摘要:

System albedo is an important climatological and environmental parameter. This paper discusses some of the problems and assumptions involved in evaluating albedo from satellite data. Clear-sky and cloud albedoes over the United Kingdom and parts of north-west Europe are examined. Spectral, temporal and spatial variations and the effect of averaging are considered. The implications of these results for those currently using and archiving albedo values and for future monitoring of system albedo are discussed.

ISSN:0143-1161    

DOI:10.1080/01431168208948375

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Previously established results of Craig (1976, 1979) and Craig and Labovitz (1980) demonstrated that Landsat data are autocorrelated and can be described by a univariate linear stochastic process known as an auto regressive integrated moving average model of degree 1, 0, 1, or ARIMA (1, 0, 1). This model has two coefficients of interest for interpretation: φandθ In a comparison of Landsat Thematic Mapper Simulator (TMS) data and Landsat MSS data several results are established:(1)The form of the relatedness as described by this model is not dependent upon system look angle or pixel size.(2)The coefficient φ increases with decreasing pixel size and increasing topographic complexity.(3)Changes in topography have a greater influence upon φ than changes in land cover class.(4)Theθ seems to vary with the amount of atmospheric haze. These patterns of variation in φandθ are potentially exploitable by the remote sensing community to yield stochastically independent sets of observations, to characterize topography, and to reduce the number of bytes needed to store remotely sensed data.

ISSN:0143-1161    

DOI:10.1080/01431168208948376

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This paper deals with the approximation of probability density functions with dependent feature trees. The optimal dependent feature trees are proposed to be constructed using criteria of mutual information and distance measures. Expressions are derived for the criteria when the distributions of the features are Gaussian. Expressions are developed for the covariances between the features connected by a path in a dependent feature tree. The case when the nodes in a dependent feature tree represent a set of features is also considered. Furthermore, experimental results from the classification of remotely sensed multispectral scanner imagery data are presented.

ISSN:0143-1161    

DOI:10.1080/01431168208948377

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The registration of Landsat images is important for multitemporal classification and for detecting change. Landsat data are now rectified to a ground coordinate system during preprocessing, hence scenes obtained over the same area are registered. The machine responsible for preprocessing the Landsat multispectral scanner data is the master data processor (MDP). This paper describes the rectification approach taken by the MDP, reviews the accuracy standards of the resultant product, and provides an assessment of the accuracy of the scene to scene registration of two Landsat images.

ISSN:0143-1161    

DOI:10.1080/01431168208948378

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The use of contextual information to identify areas of cloud and cloud shadow in digital Landsat data is described. The distance from cloud to shadow is calculated from sun elevation and azimuth, cloud base height and image geometry. Pixels with a grey level above a given threshold (Tc) are considered to be potential cloud. A 3 × 3 pixel window centred at the calculated shadow position is searched. Pixels in this window with grey levels below a second threshold (Ts) are classed as cloud shadow. If no shadow pixels are found the potential cloud is rejected. Modifications to allow for overlapping cloud and shadow are included

ISSN:0143-1161    

DOI:10.1080/01431168208948379

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A simple method has been developed for estimating wave height from synthetic aperture radar 7lpar;SAR) imagery obtained by the Seasat satellite. The method is based on measuring the contrast of the image and the wavelength of the dominant wave. A calculation has been made for two orbits made by the satellite over the North Atlantic in 1978, using digitally processed data supplied by DFVLR in West Germany. Comparison with sea truth measurements shows agreement to within about 20 per cent.

ISSN:0143-1161    

DOI:10.1080/01431168208948380

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Two cases of GOES digital infrared data were analysed during the three-hour period immediately prior to the tornado touchdown times. Clouds associated with tornadoes were compared to those without tornadoes using a combination of satellite infrared and rawinsonde data. On the basis of this limited data sample, it appears as if the altitude to which the overshooting cloud top penetrated above the tropopause is the factor which determines whether or not a tornado is formed. In these cases, the over-shooting cloud top collapsed about 15 to 30 min before the tornado touchdown.

ISSN:0143-1161    

DOI:10.1080/01431168208948381

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168208948382

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168208948383

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168208948384

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor