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

Abstract

As part of the Polynyas and Ice Production in the Ross Sea (PIPERS) project, the IcePod system onboard the LC-130 aircraft based at McMurdo Station was flown over the Ross Sea, Antarctica in November 2016 and 2017, with the purpose of repeating the same lines that NASA’s Operation IceBridge (OIB) aircraft flew over in 2013. We resampled the lidar data into 70 m pixels (similar to the footprint size of OIB L2 and ICESat data) and took the mean of the lowest 2% elevation values of 25 km (50 km) length along a flight track as the local sea level of the central 25 km (50 km). Most of the IcePod data were over the same flight lines taken by OIB in 2013, so the total freeboard changes from 2013 to 2016 and 2017 were examined. Combining with the ICESat (2003–2008), we obtained a better picture of total freeboard and its interannual variability in the Ross Sea. The pattern of the sea ice distribution supports that new ice produced in coastal polynyas was transported northward by katabatic winds off the ice shelf. Compared to ICESat years, sea ice near the coast was thicker, while sea ice offshore was thinner in the more recent OIB/IcePod years. The results also showed that, in general, sea ice was thicker in 2017 compared to 2013 or 2016—0.02–0.55 m thicker in total freeboard.

Deriving Antarctic Sea‐Ice Thickness From Satellite Altimetry and Estimating Consistency for NASA's ICESat/ICESat‐2 Missions

“…PO sector shows bi‐modes in 6 months (February, March, May, June, July, October) and is dominated by thicker and (some) multi‐year ice in three months (May, June, July). Thickness in the RS has two peak modes, 0.3 and 0.5 m in December, due to the thicker sea ice near the coast and thinner ones northward (Tian et al., 2020).…”

Estimation of thermodynamic and dynamic contributions to sea ice growth in the Central Arctic using ICESat-2 and MOSAiC SIMBA buoy data

“…After the IS2 data points within the buffer are selected, the mean, median, and modal freeboard and ice thickness are calculated. Since the modal thickness represents the thickness of the most frequently observed ice or level ice (Farrell et al, 2012;Hansen et al, 2013;Petty et al, 2016;Rack et al, 2021;Tian et al, 2020), we estimate the thermodynamic ice growth around the buoys by using the variations in the modal thickness. On the other hand, since the mean and median thickness potentially include the thickness of ridged or deformed ice, we estimate the contributions of dynamic topographical changes to the IS2 mean and median thickness.…”

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

“…Icepod aircraft surveys showed differences in regional sea-ice thickness in spring 2016 and 2017 compared to prior spring observations (Tian and others, submitted). Measurements were compared to IceBridge observations in 2013 and to ICESat data from 2003 to 2008.…”

“…Interestingly, thicker sea ice was observed in spring 2017, compared to 2013 and 2016, suggesting that the delayed ice advance in 2017 drove only a temporary decrease in ice volume, and other processes (such as deformation and winter precipitation variability) likely compensated during winter. Compared to the IceSAT period (2003–08), sea-ice thickness along the coast from TNBP northward was greater in both 2016 and 2017, while sea-ice thickness offshore of the RSP and along the flux-gate was thinner compared to 2003–08 (Tian and others, submitted).…”

“…Kwok, 2005; Kwok and others, 2017). This area was also covered by NASA's IceBridge aircraft in 2013, allowing those data to be compared to ice thicknesses observed in 2016 and 2017 (Tian and others, submitted).…”