OBSERVING THE OCEAN FROM ENVISAT: A UNESCO-BILKO TEACHING MODULE DEMONSTRATING THE SYNERGISTIC USE OF DATA FROM ENVISAT SENSORS TO STUDY OCEANOGRAPHIC PHENOMENA

摘要

The UNESCO-Bilko teaching module 'Observing the Ocean from Envisat' demonstrates how the MERIS, AATSR, ASAR and RA-2 sensors may be used synergistically and combined with data from other sources to study a range of oceanographic phenomena. The Envisat teaching module consists of an introductory tutorial covering the main features of the Bilko software, and 8 lessons on ocean applications such as the measurements of ocean productivity, the detection of internal waves, the study of global current systems, ocean fronts and eddies, coastal upwelling, river plumes and marine pollution. The Bilko project was initiated in 1987 to develop training capability in coastal and marine remote sensing. The Bilko image-processing software is designed primarily for training purposes. Its strength lies in its transparency, which makes students consider the effects of different processing steps on the reliability and validity of remote sensing products. Whilst it lacks some of the more advanced 'black box' algorithms of more specialist software, it has a number of features that makes it a versatile tool for the teaching the use of remote sensing in a number of application areas. With support from ESA the software has been substantially extended and modified to read the N1 image formats for the four Envisat sensors most commonly used in ocean and coastal remote sensing. The lessons that accompany the software provide a step by step approach to image processing and analysis. In the Envisat Module, this is done using data from AATSR, MERIS, ASAR and RA-2. The lessons include instructions for opening and studying level 1B and level 2 image data, for the use of flags and ancillary data, and in the use of standard techniques for enhancing display such as stretches and palettes. There are also examples giving students hands-on experience in the use of common statistical and numerical methods for image analysis. To aid data interpretation this is combined with relevant oceanographic background information, and a selection of references for further reading in each of the topics covered.