Specific Relationship between the Surface Air Temperature and the Area of the Terra Nova Bay Polynya, Antarctica

Abstract

Antarctic polynyas play an important role in regional atmosphere–ice–ocean interactions and are considered to help generate the global deep ocean conveyer belt. Polynyas therefore have a potential impact on the Earth’s climate in terms of the production of sea ice and high-salinity shelf water. In this study, we investigated the relationship between the area of the Terra Nova Bay polynya and the air temperature as well as the eastward and northward wind based on the ERA5 and ERAInterim reanalysis datasets and observations from automatic weather stations during the polar night. We examined the correlation between each factor and the polynya area under different temperature conditions. Previous studies have focused more on the effect of winds on the polynya, but the relationship between air temperature and the polynya area has not been fully investigated. Our study shows, eliminating the influence of winds, lower air temperature has a stronger positive correlation with the polynya area. The results show that the relationship between the polynya area and air temperature is more likely to be interactively influenced. As temperature drops, the relationship of the polynya area with air temperature becomes closer with increasing correlation coefficients. In the low temperature conditions, the correlation coefficients of the polynya area with air temperature are above 0.5, larger than that with the wind speed.

摘要

冰间湖是南极冬季 “海-冰-气”的能量交换与物质循环的主要场所,具有重要研究意义。作为海冰的主要输出来源,冰间湖的动态变化会影响局地海冰生成。且冰间湖内持续的海水结冰析盐作用将导致该海域海洋表面盐度升高,从而形成高密度高盐度的表层水,促进海洋深层水与上层水的循环。本文基于气象站观测数据与ERA5、ERA-Interim再分析数据对南极罗斯海海域的特拉诺瓦湾冰间湖开展详细研究,重点研究了该冰间湖面积与地表空气温度的详细关系。此前大部分研究都集中在冰间湖面积与南极下降风的联系,而忽略了温度与冰间湖面积的关系。研究发现,除去风对冰间湖面积的直接影响,低温环境下冰间湖面积与地表空气温度呈更高的正相关关系,而这种关系很大可能是由于温度与冰间湖的相互作用所导致。研究发现,随着温度下降,冰间湖面积与地表空气温度的关系逐渐紧密,而其与风速的关系逐渐疏远。低温环境下,冰间湖面积与空气温度的相关系数高于0.5,大于其与风速的相关系数。