J. M. Anderson

Review Article.The physical basis of current infrared remote-sensing techniques and the interpretation of data from aerial surveys

Abstract The range of infrared (IR) detectors at present available is described and a comparison is made between their performances with reference to particular applications. Due to the increasing availability and use of IR sensors the problems involved in data interpretation are becoming more widely acknowledged. Hence the major part of this paper is devoted to a detailed survey of these problems and offers a guide to those wishing to use IR data either quantitatively or qualitatively. Throughout, special reference is made to airborne IR surveys and their application to building heat loss.

The application of remote sensing data in the study of effluent dispersal in the Tay estuary, Scotland

Abstract The results of a remote sensing study have been correlated with previous research on estuarine mixing processes and with ground sampling investigations to appraise the dispersal of effluent in the Tay estuary. The advantages of using remote sensing techniques to study the distribution of convergent fronts and their effect on the dispersal of effluent are demonstrated. The application of remote sensing data in the study of the near-shore dispersion from outfalls and the short-term dispersal behaviour of outfalls are discussed with reference to two particular sewer outfalls. The results of the remote sensing studies correlate highly with ground studies of the same areas. A modified simulation model of the flushing capacity of the Tay estuary has been developed incorporating the results of the remote sensing study. The results of the model are very similar to those calculated from a physical model. The preliminary results of a study to integrate urban hydrological and outfall dispersal models with r...

The applicability of LOWTRAN 5 computer code to aerial thermographic data correction

Abstract The data available in the LOWTRAN5 computer code are applied to short path lengths for radiation in the thermal infrared range during a particular survey. The resulting calculated value for the atmospheric transmittance is compared with an experimentally derived value.

Cover Remote sensing observations of a vortex street downstream of an obstacle in an estuarine flow

(1996). Cover Remote sensing observations of a vortex street downstream of an obstacle in an estuarine flow. International Journal of Remote Sensing: Vol. 17, No. 1, pp. 1-8.

The quantitative use of Airborne Thematic Mapper thermal infrared data

Abstract Daedalus Airborne Thematic Mapper ( ATM) data, obtained between 12.14GMT and 13.44GMT on 19 June 1984 as part of the Natural Environment Research Councils Airborne MSS-84 campaign, have been used to calculate sea surface temperatures in the western English Channel. Quantitative analyses of the thermal infrared data are discussed with particular reference to boat trials and eddy structures. A method to calculate brightness temperatures and their associated errors is also discussed along with a review of two atmospheric correction procedures for the estimation of sea surface temperatures from thermal infrared data. An apparent asymmetry in the thermal infrared data is considered in the context of the atmospheric correction model used. Results show that the asymmetry can be compensated by using an effective scanner tilt angle.

A thermal plume in the Tay estuary detected by aerial thermography

Abstract The appearance of a small thermal plume detected on two successive overflights by an airborne infrared scanner operating in the 8-12 μm band is described. The spatial and temporal resolution achieved is discussed with reference to applying this technique to plumes from sewage outfalls and power stations.

Geometric processing of hyperspectral image data acquired by VIFIS on board light aircraft

The Variable-Interference-Filter Imaging Spectrometer (VIFIS) is an airborne imaging system. Unlike usual airborne spectrometers, the image acquisition of VIFIS is based on 2D sensors with its pixel spatially registered to different passing wavelengths. The correction of perturbations upon the VIFIS platform, required by the hyperspectral image generation, relies solely on the information extracted from the 2D pushbroom image flow. In this paper, we present an analysis of the distortions of the pushbroom scan caused by perturbations upon the platform. Hyperspectral image generation algorithms and band registration methods are also discussed. A practical pre-processing approach is developed to automatically track the displacements and generate up to 64 hyperspectral bands. Finally, a pre-processing example is presented as a demonstration of the overall methodology.

The thermographic survey of central Scotland

Abstract We describe the extent and format of the thermographic survey of central Scotland underwritten by the Scottish Development Agency. The geographical areas covered, meteorological conditions demanded and presentation of data are described and a selection of typical results illustrated.

Cover: Observing estuarine currents and fronts in the Tay Estuary, Scotland, using an airborne SAR with along track interferonmetry (ATI)

Estuaries are extremely dynamic environments where large and frequent changes in bathymetry and channel locations can occur. Because estuaries are major centres of population and industry, there is an ongoing requirement to monitor and predict changes in the current fields. The tidal range, surface wind speed, atmospheric pressure, fresh water inflow and most importantly the stage of the tidal cycle affect the flow vectors. Existing boat‐based methods are unable to provide measurements of current fields with sufficient spatial and depth coverage for accurate modelling of hydrodynamic processes in estuaries. Remotely sensed data offer more extensive, synoptic, spatial coverage. However, previous studies to map the full details of the current field based on conventional optical and thermal imaging have been limited by insufficient temporal coverage and the lack of identifiable features that can be tracked. Synthetic aperture radar (SAR) imaging with along‐track interferometry (ATI) has the potential to overcome both of these limitations because it can retrieve quantitative measurements of sea surface state parameters and instantaneous surface flow from a single pass over a whole estuary. The preliminary results of ATI observations over the Tay Estuary, Scotland, validated with coincident in situ boat based observations, are presented here.

Recognition of an overspill-induced estuarine frontal system in the Ria do Barqueiro, north-west Spain, using remote sensing techniques

Abstract Rising tidal waters breach a channel-bounding spit at mid-tide to carry cool, saline waters into the ebb-dominant channel of the Ria do Barqueiro. Foam lines form an evolving pointed and curving pattern bounding more and less saline waters, and mark the surface limits of the intrusive front. Repeated measurement by radiometer demonstrate the initial presence of three thermally identifiable water masses, at I6.5°C, 17.5°C and 19.8°C, and the homogenization of temperature in less than half an hour.