日本地球资源卫星一号(JERS-1)概况

介绍了日本地球资源卫星JERS-1的主要性能和技术设计概况,着重介绍了其有效载荷的性能和卫星平台的设计参数,最后对该卫星的飞行程序、研制进度和入轨初期故障的排除作了简要叙述。

Remote Sensing Monitoring of Tobacco Field Based on Phenological Characteristics and Time Series Image―A Case Study of Chengjiang County, Yunnan Province, China

Using three-phase remote sensing images of China-Brazil Earth Resources Satellite 02B (CBERS02B) and Landsat-5 TM, tobacco field was extracted by the analysis of time series image based on the different phenological characteristics between tobacco and other crops. The spectral characteristics of tobacco and corn in luxuriant growth stage are very similar, which makes them difficult to be distinguished using a single-phase remote sensing image. Field film after tobacco seedlings transplanting can be used as significant sign to identify tobacco. Remote sensing interpre- tation map based on the fusion image of TM and CBERS02B's High-Resolution (HR) camera image was used as stan- dard reference material to evaluate the classification accuracy of Spectral Angle Mapper (SAM) and Maximum Like- lihood Classifier (MLC) for time series image based on full samples test method. SAM has higher classification accu- racy and stability than MLC in dealing with time series image. The accuracy and Kappa of tobacco coverage extracted by SAM are 83.4% and 0.692 respectively, which can achieve the accuracy required by tobacco coverage measurement in a large area.

Study on Soil Gleization in Subtropic Region of China Using LBV Transformed Landsat Images

This paper describes a new type of transformed Landsat images (LBV images) and their application in discriminating soil gleization in subtropic region of China. LBV transformation was worked out by the present author for extracting useful information from original landsat images. Using this method three black and white images, L image, B image and V image, were computer generated from original bands of a Landsat scene, which covers a.large area of 34 528 km2 in Hubei and Hunan provinces in south China. Then a color composite was produced by these three images. This kind of black-and-white and color images contained rich and definite geographic information. By a field work, the relationship between the colors on the composite and the land use/cover categories on the ground was established. 37 composite colors and 70 ground feature categories can be discriminated altogether. Finally, 17 land use/cover categories and 10 subregions suffering from soil gleization were determined, and the gleization area for the study area was estimated to be 731.3 km2.

Glacier Fluctuations between 1975 and 2008 in the Greater Himalaya Range of Zanskar,Southern Ladakh

Glaciers in the Himalaya are often heavily covered with supraglacial debris,making them difficult to study with remotely-sensed imagery alone.Various methods such as band ratios can be used effectively to map clean-ice glaciers;however,a thicker layer of debris often makes it impossible to distinguish between supraglacial debris and the surrounding terrain.Previously,a morphometric mapping approach employing an ASTER-derived digital elevation model has been used to map glaciers in the Khumbu Himal and the Tien Shan.This study on glaciers in the Greater Himalaya Range in Zanskar,southern Ladakh,aims (i) to use the morphometric approach to map large debris-covered glaciers;and (ii) to use Landsat and ASTER data and GPS and field measurements to document glacier change over the past four decades.Field work was carried out in the summers of 2008.For clean ice,band ratios from the ASTER dataset were used to distinguish glacial features.For debris-covered glaciers,topographic features such as slope were combined with thermal imagery and supervised classifiers to map glacial margins.The method is promising for large glaciers,although problems occurred in the distal and lateral parts and in the fore field of the glaciers.A multi-temporal analysis of glaciers in Zanskar showed that in general they have receded since at least the mid-to late-1970s.However,some few glaciers that advanced or oscillated - probably because of specific local environmental conditions - do exist.

Spatio-temporal Variations in Plantation Forests'Disturbance and Recovery of Northern Guangdong Province Using Yearly Landsat Time Series Observations(1986-2015)

Forest disturbance plays a vital role in modulating carbon storage,biodiversity and climate change.Yearly Landsat imagery from 1986 to 2015 of a typical plantation region in the northern Guangdong province of southern China was used as a case study.A Landsat time series stack(LTSS) was fed to the vegetation change tracker model(VCT) to map long-term changes in plantation forests' disturbance and recovery,followed by an intensive validation and a continuous 27-yr change analysis on disturbance locations,magnitudes and rates of plantations' disturbance and recovery.And the validation results of the disturbance year maps derived from five randomly identified sample plots with 25 km^2 located at the four corners and the center of the scene showed the majority of the spatial agreement measures ranged from 60% to 83%.A confusion matrix summary of the accuracy measures for all four validation sites in Fogang County showed that the disturbance year maps had an overall accuracy estimate of 71.70%.Forest disturbance rates' change trend was characterized by a decline first,followed by an increase,then giving way to a decline again.An undulated and gentle decreasing trend of disturbance rates from the highest value of 3.95% to the lowest value of 0.76% occurred between 1988 and 2001,disturbance rate of 4.51% in 1994 was a notable anomaly,while after 2001 there was a sharp ascending change,forest disturbance rate spiked in 2007(5.84%).After that,there was a significant decreasing trend up to the lowest value of 1.96% in 2011 and a slight ascending trend from 2011 to 2015(2.59%).Two obvious spikes in post-disturbance recovery rates occurred in 1995(0.26%) and 2008(0.41%).Overall,forest recovery rates were lower than forest disturbance rates.Moreover,forest disturbance and recovery detection based on VCT and the Landsat-based detections of trends in disturbance and recovery(LandT rendr) algorithms in Fogang County have been conducted,with LandT rendr finding mostly much more disturbance than VCT.Overall,disturbances and recoveries in northern Guangdong were triggered mostly by timber needs,policies and decisions of the local governments.This study highlights that a better understanding about plantations' changes would provide a critical foundation for local forest management decisions in the southern China.

National Policy Change＇s Influence on the Landscape Pattern in Maoxian County

Landscape pattern analysis is becoming the core to study global or local change. Incorporated with fast, dynamic and precise spatial information technology, Landscape pattern analysis has been a foundation for the governments to make decision. In this paper, Maoxian county, located in the northwest of Sichuan Province, was selected as the study area. Landsat TM data in 1994 and Landsat ETM data in 2002, with dates are just same as the time of national policy changes, are classified to make the landscape patterns change. The result indicates that, from 1994 to 2002, owing to the policies of the project of wild wood resource protect and the project of returning land for farming to forestry （grass）, the forests has increased about 2.68%, Natural meadow has increased about 0.83%, Shrubby has increased about 0.63%, Farm land has decreased about 4.10% and the fragment of forests in 2002 is lower than in 1994. This states that the national policy actioned during 1990s have much positive influence on the landscape patterns in Maoxian county.

Evaluation of the retrieval of total suspended matter concentration in Taihu Lake,China from CBERS-02B CCD

Remote sensing techniques is used to quantify the total suspended matter concentration （CTSM）. In this study, we used remotely sensed data to retrieve the CTSM for the Taihu Lake, China, and developed an atmospheric correction algorithm especially for CBERS-02B CCD data. We simulated the remote sensing reflectance （Rr~） of CCD bands using in-situ observations made in a cruise over the Taihu Lake in autumn 2004, from which a retrieval model is established with simulated Rrs（830） and measured CTSM. In addition, we applied the atmospheric correction algorithm and retrieval model to process the CCD data over the lake in 2008 and to retrieve the CTSM. The RMS relative error between the CTSM retrieved from MODIS and from the CCD images is about 42.9%, indicating that algorithms described in this paper can be used for the application of CCD data in monitoring the CTSM distribution in the Taihu Lake.

Monitoring Local Impervious Surface Trends Using Indices Derived from Property Tax and Several Landsat Datasets

Human economic and social needs can be in conflict with ecosystem needs. Land development increases impervious surfaces causing significant negative impacts to aquatic ecosystems. Many impervious surface estimates are derived from remote sensing data, developed by using different methods and often out of date. Remote sensing data is often at scales applicable to regional management, but not local planning decisions. To date, no standardized annual dataset of percent impervious surface exists for use at both local and watershed scales. Effective communication between natural resource managers and local planners has been lacking. One solution is to monitor percent impervious surface with a relative index rather than direct measure. A relative index model can use a currency, like foundation square feet per hectare, which is useful for all decision makers. One data source for developing a relative index of impervious surface is property tax data. These data document annual land development at local scale. Here, the author presents the use of Maryland property tax data to index land development and percent impervious surface.

Analyzing the Relationship between Urban Patterns and Land Surface Temperature Using WorldView-2 and Landsat-ETM＋

Global climate destabilization as a result of the increased urbanization is one of today＇s most urgent issues. The detected urban heat island phenomenon in urbanized areas, combined with the decreased vegetation and the anthropogenic heat discharge, is an example of this climate change and in order to take proper actions to reduce this effect, the urban environmental analysis is more than necessary. This paper aims at analyzing and exploring the relationship between land uses of a densely populated urban area with the LST （land surface temperature） combining with WorldView-2 and Landsat ETM＋ satellite imagery. The available thermal band of the Landsat image is used to extract surface temperatures of the study area on a hot summer day. Continuously, the high resolution satellite image of WorldView-2 is used for extracting the land uses. Zonal statistics were applied highlighting the zones with high and low average temperatures. Additional statistical tests （correlation analysis, analysis of variance-ANOVA, etc.） were applied, for evaluating the interaction between the temperature results with the land use types.

Application of Remote Sensing for Mangrove Mapping： A Case Study of AI-Dhakira, the State of Qatar

In recent years, the pressure of increasing coastal industries and tourism activities has, in some areas, led to the clearing of many coastal habitats along the Qatar＇s shorelines for the construction of tourist resorts, tourism-related development and industrial facilities. Such threats are leading to the increasing demand for detailed mangrove maps for the purpose of measuring the extent of decline in mangrove ecosystems. Detailed mangrove maps at the community or species level are, however, not easy to produce, mainly because mangrove forests are very difficult to access. Without doubt, remote sensing is a serious alternative to traditional field-based methods for mangrove mapping, as it allows information to be gathered from the forbidding environment of mangrove forests, which otherwise, logistically and practically speaking, would be extremely difficult to survey. Remote sensing applications for mangrove mapping at the fundamental level are already well established but, surprisingly, a number of advanced remote sensing applications have remained unexplored for the purpose of mangrove mapping at a finer level. Consequently, the aim of this paper is to unveil the potential of some of the unexplored remote sensing techniques for mangrove studies. Temporal Landsat TM image of 1986, Landsat ETM image of 2000 and Resourcesat-1 LISS 3 image of 2008 are used to calculate percentage change in mangrove cover at AI Dhakira site using geometrically registered and radiometrically corrected historical Landsat and Resourcesat-1 images. Region masks are employed to isolate the unwanted area from the images. NDVI （normalized difference vegetation index） is used to detect mangroves using near-infrared and red bands which are computed from the satellite images. The ground-truthing visit to AI Dhakira site is conducted to confirm the results of the analysis. Change detection is applied and mangrove in the study area is found to have decreased by about 8.79% from 2000 to 2008.

Land cover change detection in West Jilin using ETM + images

In order to assess the information content and accuracy ofLandsat ETM+ digital images in land cover change detection,change-detection techniques of image differencing,normalized difference vegetation index,principal components analysis and tasseled-cap transformation were applied to yield 13 images. These images were thresholded into change and no change areas. The thresholded images were then checked in terms of various accuracies. The experiment results show that kappa coefficients of the 13 images range from 48.05 ～78.09. Different images do detect different types of changes. Images associated with changes in the near-infrared-reflectance or greenness detects crop-type changes and changes between vegetative and non-vegetative features. A unique means of using only Landsat imagery without reference data for the assessment of change in arid land are presented. Images of 12th June, 2000 and 2nd June, 2002 are used to validate the means. Analyses of standard accuracy and spatial agreement are performed to compare the new images (hereafter called "change images" ) representing the change between the two dates. Spatial agreement evaluates the conformity in the classified "change pixels" and "no-change pixels" at the same location on different change images and comprehensively examines the different techniques. This method would enable authorities to monitor land degradation efficiently and accurately.

China's lakes at present:Number,area and spatial distribution

Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported by 6843 digital raster images(1:100000 and 1:50000),a countrywide digital vector dataset(1:250000),and historical literature.Comparative data were corrected for seasonal variations using precipitation data.There are presently 2693 natural lakes in China with an area greater than 1.0 km2,excluding reservoirs.These lakes are distributed in 28 provinces,autonomous regions and municipalities and have a total area of 81414.6 km2,accounting for-0.9% of China's total land area.In the past 30 years,the number of newly formed and newly discovered lakes with an area greater than 1.0 km2 is 60 and 131,respectively.Conversely,243 lakes have disappeared in this time period.

Variations of the relativistic electron flux after a magnetospheric compression event

On January 21, 2015, a sharp increase of the solar wind dynamic pressure impacted the magnetosphere. The magnetopause moved inward to the region L< 8 without causing a geomagnetic storm. The flux of the relativistic electrons in the outer radiation belt decreased by half during this event based on the observations of the particle radiation monitor(PRM) of the fourth of the China-Brazil Earth Resource Satellites(CBERS-4). The flux remained low for approximately 11 d; it did not recover after a small magnetic storm on January 26 but after a small magnetic storm on February 2. The loss and recovery of the relativistic electrons during this event are investigated using the PRM data, medium-and high-energy electron observations of NOAA-15 and the Van Allen Probes, medium-energy electron observations of GOES-13, and wave observations of the Van Allen Probes. This study shows that the loss of energetic electrons in this event is related to magnetospheric compression. The chorus waves accelerate the medium-energy electrons, which causes the recovery of relativistic electrons. The Van Allen Probes detected strong chorus waves in the region L =3–6 from January 21 to February 2. However, the flux of medium-energy electrons was low in the region. This implies that the long-lasting lack of recovery of the relativistic electrons after this event is due to the lack of the medium-energy"seed" electrons. The medium-energy electrons in the outer radiation belt may be a clue to predict the recovery of relativistic electrons.