| Due to global warming,the Arctic region has become one of the regions with the most significant warming.The average air temperature in the Arctic has risen at a rate twice as global mean increase rate,i.e.Arctic amplification.Under the influence of the Arctic amplification,sea ice in high-latitude areas of the Northern Hemisphere has become an "indicator" of climate changes.The northern hemisphere sea ice acts as an important component of the coupling system between the atmosphere,ocean and sea ice in high latitude regions.Its reduction will affect the exchange of matter,energy,and flux between the atmosphere and the ocean.It has an impact on the global hydrological cycle and the Arctic ecosystem as well.Based on the breadth and complexity of the impact of Northern Hemisphere sea ice variations,mastering the dynamic changes of Northern Hemisphere sea ice,especially its spatial and temporal distribution,has reference significance for studying the global climate system.In the study of sea ice in the Northern Hemisphere,research on the Arctic Ocean sea ice has been sufficient,but research on the North Pacific and North Atlantic is relatively lacking.Therefore,this article focuses on the study of sea ice in the North Pacific and North Atlantic.The North Pacific and North Atlantic sea ice are important components of the northern hemisphere sea ice.Based on the empirical orthogonal decomposition analysis of the spring sea ice in the North Pacific and North Atlantic regions from 2000 to 2020,it is found that the first six modes of the sea ice variations in the two regions can represent the changes in the physical fields of the entire sea ice.The first two modes are the main characteristics of the sea ice variations in the North Pacific and North Atlantic.The Bering Sea and Okhotsk Sea(North Pacific)and the coastal waters of the Greenland Sea(North Atlantic)are important change regions of sea ice.On this basis,rotated empirical orthogonal decomposition was used to divide the North Pacific and North Atlantic into six sensitive areas of sea ice concentration based on the characteristics of sea ice changes.Most of the areas were concentrated in the offshore waters of the Okhotsk Sea and Greenland,highlighting the complexity and diversity of sea ice variations in the offshore waters.Secondly,correlation analysis has been conducted using observational data from the European Center for Medium Range Weather Forecasting to investigate the influencing factors and mechanisms of sea ice changes in the North Pacific and North Atlantic.The sea surface temperature in the Bering Sea area has a negative feedback mechanism for the sea ice distribution in this area.The sea surface temperature located on the western side of the American continent in the Pacific Ocean has a negative correlation with the distribution of sea ice in the Okhotsk Sea area under the influence of equatorial warm currents.Under the influence of the North Atlantic Warm Current,the sea surface temperature in the southeastern of Greenland in the North Atlantic is conducive to the formation of sea ice in the Baffin Bay.In particular,precipitation in the North Pacific mostly affects the distribution of sea ice in other regions through teleconnection.This is closely related to the North Pacific being located in the Asian monsoon region.Teleconnection between India and North China affects the northeast sea area of Sakhalin Island by increasing its sea ice.In addition,the spatiotemporal distribution of sea ice in the Shelting Bay is positively correlated with the surface air temperature of its adjacent land due to thermal properties difference between lands and sea.Affected by the Aleutian Low Pressure,the increase of sea ice in the southern of the Chukchi Peninsula is positively correlated with the sea surface temperature in the south of Aleutian Islands.In the North Atlantic,the temperature difference of the surface air causes the low pressure in Iceland,the westward wind prevails in the Davis Strait.The cold wind from the American continent causes the sea water to freeze. |
