1983–2022年南极夏季海冰区反照率的反转变化特征分析  

The analysis on reversal of variation trend in the summer albedo of Antarctic sea-ice zone from 1983 to 2022

作　　者：柯长青[1] 李海丽 沈校熠 Ke Changqing;Li Haili;Shen Xiaoyi(School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学地理与海洋科学学院,江苏南京210023

出　　处：《海洋学报》2023年第12期121-132,共12页

基　　金：国家自然科学基金项目(41976212);江苏省自然科学基金项目(BK20210193,BK20230799)。

摘　　要：海冰区反照率会影响辐射收支平衡,对全球气候变化有着重要影响。利用遥感反演的反照率数据产品分析了1983–2022年南极及其6个海域夏季海冰区反照率的时空变化,探讨了海冰密集度、气温和大气环流与海冰区反照率的关系。结果表明,卫星反演的南极夏季海冰区反照率与实测反照率结果一致。西威德尔海海冰区多年平均反照率最高(0.61),罗斯海最低(0.45)。南极夏季海冰区反照率经历了先上升(1983–2015年)后快速下降(2015–2022年)的变化。除了别林斯高晋海–阿蒙森海海冰区反照率前后两个时段均下降外,其余5个海域和南极一样出现了变化趋势的反转。南极海冰区反照率与海冰密集度显著正相关,而与气温显著负相关。1983–2015年夏季气温降低,海冰消融减弱,海冰密集度微弱上升(0.03%/a),海冰面积平均每10年增加2.07×10^(5)km^(2),导致反射的太阳辐射增多,反照率也微弱上升。2015–2022年夏季气温升高,海冰消融加剧,冰间水道和开阔水域增多,海冰密集度下降,海冰区吸收更多的太阳辐射,造成反射辐射减小,因而海冰区反照率快速下降。此外,南极环状模也是影响罗斯海和威德尔海海冰区反照率变化的因素之一。The albedo of Antarctic sea-ice zone(ASZ)can affect the radiation budget and thus has essential influence on global climate change.Using the albedo product from satellite application facility on climate monitoring,the spatio-temporal variations of summer albedo in sea-ice zone from 1983 to 2022 in Antarctica and six sea sectors were analyzed,the relationships between ASZ albedo and sea ice concentration(SIC),air temperature and atmospheric circulation were also quantified.Results show that the albedo retrieved from satellite is consistent to that obtained from in situ observations and thus the satellite-based albedo is reliable.Among the six sea sectors,Weddell West has the highest multi-year averaged albedo of 0.61,whilst Ross Sea features the lowest one of 0.45.Albedo of ASZ in summer experienced gradual increases before 2015 followed by the rapid decline(2015–2022).All sea sectors have similar ASZ albedo variations to that of Antarctica,excepting for Bellingshausen-Amundsen Seas where decreases can be found in both two periods.ASZ albedo is positively correlated to SIC and negatively related to air temperature.From 1983 to 2015,the decreased summer air temperature weakened the sea ice ablation and the SIC increased slightly(0.03%/a),sea ice area increased by 2.07×10^(5) km^(2) per decade on average,all of these led to the increase of reflected solar radiation and sea-ice zone albedo.During the summer from 2015 to 2022,as the increased temperature enhanced the sea ice ablation,more leads and open water appeared,and then decreased the SIC.The sea-ice zone thus absorbed more solar radiation and had less reflected radiation,which leads to a rapid decline of the albedo.In addition,the Antarctic annular mode is one of the driving factors changing the albedo in sea-ice zone in the Ross Sea and Weddell Sea.

关 键 词：南极夏季海冰 反照率 时空变化 气温 海冰密集度 大气环流 

分 类 号：P731.15[天文地球—海洋科学]