Advanced satellite oceanography

Duration

15h Th, 15h Pr

Number of credits

Lecturer

Aida Alvera Azcarate

Language(s) of instruction

English language

Organisation and examination

Teaching in the first semester, review in January

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit contents

This practical course consists in brief theoretical introductions, followed by practical exercises on various techniques related to the observation of water bodies (oceans, seas, lakes), mainly using satellite imaging sensors with low spatial resolution and high radiometric and spectral resolutions that detect visible light, reflective infrared and thermal infrared (AVHRR and MODIS e.g.).
The techniques studied deal with the extraction of biogeophysical parameters from the upper layer of the water column, based on the multi-spectral information recorded by these sensors. The biogeophysical parameters studied are surface temperature (Sea Surface Temperature - SST) and Ocean Color (OC). This one is related to chlorophyll-a concentration, CDOM and suspended mineral particles.
We place emphasis on the qualification of input data as well as on its meaning, on its oceanological or limnological representativeness, and on calculation protocols for bio-geo-physical parameters.
The first topic studied is OC (from MODIS sensor). We illustrate the processes used to create level 2 and 3 products from level 0/1, raw luminance data. Several concepts of physics and geometry are applied (geometric correction, radiometric calibration, reflectance, correction of the effects of aerosols, tests on the water's surface state, cloud detection tests, water turbidity, empirical models used to calculate the concentration of chlorophyll-a, validation of the results, etc.).
The second topic is the calculation and analysis of the SST (from MODIS sensor). We illustrate a calculation process involving the adjustment of an empirical model that establishes a relationship between the brightness temperature recorded by the sensor in various thermal channels and the surface temperature provided by ARC-LAKE data. This is produced by the spatio-temporal aggregation of aligned systematic measures by an Along Track Scanning Radiometer (ATSR) sensor. This procedure is a multi-source data fusion analysis technique allowing spatial resolution refinement.
The third topic is the analysis of a time series of level 3 raster files showing SST. These time series are constituted by Pathfinder data. Those are produced by aggregating measures made by AVHRR sensors embarked on the NOAA's various POES satellites. The first operation consists in product selection, product and documentation downloading, data qualification, organization and management. This operation is followed by the creation of the time series, an PCA extraction from of T-mode inertial matrix and the oceanographical interpretation of the saturation matrix shown as temporal profile and of factorial score images. A regionalization is then realized through a clustering process. Finally the spatially generalized time series are extracted by region and their oceanological interpretation is performed.

Learning outcomes of the learning unit

* Understand the nature and the oceanological meaning of the data recorded by sensors studied in the course, as well as the various levels of pre-processing used. *Apply standard processing protocols and understand their limits and how they work. * Understand the relevance of these processes' results and interpret their oceanological meaning. * Learn how to use the features of software application that perform these processes.

Prerequisite knowledge and skills

The course builds upon the skills acquired during the introductory course on satellite oceanography. All the prerequisites of this introductory course are of course required for the advanced course. Students must also have an interest in using digital tools, as well as basic training and practical experience in programming. However, due to the variety of scientific backgrounds among the students who enroll in this class, the teaching will be adapted to the students' needs. Students will also be helped by the mindset they have acquired through various scientific courses (mathematics, statistics, physics, spatial analysis ...) and technical courses (numerical methods, programming, cartography, etc.) of their former academic programmes. The oceanographical interpretation of the results of the methods used in class will rely on knowledge of lake, sea and ocean hydrodynamics, physical oceanography, and climatology... If necessary, students will search through the scientific literature in order to carry out this interpretation. 

Planned learning activities and teaching methods

The theoretical introduction of each topic will consist in a lecture before each exercise. The theoretical concepts and the technical protocol will be explained. The practical assignment will be done using various software tools (SeaDAS, Idrisi, MATLAB, Octave and/or Python). They will be organized as projects, and supervised at all times by the teaching staff in order for students to self-assess their skills by closely interacting with teachers. These practical assignments will also attempt to foster the students' curiosity and ability to come up with original solutions using free software if possible. Students are free to use the university's Idrisi license as well as other software applications through the ULg's VPN. For information on how to access these applications, students can visit the following web page: http://www.gitan.ulg.ac.be/cms. This web site also features the timetable of the class rooms of building B5a (B5a/4/18 and B5a/2/35). Students may contact the Geomatics unit if they wish to practice or advance in their practical assignments. In addition, they may use other open software resources available online (SeaDAS, R, QGIS, Octave, Python...) to independently develop the specific skills required for this study programme. Whenever possible, we encourage students to install these resources on their own personal computers.

Mode of delivery (face to face, distance learning, hybrid learning)

The teaching activities are mostly face-to-face, but students can install open software on their laptops and use licenses available from the ULg, thereby learning at their own pace outside class. Attendance is mandatory. Classes are held in rooms B5a/4/18 or B5a/2/35 according to the schedule available at http://www.facsc.ulg.ac.be/cms/c_253095/fr/horaires

Recommended or required readings

Students are, of course, encouraged to gather scientific and technical documentation in addition to the material provided in class (online literature, software help resources, online forums, reference books ...).

A non-certifying evaluation is carried out throughout practical classes, as a close interaction between students and teachers.

The certificational evaluation will consist in a personal presentation using digital slides, during the January exam session. It will deal with the three topics studied in class, and the teaching staff will ask questions about the presentation.

This standard evaluation procedure may however be modified in agreement with the students, who will be notified of any change.

The assessment criteria are as follows: clarity, coherence, logic, meticulousness, precision, completeness, brevity, relevance, cross-cutting nature (within the course and between courses), quality of mathematical interpretations (mathematical meaning of the different coefficients of the equation, e.g.), physical interpretations (dimensions and units, order of magnitude - scaling, e.g.) and geographical and oceanological interpretations (mono and multivariate spatial and temporal interaction and meaning - type - of the variables e.g.).
Furthermore, answers will also be evaluated based on the quality and the originality of the graphic illustration since graphic expression is the scientist's specificity. It further allows demonstrating a good understanding of the phenomenon.

Finally, enriching an answer with a rich personal scientific culture will also be considered a factor of excellence in the assessment.
 
> Online oral examination (update 10/12/2020)

Work placement(s)

None

Organisational remarks and main changes to the course

Ideally, classes should begin after the introductory course on ocean remote sensing; however, practical considerations related to the MER master mean classes must be held during the first term. This will not be a problem for students in the second year of the master in oceanography, but for students in the MER master this course will have to be held at the end of the term, so that enough progress will have been made in this introductory course. The scheduling, which is unfortunately not ideal, will be determined based on the timetables of students in the second year of the master in oceanography and the MER master, as well as on the availability of computer-equipped classrooms and the teaching staff.
The course will take place in room B5a/2/35 or B5a/4/18 according to the schedule provided elsewhere (http://www.facsc.ulg.ac.be/cms/c_253095/en/horaires).

Contacts

Yves CORNET, Professor
Geomatics unit, 17 (B5a), Allée du 6 Août, 4000 Liège
Phone #: +32 4 366 53 71
E-mail: ycornet@ulg.ac.be
Web: http://139.165.44.35/cms/index.php

Association of one or more MOOCs

Items online