BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:New insight from CryoSat-2 sea ice thickness for sea ice modelling
  - David Schroeder (University of Reading)
DTSTART:20170915T160000Z
DTEND:20170915T162000Z
UID:TALK79511@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Estimates of Arctic sea ice thickness are available from the C
 ryoSat-2 radar altimetry mission during the ice growth seasons since 2010.
  We derive the sub-grid scale ice thickness distribution (ITD) with respec
 t to 5 ice thickness categories used e.g. in the sea ice component CICE of
  HadGEM3 climate simulations: (1) ice thickness h < 60 cm\, (2) 60 cm < h 
 < 1.4 m\, (3) 1.4 m < h < 2.4m\, (4) 2.4 m < h < 3.6 m\, (5) h > 3.6 m. Th
 is allows us both to verify the simulated cycle of ice thickness and to in
 itialize the ITD in stand-alone simulations with the sea ice model CICE. W
 e find that a default CICE simulation strongly underestimates the ice thic
 kness\, in spite of doing a reasonable job regarding the inter-annual vari
 ability of summer sea ice extent. We can identity the underestimation of w
 inter ice growth being responsible and show that using ice and snow conduc
 tivity values on the upper end of the observed range (2.63 and 0.5 W/m/K) 
 makes sea ice growth more realistic and generally improves the model simul
 ation. Sensitivity studies provide insight on the role of ice strength\, m
 omentum and heat turbulent fluxes on the annual cycle of sea ice thickness
 . We show that the width of ITD plays an important role for the summer lea
 d fraction and basal ice melt. Furthermore\, a major discrepancy is reveal
 ed regarding the annual cycle of sub-grid scale thick sea ice (category 5)
 . According to Cryosat-2 there is a strong formation of thick ice during w
 inter\, but hardly any thick ice survives the summer. CICE simulations onl
 y show a weak seasonal cycle\, indicating that both the formation and the 
 melting of thick is underestimated. Coupled simulations with the ocean &nd
 ash\; sea ice model NEMO-CICE confirm our results highlighting that sea ic
 e physics and parameters are responsible for differences with Cryosat esti
 mates and improvements are required.
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR