Indication of recent warming process at the intermediate level in the Tyrrhenian Sea from SOOP XBT measurements

Abstract

The Tyrrhenian Sea is a sub-basin of the western Mediterranean crossed by intermediate and deep waters from the eastern basin. Across this sub-basin, temperature profiles of the water column from expendable bathythermographs (XBT) have been acquired for sixteen years along transects realized thanks to the use of commercial vessels. Since 1999 an increase of temperature has been observed at intermediate depths even if interspersed with periods of decrease. This increase involves deeper and deeper depths along the years then involving the whole sub-basin in the range 200-800 m in September 2014 when largest anomalies over the whole period are found. The paper shows evidences of this rapid heating, giving insights into the origin and the diffusion of the warmer intermediate waters then showing its evolution in years and its relationship with the Eastern Mediterranean Transient.

More Than 50 Years of Successful Continuous Temperature Section Measurements by the Global Expendable Bathythermograph Network, Its Integrability, Societal Benefits, and Future

“…XBT temperature profiles have shown a warming that could be linked to the anomalous 2003 summer (an unusually long, hot, and dry season in the southern Europe). After a return to temperature conditions prior to 2004, a new anomaly appeared in 2014 in the Tyrrhenian Sea with a warming tendency in the 200-500 m depth layer moving from south to north (Ribotti et al, 2016). Over the years, this thermal anomaly has increased and extended both in depth (up to about 700 m) and in the involved areas, which include the northeastern part of the Ligurian Sea (albeit with lower intensity).…”

The Tyrrhenian Sea Circulation: A Review of Recent Work

“…A recent warming of the LIW in the TYS was also documented in [63], which is based on the analysis of XBT data from the period 1999-2014. In 2014, the LIW layer was found to be anomalously warm, similarly to what observed in 2004, and it was consequently argued that these warmings could be related to EMT-like events, since the LIW may take about 10 years to go from the Levantine basin to the Sicily Channel (e.g., [64]).…”

Quality assurance and control on hydrological data off western Sardinia (2000–2004), western Mediterranean

“…Here, since 2005 the old WMDW has been undermined by the warmest and saltier new WMDWs that diffused all over the Western Mediterranean sub-basin due to the transfer of the Eastern Mediterranean Transient signal inside. This water is characterized by high heat and salt contents from the advected LIW, originating the new WMDW in the north-western Mediterranean sub-basin (Gasparini et al, 2005;Schroeder et al, 2006;Zunino et al, 2012;Ribotti et al, 2016).…”