Comparison of the Ice Production and Thicknesses in the Chukchi Sea Polynyas Derived From AMSR-E and SSM/I, and its Implication for Other Regions

For January-March 2003, we use ScanSAR, SSM/I and AMSR to examine the behavior of two polynyas, one large and one small, that occur along the Alaskan Chukchi coast. The large polynya, called Chukchi, forms between Cape Lisburne and Point Barrow; the smaller polynya, called Lisburne, forms between Point Hope and Cape Lisburne. Within these polynyas, the thin ice thickness distributions are derived daily from the ratio of the SMM/I 37 GHz and AMSR 36 GHz brightness temperatures; the heat fluxes from a combination of the thicknesses with meteorological data. Because the AMSR channels have a daily and seasonally dependent drift in calibration, the AMSR 36 GHz channels must first be corrected against the SSM/I 37 GHz channels. Given that the AMSR 36 GHz resolution is 12.5 km, compared with 25 km for the SSM/I 37 GHz channel, the AMSR has two advantages, a better landmask and an improved resolution. For days with active polynyas, comparison of the passive microwave data sets against ScanSAR imagery shows that AMSR provides a better definition of the polynyas. Examination of the daily and cumulative heat loss time series shows that for the Chukchi polynya, the AMSR yields a greater total heat loss than the SSM/I, while for the Lisburne polynya, the AMSR permits measurement of its productivity and resolution of its size even when the polynya size is of order of a single SSM/I pixel. Finally, in a brief example, we will show that in the southern hemisphere, the combination of ScanSAR and passive microwave permits delineation of the ice shelf boundaries and thus allows for a more precise investigation of the Ross Sea polynyas than in previous work.