ISSN:0143-1161    

DOI:10.1080/01431169608949131

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper describes two different methods which integrate contextual information in a classification process. This process aims to refine the map products given by the application of a common parametric classification algorithm. The first method is the well known Supervised Relaxation Algorithm, and makes use of the first classification, with additional contextual information. The contextual information is derived either from texture features or from other map products introducing additional information on the existing land use classes. The second method is a knowledge-based system, which makes use of image and geographical context rules. The probability figures, derived from the image classifier and the rule base are combined by the use of the Dempster-Shafer reasoning scheme. Experiments using satellite data from the Loir et Cher region (Central France), together with the appropriate ground truth data, have shown that both methods return improved classification products in terms of thematic and statistical accuracy, compared to using a parametric: image classifier alone.

ISSN:0143-1161    

DOI:10.1080/01431169608949132

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The relationship between the instrument engineering parameters and the geophysical parameters derived from a multi-frequency microwave radiometer is considered in this paper. A model is described that simulates the performance of this type of instrument and shows how the overall accuracy of the instrument is reflected in the geophysical parameter derived. This, model includes the geometric and physical aspects of the instrument, radiometric parameters and the errors associated with the instrument antenna. Wind speed is considered as an example of a derived geophysical parameter.

ISSN:0143-1161    

DOI:10.1080/01431169608949133

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The impact of spatial resolution enhancement on pattern recognition based on SSM/I measurements is evaluated. The instrument ground footprints for the 19, 22 and 37 GHz channels have considerable overlap. An objective technique can be applied to enhance spatial resolution of measurements to the spatial resolution of the 37 GHz channel. The authors utilize a Backus-Gilbert matrix transform approach. Different validation procedures have been performed to demonstrate the effectiveness of the method with the aim to ameliorate the boundary detection on pattern recognition and specially to cloud classification improvement.

ISSN:0143-1161    

DOI:10.1080/01431169608949134

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Monte Carlo simulations of photon propagation through natural water have been utilized to determine the sub-surface remote sensing reflectance,RRSW(the sub-surface value of the ratio of upwelling radiance from the nadir to the downwelling irradiance) as a function of water type (defined by the ratio of the backscattering coefficient to the absorption coefficientBb/a), solar zenith angle, and incident radiation distribution (direct or diffuse).RRSW, as opposed to volume reflectance,RV(the sub-surface value of the ratio of upwelling to downwelling vector irradiance), is directly applicable to remotely sensed data collected over natural waters. It is shown that, for a nadir viewing direction, (a)RRSWis essentially independent of solar zenith angle and incident radiation distribution and (b) the dominant factor in determiningRRSWis the optical nature of the water body itself (expressed asBb/a). A relationship between the sub-surface remote sensing reflectance averaged over solar zenith angle between 15° and 89°,RRSWand water type is found to predictRRSWwith an r.m.s. error of 9 per cent. Also addressed is the determination of the aquatic optical property,Bb/a, from the sub-surface remote sensing reflectance,RRSWThis capability along with the specific absorption and scattering coefficients of aquatic constituents can, through bio-optical models, be used to estimate the concentrations of these aquatic constituents in non-Case I waters. The empirical relationship obtained to estimateBb/a(with a r.m.s. error of 9·3 per cent) from the nadir value of the sub-surface remote sensing reflectance isBb/a= 0·0027 + 987RRSW− 34·5(RRSW)2+ 1534(RRSW)3.

ISSN:0143-1161    

DOI:10.1080/01431169608949135

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

For an area near Ocean Weather Station P in the eastern subarctic Pacific,in situobservations of surface phytoplankton pigment are compared to pigment concentration estimates from the Coastal Zone Color Scanner (CZCS). CZCS data favourably supplement thein situdata, but a few extreme CZCS estimates have erroneously elevated the temporal composites of the region in the NASA Global Data Set. Effects of CZCS subsampling, atmospheric correction, cloud and systematic error detection on accuracy and variability are examined. For the open ocean, accurate atmospheric correction and detection of cloud contamination are the most important requirements for quantitative application of CZCS data.

ISSN:0143-1161    

DOI:10.1080/01431169608949136

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The capabilities of optical and microwave satellite remote sensing for snow cover monitoring and forecasting snowmelt run-off are critically evaluated in this paper in order to improve the utilization of water resources from high mountainous catchments in the Italian Alps. Integration of snow cover data derived from visible and infrared satellite sensors is made with ground meteorological and hydrological information for three elevation zones of the Cordevole river basin of Alpine arch in eastern part of Italy. Digital image processing of nine sets of Landsat Multi-spectral Scanner System and Thematic Mapper computer compatible tapes (CCTs) representing a hydrological year have been made. Digital elevation model, slope and hill shading maps were generated and used in the study. The snow cover estimated using supervised maximum likelihood classification algorithm was observed to fit well for the Cordevole river basin model study when compared to the parallelepiped and minimum distance methods of classification. The elevation zones were classified into snow, mixed snow and aper. Daily snow cover depletion has been obtained with an approximation of second order polynomial fit to the satellite derived snow cover data. A deterministic, semi-distributed, temperature index model has been used to simulate the daily streamflow hydrograph for the snowmelt season. The simulated run-off satisfactorily approximated the measured run-off both in terms of time distribution and volume. Model performance evaluation using correlation coefficient, Nash-Sutcliffe coefficient and percentage volume deviation has indicated good results when compared to the test basins of World Meteorological Organization.

ISSN:0143-1161    

DOI:10.1080/01431169608949137

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Crop production assessments are extremely valuable because of their economic importance in influencing international trade and national economic policies. This study investigates using the Vegetation Condition Index derived from NOAA/AVHRR satellite data to estimate the maize production for the United States Corn Belt. Satellite data from 1985 to 1992 are utilized within a model and explain more than 50 per cent of the variation in the normalized yields from 42 Crop Reporting Districts. Results estimating the regional maize production are encouraging, and operational estimates using this model would be available for about two months prior to the maize harvest in the Corn Belt.

ISSN:0143-1161    

DOI:10.1080/01431169608949138

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

ERS-1 wind scatterometer (WSC) data is analysed over a wide range of terrain types for the period May 1992-April 1994. Comparison is made with Global Vegetation Index (GVI) data for the monitoring of vegetation dynamics. Results show that WSC data display a well-pronounced seasonality over most vegetated surfaces. The highest sensibility to vegetation dynamics is found over semi-arid regions and boreal zones. In these two cases, there is a marked seasonality in environmental parameters which is well depicted by σ0temporal profiles. However, the sensibility of the ERS-1 response is much less pronounced over densely vegetated surfaces. In yspite of its low spatial resolution, the usefulness of a C-band scatterometer for monitoring vegetation dynamics is shown.

ISSN:0143-1161    

DOI:10.1080/01431169608949139

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

While many reports have been published on radar backscatter characteristics of coniferous and deciduous forests, little work appears to have been done on investigating the backscatter properties of palm trees. In this study, Japanese JERS-1LHHband, European ERS-1CVVband and Russian Almaz-1BSHHband SAR data have been acquired over parts of Kedah and Penang states in West Malaysia in order to investigate the radar backscatter properties for oil palms and rubber trees for each of these sensors.

ISSN:0143-1161    

DOI:10.1080/01431169608949140

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor