摘要:

Previous authors have reported on sea-state local variations detected by satellite in the 0.8-1.1 μm channel (Landsat MSS 7). We first demonstrate that in this channel the observed change in reflectance is mainly due to sea-state. We use the Cox and Munk model to compute the sea-surface reflection coefficient for various geometrical conditions, and it is found that this model fits previous observations. The model is then, applied to cases of Landsat and SPOT sensors, and some useful recommendations are underlined.

ISSN:0143-1161    

DOI:10.1080/01431168308948558

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Major constraints on the RBV system spatial and radiometric resolution are the optical limitations of the camera lens, the sensitivity of the vidicon, the system noise and the video sampling rate. The Landsat-3 RBV lens resolution limit is 21.45 m ground equivalent half-cycle. The Earthnet video sampling rate at 7.5 megasamples, gives an across track ground pixel size of 18 m. The along track pixel size is controlled by the number of scan lines in one frame (i.e. 4125), which gives a ground equivalent pixel size of 24 m. The MTF curve calculated from the RCA manual shows an EIFOV of 45.5 m. At 21.45 m ground equivalent half-cycle, the modulation transfer factor is 5.4 per cent which with a dynamic range of 64 quantizing levels gives a two or three level contrast between black and white linear ground targets (i.e. at the extremes of the dynamic range). In the panchromatic waveband with a white level saturation at 2.013 mW/cm2-sr, most ground cover types will occur within the first 50 per cent of the dynamic range. Given the Earthnet quantization step size to r.m.s. noise ratio of 0.51, there is a 56 per cent probability of assigning a level to within ± 1 value of its correct level. This is assuming a Gaussian distribution for the system noise. The noise is equivalent to the MTF sensitivity of the system at the lens resolution limit. In this study no attempt has been made to quantify the additional noise introduced by the radiometric defects observed in the RBV data or atmospheric attenuation.

ISSN:0143-1161    

DOI:10.1080/01431168308948559

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Remote-sensing instruments allow values for certain properties of a target to be retrieved from measurements of radiation emitted, reflected or transmitted by the target. The retrieval accuracy is affected by random variations in the many target properties which affect the measurements. We describe how statistical properties of the target and theoretical models of its electromagnetic behaviour can be used to choose values for the instrument parameters which maximize the retrieval accuracy. The technique is applicable to a wide range of remote-sensing instruments.

ISSN:0143-1161    

DOI:10.1080/01431168308948560

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Atmospheric surface pressure can be remotely sensed from a satellite by an active instrument which measures return echoes from the ocean at frequencies near the 60 GHz oxygen absorption band. We optimize the instrument by selecting its frequencies of operation, transmitter powers and antenna size through a new procedure based on numerical simulation which maximizes the retrieval accuracy. The predicted standard deviation error in the retrieved surface pressure is 1 mb. In addition the measurements can be used to retrieve water vapour, cloud liquid water and sea state, which is related to wind speed.

ISSN:0143-1161    

DOI:10.1080/01431168308948561

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168308948562

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168308948564

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168308948565

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168308948566

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor