12 Years Mediterranean Satellite Data Set and Analysis
Research conducted in the framework of the EU projects EFEDA, RESRAPS, RESMEDES, and RES YSMED stresses the need to (i) correlate results obtained at specific sites with a regional or large scale overview at the conditions in the Mediterranean Basin and (
- PDF / 2,262,792 Bytes
- 13 Pages / 439 x 666 pts Page_size
- 77 Downloads / 149 Views
Abstract Research conducted in the framework of the EU projects EFEDA, RESRAPS, RESMEDES, and RESYSMED stresses the need to (i) correlate results obtained at specific sites with a regional or large scale overview at the conditions in the Mediterranean Basin and (ii) to expand short term ground based experiments with operational observation of at least a few key quantities to periods of climatological relevance. Remote sensing techniques can definitely contribute to this task. NOAA A VHRR data are still the only source with a satisfying compromise between spatial and time resolution covering a period longer than a decade of years. To serve these purposes in all regions of the basin the "Mediterranean Extended Daily One Km A VHRR Data Set (MEDOKADS)" was developed. It provides as basic quantities reflectances and radiances in different spectral regions from which products like albedo, vegetation index, land and sea surface temperatures, cloud cover and cloud classification are derived. Twelve years of data covering the western part and six years of basin wide data allow to identify regional changes and trends related to variability of the climate. Efforts are ongoing to make the full data set directly accessible and to update it in nearly real-time which is a prerequisite for a monitoring system for the Mediterranean environment.
1 Mediterranean Extended Daily One-km AVHRR Data Set (MEDOKADS) 1.1
Design of the Data Set
The data received by the HRPT receiving station of the Free University of Berlin are used to process a daily precisely navigated data set covering the Mediterranean and the surroundings (Koslowsky, 1998, Bolle, 1998). The geographic area of interest, H.-J. Bolle (ed.), Mediterranean Climate © Springer-Verlag Berlin Heidelberg 2003
166
D. Koslowsky
even if not completely filled by data, is defined by the corner coordinates: 55CNIlOOW 55 0N/42°E 27°N/lOOW 27°N/42°E. in latitude/longitude representation (geographic projection) with 111 00° resolution. The total set of data contains 2800 lines and 5200 columns. It is subdivided for faster access by regional users into four overlapping subframes of identical 1536 pixels line length defined by the coordinates of the upper left corners at 100W, 5°E, l5°E,and 27°E. This covers respectively the Iberian Peninsula, Italy, the Balkans, and the eastern Mediterranean. With the calibrated AVHRR data of its channels I to 5 the following supplemental information is delivered: observation geometry (local zenith distance and azimuth of satellite and sun, scattering angle), an origin indicator (link to date and pass number), bitmaps (land-water, cloud mask), local time, NDVI, broad band reflectance, and split-window land/sea surface temperatures as well as cloud classification (currently in preparation). With theses data a congruent 16 channel data set is build up. Daily as well as ten days composite data sets according to the maximum local NDVI's are generated. For the years 1989 to 1994 only the western and the central part so far are processed while the whole Me
Data Loading...
