Observing High Latitudes: extending the core Argo array

• Main Authors: van Wijk, E. M., Riser, S., Rintoul, S. R., Speer, K., Klatt, Olaf, Boebel, Olaf, Owens, B., Gascard, J. C., Freeland, H., Wijffels, S., Roemmich, D., Wong, A.
• Format: Conference Object
• Language: unknown
• Published: 2009
• Subjects: Arctic Ocean; Sea ice; Southern Ocean; Weddell Sea
• Online Access: https://epic.awi.de/id/eprint/21402/; https://epic.awi.de/id/eprint/21402/1/van2009m.pdf; http://www.oceanobs09.net/ac/AbstractBook_OceanObs09_v18SEP09.pdf; https://hdl.handle.net/10013/epic.33737; https://hdl.handle.net/10013/epic.33737.d001

Over the past decade, Argo floats have provided an unprecedented number of profiles of the global oceans (to 2000m depth), far surpassing the number collected historically fromship-based hydrography. The original design of the Argomission specified nominal 3 x 3 degree spacing, with 10 daysampling interval, of the oceans between 60 °N and 60 °S,excluding the high latitudes and marginal seas. The exclusionof the high latitudes was due to the inability of early floats tosample under sea-ice. Technological advances in float designin recent years now give us this capability. Advancements havecome through re-design of hardware (i.e. armoured ice floats),software (ice-avoidance algorithm and open-water test) andcommunications (Iridium), allowing the transmission of storedwinter profiles. Observing circulation in seasonally ice-coveredseas is challenging. To date, most observations have beenmade during ice-free summer periods and consequently thewinter circulation beneath the sea-ice is not well understood.Despite this, Argo has already made a significant contribution tohigh latitude research with successful deployments of floats inthe polar oceans of both hemispheres. As of December 2008,over 100 floats had been deployed above 60 °N and over 200below 60 °S. Approximately 60% of these floats are still active(the failure rate of early floats was high as the ice-capabletechnology was being developed and tested). Mortality rates ofnewer ice floats are now equivalent to those deployed in lessdemanding conditions. In fact, a number of floats deployed inthe Weddell Sea have survived for 7 years (surpassing 225profiles) equal to some of the longest-lived floats deployedglobally. The high latitudes are important deep water massformation regions. The Southern Ocean connects the globalocean basins and regulates the meridional overturningcirculation. The exposed Arctic Ocean will have importantconsequences for ocean and atmospheric circulation, moistureand heat fluxes. Therefore, both polar regions play a critical rolein setting ...