The Influence of Arctic Sea Ice Concentration Perturbations on Subseasonal Predictions of North Atlantic Oscillation Events  

作　　者：Guokun DAI Mu MU Zhe HAN Chunxiang LI Zhina JIANG Mengbin ZHU Xueying MA 

机构地区：[1]Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences,Fudan University,Shanghai 200438,China [2]CMA-FDU Joint Laboratory of Marine Meteorology,Shanghai 200438,China [3]Shanghai Frontiers Science Center of Atmosphere-Ocean Interaction,Shanghai 200438,China [4]Innovation Center of Ocean and Atmosphere System,Zhuhai Fudan Innovation Research Institute,Zhuhai 509031,China [5]CAS Key Laboratory of Regional Climate-Environment for Temperate East Asia,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [6]State Key Laboratory of Severe Weather(LaSW),Chinese Academy of Meteorological Sciences,Beijing 100081,China [7]Beijing Institute of Applied Meteorology,Beijing 100029,China [8]Yantai Vocational College,Yantai 264670,China

出　　处：《Advances in Atmospheric Sciences》2023年第12期2242-2261,I0009-I0015,共27页大气科学进展（英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.42288101,41790475,42005046,and 41775001).

摘　　要：The influence of Arctic sea ice concentration (SIC) on the subseasonal prediction of the North Atlantic Oscillation (NAO) event is investigated by utilizing the Community Atmospheric Model version 4. The optimal Arctic SIC perturbations which exert the greatest influence on the onset of an NAO event from a lead of three pentads (15 days) are obtained with a conditional nonlinear optimal perturbation approach. Numerical results show that there are two types of optimal Arctic SIC perturbations for each NAO event, with one weakening event (marked as type-1) and another strengthening event (marked as type-2). For positive NAO events, type-1 optimal SIC perturbations mainly show positive SIC anomalies in the Greenland, Barents, and Okhotsk Seas, while type-2 perturbations mainly feature negative SIC anomalies in these regions. For negative NAO events, the optimal SIC perturbations have almost opposite patterns to those in positive events, although there are some differences among these SIC perturbations due to different atmospheric initial conditions. Further diagnosis reveals that the optimal Arctic SIC perturbations first modify the surface turbulent heat flux and the temperature in the lower troposphere via diabatic processes. Afterward, the temperature in the low troposphere is mainly affected by dynamic advection. Finally, potential vorticity advection plays a crucial role in the 500-hPa geopotential height prediction in the northern North Atlantic sector during pentad 4, which influences NAO event prediction. These results highlight the importance of Arctic SIC on NAO event prediction and the spatial characteristics of the SIC perturbations may provide scientific support for target observations of SIC in improving NAO subseasonal predictions.

关 键 词：optimal Arctic SIC perturbation NAO event subseasonal prediction CNOP approach 

分 类 号：P731.15[天文地球—海洋科学] P732.4