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Analysis on Determination of Melt-onset for Sea Ice in the Chukchi Sea
Yali WANG#+, Xiaofan LUO, Yu QIN, Yongli ZHANG, Hongtao NIE, Hao WEI
Tianjin University, China
Sea ice in the Chukchi Sea is experiencing dramatic changes and thus plays a role in the Arctic marine ecosystem and carbon cycling. Based on the 1/4-degree coupled ocean and sea-ice model, covering North Atlantic-North Pacific-Arctic oceans (NAPA1/4), the determination of melt-onset for sea ice in the Chukchi Sea is analyzed. The results show that: 1) sea ice volume variations in the Chukchi Sea are determined by thermodynamics; 2) sea ice melts originally from Bering Strait, with ice bottom melting earlier and faster than its surface due to the influences of Pacific inflow; 3) melt-onset for sea ice in the Chukchi Sea is related to the thermohaline characteristics of the surface Pacific inflow over the Bering Strait, which is mainly controlled by Anadyr Strait inflow rather than the Spangberg Strait inflow. In this study, Kr=(T-Tref)/(Sref-S) is defined as a index for sea water thermohaline characteristics, where Tref and Sref indicate the reference temperature and salinity corresponding to -1.9℃ and 34.8, respectively. Kr quantifies influences of thermohaline characteristics on the sea ice melting, providing a certain predictability for the melt-onset for sea ice in the Chukchi Sea.
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