Physical and biochemical vertical profiles in the Mediterranean regions: an important tool to trace the climatology of water masses and to validate incoming data from operational oceanography

Seasonally and spatially averaged vertical profiles of temperature, salinity, dissolved oxygen, nutrients and chlorophyll-ahave been computed from in situ observations in different regions of the Mediterranean Sea using the recently released EU/ MEDAR/MEDATLAS II and EU/MTPII/MATER databases. The regions have been defined according to known dynamics important in the formation, transformation and spreading of the main water masses that circulate in the upper, intermediate and deep layers. The climatological characteristics of temperature and salinity reflect the water mass structures and the general thermohaline circulation patterns. Spatial and temporal variations on a seasonal basis of nutrients and principal biological parameters are described along with some aspects of the trophic conditions of the Mediterranean Sea. The strongest signal of variability is along the vertical; however, horizontal inhomogeneities are mostly associated with the internal dynamics. The distribution of the biochemical elements, in conjunction with hydrographic measurements of temperature and salinity, may serve as appropriate tracers for the characterisation of the main water masses (Atlantic Water, Levantine Intermediate Water and Bottom Water in the eastern and eastern basins) throughout the Mediterranean Sea. In a first approach, adequate descriptors of water properties have been obtained, useful for the quality control of incoming data in large databases and in setting-up documented procedures to improve future data management practices. Secondly, the biochemical climatological characteristics addressed in this paper are verified to be consistent with the physics of the Mediterranean Sea and are conceived useful to initialise coupled physical – biological models. The full set of spatially averaged vertical profiles can be found and downloaded from the World Wide Web data server established at OGS (http://doga.ogs.trieste.it/medar/climatologies/).