Abstract
A dataset of XBT (eXpendable BathyThermograph) temperature profiles collected by ships of opportunity along the Genova–Palermo route, since September 1999, is analyzed, together with altimetric observations and model results, with the purpose of identifying and characterizing robust circulation features along the track and investigating their variability. An anticyclone is found in the Ligurian Sea, just north of the Corsica Channel, not present in previous descriptions of the Mediterranean Sea circulation. It appears to be a recurrent feature, better defined and stronger in summer and in the beginning of autumn. In the northern part of the Tyrrhenian Sea, the well-known Bonifacio dipole shows a similar seasonality, in agreement with previous observations. However, the Bonifacio anticyclone also displays a strong interannual variability, not previously recorded, with significant variations in position and shape. In fact, the data suggest the existence of two distinct summer circulation regimes related to the position and shape of the Ligurian anticyclone. When the latter is wider, filling the entire region north of the Corsica Channel, the circulation in the northern Tyrrhenian Sea is isolated from that in the Ligurian Sea, in agreement with the common picture. However, the altimeter maps show that there are several cases in the last two decades in which the Ligurian anticyclone is small and displaced to the west, allowing an inflow through the Corsica Channel into the Tyrrhenian Sea. The two regimes appear to result from a delicate balance between the forcings acting in the two sub-basins and the topographic constraints.
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References
Abraham JP et al (2013) A review of global ocean temperature observations: implications for ocean heat content estimates and climate change. Rev Geophys 51:450–483. doi:10.1002/rog.20022
AODC (Australian Oceanographic Data Centre) (1999) Guide to MK12–XBT system (including launching, returns and faults). AODC, METOC Services, pp 1–63
AODC (Australian Oceanographic Data Centre) (2001) Expendable bathythermographs (XBT) delayed mode. Quality control manual. AODC, Data Management Group, pp 1–24
Artale V, Astraldi M, Buffoni G, Gasparini GP (1994) Seasonal variability of the gyre-scale circulation in the northern Tyrrhenian Sea. J Geophys Res 99(C7):14127–14137
Astraldi M, Gasparini GP (1992) The seasonal characteristics of the circulation in the north Mediterranean basin and their relationship with the atmospheric–climatic conditions. J Geophys Res 97(C6):9531–9540
Astraldi M, Gasparini GP (1994) The seasonal characteristics of the circulation in the Tyrrhenian Sea. In: La Violette PE (ed) The seasonal and interannual variability of the western Mediterranean Sea. Coastal and estuarine studies, vol 46. American Geophysical Union, Washington, DC, pp 115–134
Astraldi M, Balopoulos S, Candela J, Font J, Gacic M, Gasparini GP, Manca B, Theocharis A, Tintoré J (1999) The role of straits and channels in understanding the characteristics of Mediterranean circulation. Progr Oceanogr 44(1–3):65–108
Bouffard J, Vignudelli S, Cipollini P, Menard Y (2008) Exploiting the potential of an improved multimission altimetric data set over the coastal ocean. Geophys Res Lett 35:L10601. doi:10.1029/2008GL033488
Budillon G, Gasparini GP, Schroeder K (2009) Persistence of an eddy signature in the central Tyrrhenian basin. Deep Sea Res II 56:713–724
Cheng L, Zhu J, Reseghetti F, Liu QP (2011) A new method to estimate the systematical biases of expendable bathythermograph. J Atmos Oceanic Tech 28:244–265
Cheng L, Zhu J, Cowley R, Boyer T, Wijffels S (2014) Time, probe type and temperature variable bias corrections to historical expendable bathythermograph observations. J Atmos Oceanic Tech 31(8):1793–1825
Cheng L, Abraham J, Goni G, Boyer T, Wijffels S, Cowley R, Gouretski V, Reseghetti F, Kizu S, Dong S, Bringas F, Goes M, Houpert L, Sprintall J, Zhu J (2016) XBT Science: assessment of instrumental biases and errors. Bull Am Meteorol Soc. doi:10.1175/BAMS-D-15-00031.1
Cook S, Sy A (2001) Best guide and principles manual for the Ships Of Opportunity Program (SOOP) and expendable bathythermograph (XBT) operations. Prepared for the IOC-WMO-3rd Session of the JCOMM Ship of Opportunity Implementation Panel (SOOPIP-III), La Jolla, California, USA, 28–31 March 2000, JCOMM Rep, pp 1–26
Gérigny O, Coudray S, Lapucci C, Tomasino C, Bisgambiglia PA, Galgani F (2015) Small-scale variability of the current in the Strait of Bonifacio. Ocean Dyn 65(8):1165–1182
Gouretski VR, Reseghetti F (2010) On depth and temperature biases in bathythermograph data: development of a new correction scheme based on analysis of a global ocean database. Deep Sea Res I 57(6):812–833
Iacono R, Napolitano E, Marullo S, Artale V, Vetrano A (2013) Seasonal variability of the Tyrrhenian Sea surface geostrophic circulation as assessed by altimeter data. J Phys Oceanogr 43:1710–1732
Krivosheya VG (1983) Water circulation and structure in the Tyrrhenian Sea. Oceanology 23:166–171
Maillard C, Fichaut M (2001) MEDAR-MEDATLAS Protocol. Part I. Exchange format and quality checks for observed profiles. Rap. Int. TMSI/IDM/SISMER/SIS00-084, pp 1–49
Manzella GMR, Scoccimarro E, Pinardi N, Tonani M (2003) Improved near real time data management procedures for the Mediterranean Ocean Forecasting System—Voluntary Observing Ship Program. Ann Geophys 21:49–62
Manzella GMR, Reseghetti F, Coppini G, Borghini M, Cruzado A, Galli C, Gertman I, Gervais T, Hayes D, Millot C, Murashkovsky A, Özsoy E, Tziavos C, Velasquez Z, Zodiatis G (2007) The improvements of the Ships of Opportunity Program in MFSTEP. Ocean Sci 3:245–258
MedAtlas Group (1994) Specification for Mediterranean banking and regional quality controls. IFREMER, Direction Scientific, Sismer-Brest, SISMER/IS/94-014, p 29
Mertens C, Schott F (1998) Interannual variability of deep-water formation in the northwestern Mediterranean. J Phys Oceanogr 28:1410–1424
Millot C (1999) Circulation in the Western Mediterranean Sea. J Mar Syst 20:423–442
Millot C, Taupier-Letage I (2005) Circulation in the Mediterranean Sea. The handbook of environmental chemistry, vol 5, part K. Water pollution. Springer, Berlin, pp 29–66
Moen J (1984) Variability and mixing of the surface layer in the Tyrrhenian Sea. MILEX-80, Tech Rep. SACLANTCENT, REPORT-75
Napolitano E, Iacono R, Marullo S (2014) The 2009 surface and intermediate circulation of the Tyrrhenian Sea as assessed by an operational model. In: Borzelli GL, Gacic M, Lionello P, Malanotte-Rizzoli P (eds) The Mediterranean Sea: temporal variability and spatial patterns. Wiley, New York, pp 59–74. doi:10.1002/9781118847572.ch5
Napolitano E, Iacono R, Sorgente R, Fazioli L, Olita A, Cucco A, Oddo P, Guarnieri A (2016) The regional forecasting systems of the Italian seas. J Oper Oceanogr. doi:10.1080/1755876X.2015.1117767
Onken R, Robinson AR, Kantha L, Lozano CJ, Haley PJ, Carniel S (2005) A rapid response nowcast/forecast system using multiply nested ocean models and distributed data systems. J Mar Syst 56:45–66
Pierini S, Simioli A (1998) A wind-driven circulation model of the Tyrrhenian Sea area. J Mar Syst 18:161–178
Pinardi N, Allen I, Demirov E, De Mey P, Korres G, Lascaratos A, Le Traon PY, Maillard C, Manzella G, Tziavos C (2003) The Mediterranean Ocean Forecasting System: first phase of implementation (1998–2001). Ann Geophys 21:3–20
Poulain PM, Barbanti R (2005) Comparison between VOS/XBT and MEDARGO temperatures. INOGS report REL 61/2005 - OGA-31
Reseghetti F, Borghini M, Manzella GMR (2007) Factors affecting the quality of XBT data—results of analyses on profiles from the Western Mediterranean Sea. Ocean Sci 3:59–75
Rinaldi E, Buongiorno Nardelli B, Zambianchi E, Santoleri R, Poulain PM (2010) Lagrangian and Eulerian observations of the surface circulation in the Tyrrhenian Sea. J Geophys Res 115:C04024
Rio MH, Poulain P, Pascual A, Mauri E, Larnicol G, Santoleri R (2007) A mean dynamic topography of the Mediterranean Sea computed from altimetric data, in-situ measurements and a general circulation model. J Mar Syst 65(1–4):484–508
Rio MH, Pascual A, Poulain PM, Menna M, Barceló B, Tintoré J (2014) Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in situ data. Ocean Sci 10:731–744
Schroeder K, Josey SA, Hermann M, Grignon L, Gasparini GP, Bryden HL (2010) Abrupt warming and salting of the Western Mediterranean deep water after 2005: atmospheric forcings and lateral advection. J Geophys Res 115:C08029
Vetrano A, Napolitano E, Iacono R, Shroeder K, Gasparini GP (2010) Tyrrhenian Sea circulation and water mass fluxes in spring 2004: observations and model results. J Geophys Res 115:C06023
Vignudelli S, Cipollini P, Reseghetti G, Fusco G, Gasparini GP et al (2003) Comparison between XBT data and TOPEX/Poseidon satellite altimetry in the Ligurian–Tyrrhenian area. Ann Geophys 21(1):123–135
Acknowledgments
Part of the XBT probes deployed after 2009 were kindly provided by AOML/NOAA in the framework of JCOMM/SOOP activities. Many thanks to the shipping company Grandi Navi Veloci, whose collaboration started in September 1999, and to Hapag Lloyd and CMA CGM for the period 2009–2010.
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Responsible Editor: Aida Alvera-Azcárate
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Ciuffardi, T., Napolitano, E., Iacono, R. et al. Analysis of surface circulation structures along a frequently repeated XBT transect crossing the Ligurian and Tyrrhenian Seas. Ocean Dynamics 66, 767–783 (2016). https://doi.org/10.1007/s10236-016-0954-y
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DOI: https://doi.org/10.1007/s10236-016-0954-y