ISSN:0143-1161    

DOI:10.1080/01431169308904330

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An exemplary approach using Landsat Thematic Mapper data is presented, which allows us to monitor vegetation changes under the aspects of urban planning in Saudi Arabia. As a test site, the city of Al Madinah was chosen. TM data of two different acquisition dates were merged via intensity/ hue/saturation (IHS) processing to present directly the bi-temporal variations within one image product. The image product is analysed in terms of geoscientific application and its significance is discussed. Finally, how the method presented could be integrated into a possible operational vegetation monitoring system of selected regions in Saudi Arabia, is outlined.

ISSN:0143-1161    

DOI:10.1080/01431169308904331

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper investigates the potential of using vegetation index profiles from AVHRR data to monitor crop yield. A retrospective study and predictive study is presented, for 1986-1988 and 1989 respectively, for an area in Northern Greece. Results are encouraging for operational crop monitoring. Yield for wheat, cotton, rice and maize crops has been estimated to a high degree of accuracy using a simple linear relationship between NDVI and yield. However input from an agro-meteorological model is recommended to modify the model during the grain-filling period of the wheat crop. The estimates stabilize 50-100 days prior to harvest enabling an early assessment of crop yield to be made.

ISSN:0143-1161    

DOI:10.1080/01431169308904332

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper presents the possible contribution of multi-temporal Landsat Thematic Mapper (TM) data to the assessment of land-use modifications in the most important portion of the metropolitan area of Milan where rapid transformations, starting from urban areas and then gradually extending to rural areas, took place. The study area corresponds to the so-called ‘Great Milan’ which includes a protected area, the ‘South Milan Agricultural Park’, where a widespread conflict between agricultural and-urban land use has arisen. Park realisation will contribute improving agricultural activities and creating a belt for environment protection around the city. Digital thematic maps, digitizing Istituto Geografico Militare dTtalia cartography of 1888–90 and 1945–50, were extracted. Normalized Difference Vegetation Indices (NDVI) were produced from three Landsat-5 Thematic Mapper images of 1984, January, June and August, and a Multi-temporal Colour NDVI Composition (MCNC) output was produced. Maximum Likelihood Classification for land use mapping was applied both on MCNC data jointly with band 5 of June, and on 12 April 1990 Landsat TM image. Classification accuracy was assessed and results summarized. An historical analysis of land-use changes from XIX century up to today was performed by comparison of different surface classes from historical (1888–90 and 1945–50) and satellite (1984 and 1990) thematic maps. Results confirm the useful contribution of satellite remote sensing studying land-use/land-cover modifications in areas affected by phenomena of agriculture rapid transformation and residential or industrial development.

ISSN:0143-1161    

DOI:10.1080/01431169308904333

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The spectral distribution of water surface reflectance, in the visible region (0.4-0.7 µm), has been numerically estimated, for various concentration profiles of suspended matter in water, including contributions from yellow substances, chlorophyll and mineral sediment. Mie theory for light scattering, has been used to estimate extinction, scattering and absorption coefficients for a system of suspended spherical particles characterized by Junge size-distribution and containing absorbing and non-absorbing components. Significant changes in the shape of the simulated spectral reflectance have been obtained when the suspended sediment distribution in the water column, extending from the surface to the light penetration depth, varies. The preliminary theoretical results presented seem to sustain the possibility of retrieving sediment depth profile from remote sensed spectral data.

ISSN:0143-1161    

DOI:10.1080/01431169308904334

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A sequence of surface pigment images of the 1980 phytoplankton spring bloom on the Grand Banks of Newfoundland was derived from the Nimbus-7 Coastal Zone Color Scanner. This data set was augmented with shipboard observations of physical and biological data to examine spatial and temporal variability of the surface pigment fields. Ship-to-satellite comparisons were performed along a transect at 47° N and a regression was model developed for estimating satellite chlorophyll. The satellite imagery indicates upwelling events and rapid development of the spring bloom. A large bloom ofGymnodiniumdinoflagellates was observed offshore in autumn. As the season progressed, water column stratification increased and phytoplankton cell size diminished, resulting in a fairly abrupt increase in production:biomass and carbon:chlorophyll ratios. The next step would be to incorporate physical processes in a combined remote sensing/ship study to further explain biological production processes on the Grand Banks.

ISSN:0143-1161    

DOI:10.1080/01431169308904335

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Results are reported from a series of remote sensing investigations into the marine discharge of cooling water from a coastal power station complex. Qualitative observations and analyses of the spreading behaviour of the thermal discharge are presented for a range of tidal states, using ATM data from a series of aircraft overflights of the site. It is demonstrated that, under ebb flow conditions, the discharges from two adjacent outfalls are merged into an integrated surface plume in the far-field, and that the plume behaves subsequently as if generated by a single source. It is shown that the lateral spreading of the plume is inhibited significantly by coastal attachment and local thermal forcing and cross-flow effects. Calibrated overflight data from the thermal infrared bands have been used to quantify the unimpeded offshore spreading, and estimates are presented of the transverse turbulent diffusion coefficient ϵt, for the site in question. Values of ϵt, thus derived are shown to be in satisfactory agreement with estimates made directly at similar sites. Evidence is also presented to show how the presence of suspended sediment in the receiving waters, and the entrainment of bubbles and debris on the surface, can lead to the detection of the thermal discharge in visible and infrared spectral bands.

ISSN:0143-1161    

DOI:10.1080/01431169308904336

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The paper investigates the physics of radar backscatter across sea surface temperature fronts using a simple drag model followed by actual airborne radar observations. The model predicts large changes in radar cross section for low wind speed conditions. The X-band (9–43 GHz) Real Aperture Radar (RAR) observations in the vicinity of the sea surface temperature fronts show that radar cross-section variations are largely dependent on the local wind direction with respect to the front and the change in wind stress response at the front and feedbacks from the larger scale buoyancy driven circulation. Other radar imaging mechanisms are discussed.

ISSN:0143-1161    

DOI:10.1080/01431169308904337

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Abstract. Mathematical morphology seems to provide a consistent framework for an automatic analysis and description of sea ice geometry that is accessible from remote sensing imagery. This paper reviews basic concepts of the actual theory used and illustrates it by several examples based on a digitized video image, a digitized aerial photograph and a SPOT image. By means of morphological operations, floe size distributions are estimated automatically and related to fractal dimensions. The paper outlines a fast algorithm to trace single ice floes surviving in an image time sequence. The technique can be extended to monitor ice floe breakup. The analysis is performed exclusively on the basis of information about the relative order of pixel values. Physical considerations are kept to a minimum.

ISSN:0143-1161    

DOI:10.1080/01431169308904338

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper discusses basic mathematical formulations to clarify the problem of automatic segmentation of sea-ice remote sensing imagery. The work is illustrated with a SAR image. The main issue is a robust and automatic analysis of sea-ice conditions from remotely sensed data. The paper reveals some of the potential and essential features that are hidden in a class of filters often known as simple ‘shrink and expand operators’. The intensity of radiation from the ground is idealized as a measure which may have singularities. Absolutely calibrated digital images represent this measure where the measurable set are restricted to unions of picture elements. A related proposed martingale stopping time scheme makes image segmentation robust to changes in resolution. Tunable segmentations based on mathematical morphology can be controlled to give optimal ‘physically proper’ sets which are independent of calibration. This approach introduces physical knowledge, time aspects, and random geometry to the problem of image segmentation.

ISSN:0143-1161    

DOI:10.1080/01431169308904339

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor