Ovchinnikov, I Michailovich; GOIN (2008): Physical oceanography of the GOIN project in the Mediterranean Sea (1987-1990) [dataset publication series]. State Oceanographic Institute, Moscow, PANGAEA, https://doi.org/10.1594/PANGAEA.710738

This set provides 1779 CTD profiles of temperature and salinity measured with a russian "Zond-Bathometer" by the research vessels Yakov Gakkel and Vladimir Parshin, of the former Soviet Union, during 1987-1990. It is dedicated to the memory of Professor Ivan Ovchinnikov (1931-07-14 to 2000-06-10) who initiated the soviet program of research of the Mediterranean Sea and contributed significantly to the investigation of physical processes in the Mediterranean Sea.

Two large scale investigations of the Eastern Mediterranean: POEM - an international cooperative effort, and GOIN - an initiative of the former USSR, were carried out between 1985 and 1995. The two projects were not coordinated and therefore, the cruises of the two projects sometimes overlap and sometimes complement each other in time and in space.

POEM carried out six coordinated cruises with a total of 1674 stations. As a result of the careful compilation and inter-calibration of the POEM data, an accurate description of the Eastern Mediterranean general circulation was achieved (Ozsoy et al., 1989; Ozsoy et al.,1991; Robinson et al., 1991; POEM Group, 1992; Malanotte-Rizzoli et al., 1997).

Traditionally, Russian oceanographers have also shown a deep interest in the Mediterranean Sea. Prof. Ivan Michailovich Ovchinnikov, who led a series of Mediterranean cruises on R/V Vityaz and on other Soviet research vessels, played a significant role in the long term investigation of this basin. In addition to many papers on the Mediterranean Sea, Prof. Ovchinnikov also headed a group of scientists who wrote a unique comprehensive Mediterranean monograph (Ovchinnikov et al., 1976). During the nineties, Prof. Ovchinnikov initiated the Soviet scientific program aimed at investigation of sub-basin Mediterranean circulation, focusing on of the variability of the thermohaline structure related to synoptic scale eddies. From 1987 to 1990 the State Oceanographic Institute (GOIN) at Moscow, based mainly on the facilities of GOIN's branches in Odessa and Sevastopol, carried out 9 special Eastern Mediterranean cruises, during which they collected data at 1779 stations. Prof. Ovchinnikov took part in some of these cruises, emphasizing on understanding of the mechanisms of intermediate and deep water formation processes in the Aegean Sea and Levantine basin. Particular interest was excited by the discovery of the convective destruction of gravitational stability in the center of the Rhodes Gyre (Gertman et al., 1994) as well as by the discovery of intensive outflow of Aegean water via the Cretan Arc Straits (Popov, 1991), which was only recognized later on as a component of the climatic Mediterranean transient (Roether et al., 1996). Unfortunately, due to the "Perestroika" processes, which however positive, brought with them stagnation in Soviet oceanographic research activity, only preliminary analyses of the Mediterranean GOIN cruises were carried out. Recently, some more profound analyses based on the gathered data were carried out and published (Gertman et al., 2006).

Both the POEM and the GOIN projects elucidated many of the phenomenological and theoretical questions concerning the Eastern Mediterranean circulation. Nevertheless, many problems and questions remain and require further investigation and confirmation. Moreover, as mentioned above, the time period of both programs coincided with the unique climatic transient in formation of deep water in the Eastern Mediterranean. This event has been discussed widely in oceanographic publications (Klein et al., 1999; Lascaratos et al., 1999; Wu et al., 2000; Roether et al., 2006) and still attracts the interest of oceanographers involved in the numerical simulation of the event. Therefore, all the observations carried out during the relevant period are highly sought after by the oceanographers. Until now only the POEM data were available to investigators since they were included in the data base assembled within the framework of the MEDAR/MEDATLAS project. On the other hand, GOIN data were available only to that limited number of researchers, who participated in the data collection. Recently, permission was obtained from the Ukrainian Scientific Centre of Sea Ecology (formerly Odessa branch of the State Oceanographic Institute) to open these data to the general public.

Prof. Ovchinnikov always held CIESM in very high esteem. Therefore, it was suggested to publish GOIN cruise data on the CIESM web site and to dedicate this site to the memory of the late Prof. Ovchinnikov, a proposition warmly accepted by the CIESM Director General, Prof. Frederic Briand.

On this site, most of the Mediterranean GOIN data are made available. All data were obtained using Soviet CTD probes ("Zond-Bathometer"). Unfortunately, due to the limited data storage capacity, the measured data were re-sampled during the cruises. The available vertical profiles have a resolution of 10 db for the 0-400 db layer and of 100 db below the 400 db level. Calibration of the CTD's was carried out onboard the research vessels using reversing thermometers and salinometers. The assessment of the accuracy of GOIN data relative to POEM data was carried out by Hecht and Gertman (2001) and resulted in an average difference of -0.02±0.07°C for temperature and 0.01±0.03 for salinity. This data comparison also concluded that it would be possible to merge the two data sets, at least in the upper 1000 db layer. All the data presented on this site passed the quality control for gravitational instability, and, according to MEDAR/MEDATLAS QC conventions (Quality flag 3), wherever a density inversion of more then 0.03 kg/m**3 was observed on adjacent levels, the data were flagged as dubious. Cases with instability larger than 0.5 kg/m**3 were flagged as bad data (Quality flag 4).

This data set was archived in the Pangaea data library on request of the originators as a copy from the free primary archive at CIESM/ISRAMAR in 2008. For the original version see http://www.ciesm.org/marine/campaigns/sovietcruises.htm.