摘要:

The western margin of the Greenland ice sheet near Jakobshavn has retreated rapidly during the past 100 years. A vegetation trim line which marks the position of the ice marginc. AD 1880 can accurately be identified from LANDSAT MSS imagery. The possibility of identifying other former ice margin positions from satellite data opens up exciting prospects for geomorphology, glaciology, and the study of global climatic and environmental change.

ISSN:0143-1161    

DOI:10.1080/01431168708954749

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168708954751

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168708954752

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The use of a portable video-based airborne thermal sensor for thermal mapping of roads is described. The design and operational characteristics of the Barr and Stroud IRI8 thermal video frame scanner are discussed together with image processing requirements for a project of this nature. Finally, a summary of the results obtained for a project carried out in the Lothian region of Scotland is presented.

ISSN:0143-1161    

DOI:10.1080/01431168708954753

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The difference of the vertically and horizontally polarized brightness temperatures observed by the 37 GHz channel of the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7 satellite are correlated temporally with three indicators of vegetation density, namely the temporal variation of the atmospheric CO2concentration at Mauna Loa (Hawaii), rainfall over the Sahel and the normalized difference vegetation index derived from the Advanced Very High Resolution Radiometer (AVHRR) on board the NOAA-7 satellite. We find the SMMR 37GHz and AVHRR provide complementary data sets for monitoring global vegetation, the 37 GHz data being more suitable for arid and semi-arid regions as these data are more sensitive to changes in sparse vegetation. The 37 GHz data might be useful for understanding desertification and indexing CO2exchange between the biosphere and the atmosphere.

ISSN:0143-1161    

DOI:10.1080/01431168708954754

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An expression is presented for the Doppler FM rate for a radar in circular orbit that has been derived with no restrictive assumptions on the relative motion of the scatterer, which is fixed in Earth coordinates. The result is expressed in spacecraft-relative variables. The SAR case and the geosynchronous limit are briefly discussed.

ISSN:0143-1161    

DOI:10.1080/01431168708954755

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A simpie structural backscatter model for a forest stand, suitable for use with L-band HH polarized radar imagery, is used to explain the increased level of backscattering observed from flooded forests. Measurements made of relative levels of backscatter from SIR-B image data of a flooded Australian forest are consistent with an interpretation based upon scattering mechanisms involving both the tree components and the understorey or forest floor. The change in Fresnel power reflection coefficient of the ground with flooding is advanced as the cause of the enhancement in backscattered power levels.

ISSN:0143-1161    

DOI:10.1080/01431168708954756

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Analysis of Landsat Thematic Mapper (TM) image of 14 May 1984 has shown that such data can be used to survey vegetation and sediment distributions in the intertidal zone of the Wash estuary at a spatial detail comparable with current methods practised by the.Nature Conservancy Council. Multispectral classification of this TM image showed good separation of salt-marsh vegetation communities which had recently been surveyed by the Nature Conservancy Council and for which reliable training data could be taken. The sensitivity of classification performance, using both parametric and non-parametric algorithms, to apparently minor differences in phenology at training site locations demonstrates two requirements for improved salt-marsh classification. They are the need for strict definition of training data and that TM wave bands 2, 3, 4 and 5 provide suitable spectral vectors for classifying intertidal environments.

ISSN:0143-1161    

DOI:10.1080/01431168708954757

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This letter discusses the need for accurate processing of airborne multispectral data for vegetation studies. The processing includes radiometric and atmospheric corrections and allowances for environmental influences on the data. A methodology for such corrections using easily available collateral data is described and successfully applied to airborne multispectral data recorded in the Bawtry area of South Yorkshire, England.

ISSN:0143-1161    

DOI:10.1080/01431168708954758

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor