Key Laboratory of Marine Hazards Forecasting;
National Marine Environmental Forecasting Center;
Ministry of Natural Resources;
Beijing 100081;
China;
LASG;
Institute of Atmospheric Physics;
Chinese Academy of Sciences;
Beijing 100029;
China;
Ministry of Education Key Laboratory for Earth System Modeling;
Department for Earth System Science;
Tsinghua University;
Beijing 100084;
China;
initial error; tropical Indian Ocean; La Nina prediction; sensitive area; targeted observation;