Pacific Arctic Group meeting in Shanghai 2006 In

Pacific Arctic Group meeting in Shanghai, 2006 In situ measurement techniques and methods: sea ice thickness Sun Bo, Guo Jingxue, Li Na, Li Bingrui Polar Research Institute of China E-mail: sunbo@pric. gov. cn http: //pric. gov. cn 3/19/2018 1

The Issue : sea ice thickness 1. One critical parameter Knowledge of Ice thickness is one critical parameter for understanding sea ice evolution，mass balance and simulating the behaviors of ice-oceanatmosphere interaction 2. also the most difficult geophysical parameters to measure largely because of the fact that there is no reliable way to directly measure them based on satellite remote sensing 3. one of the largest uncertainties on the geophysics of sea ice changes an increasing need to develop new technique and method to measure sea ice thickness. 3/19/2018 2

Current techniques So far, five direct techniques have been commonly employed for measuring sea ice thickness in polar regions: • submarine sonar profiling • moored upward sonars • airborne laser profilometry • airborne and ground electromagnetic techniques • drilling (Rothrock et al. , 1999) 3/19/2018 3 (Haas et al. , )

In situ electromagnetic techniques and methods in sea ice physics • Ground-penetrating radar (GPR) in sea ice • Electro-magnetic Induction in SEA ice Sea water GPR 3/19/2018 4 EMI

In situ electromagnetic techniques and methods in sea ice physics • Ground-penetrating radar (GPR) in sea ice With the developments in ground penetrating radar (GPR) technology and signal processing methods may offer a powerful tool to measure the geophysics of sea ice. (1) the capabilities of the GPR measuring sea ice thickness; (2) the features of subice morphology described from radar images; (3) how useful 3 -D GPR methods and radar data analyses are for distinguishing and analyzing the subice morphology. 3/19/2018 5 Sea ice Sea water

Ground-penetrating radar (GPR) in sea ice ØUsing two- and three-dimensional GPR methods to characterize ice thickness and its underside morphology on Arctic summer sea ice the distribution of radar surveys sites and the 3 D grid surveying lines pattern (a) Sketch map of experiment area the dots indicate the radar 2 D sites, triangle indicates the 3 D site (b) the grid surveying pattern on an undeformed ice floe 3/19/2018 6 pulse. EKKO GPR radar

ØUsing two- and three-dimensional GPR methods to characterize ice thickness and its underside morphology on Arctic summer sea ice A section of two-dimensional GPR profile image from Arctic sea ice Figure Sea ice bottom topography and its contour (vertical : horizontal exaggeration is 15: 1) 3/19/2018 7

In situ electromagnetic techniques and methods in sea ice physics • Electromagnetic Measurements (EMI) in sea ice Electromagnetic induction (EMI) sounding has become an operational tool for sea ice thickness profiling on the ice, from ships and helicopters Haas, 2004 3/19/2018 8

Arctic sea ice thickness measurements in Chinese Planning for IPY activities. In situ sea ice thickness measurements using electromagnetic techniques in Pacific Arctic Sector. Questions: how cooperate using the platform of PAG We welcome discussion about future activities with relevant partners on topics of mutual interest 3/19/2018 9

Thanks for your attention! 3/19/2018 10