Sea-ice production and air/ice/ocean/biogeochemistry interactions in the Ross Sea during the PIPERS 2017 autumn field campaign

Abstract

The Ross Sea is known for showing the greatest sea-ice increase, as observed globally, particularly from 1979 to 2015. However, corresponding changes in sea-ice thickness and production in the Ross Sea are not known, nor how these changes have impacted water masses, carbon fluxes, biogeochemical processes and availability of micronutrients. The PIPERS project sought to address these questions during an autumn ship campaign in 2017 and two spring airborne campaigns in 2016 and 2017. PIPERS used a multidisciplinary approach of manned and autonomous platforms to study the coupled air/ice/ocean/biogeochemical interactions during autumn and related those to spring conditions. Unexpectedly, the Ross Sea experienced record low sea ice in spring 2016 and autumn 2017. The delayed ice advance in 2017 contributed to (1) increased ice production and export in coastal polynyas, (2) thinner snow and ice cover in the central pack, (3) lower sea-ice Chl-a burdens and differences in sympagic communities, (4) sustained ocean heat flux delaying ice thickening and (5) a melting, anomalously southward ice edge persisting into winter. Despite these impacts, airborne observations in spring 2017 suggest that winter ice production over the continental shelf was likely not anomalous.

Physical and biological properties of early winter Antarctic sea ice in the Ross Sea

“…The PIPERS cruise sampled the Ross Sea pack ice between 19 April 2017 (Julian Day 109) and 4 June 2017 (Julian Day 155) ( Fig. 1, see Ackley and others (2020) in this volume for an overview of the cruise). A total of 27 biogeochemistry sites were occupied.…”

Scientific Challenges and Present Capabilities in Underwater Robotic Vehicle Design and Navigation for Oceanographic Exploration Under-Ice

“…Along the Antarctic coast, similar processes play important roles in polynyas, where strong winds drive high rates of ice production and export from the coast plays an important role in global water mass transformation. There have been very few direct observations of these processes due to the challenges of operating in these remote and highly dynamic environments (see, e.g., in [63]).…”

“…Larger-scale operations with on-site scientists and technicians are limited by the expense and logistical challenges of operating in this environment. This is particularly true in winter, where large, multidisciplinary expeditions might occur decades apart in some regions (see, e.g., in [63,64]). Under-ice vehicles offer an attractive means to observe ice-ocean interactions in these challenging environments where capturing processes that vary dramatically across small to medium spatial scales are needed, or where traditional methods are exceedingly difficult to perform (see, e.g., in [63,65]).…”

“…This is particularly true in winter, where large, multidisciplinary expeditions might occur decades apart in some regions (see, e.g., in [63,64]). Under-ice vehicles offer an attractive means to observe ice-ocean interactions in these challenging environments where capturing processes that vary dramatically across small to medium spatial scales are needed, or where traditional methods are exceedingly difficult to perform (see, e.g., in [63,65]). As capabilities advance, particularly for long-term or long-range presence, autonomous under-ice vehicles will play an increasing role in sustained observations of the ice and ocean in both the Arctic and Antarctic [66,67].…”

Sea Ice Freeboard in the Ross Sea from Airborne Altimetry IcePod 2016–2017 and a Comparison with IceBridge 2013 and ICESat 2003–2008

“…The ATM lidar data measure the elevation of the sea ice and the DMS can be used to identify open water. As part of the Polynyas and Ice Production in the Ross Sea (PIPERS) project [20], the IcePod system with similar instrumentation, including a scanning laser for ice surface measurements, visible and thermal infrared imaging cameras for ice surface identification, two different radar systems, magnetometer, and gravimeter, onboard the NSF LC-130 aircraft based at McMurdo Station was flown over the Ross Sea, Antarctica in November 2016 and 2017. The purpose of IcePod flights was to repeat the approximate same lines that NASA's OIB aircraft flew over in November 2013, particularly the line along the Fluxgate which separates the continental shelf from the deep ocean (Shelf-Slope break).…”