for evaluating suitability of new Fourier transform spectrometer technology in future environmental satellite missions. The testbed includes a passively-aligned, double-pass cube corner Michelson interferometer that has flexibility to simulate a wide range of possible missions, including moderate spectral resolution imaging, trace chemical detection, and atmospheric sounding. Early testbed results are presented along with initial operational instruments performance assessments that are derived from testbed measurements.
Concepts and applications for multispectral/hyperspectral focal plane array (FPA) technology
James A. McAdoo
Multispectral, and ultimately hyperspectral, focal plane arrays (FPAs) represent the logical extension of two-color FPA technology, which has already shown its utility in military applications. Incorporating the spectral discrimination function directly in the FPA would offer the potential for orders-of-magnitude increase in remote sensor system performance. It would allow reduction or even elimination of optical components currently required to provide spectral discrimination in atmospheric remote sensors. The result would be smaller, simpler instruments with higher performance than exist today. Achieving these goals, however, will be difficult.. There are several challenges that must be met to enable this technology. This review identifies these challenges and provides a comparison of possible technical approaches to this problem. In addition, it provides a framework for evaluation of new concepts that might be envisioned.
Instruments and Systems III
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Geostationary wedge-filter imager-sounder
Imaging spectrometry from geostationary earth orbit (GEO) can provide the frequently-refreshed detailed information on physical properties of earth's atmosphere and surface needed to enable critical new science missions and ultimately improve operation weather forecasting. We describe and evaluate a concept for imaging spectrometry from GEO that addresses both traditional imaging and sounding applications. Our geostationary Wedge-filter Imaging Spectrometer uses spatially variable wedge filter spectrometers to collect earth radiance with approximately 2 km resolution over a 710-2900 cm-1 spectral range at 1 percent spectral resolution. The resulting instrument, based on LWIR and MWIR wedge-filter spectrometer technology recently developed by Raytheon, would be a compact, rugged imager-sounder with better sensitivity, spectral resolution, spatial resolution and full disk coverage time than current multispectral operational GEO imagers. Sounding performance was simulated with respect to a global database of 119,694 cloud-free samples using a stepwise regression algorithm. Retrieved atmospheric parameters included surface air temperature, surface skin temperature, surface water vapor, total precipitable water vapor, total ozone and vertical profiles of temperature and water vapor. Not only did the conceptual WIS-based instrument outperform the current operation GEO sounder, but also RMS error performance approached that of advance higher spectral resolution sounders. Due to its higher spatial resolution and more compete spatial coverage, WIS could achieve this high quality cloud free sounding performance roughly two times more frequently than high spectral resolution advance sounders. Combining this new technology with proven wedge spectrometer approaches for visible and near-IR wavelengths would provide imaging-sounding data from GEO with unprecedented detail and fidelity for a wide range of weather, climate, land use, ocean color and other earth science studies.
Optical characteristics of China Radiometric Calibration Site for Remote Sensing Satellite Sensors (CRCSRSSS)
Xiuqing Hu, Yuxiang Zhang, Zhiquan Liu, et al.
Duhuang site and Qinghai Lake site are selected to be China Radiation calibration site for Remote Sensing Satellite Sensors in 1996. We have conducted three field measurement campaigns in 1994, 1996 and 1999 and obtained a lot of characteristic data of atmosphere and ground reflectance. The results show that the Duhuang site has a good homogeneity with a low standard deviation of the reflectance which is less than 2 percent at VIS-SWIR range in 20 by 20 km2. The ground reflectance is between 10 percent and 35 percent at 0.35-2.5micrometers spectral range. Atmosphere measurement have shown that Aerosol optical depth at 550nm in two sites is 0.125 and 0.18, which are all small and suitable for in-flight calibration atmosphere condition. The result of Junge aerosol parameter indicate aerosol type in Duhuang is near to desert model and near to continent model in Qinghai Lake. The columnar water vapor is determined by Modified Langley plot approach in 940nm band of sun photometer. The results of it are compared with radiosonde data and different within 10 percent. The diffuse-to-global irradiance ratio by OL754 spectro radiometer is used for the irradiance-based calibration method to improve in-flight sensor calibration accuracy.
Optical system of the multispectrum CCD camera used for Earth environment observation
Jianfeng Yang, Baochang Zhao
A multiple spectrum CCD camera is presented in this paper. The camera is designed for the multiple small satellite remote sensing system that is suggested by Mr. Cheng Fangyun to observe two times every day over any place in the world. The camera designed for the remote sensing of the earth resources and its environment possesses the advantages of lighter weight and wider ground swath. It will be widely used for the mitigation of natural disasters such as forest fire, earthquake and flood, for the general survey of crops distribution, pests and estimation the yield of crops. The focal length of the camera is 154 millimeters, the field angle of view is about 29 degrees. For the orbit height of 772 kilometers, the ground swath reaches 400 kilometers, and the ground resolution is 50 meters. The camera uses a 10 microns CCD working at the visible spectrum. The four visible and near IR channels are 0.45-0.52, 0.52-0.60, 0.63- 0.69, and 0.76-0.90 micron. The total weight of the camera is 12 kilograms.
Atmospheric Science I
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Hyperspectral remote sensing of atmospheric profiles from satellites and aircraft
William L. Smith, Daniel K. Zhou, Fenton W. Harrison, et al.
A future hyperspectral resolution remote imaging and sounding system, called the GIFTS, is described. An airborne system, which produces the type of hyperspectral resolution sounding data to be achieved with the GIFTS, has been flown on high altitude aircraft. Results from simulations and from the airborne measurements are presented to demonstrate the revolutionary remote sounding capabilities to be realized with future satellite hyperspectral remote imaging/sounding systems.
Geostationary Imaging FTS (GIFTS) data processing: measurement simulation and compression
Hung-Lung Huang, Henry E. Revercomb, Jonathan Thom, et al.
GIFTS, a forerunner of next generation geostationary satellite weather observing systems, will be built to fly on the NASA EO-3 geostationary orbit mission in 2004 to demonstrate the use of large area detector arrays and readouts. Timely high spatial resolution images and quantitative soundings of clouds, water vapor, temperature, and pollutants of the atmosphere for weather prediction and air quality monitoring will be achieved. GIFTS is novel in terms of providing many scientific returns that traditionally can only be achieved by separate advanced imaging and sounding systems. GIFTS' ability to obtain half- hourly high vertical density wind over the full earth disk is revolutionary. However, these new technologies bring forth many challenges for data transmission, archiving, and geophysical data processing. In this paper, we will focus on the aspect of data volume and downlink issues by conducting a GIFTS data compression experiment. We will discuss the scenario of using principal component analysis as a foundation for atmospheric data retrieval and compression of uncalibrated and un-normalized interferograms. The effects of compression on the degradation of the signal and noise reduction in interferogram and spectral domains will be highlighted. A simulation system developed to model the GIFTS instrument measurements is described in detail.
Atomospheric Infrared Sounder (AIRS) on the Earth Observing System
AIRS, on the EOS-Aqua, produces global high precision spectra form 3.7-15.4 micron with spectral resolving power (mu) /(Delta) (Mu) equals1200 twice each day form 708 km orbital altitude. AIRS is the first hyperspectral IR spectrometer designed to support NOAA/NCEPs the operational requirements for medium range weather forecasting during its nominal 7 year lifetime. AIRS, together with the AMSU and HSB microwave radiometers, will achieve global retrieval accuracy of better than 1K rms in the lower troposphere under clear and partly cloudy condition. Based on the excellent radiometric and spectral performance demonstrated during the pre-launch testing, the assimilation of AIRS data into the forecast model is expected to result in a major forecast improvements. Launch of AIRS on the EOS AQUA is scheduled for May 2001.
Atmospheric Science II
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Comparison accuracy of atmospheric nitrogen dioxide profile retrieval from measured transmission function by two several tape spectrometers
Eleonora A. Chayanova
In the work the comparison accuracy of atmospheric NO2 density profile retrieval from measured transmission function by two several tape space spectrometers had be done. Suppose that solar radiation enters in these spectrometers through the some optical telescopic system and the mistakes of receiving system are out of the consideration. The first spectrometer is ordinary instrument with diffraction grating. This spectrometer2 measure atmospheric transmission function for several tangent altitude in 430-450 nm spectral region with resolution 1 nm by limb method using the sun as source of the radiation. The accuracy and resolution of these measurements are high enough but there is complex problem selecting the absorption of NO2 gas from another gases absorption and the retrieval of NO2 profile from transmission function. In the second spectrometer4 is used a tunable interference - polarization filter, so called Woods filter. The basic element of the Woods filter is a plate made of a double-refraction crystal placed between two mutually perpendicular polarizes. Transmission function of this filter must be coincided with the quasi-periodical vibration spectrum of an NO2 molecule for a 430-450 nm range and must pick out NO2 absorption from another gas absorption. Errors of the measurement by this spectrometer installed on satellite are compiled from fluctuation background noise, internal noise of instrument, changing slop spectrum of coming radiation and another. The comparison of mentioned above measuring instruments and methods showed that the accuracy of NO2 profile retrieval is equal into 15-35 km altitude region for both spectrometers. However the using of correlative spectrometer increase the region of available measurement to 1 0 km above and to 10 km low indicated region.
Optimized microwindows in atmospheric spectroscopy
Thomas von Clarmann, Georg Echle, Herbert Fischer, et al.
Hyperspectral remote sensing is a challenge to data analysis due to the large data rate. Since it will often not by possible to analyze the entity of measured spectral data, so-called 'micro windows' are selected which contain the bulk of information on the target state parameters to be retrieved, while any interfering signal is minimized. We discuss the benefits of a quantitative method for automatic selection of optimized sets of such micro windows for the analysis of Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) data. While MIPAS, which will be operated onboard the polar orbiting environmental satellite (ENVISAT), is not a hyperspectral instrument, it serves as an example to study the power of the micro window approach. The MIPAS instrument will measure the IR emission of various atmospheric trace gases by limb scans covering the altitude region from 6 to 68 km altitude.
Ecosystems I
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New progress in study on vegetation models for hyperspectral remote sensing
Qingxi Tong, Yongchao Zhao, Xia Zhang, et al.
Some new vegetation models for hyperspectral remote sensing are provided in this paper. They are Derivative Spectral Model (DSM), Multi-temporal Index Image Cube Model (MIIC), Hybrid Decision Tree Model (HDT) and Correlation Simulating Analysis Model (CSAM). All models are developed and used to process the images acquired by Airborne Pushbroom Hyperspectral Imager (PHI) in Changzhou area, China, 1999. Some successful applications are provided and evaluated. The results show that DSM has the ability of eliminating the background interference of vegetation analysis. MIIC is a viable method for monitoring dynamic change of land cover and vegetation growth stages. HDT is effective in precise classification of rice land while CSAM provide a possibility and theoretical basis for crop identification, breed classification, and land information extraction especially for rice.
Hyperspectral reflectance measurements for estimating eco-physiological status of plants
Yoshio Inoue, Josep Penueleus, Yann Nouevllon, et al.
An AOTF-based spectral imager was developed for hyperspectral measurement of plant reflectance in the field. A hyperspectral image cube for the spectral region between 450 nm-900 nm can be obtained at 3 to 5 nm resolution intervals within a few seconds. The system is light and compact, and both the spectral wavelengths and intervals are programmable with PC control. Wavelengths can be rapidly tuned, either sequentially or randomly. Hyperspectral measurements were taken over plant leaves and canopies using the AOTF system and a high-resolution radiometer. Both the leaf nitrogen and chlorophyll contents of the rice canopies were well estimated by multiple regression of high- resolution data in the visible and near-IR regions. A weak signal at 970nm and its normalized indices were found to be useful for estimation of leaf water content. An approach of model inversion was enabled by the use of hyperspectral data. A close and linear relation was found between measured and retrieved water contents. Further, an analysis based on concurrent measurements of hyperspectral reflectance and canopy gas exchange by eddy-covariance method suggested the potential of normalized weak signal for the spectral assessment of canopy CO2 uptake. The hyperspectral reflectance measurement has great potential for estimating the ecological and physio-chemical variables of plant leaves and canopies.
Development of a model of radiation balance near ground level and application to satellite data analysis: focus on the estimation of radiative energy from surface/air based on measurment data
Kanako Muramatsu, Noboru Fujiwara
Solar irradiance, surface and air temperatures change periodically day by day. Then we measured the surface temperature, air temperature, humidity and wind velocity types of ground object such as concrete, asphalt, soil and grass every hour for one cycle namely 24 hours. The relationship between the diurnal radiative energy form surface/air and diurnal solar irradiance was studied as a function of time. If the phases of them were adjusted to each other, a linear relationship was established between them. The relationship between diurnal radiative energy form surface and that form air were studied. The clear linear relationship was found to hold between them. The values of parameters of the relationship were determined using measured data and compared with the estimated values using the radiation balance model. Finally, we tried to estimate radiative energy from surface/air integrated over a day using Landsat/TM data.
Pattern decomposition method for hypermultispectral satellite data analysis
Noboru Fujiwara, Akiko Ono, Motomasa Daigo
We have developed 'Pattern Decomposition Method' (PDM) for multi-spectral satellite data based on linear mixing of three standard spectral patterns of ground objects, namely water, vegetation and soil. In this Method, the spectral reflectance of each pixel in a satellite image is decomposed into the three components and information of the spectra is represented by a set of three decomposition coefficients. The applicability of the PDM to continuous spectra of ground objects is studied in the wavelength region of 350-2500 nm. Especially for hyper-multispectral data analysis, data reduction is very important. The continuos spectral reflectance of land cover objects could be decomposed by the standard spectral patterns with accuracy of 4.5 percent. Mixing ratio of land cover objects in a pixel of satellite data could be evaluated using the linear mixing three decomposition coefficients. For detail analysis of vegetation change from vivid state to withered state, availability of a supplementary spectral pattern that rectify resonance absorption pattern of vivid standard vegetation for spectra of withered vegetation is also studied. The new vegetation index is proposed as a simple function of the pattern decomposition coefficients including the supplementary pattern. It is confirmed that RVIPD is linear to vegetation cover ratio and also to vegetation quantum efficiency.
Applications of orthophotomaps and fusion of Landsat TM, SPOT, and SAR images in the studies of the events to stop up water body and ecological environment in the Yangtze Three Gorges Project regio
Wunian Yang, Guoliang Pu, Jean-Pierre Paris, et al.
In this study, fusion of Landsat TM, SPOT and ERS SAR Images were done, and then an orthphotomap of the fusion image of Landsat TM453 and SPOT panchromatic image of Yunyang area, the Yangtze Three Gorges Project Region was made, which is in 1:50000 scale and up to an international standard of topographic map. With the orthphotomap, many new geological structures and disasters were identified and positioned. The biggest landslide in the Yangtze River region-JIPAZI landslide was digitized. 3D quantitatively analyzing patterns for surveying landslides and rockfalls were established with RS, GIS and GPS techniques. Through phase- separation analysis of remote sensing information field and quantitative processing of the linear structures, the relationship between geological disasters and crack structures was found out. Finally, with a synthetic analysis, these landslides and rockfalls probably to stop up river water and their environmental influence were predicted.
Airborne hyperspectral imagery for the detection of agricultural crop stress
Philip E. Cassady, Eileen M. Perry, Margaret E. Gardner, et al.
Multispectral digital imagery from aircraft or satellite is presently being used to derive basic assessments of crop health for growers and others involved in the agricultural industry. Research indicates that narrow band stress indices derived from hyperspectral imagery should have improved sensitivity to provide more specific information on the type and cause of crop stress. Under funding from the NASA Earth Observation Commercial Applications Program we are identifying and evaluating scientific and commercial applications of hyperspectral imagery for the remote characterization of agricultural crop stress. During the summer of 1999 a field experiment was conducted with varying nitrogen treatments on a production corn-field in eastern Nebraska. The AVIRIS hyperspectral imager was flown at two critical dates during crop development, at two different altitudes, providing images with approximately 18m pixels and 3m pixels. Simultaneous supporting soil sampling, and aerial photography. In this paper we describe the experiments and results.
Ecosystems II
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Estimation model of net primary production by vegetation for ADEOS-II/GLI data
Shinobu Furumi, Akiko Ono, Kanako Muramatsu, et al.
Many researchers have developed models for estimation of net primary production using satellite data. Especially, NDVI are mainly used for the model because NDVI can be obtained from NOAA/AVHRR data for global are. However, recent sensors have hyper-multispectral data and these data is expected to be effective for the monitoring of detail vegetation condition. So we developed the estimation model using a new vegetation index RVIPD that reflects all information of hyper-multispectral data and validated the model using Landsat/TM data.
Estimation of net photosynthetic rate based on in-situ hyperspectral data
Takahiro Endo, Toshinori Okuda, Masayuki Tamura, et al.
Carbon absorption o f plant is one of the essential parameters in assessing terrestrial ecosystem functions with respect to global warning. It is however, not easy to estimate carbon absorption directly on the ground. In this study, an experiment method was designed to estimate the saturated Amax from hyperspectral data in the laboratory and in the field scale. First, we measure the relationship between biochemical concentrations and parameters of 'Blackman' photosynthetic rate model. Secondly, we measure the relationship between biochemical concentration and hyperspectral characteristics. High-resolution reflectance over a range of 333-2507 nm with resolution of about 1.5-10 nm and net Amax-photon flux density (PFD) were measured respectively by the GER 2600 and Li-6400. Also, chlorophyll a, chlorophyll b, chlorophyll a + b and nitrogen concentration were quantitative analyzed from in situ measurement of cucumber's fresh leaves that were cultivated for different biochemical concentration in a greenhouse chamber. Correlation between saturated Amax and chlorophyll a and nitrogen concentration was r2 equals 0.90, and 0.91 respectively. Chlorophyll b did not show any correlation with saturated Amax. Chlorophyll a and nitrogen concentrations were estimated by using the first derivative spectral reflectance of fresh leaf. RF' at 678.011 correlated best with chlorophyll a concentration. RF' at 732.122nm correlated best with nitrogen concentration. Finally net Amax at given PFD was estimated by the photosynthetic rate model. A correlation between the actual net Amax and the estimated net Amax was r2 equals 0.74. In this study, both chlorophyll a and nitrogen concentrations show good correlation with saturated Amax.
Monitoring of the stability of boreal forest ecosystem in northeast China in relation to natural disturbance in Landsat TM imagery
Qi-Jing Liu, Akihiko Kondoh, Ryutaro Tateishi, et al.
Changbai mountain is a very important natural reserve in China as well as in the world, because it possesses a high bio-diversity, and is a typical ecosystem representing boreal vegetation. Few studies on the dynamic-equilibrium of forest in relation with natural disturbance have been reported. In this study, the change of forest vegetation in the reserve was detected by using Landsat TM images. Image differencing between 1984 and 1997 was adopted to derive new images that indicate cover type change. The natural forest in the reserve was in a status of relative equilibrium. The number of pixels with decrease in radiance was nearly the same as those with increase in radiance. It is demonstrated that the so-called climax is not a pure stand which is generally assumed to be exclusively dominated by climax species, but a complex of mosaic structure that consisted of patches in different stages of succession. This climax structure was maintained by natural disturbance like fall. The pioneer patches are permanent units in the forest community. Gaps are frequently created, and thus the pioneer patches are kept constantly. As a whole, TM imagery is effective for detecting vegetation changes, but tiny gaps with several pixels are difficult to discriminate from noise. The change inside the natural reserve was minor, while the vegetation outside the natural reserve presented an upgrading status, showing the recovery after timber cutting.
Applications I
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Hyperspectral remote sensing and GIS techniques application for the evaluation and monitoring of interactions between natural risks and industrial hazards
Alessandra Marino, Giancarlo Ludovisi, Antonio Moccaldi, et al.
The aim of this paper is to outline the potential of imaging spectroscopy and GIS techniques as tool for the management of data rich environments, as complex fluvial areas, exposed to geological, geomorphological, and hydrogeological risks. The area of study, the Pescara River Basin is characterized by the presence of important industrial sites and by the occurrence of floods, landslides and seismic events. Data were collected, during a specific flight, using an hyperspectral MIVIS sensor. Images have been processed in order to obtain updated and accurate land-cover and land-use maps that have been inserted in a specific GIS database and integrated with further information like lithology, geological structure, geomorphology, hydrogeological features, productive plants location and characters. The processing of data layers was performed, using a dedicated software, through typical GIS operators like indexing, recording, matrix analysis, proximity analysis. The interactions between natural risks, industrial installations, agricultural areas, water resources and urban settlements have been analyzed. This allowed the creation and processing of thematic layers like vulnerability, risk and impact maps.
Light energy loss and its application to estimating global energy usage
Syuzo Isobe, Shiomi Hamamura
We are now developing a system to estimate light energy loss to space using the US DMSP data and obtained many interesting results. The satellites have solar synchronous orbits with altitude around 800 km, and continuously obtain absolute flux of terrestrial surface light. City light ejected to space is mostly energy loss because the light is not sued to illuminate objects to be seen or decorated. The total amount of its energy loss in Japan estimated by us is an order of 20 billion yen. We are now estimating its loss for each cities in Japan and in the world. Further, we found a possibility to estimate energy usage of each country after obtaining a clear relation between light energy loss and electric energy usage within different areas of individual electric companies in Japan. Therefore, we would like to conclude that our continuous estimation of city light form space are and will be creating a global information of energy usage.
Applications II
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Snow cover remote sensing with multisensor data
Yujie Liu, Libo Wang, Wanping Yuan
Snow cover is an important resource of the Earth. It is a potential factor related to climate and global changes. On account of its high reflectance and low heat conductivity, the existence of snow cover can affect surface and air temperature, surface albedo, radiation balance, soil moisture and so on. It may have influence on the earth- atmosphere system. In order to study and understand the impact of snow cover on climate and hydrologic budgets, it is necessary to have variation and distribution of snow cove over a long period. Usually the snow cover data can be obtained regularly by observation of weather station, but these data are limited to point surface measurement and poorly represented in mountainous and sparsely inhabited areas. Remote sensing is a powerful tool for snow cover observations.
Analysis of data from a thermal infrared hyperspectral instrument
While reflection band hyperspectral instruments have been in use for over a decade, only recently has data from airborne thermal IR hyperspectral instruments become available. One such instrument is the Airborne Hyperspectral Imager (AHI). AHI is a pushbroom sensor developed by the University of Hawaii that spans the 8 to 11.5 micrometer spectral band with 32 spectral bands and 256 simultaneous spatial channels. While many analysis techniques used for reflection band hyperspectral processing can be applied to the thermal band, new procedures had to be developed. In particular, sensor noise and sensor non-linearity induced spectral artifacts are a greater problem than for the VNIR and SWIR. The process begins with calibration, with different calibration files being used to optimize the reduction of sensor artifacts such as shading and striping. Once the data has been calibrated to radiance units, the absorption and path radiance effects of the atmosphere can be removed, if atmospheric truth is available. Following this step, the apparent emissivity is calculated for every pixel in each band. The data is now in a form that is analogous to the apparent reflectance images developed for reflection band data. At this point spectral analysis techniques can be applied to classify the image. The procedure used here was to use an automated endmember determination algorithm, N- FINDR, to determine spectral endmembers and unmix the data cube into fractional abundances. Since some endmembers are likely to result from residual sensor and cultural artifacts, the automated endmember determination and unmixing procedure is performed interactively to optimize results. Both the fractional abundance planes and the endmember spectra themselves are then reviewed for artifacts. Selected abundance planes that correspond to real minerals can then be combined into a classification map. In this paper, AHI data collected for two applications: the detection of buried land mine application and a geological remote sensing application will be presented using similar processing steps.
Poster Session
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Toward the inversion of vegetation parameters using canopy reflectance models
Tsuneo Matsunaga, Akira Hoyano, Hideki Kobayashi
In this study, we investigated the invertibility of vegetation parameters from reflectance spectra using Kuusk's canopy reflectance model. To acquire the bi-directional reflectance factors of the vegetative surface, we developed a multi input visible and near IR spectrometer using a 2D CCD array as detector and four optical fibers as input probes. It can enable us to measure reference spectra and three target spectra simultaneously and it reduces the effect of the fluctuation of the direct solar and diffused sky radiation caused by moving clouds and changing solar direction. BRFs were acquired both in the field and in the laboratory to investigate the sensitivity of the vegetation parameters to canopy reflectance and compared with calculated ones. The sensitivity of the measured BRFs for each LAI was discussed with comparing in the visible and the near IR BRFs data. And the possibility of the retrieval of LAI information from the hot spot effect was also discussed.
Tropospheric ozone near-nadir-viewing IR spectral sensitivity and ozone measurements from NAST-I
Daniel K. Zhou, William L. Smith, Allen M. Larar
IR ozone spectra from near nadir observations have provided atmospheric ozone information from the sensor to the Earth's surface. Simulations of the NPOESS Airborne Sounder Testbed- Interferometer (NAST-I) from the NASA ER-2 aircraft with a spectral resolution of 0.25 cm-1 were used for sensitivity analysis. The spectral sensitivity of ozone retrievals to uncertainties in atmospheric temperature and water vapor is assessed in order to understand the relationship between the IR emissions and the atmospheric state. In addition, ozone spectral radiance sensitivity to its ozone layer densities and radiance weighting functions reveals the limit of the ozone profile retrieval accuracy from NAST-I measurements. Statistical retrievals of ozone with temperature and moisture retrievals from NAST-I spectra have been investigated and the preliminary results from NAST-I field campaigns are presented.
Interpretation of remotely sensed data on black spruce and paper birch communities in Alaskan boreal forest enhanced by fire with extended SAIL model
Keiji Kushida, Masami Fukuda
We measured spectral characteristics of black spruce and paper birch communities' elements such as forest floor and leaves to analyze relationships between remotely sensed data and forest structural characteristics in Caribou-Poker Creeks Research Watershed (CPCRW). Remote sensing technique is necessary as a tool for monitoring boreal forest functions and changes including forest fire influences. There are many radiative transfer models of vegetation canopies, however little field measurements of spectrum of boreal forest elements except for studies by Daughtry, Mesearch, or BOREAS Project. This is one of the reasons why we can hardly apply radiative transfer models to interpret satellite data black spruce communities in CPCRW. As a result of SAIL radiative transfer model calculation with these measured values, we proposed charts to interpret atmospherically corrected Landsat TM data of the communities form upper layer leaf area indices, forest floor types, and leaf spectral characteristics.
Atmospheric transmission model development with Fourier-transformed Voigt profile
Hirokazu Kobayashi
Author developed a line-by-line atmospheric transmission model based on the Fourier transformed Voigt function. The Voigt function is presented in an integrated form, and direct computation of the function profiles involves a high computational cost because of its numerical characteristics which introduces slow numerical convergency at some area. Many investigations were performed using the polynomial- fitting-to-the-function method to reduce this computation cost. Author introduced a Fourier transformed Voigt function, and developed a line-by-line transmission model for multiple species and lines. In this model, all line-by- line calculations are done in the numerical space which will be Fourier transformed to the wavenumber space a the end of a process. The developed algorithm uses no approximation method for line shape calculation, and has no limitations for the wavenumber resolution and the wavenumber range. Furthermore, the algorithm represents randomly positioned absorption lines by the uniform method and requires no line shapes mapping into the wavenumber space. The model indicates a straight forward implementation procedure of the high-resolution radiation/transmission calculation with huge absorption liens. Author implemented the model on a parallel computing environment and verified that the model calculation performance can be expanded with increasing the number of computing nodes.
Regional distribution of sensible and latent heat fluxes over rice paddies using satellite infrared temperature and a heat-budget model
Dai Matsushima
This study aims at evaluating regional distribution and diurnal variation of surface sensible and latent heat fluxes over vegetation using limited number of satellite IR images, meteorological data, and a numerical heat budget simulation together. Data used in this study are as follows: NOAA-AVHRR thermal IR image for retrieving surface temperature, surface and upper meteorological data, time series of solar radiation, and leaf area index for determining surface aerodynamic conditions. To evaluate sensible heat flux, retrieving the surface effective temperature of sensible heat flux is required. This temperature is different from IR temperature in general, even an original IR temperatures is atmospherically corrected and a correction of emissivity is performed.