Context and Objectives

Several satellites measure Sea Surface Temperature (SST), each of these with different technical specificities and error sources. Together with in situ data, they form a highly complementary data set. The creation of merged SST products, integrating the strengths of each of its components and minimising their weaknesses, is however not an easy task, but it is certainly a desirable goal that has generated a large amount of research over the last years. The objectives of this project are:

  1. To develop a technology that allows to merge different data sets at very different sampling intervals (in space and time) and create an integrated product at the highest sampling frequency and with the highest quality possible.
  2. To provide improved, merged analyses of variables such as SST and chlorophyll.
  3. Obtain a better understanding of the diurnal cycle of the studied variables.
  4. To better understand the relation between variables (and take advantage of this improved knowledge to ameliorate the analyses).
  5. Using the above-mentioned developments, explore the capability of DINEOF to produce SST forecasts based on multi-variate EOFs and model forecasts.
  6. Finally, to improve DINEOF to meet user needs and required precision.

Methodology

DINEOF is a technique to infer missing data is satellite data sets. In this project we will further develop DINEOF so that it can merge different data sets. First, an initial DINEOF reconstruction of a data set with a high spatial resolution will be made, and the EOF basis obtained will be used as the covariance matrix needed to subsequently include into the analysis other data sources (satellite and in situ). Error estimations for each data set will be used to weight their influence in the final product. Special attention will be given to the diurnal cycle and the effect of diurnal warming in the quality of the measurements, and multivariate DINEOF analyses will be performed to investigate the influence of variables like wind and turbidity in these warming events. Finally, by combining satellite SST fields and model forecasts using a multivariate DINEOF, we will investigate the capability of DINEOF to produce SST forecasts, which will be compared to the forecasts provided by numerical analyses.

Publications

A list of publications realised in the frame of the HiSea project:

Peer reviewed publications in international journals

  • A. Alvera-Azcárate, D. Sirjacobs, A. Barth, and J.-M. Beckers. Outlier detection in satellite data using spatial coherence. Remote Sensing of Environment, 119:84-91, 2012.
  • A. Alvera-Azcárate, C. Troupin, A. Barth, and J.-M. Beckers. Comparison between satellite and in situ sea surface temperature data in the Western Mediterranean Sea. Ocean Dynamics, 61(6):767-778, 2011.

Presentations at conferences, workshops, etc.

A list of presentations realised in the frame of the HiSea project at international conferences, workshops, internal meetings, etc:
  • Aida Alvera-Azcárate, Alexander Barth, Marie-Eve Toussaint and Jean-Marie Beckers. HiSea: High resolution merged satellite sea surface temperature fields. Belgian Earth Observation Day (BELSPO). Oudenburg, Belgium, 25 May 2011. Oral presentation + poster. Oral presentation and Poster presentation
  • Aida Alvera-Azcárate, Alexander Barth, and Jean-Marie Beckers. Merging satellite and in situ sea surface temperature data using DINEOF. Geophysical Research Abstracts, Vol. 13, EGU2011-5939. EGU General Assembly 2011. Oral presentation.
  • Aida Alvera-Azcárate, Alexander Barth, and Jean-Marie Beckers. Satellite and in situ sea surface temperature comparison and merging in the Mediterranean Sea. Third International Workshop on Advances in the Use of Historical Marine Climate Data (MARCDAT-III). 2-6 May 2011, Frascati (Italy). Oral presentation. .
  • A. Alvera-Azcárate, C. Troupin, A. Barth, and J.-M. Beckers. An EOF-based technique to compute merged high resolution sea surface temperature fields. 44th International Liège Colloquium on Ocean Dynamics, 7-11 May 2012. Liège (Belgium). Oral presentation.

Organization of the 44th International Liege Colloquium

The 44th edition of the International Liège Colloquium was devoted to the topic Remote sensing of colour, temperature and salinity - new challenges and opportunities. The colloquium was co-organized by K. Ruddick (MUMM) and A. Alvera-Azcárate (Ulg). A total of 120 abstracts were submitted and keynote speakers presented the latest developments on the fields of remote sensing of colour, temperature and salinity. A special issue is under preparation for publication at Remote Sensing of Environment. Twenty six manuscripts were submitted and are now in various stages of the revision process. Official webpage.

Others

Results obtained in the frame of HiSea

Satellite plus in situ data merging in the western Mediterranean Sea. The year of the analysis is 1999. Satellite data are from the AVHRR sensor on board NOAA POES. In situ data are obtained from 5 databases: World Ocean Database 2005, MEDAR/Medatlas, Coriolis data center, the International Council for the Exploration of the Sea (ICES) and the International Comprehensive Ocean-Atmosphere Data Set (ICOADS).

Download video here.

Application of DINEOF-OI to a polar-orbiting dataset (AVHRR NAR-18) and a geostationary dataset (SEVIRI) for the year 2009. Only one frame per day is showed, but the merged dataset has the temporal resolution of the geostationary satellite (3 hours).

Download video here.

Application of DINEOF-OI to a Total Suspended Matter dataset, consisting of a polar-orbiting dataset (MODIS) and a geostationary dataset (SEVIRI) for the year 2008. Only one frame per day is showed, but the merged dataset has the temporal resolution of the geostationary satellite (15 minutes).

Download video here.

Reports

  • First annual report, pdf.
  • Final report, pdf.