A study of the early warning signals of abrupt change in the Pacific decadal oscillation
Wu Hao†a),b), Hou Weib), Yan Peng-Chengb),c), Zhang Zhi-Senb),c), Wang Kuod)
       
The LLEs of PDO index in each time period and total time series (The bars represent the LLEs of the PDO index in each time period, thick black dotted line is for the LLE of the total series).