Arctic Ocean warming: submarine and acoustic measurements

A Global Ocean Acoustic Observing Network

“…The 1994 "Transarctic Acoustic Propagation" experiment (TAP) and the 1999 "Arctic Climate Observations using Underwater Sound" (ACOUS) experiment measured warming which was confirmed by submarine measurements during the Submarine Ice Exercises (SCICEX) [35].…”

Arctic Climate Observations Using Underwater Sound (ACOUS)

“…We can make the same calculation as a function of range along the section using the SCICEX data and we find that in the regions of the cores of the AIW circulation near the Lomonosov Ridge, Mendeleyev Ridge, and the Chukchi Rise the heat flux is ~ 6 W/m 2 . Presumably some large fraction of this heat is circulating out of the Arctic Ocean, but the rest is warming the Arctic waters adjacent to these warm cores that has been noted in the SCICEX data [2], and also penetrating the pycnocline where it can melt the sea ice. Rothrock et al [3] calculate that a 4 W/m 2 increase in heat flux from the ocean to the ice could explain the observed 1.4 m thinning of sea ice over the last 20 years.…”

“…Fig. 1 from this year's work [2] shows the relationship between the travel times of modes 2 and 3 on the path along the SCICEX section and the total section-average temperature (averaged over range and depth) (upper panel) from which the heat content can be computed (lower panel) of the AIW layer. The relationship of modal travel times and the section-average AIW parameters is well approximated by linear regressions, a very important result, that shows the value of monitoring acoustic travel times for making measurements of these important AIW properties.…”

SCICEX Investigations of the Arctic Ocean System

“…Beginning with SCICEX-95 and continuing through the SCICEX-2001 deployment, cross-basin transects were undertaken to collect the chemical and physical oceanographic data necessary to monitor changes in the water column and investigate this issue. Several SCICEX-related studies focused on the Atlantic Water (AW) layer (Gunn and Muench 2001), also known as Arctic Intermediate Water (AIW; Mikhalevsky 1999), the boundaries of which are defined to cross the 0 °C isotherms above and below the AL temperature maxima (Mikhalevsky et al 2001). Gunn and Muench (2001) examine AW layer mean and maximum temperatures collected from 1995-1999 to show that warming continued from 1995 until 1998, but was replaced by a slight cooling during 1998-1999.…”

“…They propose northward currents along the flanks of the arctic ridges as mechanisms for advecting warm Atlantic water from the Eurasian continental margin into the central Arctic Ocean. Mikhalevsky et al (2001) examine the SCICEX SSXCTD data (Appendix 2) through the 2000 USS L Mendel Rivers deployment and find that the warming trend did not stop during 1998-1999, it continued between 1999 and 2000. They confirm these results using acoustic thermometry data collected during the Transarctic Acoustic Propagation Experiment (TAP; Mikhalevsky et al 1995;1996; and ACOUS (Mikhalevsky 1999).…”