摘要:

Data from the NOAA-7 Advanced Very-High-Resolution Radiometer (AVHRR) have been used on a routine basis for sea surface temperature (SST) retrieval at the Centre de Meteorologie Spatiale (CMS) in Lannion (France) since September 1983. Operational SST retrieval is still practised at CMS, using NOAA-9 data. Two methods are used. The first, which is automatic, produces numerical fields (resolution: 15 × 15 nautical miles); the second is manual and produces graphic documents (resolution about 10 km). The corresponding products are published in a monthly bulletin,SATMER. The accuracy of satellite SSTs has been tested by various methods, the results of which are discussed. Some case studies of SST time variability in the Mediterranean are presented. One of the main conclusions is the need for mesoscale (10 km) numerical SST fields produced as often as possible (daily) by interactive methods.

ISSN:0143-1161    

DOI:10.1080/01431168608948903

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In this paper, the possibility of predicting sea-surface wind speed, given values for whitecap cover and other environmental parameters, is examined. The performance of a number of different techniques of statistical calibration is evaluated in relation to four data sets. The performance of the methods is also examined when they are applied to simulated data sets; robustness is a particular concern. Some general conclusions are drawn in relation to which of the methods are to be recommended for use.

ISSN:0143-1161    

DOI:10.1080/01431168608948904

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The applicability of an X-band (9·4 GHz) real aperture radar (RAR) and an infrared (IR) radiometer to discriminate between crude-oil spills and monomolecular sea slicks is investigated over the same sea area. The results from quasi-simultaneous overflights over a crude-oil spill and three different sea slicks (oleyl alcohol, di-(ethylenglycol)-mono-isostearyletherand methyl oleate)show that the advantage of an imaging radar is its uniequi vocal potential for surveying large sea surfaces and that the advantage of an IR sensor is its ability to determinate quickly the thick centres of crude-oil spills. However, neither the RAR nor the IR radiometer can discriminate between crude-oil spills and sea slicks. Therefore, an airborne coastal patrol with the objective of monitoring oil pollution must comprise a package of additional sensors, e.g. a microwave radiometer and/or a lidar system.

ISSN:0143-1161    

DOI:10.1080/01431168608948905

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Localized flow patterns in the vicinity of a headland-associated linear sandbank (the Scarweather Sands, northern Bristol Channel), cannot be detected in temporally averaged observations using conventional oceanographic measuring techniques. Airborne Thematic Mapper (ATM) data has been used previously to identify such patterns at one particular stage of a tidal cycle, using suspended sediments in the surface waters as passive tracers.

ISSN:0143-1161    

DOI:10.1080/01431168608948906

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Cloud observations from 124 surface stations for 12.00 hours G.M.T. for the 20 day period 22 July to 10 August 1983 have been compared with retrievals made using the cluster technique of Desboiset al. from METEOSAT radiances measured at 11.30hours G.M.T. The location, France and southern Britain, and time period, summer 1983, were selected to coincide with one of the regions designated for special study in the validation phase of the International Satellite Cloud Climatology Project (ISCCP). Total and low cloud amounts were compared. For total cloud amount 29 percent of the retrievals were fully in agreement with the surface observations and 64 per cent of differences were within ± 1 okta. In the case of low cloud, 33 per cent agreed fully and 64 per cent of the differences were within ± 1 okta. It must be noted that many of these successes (55 per cent in the total cloud amount and 71 per cent in the low cloud amount) were for cases of totally clear or totally cloudy skies and often when only one cloud layer was present.

ISSN:0143-1161    

DOI:10.1080/01431168608948907

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The problems of mapping the land use and land cover of a large area of central Guangdong Province of China from LANDSAT MSS data were examined with reference to the manual and digital approaches. Based on intensive field study of a test site in the study area, we discovered the importance of topographic effects, slopes, seasons, cropping system and the intensity of land use in affecting the accuracy of the resultant maps. It was concluded that visual interpretation was essential in providing the level of reference required for the image interpreter to perform the digital analysis satisfactorily. In view of the coarse spatial resolution of the LANDSAT MSS data it is recommended that the most straightforward digital analysis involving the use of the supervised approach with the minimum Euclidean distance classification and an iterative selection of training areas be adopted for the land-use/land-cover mapping of the whole study area to achieve an accuracy of 80 per cent for eight level I and fifteen level II categories of the land-use and land-cover classification scheme.

ISSN:0143-1161    

DOI:10.1080/01431168608948908

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An ultralight aircraft was used to make concurrent, near continuous measurements and to acquire spectral responses in several wavelengths over various ground features: water bodies (river and irrigation channels), geomorphological features (sand banks, levees, iron crust), aquatic vegetation (rice and spontaneous aquatic vegetation) and stubbles (millet and sorghum). The experiment was performed in Mali, along the Niger river. The airborne instrumentation made it possible to collect simultaneously spectral responses in the MSS and SPOT bands, flying height by laser rangefinder and colour video tapes of the area over-flown. Five profiles, several kilometres long, were obtained at heights above the ground varying from 20 to 75 m. Along each profile spectral data and flying height were scanned every 0-1 s and recorded on the audio channel of a videotape, after multiplexing and analogue-to-digital conversion. The preliminary data analysis suggest a very high potential for ultralight aircraft in remote sensing applications.

ISSN:0143-1161    

DOI:10.1080/01431168608948909

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor