ICEBell Ice Mass Balance in the Bellingshausen Sea James Clark Ross, Nov 2010 Participants BAS (Maksym), SAMS (Wilkinson) WHOI, DTU, U Manitoba,UTSA Partners UCL, DAMTP, UCSC

ICEBell Snow and ice processes, mass balance, and air-ice-ocean interactions in the Bellingshausen Sea

ICEBell Rothera Primary Objectives Snow and sea ice thickness distribution Cryosat/ICESat algorithms Snow and ice melt processes Satellite snow depth ICEBell Programme AUV-based 3D ice draft measurements Airborne topographic mapping (ex Rothera)‏ In situ snow and ice thickness and properties Nominal cruise track (ice condition dependent)‏ Red boxes show primary areas of interest‏

Ice Concentration Trends September Snow Depth Why the Bellingshausen Sea? Ice extent has seen the largest declines in the Bellingshausen – declines in ice season length rival those for the Beaufort/Chukchi Subject to frequent extreme deformational events that impact ice thickness distribution Has some of the deepest snow cover in the Antarctic – important impacts on flooding and snow ice formation, summer melt processes, and interpretation of satellite altimetry data

Observed Annual Average ICESat thickness estimates Ice Thickness Distribution No large-scale detailed measurements of snow and ice thickness distribution in Antarctic Currently, large discrepancy between in-situ and satellite altimeter estimates Ice thickness determined primarily from ship- based visual observations –Biased to thin ice areas –Does not adequately account for ridging Satellite estimates complicated by deep snow cover –large uncertainty in satellite snow depths Relationship between snow distribution and ice thickness distribution not well known

ICEBell Rothera Primary Objectives Snow and sea ice thickness distribution Cryosat/ICESat algorithms Snow and ice melt processes Satellite snow depth Ice-upper ocean interactions ICEBell Programme AUV-based 3D ice draft measurements Airborne topographic mapping (ex Rothera)‏ In situ snow and ice thickness and properties Nominal cruise track (ice condition dependent)‏ Red boxes show primary areas of interest‏

Nov 5 Ice Conditions Large interannual variability so exact cruise track will be contingent Conditions as of 23/09/10 are similar to 2007 conditions

WHOI SEABed AUV (Hanu Singh) Floe scale survey (500 x 500 m) ~ 4 hours 230 kHz multibeam sonar CTD + ADCP Microstructure probe 7-band optical radiometer

Open Water Complex ridge system Example of ice bottom topography from an AUV multibeam survey Courtesy J. Wilkinson

BAS MASIN twin-otter will overfly sampling sites providing detailed surface topography of ice floes This may occur prior, during or after occupation Riegl Q140/240 scanning lidar Honeywell GPS/INS GPS rcvrs (Javad, Trimble, Ashtech) Provides sea-ice freeboard swaths => Thickness + detailed mapping of ridges and leads Images Courtesy of Rene Forsberg DTU-space Airborne Lidar (BAS/DTU)

Surface Characterisation ( U of M, BAS, SAMS, UTSA, DRI) Terrestrial 3D laser mapping of snow surface EM-31 surveys and conventional drilling Snow depth distribution, properties and flooding extent (GPR) Ice structure, properties, biology (coring)

SAMS Ice Mass Balance Buoys Monitor surface and basal melt Several spar freeze-in buoys Provide beacons for Twin over-flights Some will form arrays for deformation information

Air-ice-ocean interactions Airborne boundary layer flux measurements from Twin-Otter. (BAS) Oceanographic observations (CTD) (SAMS/BAS) Microstructure under melting sea ice (SAMS) Locations of CTD stations occupied in 2007 Blue line is a possible cruise track for JR240

NASA IceBridge flight in support of ICEBell Likely date ~22 Oct Flight above is for a “light” ice year is likely to be light to moderate. In this case, we will operate more to the west of Alexander Island than to the North Cruise area of interest

Precise cruise track will depend on ice conditions and success of Twin overflights. The primary criteria are 1) successful completion of surveys and overflights over a range of ice types 2) Penetration into the main ice pack (past the broken ice of the marginal ice zone)

Polarview Near daily imagery for aiding navigation in ice and cruise track planning High resolution radar imagery from Envisat and Radarsat-2 ( m resolution) Example subscene of western edge of Charcot Island ~30km x 60 km