As a typical next-generation radar system, multistatic radar operates with distinct transmit and receive antennas, which can obtain three or more simultaneous echo datasets [1] . Such radar system has great potential in increasing the capability, reliability and flexibility of future SAR missions [2] . Recent years, various spaceborne multistatic SAR configurations have been introduced [3] , [4] , and the datasets are relatively scant due to the difficulty in constellation configurations. A multistatic radar system was developed in the anechoic chamber of Laboratory of Target Microwave Properties in 2021, which supposed to provide large amounts of radar cross section (RCS) and imaging data in the future. The amplitude of the RCS was calibrated using a metallic sphere, and the accuracy of the multistatic radar system was validated, which demonstrated the capability of the system.

Height is an important indicator of rice growth condition and phenological period. The Polarimetric SAR Interferometry (PolInSAR) has proven a valuable technique for providing structural metrics of vegetation. Anechoic chamber experiments, allowing a high flexibility in the configuration of operating parameters, such as frequency and baseline, is the most convenient and feasible way to study the potential of PolInSAR in rice height retrieval. In this study, the first PolInSAR measurements of a recently built anechoic chamber, The Laboratory of Target Microwave Properties (LAMP), were presented and analyzed versus frequency and baseline, and rice height was retrieved using the measurement data. The results confirm that LAMP has the ability of PolInSAR, and the height of rice in milk stage is retrieved more precisely in the frequency range of 2.5 to 4.7GHz, when the baseline is 0.5°. The results are expected to contribute to studying and to defining the operation modes for future SAR missions.

Bistatic radar system has attracted lots of studies on earth observation while lacking of data. An indoor bistatic system built in Laboratory of Target Microwave Properties (LAMP) was introduced, and the preliminary bistatic imaging experiments of a metallic cuboid by Inverse SAR (ISAR) was implemented. The characteristics of edge diffraction and specular reflection of electromagnetic wave could be observed clearly on the bistatic images, that highly consistent with the theory of electromagnetic wave. The results demonstrated the capability of this indoor bistatic system, promising to provide more bistatic data for further researches.

A prompt and accurate assessment of buildings' damage is critical for disaster management and emergency response. With the development of high-resolution synthetic aperture radar (SAR) and deep-learning methods, more efficient damage assessment techniques based on building-units are possible. This paper proposes a new building damage assessment method using high-resolution SAR images based on semantic change detection. It utilizes a Siamese-based module for damage change detection together with an attention mechanism-based module for semantic segmentation of the damage maps. To evaluate the proposed model, a new damage assessment dataset is constructed from the SAR imagery originated from the battle of Aleppo, Syria, for model training and testing. The experiments performed on this dataset show an overall accuracy of 88.3%. The proposed method effectively identifies the damaged areas of the buildings and grade the damage condition.

This paper mainly analyzes the change of InSAR phase with deformation and displacement by using multifunctional microwave indoor measurement. The experimental target adopts the high-voltage line tower component with strong scattering - metal tripod, which causes “deformation” by padding the bottom of the tripod by 5mm. According to the experimental principle of equal height interference fringes of electromagnetic waves, the measured data before and after deformation of the metal tripod are processed to obtain the phase data at different incident angles, The consistency between the InSAR phase change after phase unwrapping and the actual vertical deformation of the tripod is verified, which provides a basis for the accurate evaluation of InSAR crustal deformation monitoring, and has a good reference for the influence of different working parameters, especially the incident angle on InSAR results.

In this paper, the Laboratory of Target Microwave Properties (LAMP) was introduced and a full-parameters microwave properties measurement experiment for soil salinized process was demonstrated. In this experiment, the microwave characteristic of three targets of soil in different soil salinized stage were measured in a non-interference environment. The changes of soil salt content and distribution can be reflected in radar images. In the future, more experiments should be carried out to acquire and analyze the weak signal.

In this work, we apply the supervised descent method (SDM) to 3-D limited data inversion. In the measurement of the far field, the scattered field in 3-D measurement is small in magnitude and easily polluted by noise. Combining with limited observed data, the inversion problem is highly nonunique and ill-posed. To mitigate the ill-posedness, the model-based inversion is adopted by describing metallic targets based on prior information. Then, a series of generic descent directions is learned in the training stage iteratively using SDM. During inversion, the values of these model-based parameters are reconstructed directly using the learned directions. This approach is validated using both synthetic and experimental data. All simulations and experiments are conducted in a monostatic measurement setup to match real measurement conditions. The results show that by choosing proper prior information, the model-based SDM inversion can effectively compensate for the lack of data and achieve decent accuracy.

Measurement of microwave characteristics for targets in an anechoic chamber could improve the cognition of EM waves scattering mechanism. In this paper, a Full-Parameters Microwave Properties Measurement System (LAMP) was introduced, including the overall capabilities, the antenna RF system and etc. The Radar Cross Section (RCS) measurement and SAR images measured by LAMP, were demonstrated in this paper, when the frequencies of EM waves, the incidence angles and the azimuth angles varied It was verified that the accuracy of RCS of a metal sphere measured by LAMP was 1.09dBsm and 1.00dBsm in HH and VV polarization, respectively, comparing with Mie scattering computational results, when the frequency involved ranging from 2.5GHz to 18GHz.

The objective of this paper is to use the partial least squares regression as a modeling method to establish the relationship between soil moisture and polarimetric decomposition parameters which are obtained by T3 matrix and H/A/α polarimetric decomposition with full-polarization RADARSAT-2 SAR image. The results show that the parameter set of T3 matrix have the minimum accuracy comparing with the other three decomposition ways of the H/A/α. The best results of the H/A/α is the Eigenvector parameter set. However, it is still lower than the inversion of parameter combinations with R2of 0.84 for calibration and R2of 0.77 for validation. It indicates that the polarimetric decomposition parameters can be used for mapping soil moisture in Huanghe Delta.

A prompt and accurate assessment of building damage is critical for disaster assistance and emergency monitoring. Polarimetric synthetic aperture radar (PolSAR) has become one of the most effective methods in damage assessment, owing to its all-weather/all-time observation ability and abundant polarization scattering information of target. In this study, we discussed the distribution law of Touzi decomposition polarization parameters before and after building collapse, based on the ALOS PALSAR data in the L band and the simulated SAR images in the Ku band. The experimental results show that the as1component obtained by Touzi decomposition can be used for building damage assessment, and is universal in L-band and Ku-band SAR images.

Information of crop phenology is essential for evaluating crop productivity and crop management. Synthetic Aperture Radar (SAR), with the advantage of all-weather, day-night imaging and clouds penetrability, is an effective way for rice growth monitoring. In this study, we developed a method for remotely determining phenological stages of paddy rice with sixteen polarimetric SAR images. The method consists of three procedures: (I) Classified the transplanted rice (T-R) and the direct-sown rice (D-R) field; (II) Sensitivity analysis of polarimetric parameters versus rice phenology; (III) Reconstructing the time-series polarimetric parameters profiles of rice by time-frequency analysis; (IV) Specifying the phenological stages by detecting the maximum point, minimal point and inflection point from the smoothed polarimetric parameters time profile. Three keys phenological periods of rice were detected with the the accuracy of about 84%.

The objective of this paper is to evaluate the potential of Gaofen (GF)-3 quad-polarized Synthetic Aperture Radar (SAR) for coastal wetland observation. The north coastal wetland of Zhejiang is selected as the test case, which is operated by on-site measure as reference results, matched up with three scenes of GF-3 Quad Polarized Strip I (QPSI) mode SAR imagery. Based on the collected datasets, three well-known methods of Pauli, Freeman and H/A/Alpha decomposition are performed to data processing, and the experimental results reveal that reliable observation capability of GF-3 quad-polarized SAR is verified. The promising preliminary results indicate that GF-3 is encouraging for operational implementation, especially for coastal wetland observation.

The use of a microwave scattering model is fundamental to rice monitoring by synthetic aperture radar (SAR), and an ear scattering model is necessary to improve the accuracy of the microwave scattering model of the rice field. A novel rice ear scattering model, the multisphere ear scattering model, was developed by incorporating the microstructure of rice ear panicles, including the ear grain parameters in particular. A virtual ear model was used to simulate the ear morphology, and a multisphere scattering model was used to simulate the ear scattering. The multisphere ear scattering model has the potential to retrieve grain parameters from SAR imagery. The new model was also compared with a traditional two-cylinder ear model; the large discrepancy in the simulation results shows the necessity of carrying out a verification experiment.

The successful launch of the GF-4 satellite has greatly enhanced wide-swath and high-frequency imaging capabilities, both of which are urgently needed in the fields of ship detection and monitoring. In this letter, the applicability of GF-4 satellite data for ship recognition and maritime traffic surveillance was investigated. It is concluded that the movement of ships, the velocity and direction, for instance, can be detected by using either a single GF-4 image that has short time lags between bands, or time-series GF-4 images that have a short interval between their acquisition times, implying that GF-4 satellite images have the potentiality for the monitoring of moving ships.

Scattering from rice leaves contributes substantially to total vegetation canopy backscattering and detailed knowledge about it is necessary for developing a microwave scattering model. A parabolic curve is generally adopted to simulate the leaf shape but this is rarely incorporated into the calculation of the scattering. In this paper, two specific models, one based on physical optics (PO) approximation and the other on the discrete dipole approximation (DDA), are presented to involve the parabolic leaf curvature effects. Three typical leaves were chosen from 1433 parabolic leaves obtained during ground measurements. The PO and DDA models were used to calculate the leaf scattering. The generalized Rayleigh-Gans (GRG) approximation was also included in the simulation. The method of moments, a computational electromagnetic method, was utilized to evaluate the accuracy of each model. Validation of the models was conducted at incidence angles ranging from 10° to 60°, incidence azimuthal angles ranging from 0° to 360°, and incidence frequencies of 1.2 GHz (L-band), 5.4 GHz (C-band), and 9.65 GHz (X-band). Among the GRG approximation, the DDA model and the PO model, the latter gave the best accuracy ->65% in the cases tested, while the GRG model was the least accurate. The high accuracy of the PO model was maintained at both the low and high frequency bands. The PO model, therefore, has great potential for use to interpret radar measurements from rice fields and other types of vegetation canopy.

Rice fields occupy a land area of more than 100 million ha in Asia, feed about 3.5 billion people worldwide. There is a significant interest in the information provided by remote sensing about rice fields in a timely and efficient manner. Information on phenological development is a fundamental key to rice monitoring because it describes the actual state of the rice plants and their relation with the pedoclimatic conditions. As part of an ongoing effort to explore the use of polarimetric SAR data in rice monitoring, this study proposed an automated method of rice phenology retrieval using a feature optimization strategy integrated support vector machine (SVM) and sequential forward selection (SFS). The optimal polarimetric variables for each phenological stage were acquired, based on which eight rice phenological stages were retrieved automatically. The accuracies were higher than 90% except for the dough stage and the transition period between two stages.

Rice leaf scattering contributes substantially to total vegetation canopy backscattering. A modified Physical Optics (PO) approximation model and a specified Discrete Dipole Approximation (DDA) model have been developed that involves parabolic leaf curvature effects. Three typical leaves are chosen among 1433 pieces of parabolic leaves sampled in a ground measurement. PO, DDA, Generalized Rayleigh Gans (GRG) approximation, were used to calculate the leaf scattering, respectively. The method of moments (MOM), a computational electromagnetic method, is utilized to evaluate each models' accuracy. Validation work is conducted under the incidence angles 10° ~ 60°, incidence azimuthal angle 0° ~ 360°, incident frequencies L Band (1.2 GHz), C Band (5.4 GHz) and X Band (9.65 GHz). Compared with DDA and GRG, the modified PO model presents the maximum accuracy in >84% testing cases, and retains the high accuracy in both the low and high frequency band.

This paper proposed a modified Water Cloud Model (MWCM) for rice variable estimation during the whole growth season with eight RADARSAT-2 quad-pol SAR images. The improvements achieved with the MWCM include considering the heterogeneity of water content of the rice canopy in different directions and different phenologies, and applying the scattering components from an improved polarimetric decomposition in the model instead of the backscattering coefficients. With the MWCM, four rice variables were estimated through the genetic algorithm, including leaf area index (LAI), rice height (h), volumetric water content of total canopy (mv) and ear biomass (De). The validation was conducted using the field data with the average R2of each variable above 0.8. The median relative error (MRE) of the rice variables ranged from 9% to 15% in most phenological stages. The results demonstrated that the MWCM works well for the estimation of rice biophysical parameters with polarimetric SAR data, and it is significant to consider the heterogeneity of water content of the rice canopy in the horizontal direction for estimation of rice variables during the whole rice growth season.

Aerodynamic roughness is an important parameter for urban meteorological and climate studies. Buildings in urban areas alter the surface roughness and the drag effect of urban surfaces, which in turn affects urban boundary layer dynamics. Polarimetric Synthetic Aperture Radar is considered to be an effective means for aerodynamic roughness retrieval because polarimetric parameters are sensitive to the surface roughness and geometric structure of a given target. In this paper, the correlation between radar polarimetric parameters and aerodynamic roughness in urban areas are analyzed. And then the optimal polarimetric parameter for the aerodynamic roughness calculation was determined. Finally a quantitative relationship was set up to retrieve the aerodynamic roughness length in urban areas from polarimetric SAR data.

Coastal wetland ecosystems are among the most productive yet highly threatened systems in the world, and population growth and increasing economic development have resulted in extremely rapid degradation and loss of coastal wetlands. Synthetic aperture radar (SAR) has proved to be of great potential in wetland applications, such as characterizing wetland types and mapping wetland inundation extent, based on the fact that the SAR backscatter signal from the wetland depends mainly on the wetland vegetation and hydrodynamic. However, the absence of ground observations has limited calibration and validation of water depth estimated from satellite SAR data. This letter aims to explore the potential for retrieving the water depth in freshwater marshes using L-band SAR backscattering coefficients. We present an innovative approach for combining backscattering coefficients and interferometric data to estimate water depth from L-band SAR data. The technique was applied to freshwater marshes in the Yellow River Delta using an Advanced Land Observing Satellite Phased Array L-band SAR data set acquired between 2007 and 2010. It is shown that the combination of L-band backscattering coefficients and interferometric data could provide information on the hydrodynamic of the Yellow River Delta with high spatial resolution.

The ear layer, which is a component of rice, is crucial to rice monitoring and yield estimation. By adding in the ear layer, we have extended the original coherent microwave scattering model, which is based on both the first-order solution of the radiation transfer equation and Monte Carlo numerical simulation methods, to full stage of rice. The detailed scene generation and the geometrical description of rice elements are presented. The propagation path of scattering in rice canopy is reduced. Two approximation methods are used to fit the curving ear by straight cylinders. Ground truth measurements of rice fields in heading stage, including the curvature of ear, were acquired extensively at Jinhu, Jiangsu in eastern China. Measured parameters are used in the new extended model to calculate the C-band backscattering coefficients of rice field. The simulation results are used for comparison with the backscattering coefficients extracted from RADARSAT-2 images to test the validity of the coherent scattering model with the mean absolute error reaching <; 3.3 dB in the copolarization mode. Theoretical analysis reveals that the ear morphology can largely affect the backscattering behavior of the rice field.

Lop Nur, located at the east end of Tarim Basin, northwest China, is a huge vanished lake dried up before the 1970s. With the advantage of penetration capability and sensitivity to moist saline materials, synthetic aperture radar revealed the subsurface lacustrine deposits, delineated the partially buried shorelines and depicted a complete picture of Lop Nur Lake that leads to three important scientific findings in this study. Based on scattering mechanism interpretation of polarimetric and multiple frequency SAR data, field investigation and sample analysis, it is found that the total area of the vanished Lop Nur Lake is more than 10,300 km2, much larger than earlier reports. The relatively younger West Lake is superposed on the top of the lacustrine deposits of East Lake which makes the well known “Ear” feature of Lop Nur, so the west part of the shoreline is buried and not visible on optical remote sensing images. Therefore the Lop Nur Lake actually has nearly circular, closed shorelines. The drying-up process of East Lop Nur Lake went through six phases according to the shorelines interpreted from multiple SAR data. The shrinking phases of Lop Nur Lake indicate the climate changes between dry and wet environment conditions.

Lop Nur is a salt lake in the central part of Eurasia continent. The lake occupied an area of 10,000 km2at the beginning of holocene epoch and totally dried up in the last century. The study of L-band radar backscattering indicates significant signal penetrating under ground surface. Thus, subsurface information can be extracted from radar images. This paper presents polarimetric decomposition results using ALOS PALSAR data, and established an empirical relationship between multiple scattering and subsurface salinity. Combined with ground surface calcium content retrieved from hyperspectral imaging, as well as precise topographic data from GLAS, some interesting deposition features formed during the evolution is discussed.

China is the largest rice producer in the world. Guizhou province is an important rice growing area in the southwest of China. However, rice monitoring with remote sensing data has great difficulties in this region due to its perennial cloud-coverage weather and undulating terrain. With the emergence of polarimetric SAR data and state of art methods for polarization information extraction, rice monitoring in this region is more promising. In this study, multi-temporal RADARSAT-2 polarimetric SAR data set was acquired in Guizhou, China. The Freeman-Durden, Cloude-Pottier and the Touzi decompositions were used for classification and rice scattering mechanism analysis.

Two layer water cloud model (WCM2), which is a refined version of the conventional water cloud model (WCM), considering the vertical inhomogeneity in the vegetation layer. The vertical inhomogeneity of the vegetation layer is described by the distribution of water content per unit volume. A piecewise linear function is used to describe the distribution of water content per unit volume. We analyze the variation tendency of vegetation scattering under different vertical inhomogeneity conditions by means of WCM2 and validate it using a physically-based model developed at Tor Vergata University, Rome, Italy. The result shows that the vertical inhomogeneity affects vegetation scattering significantly. Comparison between model predications and field measurements on radar backscattering coefficients for soybean shows WCM2 has the potential to get a better prediction result.

The discrepancies caused by different cluster merging algorithms in fully polarimetric SAR classification are analyzed here. There are two often-used merging schemes, i.e., merging first to desirable cluster numbers and then iterative clustering and, the agglomerative hierarchical clustering, both using three different between-cluster distance measures herein. One sub-image of RadarSat-2 SAR SLC image is used here. The results illustrate that (1) The choice of between-cluster distance measures in merging scheme one affects the merging results obviously. (2) the agglomerative hierarchical clustering, the merging scheme two can significantly alleviate these discrepancies caused by different between-cluster distance measures and get almost the same merging results. (3) the agglomerative hierarchical clustering also will gain the stability of merging sequence when Pct is small enough.

This paper investigates the S-band backscattering variation of wheat in its four growing seasons, with the purpose of providing a reliable method for wheat identification and monitoring using satellite S-band synthetic aperture radar (SAR) data. The study is based on the tower-based scatteromerer experiment conducted on the wheat fields at the remote sensing test site of Institute of remote sensing applications Chinese academy of sciences. During the entire growing season, we carried out four experiments and got a great amount of backscatter data including the HH and VV polarization. Synchronously, a wide range of plant parameters, such as biomass, soil moisture and canopy height were measured. This paper describes these experiments and analyzes wheat temporal backscattering variation at S-band with corresponding ground parameters.

In the southwest of China, Synthetic aperture radar (SAR) is anticipated to provide an important tool for forestry inventory because of its all weather capabilities. In this paper, Zhazuo area in Guizhou Province of southwest China, with typical Karst landform, was selected as the test site, and six RADARSAT-2 polarimetric images were used for experiments. Methods for forest mapping based on polarimetric decomposition and multi-temporal polarimetric SAR data fusion were proposed. Experiments showed that polarimetric signatures of forest were significantly different with other targets, and fusion of multi-temporal RADARSAT-2 images can effectively improve image quality and enhance forest and deforestation information.

Synthetic Aperture Radar (SAR) has the penetration of the drying dielectric layer, which can detect subsurface targets and buried characteristics. It took fully polarimetric SAR datasets of the subsurface in Lop Nur Palaeo-lacustrine basin for example to compute Shannon entropy parameter and analyze its image features, and then compare those with the other polarization parameters and polarization decomposition results from scattering mechanism and image features. The results show that the introduced Shannon entropy can describe the actual situation and express the image features more obvious in study area, so it has an important reference value for subsurface targets detection and buried characteristics extraction.

This paper presents the volume scattering mechanism of subsurface and analyzes the fundamental cause of “Ear” feature of Lop Nur on SAR images. ALOS PALSAR image acquired in 2007 was collected, and the Cloude decomposition method was conducted on the calibrated image to extract the volume scattering component. Two field investigations were conducted in 2006 and 2008 respectively, and lots of precise soil samples were gathered for the parameters analysis. Validation of the model is also conducted based on the surveying parameter and the image processing results, and the fitting effect is relatively good. According to the analysis on the parameters of the model, it is found that salinity at subsurface is the fundamental reason to “Ear” feature, which is strongly correlated with Lop Nur evolution.

This paper presents fundamental reason to Lop Nur “Ear” feature based on polarimetric decomposition technology. Lop Nur is located at the east Tarim Basin in China, and in history, all the major rivers running in Tarim Basin converged to this lowest place. Lop Nur belongs to arid region, and satisfies penetration conditions for SAR signals. Through comparison between decomposed volume scattering contribution and sub-surface salinity, it is found that subsurface properties (such as salinity) is the fundamental reason to “Ear” feature. And dynamic mechanism of geomorphology builds the relationship between surface and subsurface evolution processes, and indirectly unifies previous points on the reasons to formation of Lop Nur “Ear”. Polarimetric technology is anticipated to be used to retrieve more information and to help extend applications in environment of arid region.

In this paper, an experiment that is oriented to discriminate between different oil slicks using polarimetric SAR image was introduced. Dark patches which often appear in SAR images such as biogenic slicks, atmospheric front, and crude oil with different chemical composition were identified according to the result of Eigenvector-Eigenvalue based Incoherent Target Decomposition. The experiment demonstrated that polarimetric SAR can be of great help in classifying of oil spills.

The bloom of algae called Enteromorpha prolifera posed a potential threat to the Olympic sailing competition in June 2008. Synthetic Aperture Radar (SAR) technology plays an irreplaceable role in algal blooming monitoring. Based on the analysis of various influence factors, a procedure for E.P. detection is proposed. In this paper, multi-temporal SAR images especially with short time interval, currents datum from buoys and wind products retrieved from SeaWinds scatterometer have been employed for E.P. dynamic monitoring and drift trend analysis. The result of analysis shows SAR, currents and wind datum are available for forecasting the trend of the E.P. drift.

High resolution SAR (Synthetic Aperture Radar) will provide an innovative tool for urban area applications. Nevertheless, interpretation of SAR image in urban area is far from solved by the increase of spatial resolution. It is usually difficult to establish a determined relationship between scattering centers in high resolution SAR images and the basic units of building targets. In order to thoroughly understand the backscattering behaviour of building targets in high resolution SAR images, a method of high resolution SAR imaging simulation based on electromagnetic model is proposed in this paper, which mainly includes 3-D model establishment for the building target, triangular facets partition, RCS prediction for each facet, and SAR imaging through coherent superposition of echo from each triangular facet. Through comparison of the simulated and the original SAR image, building scatter mechanisms in high resolution SAR images can be well interpreted.

This paper aims to get the relationship between drought and crop growth. By investigating synthetic aperture radar (SAR) backscattering coefficients, HH- and VV- polarization were found different due to influence from canopy, because of strong attenuation of the VV- polarization by the vertically oriented wheat stems. In small incidence angle, HH is sensitive to soil moisture, while VV is more sensitive to canopy. Two classes of crop with low and high soil moisture are investigated by ¿water-cloud¿ model with vegetation descriptor vegetation water mass (VWM). Parameters of the model show that in drought the crop growth will be worse. This research presents that it is possible to study the influence of drought to wheat growth with small incidence angle of C-band SAR.

Subsurface microwave remote sensing is a direction of Synthetic Aperture Radar (SAR) research. With the penetration capability, SAR is capable of detecting the subsurface targets and materials, especially in arid environment. Lop Nur Lake is located at the east of Tarim Basin in Xinjiang province of China, which is described as ¿dry core¿ of the world, and it can provide conditions for SAR penetration. This paper presents preliminary analysis about Lop Nur, and gives out an abstract subsurface structure about it. Then, the major scattering processes are concluded and a two-layer scattering model is developed. Based on parameters of soil samples, some rules about Lop Nur evolution will be figured out. With Genetic Algorithm (GA), an inversion procedure is constructed. All the attempts are viewed as the basis of future comprehensive interpretation about Lop Nur phenomenon.

The coupling relationship between urban vegetation and land surface temperature (LST) has been of great interest to a variety of environmental studies. This paper retrieves the urban vegetation and LST utilizing Terra ASTER imagery in the year 2007, and analyzes their coupling relationships accordingly, so as to provide the basis for decision making of ecological planning and environment protection. It turns out that NDVI, urban vegetation abundance (UVA) and urban forest abundance (UFA) are all in negative correlation with land surface temperature (LST), so that Urban vegetation and urban forest are both capable in decreasing LST. The influence of urban vegetation and urban forest varies with pixel aggregation, and peaks around 90 m ~ 120 m resolution. At the end of this paper, some future efforts on the analysis are pointed out.

As the high resolution radar satellite's has been successfully launched, its ability of the typical target's recognition monitor enhances a lot. This article mainly does analysis based on the RADARSAT2 quad-polarimetric data, compared scattering properties of typical target feature with two temporal full polarized data, and used the measured data to drive MIMICS (Michigan Microwave Canopy Scattering model) model and carry on the multi-wave band full polarization backscattering simulation about the farmland and forest. Then we carried on the comparison between X, C band SAR image gain's actual scattering value and simulation value in order to infer the typical target feature' scattering properties rule of S band. With anticipation of HJ-1-C satellite soon launched by China and then we can carrry on the comparison with the fact. Along with the full polarized data's development, the typical target feature's scattering properties analysis will be more perfect.

This paper presents the research results about Lop Nur using full-polarimetric technology. Lop Nur Lake is one of the driest places in the world and finally lost its last drop of water in 1972. It is well known for its ¿Earth Ear¿ feature in optical remote sensing images. Likewise, ¿Ear¿ feature is shown in Synthetic Aperture Radar (SAR) images, and even larger because of penetration effect. With the penetration capability SAR is capable of detecting the subsurface targets and materials, especially in arid environment. As for SAR images, both C-band and L-band, there are two key features about Lop Nur area. One is the whole Lop Nur area is high-bright that means the backscattering is much stronger than other sites, such as Gobi, desert and so on. The other feature is the ¿Ear¿ pattern formation. polarimetric analysis about these two questions will be conducted based on past research results and field investigations.

Wenchuan Earthquake has caused many huge landslides in the rivers in Sichuan Province. Synthetic Aperture Radar (SAR) technology played an irreplaceable role in rapid response to Wenchuan Earthquake monitoring and damage assessment. In this paper, Tangjiashan Dammed Lake was taken as a case study area for fast extracting and change detection with continuously acquired multi-temporal high-resolution SAR images. By June 12, 2008, we had identified dozens of dammed lakes in the area heavily affected by the Wenchuan Earthquake using high-resolution SAR images. In order to make a scientific evaluation of the disaster situation and provide efficient and instantaneous rescue action in the future, an effective method was developed for rapid extraction and change detection of dammed lakes.

This paper presents the observation from SAR images of the dried Lop Nur Lake in Xinjiang of west China. Lop Nur Lake is one of the driest places in the world and finally lost its last drop of water in 1972. It is well known for its "human ear shape" feature in optical remote sensing images. Likewise, the "ear" feature is shown in synthetic aperture radar (SAR) images, and is even larger because of the penetration effect. The universal existence of lacustrine deposit with high water content and salinity are undetectable by previous remote sensing images in Lop Nur Lake. We have made some laboratory experiments about subsurface soils and developed an improved dielectric model for moist saline soil at microwave bands. A field trip was conducted from October 25 to November 8, 2006 to validate the image interpretation results. As an important indicator for environment degradation and climate change study in arid region, Lop Nur does need long-term and overall research to answer many scientific questions.

On the 7thof December 2007, the 146,000-ton oil tanker, Hebei Spirit, was wrecked and leaked more than 10,000 ton crude oil onto the sea off the west coast of the South Korea. In this paper, the monitoring of the oil spills in this pollution accident using multi-temporal Synthetic Aperture Radar (SAR) and microwave scatterometer (QSCAT and ASCAT) data was illustrated. The impact of this oil spill pollution on the China's marine environment was evaluated. The result shows the capability and the effectiveness of microwave remote sensing data in oil spill monitoring and forecasting.

HJ-1C will be launched at the end of 2008, it is a component of HJ satellites which are developed in China. HJ-1C SAR has a frequency of S-band (3.2 GHz), VV single polarization, and incident angle range from 25deg-47deg. Soil moisture retrieval using L- and C-band radar has been widely studied, but little attention was paid to S-band data. For the application of HJ-1C SAR, in this paper, the available data of S-band radar data by PALS (Passive and Active L- and S-band sensor) from SGP99 and SMEX02 experiments was used to study the potential of soil moisture change retrieval using S-band single polarization radar.

Land surface temperature (LST) is of great interest to a variety of environmental studies. In this paper, Beijing is chosen as study area, and a time series of Landsat TM/ETM+ and ASTER images are utilized to learn the distribution and change of LST within this city. Generalized single-channel method and split-window algorithm are applied respectively in the retrieval of LST from Landsat TM/ETM+ images and ASTER images. The LST data are converted to histogram equalized maps and then synthetically compared and analyzed. Spatial distribution of LST in the summer of each year is concluded, as well as the temporal diversion. It is learned that the Heat Island Effect has been mitigated since the year 1999. In the final part, the achievement and disadvantages of this analysis are concluded, and the future efforts are pointed out as well.

An automatic oil spill identification system was introduced in this paper. It was designed to work independently to detect oil spills in ENVISAT ASAR level 1b images (of WS, IMP and APP mode). The absolute calibration, geometric correction without any GCPs, dark patches segmentation based on wind force levels, dark patches feature extraction, drifty trend prediction and identification confidence evaluation are the essential components of the system. The system works well for its accuracy of 85% in discriminating between oil spills and look-alikes in the case of 60 scenes of examined images.

Oil spill pollution is a major environmental threat for many countries in the world, which can cause serious damage to marine environment. Synthetic aperture radar (SAR) has become a valuable tool for marine oil spill monitoring, because of its all-weather and all-day capabilities. However, interpretation of marine SAR imagery is often ambiguous, and some other look-alike features often pose a fundamental challenge to the identification of oil spills and make the discrimination between oil spills and the look-alikes become a necessary procedure. In this paper, co-occurrence matrix method is employed to extract textural features of marine SAR image first, then these features are analyzed and optimized, and then support machine vector (SVM) method is used to identify oil spills in SAR images. Experiments on several SAR images show that method proposed in this paper can improve the detection and identification of oil spill in SAR images.

Most paddy rice in southern China grows in warm, humid and rainy areas where it is hard to acquire optical remote sensing data. In this study, a semi-empirical backscattering model was proposed to estimate leaf area index (LAI) of rice in the area using ENVISAT Advanced Synthetic Aperture Radar (ASAR) alternating polarization data. Ground measurements of LAI, water content and height of rice in the test site were collected and the model fitted at the same time as the acquisition of ASAR data. LAI estimated from the model was compared with ground measurements to evaluate the accuracy of the model. The results showed that the model provides a promising alternative to optical remote sensing data for predicting LAI of rice in southern China.

Urban forest is of great interest to a variety of scientific and urban planning applications. This paper presents a strategy for calculating tree canopy density in urban areas using Landsat ETM+ imagery and calculating its ecological value. The strategy consists of two key steps: one is to extract urban tree canopy area from remote sensing images; the other is to calculate the ecological value of urban forest. The extraction of tree canopy area from remote sensing imagery is carried out using classification models, which are based on empirical relationships between forest coverage and the spectrum on Landsat imagery, and are generated using regression tree techniques. The calculation about urban forest is carried out introducing CITYgreen model. In the analysis, the zone inside the 4th Ring Road in Beijing is chosen as study area; and a Landsat ETM+ image taken in 2001 is used applying this strategy to analyze the urban forest. In the following part, the results of the analysis are presented. At the end, the accuracy of tree canopy density is reviewed, and some possible reasons for the error are discussed, as well as the advantages and disadvantages of this strategy.

Urban heat island means the urban area has a higher temperature than peripheral regions, especially in summer. The result that urban temperature is higher than rural area is because the special urban underlining surface, human heat resources and local atmosphere circumfluence. Study indicates that urban land surface temperature and urban vegetation fraction are two important factors in urban heat island (HI) research. By retrieving urban land surface temperature and urban vegetation fraction with ASTER data, this article presents the approximate linear relation between urban land surface temperature and urban vegetation fraction. The result reveals that the ASTER images can be used in urban heat island research to reflect the temperature distribution, illustrate the heat intensity and provide macroscopic data support for the decision-making departments. The urban land surface temperature can be the most important evaluation factor in urban heat island.

In order to provide relevant data and decision support information to the Beijing Olympic Organizing Committee and International Olympic Organizing Committee, we are building up an environmental remote sensing monitoring system for Beijing 2008 Olympic Game using multiresolution, multiband, multitemporal remote sensing method and virtual reality technique. This system has four main features: 1) a 10 years long term monitoring from 1999 to 2008; 2) a stereo observation from spaceborne, airborne and ground remote sensing means; 3) a large area monitoring from Olympic game sites, Beijing area to its surrounding areas; 4) comprehensive monitoring for ecological environment, engineering construction, environmental pollution, traffic situation etc. This system serves as a huge platform for dynamic Earth observing monitoring and virtual Olympic environment with annual report and seasonal report forms. This work presents a preliminary result of constructing the system for Beijing 2008 Olympic Game.

In the summer of 2003, the most serious flood since 1991 occurred in the catchments of Huai River in central of China. Many of areas were inundated. The Chinese Ku-band airborne radar system and Canadian RADARSAT were used for flood monitoring and damage assessment. Based on the analysis of the SAR data and related database, the area of flood inundation is more than 3800 km/sup 2/. The land types of flood inundation includes in farmland, residential site, woodland/grassland, fishpond, and bottomland. Further, the extent and distribution of flood and damage assessment were indicated, and the suggestions on flood prevention and control were provided.

This work had presented the expressions for imaginary part of dielectric constant of moisture salt soil at low and high frequencies respectively, which is a function of 1) soil water content and 2) soil salt content. This result makes it possible to retrieve the soil salt content that is often useful for monitoring plantation's salinization in inland countries. To establish the relationship between imaginary part and soil physical characters, namely soil moisture and salt content, the relationship between imaginary part of dielectric constant /spl epsiv/" and soil bulk conductivity /spl sigma//sub a/ relationship between soil bulk conductivity /spl sigma//sub a/, and conductivity of soil solution /spl sigma//sub w/, relationship between conductivity of soil solution /spl sigma//sub w/ and soil solution concentration, and relationship between soil solution concentration and soil salt content have been established gradually. According to these correlations (/spl epsiv/" /spl sim/ /spl sigma//sub a/ /spl sim/ /spl sigma//sub w/ /spl sim/ S/sub M./ /spl sim/ S), the expressions for /spl epsiv/" /spl sim/ S and M, had been directly made and simplified as approximations with four free parameters at low frequencies or with five free parameters at high frequencies. The two models for low and high frequencies had been examined and calibrated by 150 soil samples that had been watered and salinized distinctly in lab and a good agreement with the measured data had been achieved with the coefficients between the calculated and the measured greater than 0.9.

Remote sensing plays an important role in the mineral exploration. One of the common applications is to locate alteration zones related to gold deposits. Many studies based on landsat thematic mapper (TM) imagery have been carried out and several methods have been developed. However, the advanced spaceborne thermal emission and reflection radiometer (ASTER) imagery, which has better spectral resolution (14 bands) and spatial resolution (15 m in VNIR bands), was not widely used in this application field. This article indicates the ASTER imagery application in locating alteration zones in Laizhou area of Shandong Province. First, we studied the geological information and main alteration minerals' spectral features of the study area. Based on the above work, we calculated some band ratios (b4/bl, b4/b6, b3/b2) to enhance spectral response of some mineral materials and vegetations. Then, a principal component analysis was applied to these band ratios. After applying PCA, the eigenvector matrix was analyzed to identify which PC (principal component) contained more useful information of alteration minerals. We chose the PC that enhanced the response of alteration minerals and reduced the response of vegetations, from which we could discriminate the alteration rocks. The satisfactory result shows that ASTER imagery works well in the exploration of alteration zones

Radar backscattering response has the potential of retrieving desired snow parameters, such as snow water equivalence, snow depth, liquid water content which are important factors in hydrological investigation. The objective of this study is to develop an algorithm which can decompose the scattering of wet snow and also develop new description of surface scattering. There are two scattering sources - the volume scattering component from snow pack and the air-snow surface scattering component - for radar backscattering while observing wet snow. Depending upon which scattering component is dominant and then controls the response to snow wetness, an algorithm can be developed to quantitatively describe the relationship between this two scattering sources and snow wetness. We have established a model - simulated at C-bandata-base by using two scattering components. The database covers the most possible wet snow physical properties and surface roughness conditions. Using this data-base, an inversion algorithm can be developed for using C-band multi-polarization measurements. The newly developed algorithm mainly involved two steps: 1) decomposes the surface and volume scattering signals, and 2) then use each scattering component to estimate snow wetness

There are some problems not to be resolved very well, when we merge images by the wavelet transform method. One problem is how many levels the original images should be decomposed to, in order to make fusion images obtain more information. Other problem is how to reduce the spectral distortions of the fusion images more efficiently, when we enhance the spatial resolution of the low-resolution images. We rightly select the number of wavelet decomposition levels by computing entropy of the fusion images. When performing wavelet reconstruction, we introduce the local correlation coefficient and set up the different thresholds at different levels of wavelet decomposition, in order to reduce the spectral distortions of the fusion images. In our experiment we merge three multispectral images with a panchromatic image of Quickbird data by our method. The results demonstrate that our method is a good fusion method to increase information and reduce spectral distortions.

Edge detection is important and key to image segmentation, information extraction, mapping etc. It is more difficult with SAR images than optical images, because of speckle. The aim of the paper is to show how boundaries between land and water can be detected from SAR images by using wavelet transform method, block-tracing algorithm and snake algorithm. The Ku-Band SAR image was obtained on 14 July 2003. The test area is near Huai River, located in city of Fuyang, Anhui Province. This SAR is made by Institute of Electronics, Chinese Academy of Sciences. Its azimuth resolution is 1.25 m and its range resolution is 1.2 m. To detect water edge, we apply a wavelet transform method to obtain the low-resolution image of the original image and suppress the speckle. Then we use a block-tracing algorithm to determine the coarse boundary between land and water and obtain a continuous edge. In the end, we use the snake algorithm to obtain the accurate edge. The result proves our method is a good method.

This paper presents the experimental results regarding changes in the dielectric properties of artificially moistened and salinized soils and on soil samples taken from a salt lake. The complex dielectric constants of soil samples were measured using a microwave network analyzer. We evaluated the real and imaginary parts of dielectric constants of artificially moistened and salinized soil samples prepared in the laboratory as a function of microwave frequency, salinity, and water content The frequency and the salinity of soils have little influence on the real part of dielectric constant /spl epsiv/'. The results show that, in the frequency range of 1-6 GHz, the imaginary part /spl epsiv/" has greater sensitivity to soil salinity. The dielectric constant measurements for soil samples collected in Jilantai Salt Lake are in agreement with the results of the artificially moistened and salinized laboratory soil samples. These dielectric measurements were subsequently compared with the backscattering coefficients extracted from a RADARSAT image (C-HH) that was acquired at same time with the soil sampling at the Jilantai Salt Lake area. We discovered that the correlation coefficient between /spl sigma//sup 0/ extracted from the RADARSAT image and /spl epsiv/" measured in the soil sample is 0.70. The correlation coefficient between /spl sigma//sup 0/ and the soil sample salinity is 0.69. This suggests that soil salinity has a significant contribution to the backscattering coefficient, /spl sigma//sup 0/ recorded in a SAR image. Consequently, a SAR image can be a useful tool for monitoring soil salinity.

CMODIS installed in SZ-3 spacecraft is the first Chinese medium resolution spectrometer with 34 channels in the range from the visible to the infrared. Unfortunately, sharp and repetitive strips over the image exist in many channels of CMODIS can distractingly and obstructively affects the interpretation and application of CMODIS data. This paper: 1) discusses the causes of the striping; 2) presents a new frequency domain finite impulse response filter (FIR) for removing the striping in the data with minimum distortion into the filtered data; 3) quantitatively compares the results obtained with the new filtering method with those produced by traditional destriping methods (e.g., low pass filtering, moment matching) on the CMODIS georectified and no-georectified data of inhomogeneous targets. Results show that the finite impulse response filter, implemented in frequency domain, is superior to other methods evaluated in destriping and preservation of image information. The importance of proper destriping for classification is demonstrated. The finite impulse response filter is also applicable in striping removal of other multisensor remote Sensing data.

Discrimination of blue-ice domain is very important for meteorolite searching and Antarctic inland ice sheet evolvement research. Application of SAR interferometric coherence to blue-ice domain target discrimination is studied over polar inland ice. For the region of Grove Mountains in East Antarctica, interferometric coherence analysis is carried out for a pair of tandem ERS- 1/2 SLC full scenes acquired in February 1996. The investigation indicates significant differences in coherence between blue-ice and other ice sheet features, providing possibilities for target discrimination. The generated blue-ice domain map is compared to a reference blue-ice domain map extracted from TM image acquired in 1990. The final results indicates good consistency.

This paper mainly discusses the research deducing atmospheric Precipitable Water Vapor (PWV) from tropospheric zenith wet delay using ground-based GPS receivers. China GreatWall and ZhongShan stations in Antarctica were taken as the researching sites. The data from SCAR Antarctic GPS Campaigns Epoch 1998/1999/2000 are used to construct the GPS analytical networks. A high-accuracy GPS processing software package-GAMIT/GLOBK is utilized; Multiple schemes are adopted. Two kinds of models, Saastamonien and Hopfield, are used to calculate the zenith hydrostatic delay. Before calculating the atmospheric Precipitable Water Vapor (PWV), we firstly use the long-term meteorological data of the two stations to calculate the conversion ratio-K, which is accommodated with the time period January and February of the two stations. After that wet zenith delay are transferred into PWV. In situ observed rainfall are combined to analyzing. Good results are achieved for all sessions and both stations.

Digital elevation information of Antarctic in-land ice sheet is very important in research of ice flow. ASTER (Advanced Spaceborne Thermal Emission and Reflectance Radiometer) is an imaging instrument on board Terra-the first Earth Observing System (EOS) satellite. The ASTER Earth Observation Satellite offers nearly simultaneous capture of stereo images, minimizing temporal changes and sensor modeling errors. Band 3 of the VNIR sensor includes two channels, a nadir looking scene and a backward looking scene. This provides stereo coverage from which a DEM can be automatically extracted. For the research region of Antarctic Grove Mountains, a pair of ASTER L1A stereo scene product acquired in December 27/sup th/ 2001 is used to extract digital elevation model. Accuracy of the DEM is highly dependent on the source of the ground control points used. Several field ground control points in this region are selected. The final DEM result is compared to DEM surveyed in 2000 using GPS by Chinese surveyors, which indicates good accuracy and powerful usability of ASTER DEM construction in tough Antarctic in-land environment.

Most application of polarimetric SAR imagery require more efficient processing technique which achieves two fundamental goals. The first one is to detect and classify the constituent remotely sensed scenes from pixels to pixels in the imagery. The second one is to reduce the data dimensions without loss of critical information because the fully polarimetric SAR data can be processed just as multi-dimensional images, which could like multi-bands spectrometer images. It is the increased use of spatial data in remotely sensed images that we can get the valuable extraction. But there is composing complexity among the polarimetric imagery texture comparing some hyperspectral images. Some strong backscatters may exist under arid surfaces and contaminate some adjacent pixels. The contamination of imagery decreases the precision of classification. To determine the pixel distance in spatial coordinate is a key to debar some difficulty in front of polarimetric SAR data. The approach to link the nature and cause of spatial variation in image is to use the variograms and subsequent Kringing theory. The data results from the fully polarimetric images prove that the variograms are the tool used to link models of radar backscattering scenes. Some directional variograms aim to indicate the backscattering anisotropy, the height of the sills of the variograms are related to the kinds of the remotely sensed objects and the range of the influence is related to the acting distance on pixels of scenes.

Some progress has been made in recent years in the development of microwave remote sensing for the salinity of soil. In order to further understand the influences of salinity on the dielectric properties of soil, soils with different texture are collected and made into samples with different salinity and moisture content. In this paper, we describe the use of open-ended coaxial probes for the measurement of dielectric properties of soil samples. We evaluate the microwave dielectric behavior of moist soil-salinity mixtures as a function of salinity, water content, and soil textural compositions, using the dielectric measurements of five soils ranging from sandy loam to silty clay at frequencies between 0.2GHz and 20GHz at room temperature. For solution of salt soil, especially at lower frequencies dielectric loss depends on the salinity. Furthermore, salinity has influence on static dielectric constant and relaxation time of soil solution. The real part of dielectric constant slowly declines with the increment of salinity. Therefore we cannot neglect the influences of salinity on microwave dielectric behavior of moist salt soil at P, L, C-band of microwave remote sensing. We add salinity factor into the Dobson semiempirical soil mixing model. The improved models yields values that correlate well with the results of dielectric measurement.

At present, monitoring, conservation and wise use of wetlands has become an international trend. Using Landst-7 ETM+ data acquired on Oct. 2000, we conducted a digital and rapid estimation of wetland vegetation biomass in the Poyang wetland natural conservation area, which is one of the seven international importance wetlands in China. Firstly, using the ETM band 4, 3 and 2 false color composite as one of the main references, we planned a reasonable sampling biomass field route. Based on geometric co-registration of both the field GPS positioning data and the ETM data, the linear relationships among the field biomass data and some transformed data derived from the ETM data were analyzed statistically. The results show that the sampling biomass data have the best positive correlation to DVI vegetation index data with a coefficient of 0.8546. Therefore, a linear regression model established between the sampling data and DVI data, was applied to estimate the total biomass of the whole Poyang Lake natural conservation area. The resultant total biomass is 10.98/spl times/10/sup 4/t.

Wetland identification and dynamic monitoring is an important application for remote sensing technology due to the increasing relevance of environmental considerations. Using Landsat TM/ETM data, we analyze the image brightness curves of typical objects in the largest freshwater lake area---the Poyang Lake, which is one of the seven international importance wetlands in China. The result shows that the optimal combination bands for TM image interpretation are TM4, TM3, and TM2 assigned with R, G and B primitive color respectively. Based on image interpretation results, we establish the wetland classification system for Poyang International Importance Wetland and classify TM image of 1994 and ETM image of 2000 using supervised maximum likelihood algorithm. The wetland changes of Poyang Lake natural conservation area before and after 1998 Great Flood are analyzed and compared.

To smooth coherent speckle noise and preserve edge information in SLC SAR images as precise as possible, a new algorithm called all direction auto-adaptive dynamic window filtering method based on coherent speckle statistic characteristic and analysis of spatial filtering algorithms for SAR image, is developed in this paper. For every processing pixel the filtering window is divided into mutually exclusive all direction sub-windows according to the complexity of image texture and edge existence. Local relative standard deviation is used to determine whether the local filtering window area is homogeneous. Then a Kuan filter and a 3/spl times/3 directive operator are incorporated to process the SAR image. The proposed method can auto-adaptively modulate its filtering window size and selection of filtering pixels. The developed method is applied to a single-look ERS SAR image. Experimental results show that the performance of the method is satisfactory in both speckle suppression and preservation of image details.

This paper analyzes the long sequence time series NDVI datasets and yields statistic results respectively, using simple differencing, slope map of biomass, and principle component analysis techniques. The correlation characteristics for the images of change acquired according to the algorithms mentioned above, implies that the majority pixels of the different land covers have experienced nearly the same changes in change direction and magnitude. The change of biomass of land-cover classifications between the 1980s and present are detected from the satellite data, and the land covers of the former 10 years (1981-1991) are in a better growth than the latter 10 years (1991-2001). Based on the discussion of the exotic factors affected the NDVI, like satellite shift or sensor degradation, the statistics on the slope images of biomass indicates that land cover deteriorated extensively in the past few years. The degradation of grassland or deforestation of forest regions confirmed such a fact that the status of the vegetation of the west part of China in the past 20 years (1981-2001) is suffering an extensive deterioration and only an improvement in part of the region.

ERS-l/ERS-2 synthetic aperture radar interferometry and Landsat TM was used to study the Maergaichaka fault where Manyi earthquake occured on Nov. 8, 1997 in Tibet, China. We derived an accurate digital elevation model(DEM) and the deformation interferogram of the Manyi earthquake using a tandem ERS-l/ERS-2 image pair and modeled the left- lateral slip of the fault in three dimension using half infinite elastic model. Detail geological and geomorphological offsets revalued using river valleys and structural markers on the Landsat ETM images at different scales are used to constrain the localization, total displacement at the Maergaichaka fault, Tibet China. The river network morphology associated with small rivers is offset by several meters to several kilometers along the maergaichaka fault. Our results indicates that the leftlateral slip of the fault has accommodated the shortening of the India-Eurasian lithospheric plates.

A study on efficient visualization and real-time interactivity of large-scale scenes is discussed. Introducing parallel processing technology, we present a parallelizable strategy with the pipeline algorithm, realize this parallel algorithm based on shared-memory, and then apply this program to a test site, the Peking Olympic Games planning mixed scenes, including real-time rendering, dynamical texture loading, quick browsing and so on. The results show a running performance and real-time interactivity improvement of DEPS (Digital Earth Prototype System) when using this algorithm. The parallel program of this paper was developed and running on a Silicon Graphics multiprocessor, Onyx 3200, with four MIPS R12000 processors and InfiniteReality 3 graphic accelerator, under IRIX 6.5 operating system.

Real-time simulation technologies of a large-scale virtual scene are studied. Besides the building of LOD models (including terrain and cultural features) based on a viewpoint in the Peking Olympic Games Planning Regions as a demonstration area, we adopt Active Surface Definition, a real-time framework, to manage the terrain data, apply ClipTexture to manage the high-resolution textures efficiently, and utilize parallel processing technology to deploy the scene data dynamically, which result in higher fidelity and better simulation effects in the virtual scene we finally build up.

Sharp and repetitive stripes exist in many bands of Chinese Moderate Imaging Spectroradiometer (CMODIS) images because of gain and offset variations between neighboring forward and reverse scans of 22 detectors, which can distractingly and obstructively affect the interpretation and application of CMODIS data. In this letter, we suggest a method for destriping based on a finite-impulse response (FIR) filter in frequency domain and present the results obtained with the method on the experimental CMODIS images of heterogeneous targets. We also compare the method with some traditional destriping methods (e.g. lowpass filtering, moment matching) and display the result of comparison using one of the images. The destriping effectiveness is evaluated by means of appropriate indexes of quality in this letter.

This paper presents the experimental results regarding changes in the dielectric properties of artificially moistened and salinized soils and on soil samples taken from a salt lake. The complex dielectric constants of soil samples were measured using a microwave network analyzer. We evaluated the real and imaginary parts of dielectric constants of artificially moistened and salinized soil samples prepared in the laboratory as a function of microwave frequency, salinity, and water content. The soil moisture strongly affected the real part of dielectric constant /spl epsiv/'. The frequency and the salinity of soils have little influence on the real part of dielectric constant /spl epsiv/'. The imaginary part of the dielectric constant /spl epsiv/'' is strongly affected by both the salinity and moisture of soil samples, especially at low frequencies. When f<2 GHz, the imaginary part /spl epsiv/'' decreases with each increment of frequency; in contrast, at higher frequencies, /spl epsiv/'' tends toward a constant. The results show that in the frequency range of 1-6 GHz, the imaginary part /spl epsiv/'' has greater sensitivity to soil salinity. Therefore, C and L band are more suitable for soil salinity detection, but L band is better than C band. The dielectric constant measurements for soil samples collected in Jilantai Salt Lake are in agreement with the results of the artificially moistened and salinized laboratory soil samples. These dielectric measurements were subsequently compared with the /spl sigma//sup 0/ backscattering coefficients extracted from a RADARSAT image (C-HH) that was acquired at same time with the soil sampling at the Jilantai Salt Lake area. We discovered that the correlation coefficient between /spl sigma//sup 0/ extracted from the RADARSAT image and /spl epsiv/" measured in the soil sample is 0.70, whereas the correlation coefficient of /spl sigma//sup 0/ and /spl epsiv/' is 0.27. The correlation coefficient between /spl sigma//sup 0/ and the soil sample salinity is 0.69. This suggests that soil salinity has a significant contribution to the backscattering coefficient /spl sigma//sup 0/ recorded in a synthetic aperture radar (SAR) image. Consequently, a SAR image can be a useful tool for monitoring soil salinity.

Using the Vector Microwave Network Analyzer in broad band (from 0.2 to 18 GHz), a controlled laboratory experiment was conducted on artificially prepared wet saline soil samples. The complex dielectric constants of soil samples in a wide range of moisture and salinity contents were measured and the relationship to the moisture and salinity of the soils were analyzed. The experiment results shows that the imaginary part of the dielectric constant of wet soil is more sensitive to the salinity of soils at low frequency range (f<5 GHz). It indicates that L band or P band SAR can be more effective in soil salinity detection. Secondly, 41 soil samples were collected along a profile from a dried salt lake in late April of 2001. Their moisture and salinity vary along the profile differently. The Vector Microwave Network Analyzer measured the complex dielectric constants of the collected soil samples in laboratory. C band, HH polarization RADARSAT data were simultaneously acquired on April 23, 2001. The backscatter intensity taken from RADARSAT image correlates with the complex dielectric constant. The correlation coefficient between the backscatter intensity and the real part of the complex dielectric constant is 0.23, and the imagine part of the complex dielectric constant is 0.66. This result shows that SAR will contribute to salinity monitoring program.

In this study, an established microwave backscatter model is used to predict the radar backscatter behavior of rice and to understand the interaction between backscatter and the rice canopy during its growth cycle. The emphasis of this study is to understand the effect of physical plant parameters on the backscatter signatures as a function of polarization and how these signatures vary during a complete growth cycle of rice. Inputs to the backscatter model included the physical parameters of rice as obtained through field measurements. These measurements were acquired within a few days of multiple RADARSAT acquisitions of the Zhaoqing test site in southern China. RADARSAT observations and the modeling results were then compared and analyzed. The results show that the interaction mechanisms change during the nice growth cycle and that polarimetric and/or multi-polarization measurements at C-band will contribute to rice monitoring programs.

Grove Mountains locates to the southwest of Princess Elizabeth Land, inland areas of east Antarctica. Field Work in Grove Mountains is very difficult. Interferometric SAR is a powerful tool in DEM generation, vertical change detection and determining the velocities and directions of ice streams. After the field GPS/RTK surveying work in Grove Mountains during the 1999/2000 summer season, we got the topographical map. Further research about Grove Mountains is ongoing. With the tandem radar image of ERS-1/2 in 1996.2, we generated DEM of this region.

Some results of analysis conclude that the internal wave can affect the sea wind-generated wave crucially, so that the spectrum accounts for the interactions between the two kinds of sea water masses. These backscattering coefficients of the internal wave sea surface of the South China Sea are calculated using some existing models and the results are compared with the calculations of SIR-C/X-SAR data. Different results among the radar bands exist and are affected by sea surface roughness. The ocean wave spectrum is derived from the X-SAR image. Finally, we point out that the tidal current is the main factor that causes the internal waves.

After the mosaic and geometric correction of 6 scenes of TM data, this paper analyzes the distributions of the strata exhibited in the Kalpin area, which underlie the precise interpretation of the structure. Integrated SIR-A data analysis and processing with field surveys, the information of secondary order structure and the borderline of geological bodies under shallow sediments are analyzed in this paper. The movements and the planar reappearance of the thrust sheets implies a Kalpin area strike sinistral slip of E-W and NE trend in a N-S trend compressional tectonic setting, which indicates the deformation frame and its kinematic process. Combined with the new advances of structural geology, the structure deformation features are described in detail, and strike-slip fault related models and GIS techniques are applied in the precise interpretation of the planar structures in Kalpin orogeny. Therefore, the structural shortening of sinistral slip is calculated precisely using the remote sensing data, which provide us with a new quantitative means for planar structure research.

This paper presents the modeling results of dielectric constants from different rice growth stages in Zhaoqing test site using Debye-Cole dual-dispersion model of vegetation. In the test site, two crops of early season rice and late season rice are planted in 1997 and 1996, and the growing period of rice crop is divided into five major stages: transplant, seedling developing, ear differentiation, heading and mature period. Based on the results, the paper discussed the influences from microwave frequency, gravimetric moisture content of rice, temperature, salinity and bulk density of dry vegetation materials on dielectric constant. The rice crops of different growth stages have the various dielectric constants, and the dielectric constants of early and late season rice crops show the diverse changes. The parameters, including in microwave frequency, gravimetric moisture content of rice, temperature and bulk density of dry vegetation materials, made the influence on dielectric constant, but salinity had no effect on the dielectric constant.

A novel edge detection algorithm for remote sensing images, which combines the image gray level gradient and the fractal self-similarity character of image edges based on fractal theory, is introduced. The self-similarity coefficient between the element block and the local block, which are both centered at the current pixel being processed, in addition to gray level gradient decision-making criteria, are used to make the decision about the existence of image edges. A binary operator is then used to threshold its magnitude and produce the edge map of the image. The results of the experiment are presented which show the effectiveness and the noise resistance of the proposed new algorithm for remote sensing image edge detection.

Urban 3D visualization is an exciting domain, with a growing number of important applications. Researches on VR (Virtual Reality) and GIS (Geographic Information System) provide strong technological support for real-time visualization of urban scenery. This paper focuses on the interconnection and interoperability between urban 3D visualization technology and GIS, including a scheme to exchange data between the GIS database and rendering engines for visualization, navigation and manipulation. A virtual scene of IRSA (Institute of Remote Sensing Applications), based in Beijing, China, which shows a fusion between urban 3D visualization and GIS is presented and realized.

Detailed outcrop data of the bed attitudes combining with the fault-related folding theory can help interpret the seismic profiles precisely according to the algorithm of the geodesic line. This paper propose a new means to acquire the structure strike and dip data from the remote sensing data, by which constrain geological structures in three dimensions using the fault related fold models. Here, the new numerical method is introduced for the first time to measure the strike and dip of bedding using the declassified high resolution images acquired by the optical satellite Corona. The attitude data derived from the remote sensing datasets are consistent with the direct measurements in the field survey in Kuqa rejuvenated foreland basin of Tarim Basin, northwest of China, and also can be used to help interpret the seismic profiles and constrain the complex structure in the foreland basin area. Therefore, the method presented will contribute a lot to the interpretation of the seismic profiles for petroleum exploration and will play an important role in the geological exploration and prospecting, especially in the area at the initial stage of the geological reconnaissance with great advantages of low expenses and rapidity.