TY - JOUR

T1 - The sudden ocean warming and its potential influences on early−frozen landfast ice in Prydz Bay, East Antarctica

AU - Hu, Haihan

AU - Zhao, Jiechen

AU - Ma, Jingkai

AU - Bashmachnikov, Igor

AU - Gnatiuk, Natalia

AU - Xu, Bo

AU - Hui, Fengming

PY - 2024/5/1

Y1 - 2024/5/1

N2 - The ocean conditions beneath the ice cover play a key role in understanding the sea ice mass balance in the polar regions. An integrated high-frequency ice-ocean observation system, including Acoustic Doppler Velocimeter, Conductivity-Temperature-Depth Sensor, and Sea Ice Mass Balance Array (SIMBA), was deployed in the landfast ice region close to the Chinese Zhongshan Station in Antarctica. A sudden ocean warming of 0.14°C (p < 0.01) was observed beneath early-frozen landfast ice, from (−1.60 ± 0.03)°C during April 16–19 to (−1.46 ± 0.07)°C during April 20–23, 2021, which is the only significant warming event in the nearly 8-month records. The sudden ocean warming brought a double rise in oceanic heat flux, from (21.7 ± 11.1) W/m2 during April 16–19 to (44.8 ± 21.3) W/m2 during April 20–23, 2021, which shifted the original growth phase at the ice bottom, leading to a 2 cm melting, as shown from SIMBA and borehole observations. Simultaneously, the slowdown of ice bottom freezing decreased salt rejection, and the daily trend of observed ocean salinity changed from +0.02 d−1 during April 16–19, 2021 to +0.003 d−1 during April 20–23, 2021. The potential reasons are increased air temperature due to the transit cyclones and the weakened vertical ocean mixing due to the tide phase transformation from semi-diurnal to diurnal. The high-frequency observations within the ice-ocean boundary layer enhance the comprehensive investigation of the ocean’s influence on ice evolution at a daily scale.

AB - The ocean conditions beneath the ice cover play a key role in understanding the sea ice mass balance in the polar regions. An integrated high-frequency ice-ocean observation system, including Acoustic Doppler Velocimeter, Conductivity-Temperature-Depth Sensor, and Sea Ice Mass Balance Array (SIMBA), was deployed in the landfast ice region close to the Chinese Zhongshan Station in Antarctica. A sudden ocean warming of 0.14°C (p < 0.01) was observed beneath early-frozen landfast ice, from (−1.60 ± 0.03)°C during April 16–19 to (−1.46 ± 0.07)°C during April 20–23, 2021, which is the only significant warming event in the nearly 8-month records. The sudden ocean warming brought a double rise in oceanic heat flux, from (21.7 ± 11.1) W/m2 during April 16–19 to (44.8 ± 21.3) W/m2 during April 20–23, 2021, which shifted the original growth phase at the ice bottom, leading to a 2 cm melting, as shown from SIMBA and borehole observations. Simultaneously, the slowdown of ice bottom freezing decreased salt rejection, and the daily trend of observed ocean salinity changed from +0.02 d−1 during April 16–19, 2021 to +0.003 d−1 during April 20–23, 2021. The potential reasons are increased air temperature due to the transit cyclones and the weakened vertical ocean mixing due to the tide phase transformation from semi-diurnal to diurnal. The high-frequency observations within the ice-ocean boundary layer enhance the comprehensive investigation of the ocean’s influence on ice evolution at a daily scale.

KW - Zhongshan Station

KW - in-situ observation

KW - landfast ice

KW - oceanic heat flux

KW - sudden ocean warming

UR - https://www.mendeley.com/catalogue/724b5b21-1009-33ed-a846-d579b56d89c0/

U2 - 10.1007/s13131-024-2326-7

DO - 10.1007/s13131-024-2326-7

M3 - Article

VL - 43

SP - 65

EP - 77

JO - Acta Oceanologica Sinica

JF - Acta Oceanologica Sinica

SN - 0253-505X

IS - 5

ER -