Introduction Characteristics of sea ice distribution Sea ice
Introduction: Characteristics of sea ice distribution Sea ice concentration February August Arctic Antarctic SSM/I data(provided by NSIDC, 1993 -1998)
Experimental design: CCSR OAGCM ‘MIROC’ Surface air temperature, humidity Short- Long- Precipiwind velocity wave tation *Atmosphere concentration CCSR/NIES AGCM 5. 6 Skin temperature Resolution: 5. 6° snow *Sea ice snow thickness Thermodynamics: Sea ice Semtner 1976( 0 layer) thickness velocity Hunke and Ducowicz 1997 (EVP rheology) Mixed layer Resolution: 2. 8° velocity *Ocean Resolution: 2. 8° temperature CCSR OGCM’COCO’ 2. 1 Ocean heat transport convergence
ONLINE: Sea ice simulation by the CCSR OAGCM ‘MIROC’. Observation OAGCM (SSM/I, 1995 -1999, NSIDC) concentration winter(Feb. ) summer(Aug. ) Overestimated at the North Atlantic and the North Pacific.
OFFLINE: Sea ice simulation by the offline sea ice model. Concentration Observation(SSM/I, NSIDC) Model Winter(Feb) Summer(Aug)
Summary: Concentration (August)
Dynamical ice sheet part (Saito 2002)
Steady state response of Greenland Ice vol. to warming
Sea level change in 21 century
<< Source of uncertainties of ice sheet - sea level change>> (10 cm --> 4 cm per century ) -North Atlantic response (CGCMs; seaice + THC) (Not uniform polar amplification in the north Atlantic!) -High resolution feature at the margin of Greenland (smaller response compared to the central part of the Greenland ice sheet) -Accumulation change compensates the temp. change a little (response of weather pattern to GH warming is important!) (4 cm --> 1. 4 cm per century) -Ice sheet Dynamics of careful treatment of the margin topography should be simulated carefully. - Climatic history affecting the long term sea level change.
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